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Postmenopausal Hormone Therapy and Colorectal Cancer Risk by Molecularly Defined Subtypes and Tumor Location

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Background: Postmenopausal hormone therapy (HT) is associated with a decreased colorectal cancer (CRC) risk. As CRC is a heterogeneous disease, we evaluated whether the association of HT and CRC differs across etiologically relevant, molecularly defined tumor subtypes and tumor location. Methods: We pooled data on tumor subtypes (microsatellite instability status, CpG island methylator phenotype status, BRAF and KRAS mutations, pathway: adenoma-carcinoma, alternate, serrated), tumor location (proximal colon, distal colon, rectum), and HT use among 8220 postmenopausal women (3898 CRC cases and 4322 controls) from 8 observational studies. We used multinomial logistic regression to estimate odds ratios (OR) and 95% confidence intervals (CIs) for the association of ever vs never HT use with each tumor subtype compared with controls. Models were adjusted for study, age, body mass index, smoking status, and CRC family history. All statistical tests were 2-sided. Results: Among postmenopausal women, ever HT use was associated with a 38% reduction in overall CRC risk (OR =0.62, 95% CI = 0.56 to 0.69). This association was similar according to microsatellite instability, CpG island methylator phenotype and BRAF or KRAS status. However, the association was attenuated for tumors arising through the serrated pathway (OR = 0.81, 95% CI = 0.66 to 1.01) compared with the adenoma-carcinoma pathway (OR = 0.63, 95% CI = 0.55 to 0.73; Phet =.04) and alternate pathway (OR = 0.61, 95% CI = 0.51 to 0.72). Additionally, proximal colon tumors had a weaker association (OR = 0.71, 95% CI = 0.62 to 0.80) compared with rectal (OR = 0.54, 95% CI = 0.46 to 0.63) and distal colon (OR = 0.57, 95% CI = 0.49 to 0.66; Phet =.01) tumors. Conclusions: We observed a strong inverse association between HT use and overall CRC risk, which may predominantly reflect a benefit of HT use for tumors arising through the adenoma-carcinoma and alternate pathways as well as distal colon and rectal tumors.
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Postmenopausal Hormone Therapy and Colorectal Cancer Risk by
Molecularly Defined Subtypes and Tumor Location
Julia D Labadie, DVM, MSPH, PhD,
1,2
Tabitha A Harrison, MPH,
1
Barbara Banbury, MS, PhD,
1
Efrat L Amtay, MPH, PhD,
3
Sonja Bernd, PharmD, PhD,
4
Hermann Brenner, MD, MPH,
3,5
Daniel D Buchanan, PhD,
6
Peter T Campbell, MS, PhD,
7
Yin Cao, MPH, ScD,
8,9,10
Andrew T Chan, MD, MPH,
11,12
Jenny Chang-Claude, PhD,
13,14
Dallas English, MSc, PhD,
15,16
Jane C Figueiredo, PhD,
17,18
Steven J Gallinger, MD, MSc,
19
Graham G Giles, MSc, PhD,
15,16,20
Marc J Gunter, PhD,
21
Michael Hoffmeister, MSc, PhD,
3
Li Hsu, PhD,
1,22
Mark A Jenkins, PhD,
16
Yi Lin, MS,
1
Roger L Milne, MSc, PhD,
15,16,20
Victor Moreno, MD, PhD,
23
Neil Murphy, MSc, PhD,
21
Shuji Ogino, MD, PhD, MS,
24
Amanda I Phipps, MPH, PhD,
1,2
Lori C Sakoda, MPH, PhD,
1,25
Martha L Slattery, MPH, PhD,
26
Melissa C Southey, PhD,
15,20,27
Wei Sun, PhD,
1
Stephen N Thibodeau,
PhD,
28
Bethany Van Guelpen, MD, PhD,
29
Syed H Zaidi, PhD,
30
Ulrike Peters, MPH, PhD,
1,2
Polly A Newcomb, MPH, PhD,
1,2,
*
1
Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA;
2
Department of Epidemiology, University of Washington, Seattle, WA,
USA;
3
Division of Clinical Epidemiology and Aging Research, German Cancer Research Center (DKFZ), Heidelberg, Germany;
4
Division of Cancer Epidemiology and
Genetics, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA;
5
Division of Preventive Oncology, German Cancer Research Center (DKFZ) and
National Center for Tumor Diseases (NCT), Heidelberg, Germany;
6
Colorectal Oncogenomics Group, Department of Clinical Pathology, The University of Melbourne,
Parkville, Victoria, Australia;
7
Behavioral and Epidemiology Research Group, American Cancer Society, Atlanta, GA, USA;
8
Division of Public Health Sciences,
Department of Surgery, Washington University School of Medicine, St Louis, MO, USA;
9
Alvin J. Siteman Cancer Center at Barnes-Jewish Hospital and Washington
University School of Medicine, St Louis, MO, USA;
10
Division of Gastroenterology, Department of Medicine, Washington University School of Medicine, St Louis, MO,
USA;
11
Division of Gastroenterology, Massachusetts General Hospital, Boston, MA, USA;
12
Clinical and Translational Epidemiology Unit, Department of Medicine,
Massachusetts General Hospital, Boston, MA, USA;
13
Division of Cancer Epidemiology, German Cancer Research Center (DKFZ), Heidelberg, Germany;
14
University
Medical Centre Hamburg-Eppendorf, University Cancer Centre Hamburg (UCCH), Hamburg, Germany;
15
Cancer Epidemiology Division, Cancer Council Victoria,
Melbourne, Victoria, Australia;
16
Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne,
Melbourne, Victoria, Australia;
17
Department of Medicine, Samuel Oschin Comprehensive Cancer Institute, Cedars-Sinai, Los Angeles, CA, USA;
18
Department of
Preventive Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA;
19
Lunenfeld Tanenbaum Research Institute, Mount Sinai
Hospital, University of Toronto, Toronto, Ontario, Canada;
20
Precision Medicine, School of Clinical Sciences at Monash Health, Monash University, Clayton, Victoria,
Australia;
21
Nutrition and Metabolism Section, International Agency for Research on Cancer, World Health Organization, Lyon, France;
22
Department of Biostatistics,
University of Washington, Seattle, WA, USA;
23
Oncology Data Analytics Program, Catalan Institute of Oncology-IDIBELL, L’Hospitalet de Llobregat, Barcelona, Spain;
24
Program in MPE Molecular Pathological Epidemiology, Department of Pathology, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA;
25
Division of Research, Kaiser Permanente Northern California, Oakland, CA, USA;
26
Department of Internal Medicine, University of Utah, Salt Lake City, UT, USA;
27
Genetic Epidemiology Laboratory, Department of Clinical Pathology, University of Melbourne, Melbourne, Victoria, Australia;
28
Division of Laboratory Genetics,
Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA;
29
Department of Radiation Sciences, Oncology Unit, Umea˚ University, Umea˚,
Sweden; Wallenberg Centre for Molecular Medicine, Umea˚ University, Umea˚ , Sweden and
30
Ontario Institute for Cancer Research, Toronto, Ontario, Canada
*Correspondence to: Polly Newcomb, PhD, MPH, Fred Hutchinson Cancer Research Center, Mailstop M4-B402, PO Box 11024, Seattle, WA 98109-1024, USA (e-mail: pnew-
comb@fredhutch.org).
Abstract
Background: Postmenopausal hormone therapy (HT) is associated with a decreased colorectal cancer (CRC) risk. As CRC is a
heterogeneous disease, we evaluated whether the association of HT and CRC differs across etiologically relevant, molecularly
defined tumor subtypes and tumor location. Methods: We pooled data on tumor subtypes (microsatellite instability status,
CpG island methylator phenotype status, BRAF and KRAS mutations, pathway: adenoma-carcinoma, alternate, serrated), tu-
mor location (proximal colon, distal colon, rectum), and HT use among 8220 postmenopausal women (3898 CRC cases and
4322 controls) from 8 observational studies. We used multinomial logistic regression to estimate odds ratios (OR) and 95%
confidence intervals (CIs) for the association of ever vs never HT use with each tumor subtype compared with controls.
Received: 11 March 2020; Revised: 20 April 2020; Accepted: 12 May 2020
©The Author(s) 2020. Published by Oxford University Press.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/),
which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.
1of9
JNCI Cancer Spectrum (2020) 4(5): pkaa042
doi: 10.1093/jncics/pkaa042
First published online 19 May 2020
Article
Models were adjusted for study, age, body mass index, smoking status, and CRC family history. All statistical tests were 2-
sided. Results: Among postmenopausal women, ever HT use was associated with a 38% reduction in overall CRC risk (OR
¼0.62, 95% CI ¼0.56 to 0.69). This association was similar according to microsatellite instability, CpG island methylator
phenotype and BRAF or KRAS status. However, the association was attenuated for tumors arising through the serrated
pathway (OR ¼0.81, 95% CI ¼0.66 to 1.01) compared with the adenoma-carcinoma pathway (OR ¼0.63, 95% CI ¼0.55 to 0.73;
P
het
¼.04) and alternate pathway (OR ¼0.61, 95% CI ¼0.51 to 0.72). Additionally, proximal colon tumors had a weaker associa-
tion (OR ¼0.71, 95% CI ¼0.62 to 0.80) compared with rectal (OR ¼0.54, 95% CI ¼0.46 to 0.63) and distal colon (OR ¼0.57, 95%
CI ¼0.49 to 0.66; P
het
¼.01) tumors. Conclusions: We observed a strong inverse association between HT use and overall CRC
risk, which may predominantly reflect a benefit of HT use for tumors arising through the adenoma-carcinoma and alternate
pathways as well as distal colon and rectal tumors.
Colorectal cancer (CRC) is a heterogeneous disease that evolves
through multiple pathways defined by genetic and epigenetic
events (1,2). Four tumor markers have been commonly used to
better characterize this heterogeneity: microsatellite instability
(MSI), CpG island methylator phenotype (CIMP), somatic muta-
tions in BRAF, and somatic mutations in KRAS. Together, these
tumor markers approximate 3 distinct molecular pathways of
colorectal carcinogenesis: adenoma-carcinoma (traditional), al-
ternate, and serrated (1,3,4). These pathways are established
early in disease pathogenesis and can be identified within pre-
cancerous lesions by microscopy (3,58). Research has shown
that these tumor types have distinct appearances, predilections
for locations within the colon, and biologic behaviors (810). As
such, it is plausible that the epidemiologic factors underlying
their etiologies could also differ.
Multiple lines of evidence, including randomized controlled
trials, show that postmenopausal hormone therapy (HT) is as-
sociated with a decreased risk of CRC (1120). The reduction in
risk, about 20%–40% in recent analyses, has been observed in
users of estrogen alone as well as combined estrogen plus pro-
gestin. Few studies have evaluated whether the association of
HT use and CRC risk differs by molecularly defined CRC sub-
types; however, such information might increase the under-
standing of the mechanisms for this beneficial effect. Current
literature suggests that HT use is associated with a lower risk of
MSI-low or microsatellite stable tumors (MSI-L/MSS) and possi-
bly with a lower risk of CIMP-negative and BRAF wild-type
tumors (21,22). HT use has only been associated with KRAS
wild-type tumors in the distal colon in 1 previous study (23).
Regarding tumor location, the association of HT use and CRC is
reportedly stronger among tumors of the distal colon compared
with the proximal colon (22,24). To our knowledge, no study
has evaluated both tumor markers and location in relation to
HT use to provide a comprehensive understanding of subtype-
specific CRC risk.
In this study, we examined HT use in relation to molecularly
defined CRC subtypes using available data from the Colon
Cancer Family Registry (CCFR) (21,25,26) and 7 studies contrib-
uting to the Genetics of Epidemiology of Colorectal Cancer
Consortium (27,28). Specifically, we evaluated each of the 4
common tumor markers (MSI, CIMP, BRAF, and KRAS) sepa-
rately, as well as 3 pathways of carcinogenesis defined by com-
binations of those markers and tumor location.
Methods
Study Populations
Data from 8 observational studies of CRC were pooled: the
Cancer Prevention Study II (CPS-II) (29), the German Darmkrebs:
Chancen der Verhutung durch Screening Study (DACHS) (30,31),
the Diet Activity and Lifestyle Study (DALS) (32), the Swedish
population of the European Prospective Investigation into
Cancer (EPIC) (33), the Melbourne Collaborative Cohort Study
(MCCS) (34), the Nurses’ Health Study (NHS) (35,36), the
Northern Sweden Health and Disease Study (NSHDS) (37), and 3
population-based sites from the Colon Cancer Family Registry
(21,25,26). Each study included women diagnosed with incident
invasive CRC and contemporaneous unaffected controls. Only
women with tumor marker data were eligible for inclusion in
this analysis. Study-specific details are described in the
Supplementary Methods (available online). All participants pro-
vided informed consent for participating in this research, and
studies were approved by their respective Institutional Review
Boards.
Data Collection and Harmonization
The harmonization procedure and ascertainment of HT use are
described in more detail in the Supplementary Methods (avail-
able online). Information on demographics and environmental
risk factors was collected via telephone or in-person interviews
and/or structured self-completed questionnaires (24,38,39). HT
use was generally ascertained as any self-reported use at base-
line survey. Additionally, ever use of formulation-specific (es-
trogen-only or estrogen plus progestin) HT use was derived
from 3 studies (CCFR, CPSII, and NHS). HT nonusers at reference
time were used as the comparison group. Postmenopausal sta-
tus was harmonized as either 1) study-derived menopausal sta-
tus, if available; 2) self-reported menopausal status, if study-
derived data were not available; or 3) age 55 years and older, if
study-derived and self-reported data were not available (40).
Tumor Characteristics and Molecular Subtyping
Tumor marker testing was conducted using DNA extracted
from formalin-fixed, paraffin-embedded tumor tissue speci-
mens. Individual study protocols varied, as outlined below and
further detailed in the Supplementary Methods (available
online).
MSI testing was primarily conducted using polymerase chain
reaction (PCR) following the National Cancer Institute Bethesda
Consensus Panel (CCFR, CPS-II, MCCS, NHS) (41). Typically, 4 or
more interpretable markers were required to classify tumors,
with some variation across studies outlined in Supplementary
Table 1 (available online). Additional methods used include im-
munohistochemistry (NSHDS, EPIC, and a subset of CCFR and
MCCS) and mononucleotide marker panels (DACHS, DALS)
(Supplementary Methods, available online). Tumors were classi-
fied as MSI-high (MSI-H) if at least 30% of the markers showed
2of9 | JNCI Cancer Spectrum, 2020, Vol. 4, No. 5
instability and MSI-L/MSS if less than 30% of the makers showed
instability. MSI status could be determined for 3639 CRC cases
(93.4%).
Most studies used Methylight (42) methylation analysis to
determine CIMP status, classified as positive or negative based
on either an 8- (CPS-II, EPIC, NHS, NSHDS) (43,44) or 5-gene
(CCFR, MCCS) (4547) panel. The percent of methylated refer-
ence value was calculated to determine whether each gene was
positive for methylation (generally percent of methylated refer-
ence >10). DACHS used a different 5-gene panel (48,49) to de-
termine CIMP status and based methylation on the presence or
absence of the methylation-specific PCR product. DALS (50) de-
termined CIMP status using a classic panel of CpG islands (51,
52). Specific genes included in each panel, details of calling
methylation status, and number of methylated genes present to
classify a tumor as CIMP-positive are outlined in
Supplementary Table 2 (available online). CIMP status could be
determined for 3453 CRC cases (88.6%).
Studies used PCR, sequencing, and immunohistochemistry
techniques to assess BRAF and KRAS mutations, as detailed in
the Supplementary Methods (available online). The majority of
studies evaluated BRAF via V600E mutations in exon 15 and
KRAS via mutations in codons 12 and 13, although a few evalu-
ated additional loci. BRAF and KRAS status could be determined
for 3564 (91.4%) and 3435 (88.1%) CRC cases, respectively.
Tumor pathways were defined as follows, consistent with
previously suggested classifications (3,8): 1) Adenoma-
carcinoma (traditional) pathway (MSS/MSI-L, CIMP-negative,
BRAF wild-type, KRAS wild-type), 2) alternate pathway (MSS/
MSI-L, CIMP-negative, BRAF wild-type, KRAS-mutated), and 3)
serrated pathway (CIMP-positive, BRAF-mutated, KRAS wild-
type). Tumor pathway could be classified for 2401 CRC cases
(61.6%).
Tumor location was obtained from registry and pathology
reports. Location was grouped based on the International
Classification of Diseases (ICD-9) codes as follows: 1) Proximal
(153.0/Hepatic flexure, 153.1/Transverse colon, 153.4/Cecum,
153.6/Ascending colon), 2) distal (153.2/Descending colon, 152.3/
Sigmoid colon, 153.7/Splenic flexure), and 3) rectal (154.0/
Rectosigmoid junction, 154.1/Rectum). Tumor location could be
classified for 3808 CRC cases (97.7%).
Statistical Analysis
We excluded women who were pre- or perimenopausal at study
baseline (934 cases, 760 controls) and those with missing data
on HT use (208 cases, 209 controls). After exclusions, 3898 CRC
cases and 4322 controls were included in our analyses
(Figure 1).
Odds ratios (ORs) and 95% confidence intervals (CIs) from lo-
gistic regression models were used to approximate the relative
risks for the association of HT use and CRC. Separate models
were evaluated for each tumor-specific outcome using multino-
mial logistic regression with tumor marker status vs control as
the outcome (eg, BRAF-mutated or BRAF wild-type vs control).
All models included study site as well as covariates selected a
priori based on known associations with both HT and CRC.
Figure 1. Overview of participants included in analytic population. A-C ¼adenoma-carcinoma; CIMP ¼CpG island methylator phenotype; HT ¼postmenopausal hor-
mone therapy; MSI ¼microsatellite instability. *Estrogen-only and estrogen plus progestin groups are not mutually exclusive.
J. D. Labadie et al. | 3 of 9
These included age in years, body mass index (BMI; normal or
underweight [BMI <25], overweight [BMI 25–30], obese [BMI
>30], unknown), smoking status (current, former, never, un-
known), and first-degree relative with CRC (yes, no, unknown).
Secondary analyses were conducted for estrogen-only therapy
and combined estrogen plus progestin therapy. For multinomial
logistic regression models, Wald v
2
tests were used to evaluate
heterogeneity in odds ratios by tumor marker status (53).
Additionally, sensitivity analyses were conducted excluding
1) women aged 45 years and younger (n ¼131) and 2) women
with probable Lynch syndrome based on 4 tumor markers (de-
fined as MSI-H, CIMP-negative, BRAF wild-type, KRAS wild-type;
n¼89), because both populations may have unique factors al-
tering their CRC risk. We also performed a meta-analysis of the
association of any HT use and CRC risk to evaluate heterogene-
ity by study site.
All analyses were conducted using R version 3.5.2 with a 2-
sided Pless than .05 considered statistically significant.
Results
Baseline population characteristics of the 8220 postmenopausal
women in our study are shown in Table 1. Compared with
Table 1. Baseline characteristics of 8220 postmenopausal women by case-control status
Characteristics
a
Overall Case Control
(n ¼8220) (n ¼3898) (n ¼4322)
Age, mean (SD), y 65.28 (9.08) 64.79 (9.54) 65.72 (8.62)
Age group, y
<45 101 (1.2) 84 (2.2) 17 (0.4)
45–55 828 (10.1) 464 (11.9) 364 (8.4)
55–65 2780 (33.8) 1246 (32.0) 1534 (35.5)
65–75 3309 (40.3) 1561 (40.0) 1748 (40.4)
>75 1202 (14.6) 543 (13.9) 659 (15.2)
First-degree relative with CRC
Yes 1251 (15.2) 722 (18.5) 529 (12.2)
No 6633 (80.7) 2994 (76.8) 3639 (84.2)
Missing 336 (4.1) 182 (4.7) 154 (3.6)
Body mass index
Normal or underweight 3659 (44.5) 1613 ( 41.4) 2046 (47.3)
Overweight 2818 (34.3) 1322 (33.9) 1496 (34.6)
Obese 1571 (19.1) 870 (22.3) 701 (16.2)
Missing 172 ( 2.1) 93 (2.4) 79 (1.8)
Smoking
Current smoker 948 (11.5) 522 (13.4) 426 (9.9)
Former smoker 2619 (31.9) 1285 (33.0) 1334 (30.9)
Never smoker 4477 (54.5) 2012 (51.6) 2465 (57.0)
Missing 176 (2.1) 79 (2.0) 97 (2.2)
Self-reported race
White 8077 (98.3) 3780 (97.0) 4297 (99.4)
Other 113 (1.4) 98 (2.5) 15 (0.4)
Missing 30 (0.4) 20 (0.5) 10 (0.2)
Study
CCFR 1985 (24.1) 1215 ( 31.2) 770 (17.8)
CPSII 893 (10.9) 412 ( 10.6) 481 (11.1)
DACHS 2074 (25.2) 872 ( 22.4) 1202 (27.8)
DALS 891 (10.8) 427 (11.0) 464 (10.7)
EPIC Sweden 129 (1.6) 37 (0.9) 92 (2.1)
MCCS 455 (5.5) 185 (4.7) 270 (6.2)
NHS 1649 (20.1) 686 (17.6) 963 (22.3)
NSHDS 144 (1.8) 64 (1.6) 80 (1.9)
Any postmenopausal hormone therapy use
Ever 3112 (37.9) 1262 (32.4) 1850 (42.8)
Never 5108 (62.1) 2636 (67.6) 2472 (57.2)
Estrogen-only
Ever 1160 (14.1) 506 (13.0) 654 (15.1)
Never 3323 (40.4) 1778 (45.6) 1545 (35.7)
Missing 3737 (45.5) 1614 (41.4) 2123 (49.1)
Estrogen plus progestin
Ever 717 (8.7) 328 (8.4) 389 (9.0)
Never 3758 (45.7) 1961 (50.3) 1797 (41.6)
Missing 3745 (45.6) 1609 (41.3) 2136 (49.4)
a
No. (%) shown unless otherwise indicated. CCFR ¼Colon Cancer Family Registry; CPSII ¼Cancer Prevention Study II; CRC ¼colorectal cancer; DACHS ¼Darmkrebs:
Chancen der Verhutung durch Screening Study; DALS ¼Diet Activity and Lifestyle Study; EPIC ¼European Prospective Investigation into Cancer; MCCS ¼Melbourne
Collaborative Cohort Study; NHS ¼Nurses’ Health Study; NSHDS ¼Northern Sweden Health and Disease Study.
4of9 | JNCI Cancer Spectrum, 2020, Vol. 4, No. 5
controls, cases were more likely to have a family history of CRC
and be current or former smokers. Cases were less likely to be
HT users than controls (32.4% vs 42.8%). Among those with
formulation-specific data, cases were less likely than controls to
use both estrogen-only (22.2% vs 29.7%) and estrogen plus pro-
gestin formulations (14.3% vs 17.8%).
Multivariable-adjusted associations between HT use, HT for-
mulation, and overall- and tumor marker–specific CRC risk are
presented in Figure 2 and Supplementary Table 3 (available on-
line). Ever use of HT was associated with a 38% reduction in CRC
risk (OR ¼0.62, 95% CI ¼0.56 to 0.69). Both use of estrogen-only
(OR ¼0.71, 95% CI ¼0.62 to 0.83) and estrogen plus progestin
(OR ¼0.76, 95% CI ¼0.64 to 0.91) formulations were associated
with reduced CRC risk, although the effect estimates were at-
tenuated compared with any HT use in this subsample of the
study population. Few differences in baseline characteristics
were noted between women with and without formulation-
specific data (Supplementary Table 4, available online).
Among cases with respective tumor marker data, 19.8% were
MSI-H (n ¼719), 24.3% were CIMP-positive (n ¼841), 18.4% were
BRAF-mutated (n ¼654), and 32.0% were KRAS-mutated
(n ¼1098). Ever use of HT was associated with reduced risk of al-
most all tumor marker subtypes of CRC, with some variation
across subtypes (Figure 2;Supplementary Table 3, available on-
line). The association of ever HT use and CRC was attenuated
among CIMP-positive cases (OR ¼0.74, 95% CI ¼0.63 to 0.87)
compared with CIMP-negative cases (OR ¼0.62, 95% CI ¼0.55 to
0.69) (P
het
¼.04). This trend was consistent across HT formula-
tions, although the difference in odds ratios was not statistically
significant. HT use was inversely associated with both KRAS-
mutated and wild-type individuals. This association was con-
sistent for estrogen-only use; however, estrogen plus progestin
formulations were not statistically significantly associated with
KRAS-mutated individuals (OR ¼0.90, 95% CI ¼0.70 to 1.14; P
het
¼0.09). No differences were observed for MSI or BRAF mutation
status.
Of 2401 tumors (61.6%) that were able to be classified by
pathway, the majority were classified as adenoma-carcinoma
pathway tumors (48.4%; n ¼1162), with 32.9% classified as alter-
nate pathway (n ¼790) and 18.7% as the serrated pathway
(n ¼449). No major differences in baseline characteristics were
noted between women who were and were not able to be classi-
fied by pathway (Supplementary Table 4, available online). The
effect estimates for HT use in both the adenoma-carcinoma and
alternate pathways were similar to that seen for HT overall (ad-
enoma-carcinoma OR ¼0.63, 95% CI ¼0.55 to 0.73; alternate
OR ¼0.61, 95% CI ¼0.51 to 0.72). However, the effect estimate
was attenuated and no longer statistically significant for tumors
that arose via the serrated pathway (OR ¼0.81, 95% CI ¼0.66 to
1.01; P
het
vs adenoma-carcinoma ¼.04). This difference was not
consistent across HT formulation: for estrogen-only formula-
tions, ever use was statistically significantly inversely associ-
ated with all 3 pathwa ys (adenoma-carcin oma OR ¼0.71, 95%
CI ¼0.57 to 0.88; alternate OR ¼0.60, 95% CI ¼0.47 to 0.77;
Figure 2. Association between postmenopausal hormone therapy (HT) use and colorectal cancer (CRC), overall and formulation specific. A-C ¼adenoma-carcinoma;
CI ¼confidence interval; CIMP ¼CpG island methylator phenotype; CRC ¼colorectal cancer; MSI ¼microsatellite instability; OR ¼odds ratio.
*Wald P<0.05. Wald Pvalues are comparing within-group odds ratios; reference groups are BRAF wild-type, KRAS wild-type, CIMP negative, traditional, distal colon.
Controls are used as reference for all odds ratios. All odds ratios are adjusted for age, body mass index, smoking status, and first-degree family history of CRC.
‡Formulation-specific data were only available for a subset of women (n ¼4483 for estrogen-only; n ¼4475 for estrogen plus progestin).
J. D. Labadie et al. | 5 of 9
serrated OR ¼0.72, 95% CI ¼0.54 to 0.98), and there was no sta-
tistical difference between pathways. However, for estrogen
plus progestin formulations, ever use was only statistically sig-
nificantly associated with tumors that arose via the adenoma-
carcinoma pathway (OR ¼0.70, 95% CI ¼0.55 to 0.91).
Most tumors were located in the proximal colon (47.3%),
with tumors of the distal colon (29.4%) only slightly more com-
mon than rectal tumors (23.3%). Compared with distal colon
(OR ¼0.57, 95% CI ¼0.49 to 0.66) and rectal tumors (OR ¼0.54,
95% CI ¼0.46 to 0.63), the effect estimate for the association of
HT use and proximal colon tumors was attenuated (OR ¼0.71,
95% CI ¼0.62 to 0.80; P
het
vs distal ¼.01). This trend was consis-
tent across HT formulations, although there was no statistical
difference between proximal and distal colon tumors for
estrogen-only formulation (P
het
¼.32).
No substantial changes in results were noted after removing
either the 131 women aged 45 years and younger or the 89 wom-
enwith molecularly defined Lynch syndrome (Supplementary
Tables 5 and 6, available online). Meta-analysis results were
consistent with our pooled main analysis (summary OR ¼0.64,
95% CI ¼0.58 to 0.71; P
het
¼.10).
Discussion
In this large pooled study of postmenopausal women, HT use,
regardless of formulation type, was associated with a decreased
risk of CRC, consistent with prior research (1120). In general,
this inverse association was observed irrespective of MSI, CIMP,
BRAF,orKRAS status. However, when considering all tumor
markers together and grouping cases by common pathways and
tumor location, the association was attenuated for tumors aris-
ing via the serrated pathway and for proximal colon tumors.
Our results do not support the hypothesis that the associa-
tion of HT and CRC differs by the individual tumor markers MSI,
BRAF, and KRAS. Strong inverse associations were observed for
HT use and CRC, regardless of BRAF and KRAS status. Prior stud-
ies found a nearly 20% reduced risk among ever HT users irre-
spective of BRAF and KRAS mutation status, although effect
estimates did not reach statistical significance (22,23). These
studies had substantially smaller samples sizes than ours, con-
tributing to reduced power to detect difference in effect. We ad-
ditionally observed strong inverse associations for HT use and
both MSI-L/MSS and MSI-H CRC. Prior research is somewhat
conflicting regarding the association of HT and MSI status, with
most studies suggesting an association only among MSI-L/MSS
patients (22,24,54). There are many possible explanations for
this discrepancy, including sample size, study design, reference
period used for ascertaining HT use, and panels used to classify
MSI status. Because prior studies have indicated high concor-
dance across MSI panels (41), we suspect the latter had the least
influence.
We found some evidence that the association of HT differs
by CIMP status, with an attenuated effect estimate observed for
CIMP-positive tumors. A previous study had similar findings,
reporting a borderline inverse association among CIMP-
negative tumors and no association for CIMP-positive tumors
(22,47). This finding should be interpreted with caution because
CIMP is not consistently defined across studies, and CIMP preva-
lence may be affected by detection method and sample quality.
Our results suggest that a comprehensive approach of con-
sidering tumor markers together as pathways may reveal other-
wise nebulous patterns. Our findings indicate that the
association of HT use and CRC was largely driven by tumors
arising via the adenoma-carcinoma and alternate pathway.
These tumors make up the majority of CRC cases, whereas ser-
rated tumors represent about 20%–30% of CRC (1,3,8,5557).
Serrated tumors, characterized as CIMP-positive, BRAF-mutated,
and KRAS wild-type, tend to behave more aggressively, with
faster progression and poorer prognosis (3,8,10,56,5860).
Based on the different biologic behavior, appearance, distribu-
tion of tumor markers, and genetic susceptibility of serrated
tumors, it is plausible that HT may indeed play a lesser role in
their pathogenesis.
We also observed a weaker association for tumors of the
proximal colon, consistent with prior studies (22,24). There is
evidence that serrated tumors are more likely to develop in the
proximal colon (8,61,62), so it is unclear whether these are in-
dependent associations. In our study, most serrated tumors
(n ¼391) were in the proximal colon. The association of HT use
and proximal tumors was similar (OR ¼0.68, 95% CI ¼0.60 to
0.78) after removing serrated tumors from analysis, suggesting
an independent association. However, 43.1% (n ¼776) of proxi-
mal tumors could not be classified by pathway because of in-
complete tumor marker data, so this analysis is limited. The
proximal and distal colon have different embryologic origins,
microbiomes, and microenvironments (6266). As such, they ap-
pear to be predisposed to different tumor types. For instance,
proximal colon tumors are more likely to be MSI-H, CIMP-posi-
tive, and mucinous and occur more commonly in women and
older individuals (6771). Further research is needed to better
elucidate whether differences in the proximal colon make it
less sensitive to the effects of estrogens (ie, fewer receptors, dif-
ferent microbiota), whether precancerous lesions in the proxi-
mal colon are estrogen insensitive based on differences in the
carcinogenic pathway, or some combination of factors.
Our results indicate that both estrogen-only and estrogen
plus progestin formulations reduce CRC risk. In general, effect
estimates were attenuated for estrogen plus progestin formula-
tions compared with estrogen-only formulations, perhaps
reflecting smaller exposure frequencies. However, overall
trends were similar. Two main exceptions were present. First,
whereas estrogen-only and any HT use were associated with
about a 40% reduction in tumors arising via the alternate path-
way, estrogen plus progestin use was not statistically signifi-
cantly associated with these tumors. This may indicate that
alternate pathway tumorigenesis is specifically modified by es-
trogen and not progestin. Likewise, there was a null association
between estrogen plus progestin use and proximal colon
tumors despite a 24%–29% reduction in risk with estrogen-only
or any HT, respectively.
To our knowledge, this is the largest study to assess whether
the association of HT use and CRC differs by individual tumor
markers and location. In addition, it is one of few investigations
that combines multiple tumor markers to evaluate tumor path-
way–specific associations. Some limitations should be consid-
ered in interpreting our results. First, all exposure and
epidemiologic covariate information included in this analysis
was based on self-report, which could lead to exposure misclas-
sification. Second, HT use was assessed only during the refer-
ence period, and detailed information on dose, frequency, and
duration of use was not routinely available. Third, we were not
able to assess endogenous hormones that may reflect age at
menarche, parity, or breast feeding, which may also influence
CRC risk. Fourth, there is some evidence that HT users may be
more likely to undergo CRC screening (72,73). It is unclear how
this may impact our results because this relationship may be
complicated by differences in sensitivity of screening detection
6of9 | JNCI Cancer Spectrum, 2020, Vol. 4, No. 5
for specific CRC subtypes. Temporal trends and regional differ-
ences in screening and HT use may also influence observed
associations. Finally, although this study includes populations
in many locales, the participants were predominantly white,
and therefore, these findings may not be generalizable to other
racial and ethnic groups.
In this large, multisite study we observed a strong inverse
association between HT use and CRC risk, regardless of individ-
ual tumor markers and HT formulation. The decreased risk may
predominantly reflect tumors of the distal colon or rectum and
those arising via the adenoma-carcinoma (traditional) pathway,
because the association was relatively weaker among proximal
colon tumors and those arising via the serrated pathway.
Further investigation into the mechanisms underlying these
differences may add to our understanding of subtype-specific
CRC risk and pathways of tumorigenesis.
Funding
Genetics and Epidemiology of Colorectal Cancer
Consortium: This work was supported by the National
Cancer Institute, National Institutes of Health, US
Department of Health and Human Services R01 CA176272,
U01 CA137088, and U01 CA164930. This research was funded
in part through the National Institutes of Health/National
Cancer Institute Cancer Center Support Grant P30 CA015704.
The Colon Cancer Family Registry (CCFR) was supported
in part by National Cancer Institute/National Institutes of
Health award number U01 CA167551 and through National
Cancer Institute/National Institutes of Health U01/U24 coop-
erative agreements with the following CCFR sites: Ontario
(OFCCR) (CA074783), Seattle (SCCFR) (CA074794 and R01
CA076366), and Australasian (ACCFR) (CA074778 and
CA097735). The content of this manuscript does not neces-
sarily reflect the views or policies of the National Cancer
Institute or any of the collaborating centers in the CCFR, nor
does mention of trade names, commercial products, or
organizations imply endorsement by the US government,
any cancer registry, or the CCFR.
CPS-II: The American Cancer Society funds the creation,
maintenance, and updating of the Cancer Prevention Study
II cohort. This study was conducted with Institutional
Review Board approval.
DACHS: This work was supported by the German
Research Council (BR 1704/6–1, BR 1704/6–3, BR 1704/6–4, CH
117/1–1, HO 5117/2–1, HE 5998/2–1, KL 2354/3–1, RO 2270/8–1,
and BR 1704/17–1), the Interdisciplinary Research Program of
the National Center for Tumor Diseases, Germany, and the
German Federal Ministry of Education and Research
(01KH0404, 01ER0814, 01ER0815, 01ER1505A, and 01ER1505B).
DALS: National Institutes of Health (R01 CA48998).
EPIC: The coordination of EPIC is financially supported by
the European Commission (DGSANCO) and the
International Agency for Research on Cancer. The national
cohorts are supported by Danish Cancer Society (Denmark),
Swedish Cancer Society, Swedish Research Council, and
County Councils of Ska˚ ne and V
asterbotten (Sweden).
MCCS: This cohort recruitment was funded by VicHealth
and Cancer Council Victoria. The MCCS was further supported
by Australian National Health and Medical Research Council
grants 509348, 209057, 251553, and 504711 and by
infrastructure provided by Cancer Council Victoria. Cases, and
their vital status were ascertained through the Victorian
Cancer Registry and the Australian Institute of Health and
Welfare, including the National Death Index and the
Australian Cancer Database.
Harvard cohort (NHS): NHS is supported by the National
Institutes of Health (R01 CA137178, P01 CA087969, UM1
CA186107, R01 CA151993, R35 CA197735, K07 CA190673, and
P50 CA127003).
NSHDS: Swedish Cancer Society; Cancer Research
Foundation in Northern Sweden; Swedish Research Council;
J C Kempe Memorial Fund; Faculty of Medicine, Umea˚
University, Umea˚ , Sweden; and Cutting-Edge Research
Grant from the County Council of V
asterbotten, Sweden.
Fred Hutchinson Cancer Research Center investigators
were also supported by National Institutes of Health T32
CA094880 and National Institutes of Health K05 CA152715.
Notes
Role of the funders: The funders had no role in the design of the
study; the collection, analysis, and interpretation of the data;
the writing of the manuscript; and the decision to submit the
manuscript for publication.
Authors contributions: Conceptualization: JDL, MH, PAN; Data
curation: TAH, BB, YL, UP; Formal analysis: JDL, BB, LH, YL, WS;
Funding acquisition: HB, PTC, ATC, JC, JCF, SJG, GGG, MJG, MH,
MAJ, RLM, VM, NM, SO, LCS, MLS, SNT, BV, UP, PAN;
Investigation: all authors; Methodology: JDL, LH; Project admin-
istration: TAH, UP; Resources: HB, PTC, ATC, JC, JCF, SJG, GGG,
MJG, MH, MAJ, RLM, VM, NM, SO, LCS, MLS, SNT, BV, UP, PAN;
Supervision: UP, PAN; Visualization: JDL; Writing - original draft:
JDL, TAH, UP, PAN; Writing - review & editing: all authors.
Disclosures: The authors have no conflicts of interest to
disclose.
Acknowledgments: SCCFR: The authors would like to thank the
study participants and staff of the Hormones and Colon Cancer
and Seattle Cancer Family Registry studies (CORE studies). CPS-II:
The authors thank the CPS-II participants and Study Management
Group for their invaluable contributions to this research. The
authors would also like to acknowledge the contribution to this
study from central cancer registries supported through the
Centers for Disease Control and Prevention National Program of
Cancer Registries and cancer registries supported by the National
Cancer Institute Surveillance Epidemiology and End Results pro-
gram. DACHS: We thank all participants and cooperating clini-
cians, and Ute Handte-Daub, Utz Benscheid, Muhabbet Celik, and
Ursula Eilber for excellent technical assistance. EPIC: Where
authors are identified as personnel of the International Agency for
Research on Cancer/World Health Organization, the authors alone
are responsible for the views expressed in this article, and they do
not necessarily represent the decisions, policy, or views of the
International Agency for Research on Cancer/World Health
Organization. Harvard cohort (NHS): The study protocol was ap-
proved by the institutional review boards of the Brigham and
Women’s Hospital and Harvard T.H. Chan School of Public Health,
and those of participating registries as required. We would like to
thank the participants and staff of the NHS for their valuable con-
tributions as well as the following state cancer registries for their
help:AL,AZ,AR,CA,CO,CT,DE,FL,GA,ID,IL,IN,IA,KY,LA,ME,
MD,MA,MI,NE,NH,NJ,NY,NC,ND,OH,OK,OR,PA,RI,SC,TN,
J. D. Labadie et al. | 7 of 9
TX, VA, WA, WY. The authors assume full responsibility for analy-
ses and interpretation of these data. MCCS: Melbourne
Collaborative Cohort Study cohort recruitment was funded by
VicHealth and Cancer Council Victoria. The MCCS was further
augmented by infrastructure provided by Cancer Council Victoria.
Cases and their vital status were ascertained through the
Victorian Cancer Registry and the Australian Institute of Health
and Welfare, including the National Death Index and the
Australian Cancer Database. NSHDS: The NSHDS investigators
thank the Biobank Research Unit at Umea˚University,the
V
asterbotten Intervention Programme, the Northern Sweden
MONICA study, and Region V
asterbotten for providing data and
samples and acknowledge the contribution from Biobank Sweden,
supported by the Swedish Research Council (VR 2017–00650).
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J. D. Labadie et al. | 9 of 9
... Furthermore, several meta-analysis studies revealed that HRT reduced the risk of developing CRC in microsatellite-stable states [42], as well as improving mortality rates in female CRC patients [59,60]. In addition, Labadie et al. (2020) [61] has also confirmed the strong inverse correlation between HRT use and overall CRC risk in postmenopausal females, suggesting efficient chemopreventive actions for HRT by inhibiting adenoma-carcinoma in CRC. In contrast, a few epidemiological studies have failed to detect associations between the HRT and CRC incidence in postmenopausal females [62][63][64][65]. ...
... In contrast, treatment with conjugated equine estrogens alone showed no effects on CRC incidence [28], suggesting that estrogen monotherapy has limited anticancer activity, whereas the addition of progesterone could have more potent chemopreventive actions against CRC [28,66]. Although Labadie et al. (2020) [61] reported that estrogen, both alone and in combination with progestin, reduced the risk of CRC, they proposed that the protective roles were mediated by E2, not progestin, in CRC. ...
Research
Full-text available
Abstract Several epidemiological studies have reported that the use of female sex steroid hormones could reduce the risk of colon cancer (CRC). This review summarizes the available data related to estradiol (E2) and progesterone (P4) single and dual treatments in CRC male and female in vitro and in vivo models, mainly from preclinical studies, alongside their potential molecular mechanisms. Most of the studies showed that E2 exogenous treatment and/or reactivation of its beta receptor (ERβ) significantly inhibited cell proliferation, induced cell cycle arrest, and promoted apoptosis by modulating several molecular pathways. Likewise, the inhibition of ERα receptors produced similar antitumorigenic actions, both in vivo and in vitro, suggesting that E2 could have dual opposing roles in CRC that are dependent on the expression profile of its nuclear receptors. The available studies on P4 are scarce, and the results revealed that in vitro and in vivo treatments with natural and synthetic progesterone were also associated with promising tumoricidal actions. Nevertheless, the combination of E2 with P4 showed enhanced anticancer activities compared with their monotherapy protocols in male–female cell lines and animals. Collectively, the studies suggested that the female sex steroid hormones could provide a novel and effective therapeutic strategy against CRC.
... This study consisted of 9,789 patients diagnosed with CRC and 11,231 controls from 11 observational studies within the Genetics and Epidemiology of Colorectal Cancer Consortium (GECCO) and the Colon Cancer Family Registry (CCFR) with available tumor marker and smoking data. Participating studies were previously described and summarized in Table 1 [25,26]. All participants provided written informed consent, and each study was approved by the relevant research ethics committee or institutional review board. ...
... Details on data collection and harmonization of tumor marker data were summarized and published previously [25][26][27]. Briefly, testing for MSI, BRAF gene mutations, KRAS gene mutations, and CIMP status was conducted previously by each study and according to individual study protocols. ...
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Background Smoking is associated with colorectal cancer (CRC) risk. Previous studies suggested this association may be restricted to certain molecular subtypes of CRC while large-scale comprehensive analysis is lacking. Methods A total of 9,789 CRC cases and 11,231 controls of European ancestry from 11 observational studies were included. We harmonized smoking variables across studies and derived sex-study-specific quartiles of pack-years of smoking for analysis. Four somatic colorectal tumor markers were assessed individually and in combination, including BRAF mutation, KRAS mutation, CpG island methylator phenotype (CIMP), and microsatellite instability (MSI) status. A multinomial logistic regression analysis was used to assess the association between smoking and risk of CRC subtypes by molecular characteristics, adjusting for age, sex, and study. All statistical tests were 2-sided and adjusted for Bonferroni correction. Results Heavier smoking was associated with higher risk of CRC overall and stratified by individual markers (P trend <0.001). The associations differed statistically significantly between all molecular subtypes, which was the most statistically significant for CIMP and BRAF. Compared to never smokers, smokers in the 4th quartile of pack-years had an 90% higher risk of CIMP-positive CRC (OR = 1.90; 95% CI: 1.60–2.26), but only 35% higher risk for CIMP-negative CRC (OR = 1.35; 95% CI: 1.22–1.49; P difference=2.1x10-6). The association was also stronger in tumors that were CIMP-positive, MSI-high or KRAS-wildtype when combined (P difference <0.001). Conclusion Smoking was associated with differential risk of CRC subtypes defined by molecular characteristics. Heavier smokers had particularly higher risk of CRC subtypes that were CIMP-positive and MSI-high in combination, suggesting that smoking may be involved in the development of colorectal tumors via the serrated pathway.
... We also estimated separate models comparing AN risk among men to women who never used HRT because HRT has been associated with a significantly lower CRC risk. 17 Overall PA was assessed by metabolic equivalenthours (MET-h) comprising light recreational PA, light and hard physical work and moderate to intense PA. We also created a score for red and processed meat intake, and a "healthy food score" for fruit, vegetable and whole grain intake (see Table S1 for details). ...
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Colorectal cancer (CRC) incidence and prevalence of its precursors are substantially higher among males than among females in most countries but the reasons for the male excess risk are incompletely understood. We aimed to assess to what extent it is explained by known risk factors. Prevalence of advanced neoplasia (AN, i.e. CRC or advanced adenoma) and CRC risk and preventive factors were ascertained among 15,985 participants of screening colonoscopy aged 55-79 years in Germany. Logistic regression was used to calculate odds ratios (ORs) for the association between male sex and AN with and without adjustment for known risk and preventive factors. In age-adjusted comparisons, men had twofold increased risk for AN compared to women (OR=1.98, 95% CI 1.79-2.19). After comprehensive adjustment for medical, lifestyle and dietary factors, the OR was reduced to 1.52 (95% CI 1.30-1.77), suggesting that these factors accounted for 47% of male excess risk. Male excess risk increased from proximal colon to distal colon and rectum, with age-adjusted ORs (95% CI) of 1.63 (1.38-1.91), 2.13 (1.85-2.45) and 2.36 (1.95-2.85), respectively, and with the proportion of excess risk explained by covariates being lower for AN in the rectum (26%) than for AN in the proximal (52%) or distal colon (46%). Male excess risk was somewhat lower (age-adjusted OR 1.87) and explained excess risk was smaller (36%) when men were compared to women who never used hormone replacement therapy. In conclusion, most of the male excess risk and the potential to overcome it remain to be explored by further research. This article is protected by copyright. All rights reserved.
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Diabetes is an established risk factor for colorectal cancer. However, colorectal cancer is a heterogeneous disease and it is not well understood whether diabetes is more strongly associated with some tumor molecular subtypes than others. A better understanding of the association between diabetes and colorectal cancer according to molecular subtypes could provide important insights into the biology of this association. We used data on lifestyle and clinical characteristics from the Colorectal Cancer Family Registry (CCFR) and the Genetics and Epidemiology of Colorectal Cancer Consortium (GECCO), including 9,756 colorectal cancer cases (with tumor marker data) and 9,985 controls, to evaluate associations between reported diabetes and risk of colorectal cancer according to molecular subtypes. Tumor markers included BRAF and KRAS mutations, microsatellite instability and CpG island methylator phenotype. In the multinomial logistic regression model, comparing colorectal cancer cases to cancer-free controls, diabetes was positively associated with colorectal cancer regardless of subtype. The highest OR estimate was found for BRAF-mutated colorectal cancer, n=1,086 (ORfully adj : 1.67, 95% CI: 1.36-2.05), with an attenuated association observed between diabetes and colorectal cancer without BRAF-mutations, n=7,959 (ORfully adj : 1.33, 95% CI: 1.19-1.48). In the case only analysis, BRAF-mutation was differentially associated with diabetes (pdifference =0.03). For the other markers, associations with diabetes were similar across tumor subtypes. In conclusion, our study confirms the established association between diabetes and colorectal cancer risk, and suggests that it particularly increases the risk of BRAF-mutated tumors.
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The large bowel shows biomolecular, anatomical and bacterial changes that proceed from the proximal to the distal tract. These changes account for the different behaviour of colon cancers arising from the diverse sides of the colon–rectum as well as for the sensitivity to the therapy, including immunotherapy. The gut microbiota plays an important role in the modulation of the immune response and differs between the right colon cancer and the left colorectal cancer. The qualitative and quantitative difference of the commensal bacteria between the right side and the left side induces epigenetic changes in the intestinal epithelial cells as well as in the resident immune population. The second player in the pathological homeostasis of colorectal cancer is the differences of the genetic features of cancer cells and the different effects that microsatellite instability, chromosomal instability and the CpG island methylator phenotype induce on the immunological organisation of the tumour microenvironment. The third player is the immunological composition of the tumour microenvironment, which changes under the influence of both genetic structures and gut microbiota. All these three players influence each other. This review describes these three aspects, highlights their interactions and discusses data from reported clinical trials. Click here to listen to the Podcast
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[USE HYPERLINK PROVIDED IN THE COMMENTS TO READ THE FULL TEXT] Red and processed meat is an established risk factor for colorectal cancer (CRC). However, exact mechanisms to explain the associations remain unclear. Few studies have investigated the association with CRC by molecular tumor features, which could provide relevant information on associated molecular pathways. In this population-based case-control study from Germany (DACHS), 2449 cases and 2479 controls provided information on risk factors of CRC and completed a food frequency questionnaire. Multivariable logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CI) for the associations between meat intake and risk of CRC by molecular pathologic features and specific subtypes. Red and processed meat intake was associated with increased risk of colorectal (>1 time/day vs ≤1 time/week OR 1.66, 95% CI 1.34-2.07), colon and rectal cancer. Among the single molecular tumor features investigated, the results were similar for associations of red and processed meat with CRC risk by microsatellite instability, CpG island methylator phenotype, BRAF, oestrogen receptor-β and p53 status. Red and processed meat intake was associated less strongly with risk of KRAS-mutated CRC (OR >1 time/day vs ≤1 time/week: 1.49, 95% CI 1.09-2.03) than with risk of KRAS-wildtype CRC (OR 1.82, 95% CI 1.42-2.34; p heterogeneity 0.04). These results support an association between red and processed meat and CRC risk similar for subsites of CRC and most of the investigated major molecular pathological features. Potential differences were observed in more specific subtype analyses. Further large studies are needed to confirm these results and to help further elucidate potential underlying mechanisms.
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Context.—Serrated adenomas can be morphologically subdivided into traditional and sessile types. They are thought to have a comparable rate of cancer progression like conventional adenomas, but they potentially have a faster rate of growth through methylation pathway(s). They share similar morphologic features with both the conventional adenoma and the hyperplastic polyp in a fashion that is different from a mixed adenoma and a hyperplastic polyp. Objective.—To describe the histopathologic features of traditional serrated adenoma and sessile serrated adenoma and their comparison with traditional adenomas and hyperplastic polyp. Data Sources.—Relevant articles in peer-review journals and the authors' working experience as practicing surgical pathologists with a specific interest in gastrointestinal pathology. Conclusions.—Both types of serrated adenomas, traditional serrated adenoma and sessile serrated adenoma, are morphologically distinct, clinically important entities, and they can be diagnosed accurately in routine practice.
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Background: Regular use of aspirin and nonsteroidal anti-inflammatory drugs (NSAIDs) for a longer period has been inversely associated with colorectal cancer (CRC) risk. However, CRC is a heterogenic disease, and little is known regarding the associations with molecular pathological subtypes. Methods: Analyses included 2444 cases with a first diagnosis of CRC and 3130 healthy controls from a German population-based case control study. Tumor tissue samples were analyzed for major molecular pathological features: microsatellite instability (MSI), CpG island methylator phenotype, B-Raf proto-oncogene serine/threonine kinase (BRAF) mutation, and Kirsten rat sarcoma viral oncogene homolog gene (KRAS) mutation. Information on past and current use of NSAIDs, including aspirin, was obtained by standardized interviews. Multinomial logistic regression models were used to calculate adjusted odds ratios (ORs) and 95% confidence intervals (CIs). All statistical tests were two-sided. Results: Regular use of NSAIDs was associated with a reduced CRC risk if tumors were MSS (OR = 0.66, 95% CI = 0.57 to 0.77), BRAF wildtype (OR = 0.67, 95% CI = 0.58 to 0.78), or KRAS wildtype (OR = 0.68, 95% CI = 0.58 to 0.80). Regular NSAID use was less clearly and mostly not statistically significantly associated with CRC risk reduction for MSI-high, BRAF-mutated, or KRAS-mutated CRC. In more specific analyses on MSI-high CRC, regular use of NSAIDs was associated with much stronger risk reduction in the absence of BRAF or KRAS mutations (OR = 0.34, 95% CI = 0.18 to 0.65) but not with KRAS- or BRAF-mutated MSI-high CRC (Pheterogeneity < .001). Results for just aspirin use were similar. Conclusion: Our study suggests variation in risk reduction of CRC subtypes following regular use of NSAIDs and aspirin. Regular use of NSAIDs and aspirin may be more strongly associated with risk reduction of MSI-high CRC without KRAS or BRAF mutation.
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Context: Colonoscopy with detection and removal of adenomas is thought to be a powerful tool to reduce colorectal cancer (CRC) incidence. However, the magnitude of the protection in the population setting remains uncertain, in particular with respect to right sided colon cancer. Objective: To assess the association between previous colonoscopy and risk of CRC in a population-based case-control study from Germany. Design: Case-control study (DACHS-study), 2003–2007. Setting: Population-based study in the Rhine-Neckar area, Germany. Participants. 1,765 cases and 2,002 controls. Main Outcome measures. A detailed lifetime history of CRC risk factors and preventive factors, including history and results of previous colonoscopies, and of medical data were obtained by self-reports and medical records from 1,765 cases and 2,002 controls. Odds ratios of CRC associated with colonoscopy in the preceding 10 years were estimated, adjusting for sex, age, education, participation in general health screening examination, family history of CRC, smoking, body mass index, use of anti-inflammatory drugs and hormone replacement therapy. Results: Overall, colonoscopy in the preceding 10 years was associated with a 77% lower risk of CRC. Adjusted odds ratios (95% confidence intervals) for any CRC, right sided CRC and left sided CRC were 0.23 (0.19–0.27), 0.42 (0.33–0.53) and 0.16 (0.13–0.20), respectively. Strong risk reduction was seen for all cancer stages and at all ages above 50 years, and it increased over the years, in particular in the proximal colon. Conclusions: Colonoscopy can provide very strong protection from CRC in the population setting. While protection is particularly strong with respect to left-sided CRC, substantial risk reduction by more than 50% can also be achieved for cancer in the right colon.