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Rowan T Chlebowski,
Anne McTiernan,
Jean Wactawski-Wende,
JoAnn E Manson,
Aaron K Aragaki, Thomas Rohan,
Eli Ipp,
Virginia G Kaklamani,
Mara Vitolins,
Robert Wallace,
Marc Gunter,
Lawrence S Phillips,
Howard Strickler,
Karen Margolis,
David M Euhus
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ABSTRACT: Emerging evidence suggests that metformin may reduce breast cancer incidence, but reports are mixed and few provide information on tumor characteristics. Therefore, we assessed associations among diabetes, metformin use, and breast cancer in postmenopausal women participating in Women's Health Initiative clinical trials.
In all, 68,019 postmenopausal women, including 3,401 with diabetes at study entry, were observed over a mean of 11.8 years with 3,273 invasive breast cancers diagnosed. Diabetes incidence status was collected throughout follow-up, with medication information collected at baseline and years 1, 3, 6, and 9. Breast cancers were confirmed by review of central medical records and pathology reports. Cox proportional hazards regression, adjusted for breast cancer risk factors, compared breast cancer incidence in women with diabetes who were metformin users or nonusers with breast cancer incidence in women without diabetes.
Compared with that in women without diabetes, breast cancer incidence in women with diabetes differed by diabetes medication type (P = .04). Women with diabetes receiving medications other than metformin had a slightly higher incidence of breast cancer (hazard ratio [HR], 1.16; 95% CI, 0.93 to 1.45), and women with diabetes who were given metformin had lower breast cancer incidence (HR, 0.75; 95% CI, 0.57 to 0.99). The association was observed for cancers positive for both estrogen receptor and progesterone receptor and those that were negative for human epidermal growth factor receptor 2.
Metformin use in postmenopausal women with diabetes was associated with lower incidence of invasive breast cancer. These results can inform future studies evaluating metformin use in breast cancer management and prevention.
Journal of Clinical Oncology 06/2012; 30(23):2844-52. · 18.37 Impact Factor
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Ying Huang,
Dennis G Ballinger,
James Y Dai,
Ulrike Peters,
David A Hinds,
David R Cox,
Erica Beilharz,
Rowan T Chlebowski,
Jacques E Rossouw,
Anne McTiernan, Thomas Rohan,
Ross L Prentice
Genome Medicine 03/2012; 4(3):19.
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Garnet L Anderson,
Rowan T Chlebowski,
Aaron K Aragaki,
Lewis H Kuller,
JoAnn E Manson,
Margery Gass,
Elizabeth Bluhm,
Stephanie Connelly,
F Allan Hubbell,
Dorothy Lane,
Lisa Martin,
Judith Ockene, Thomas Rohan,
Robert Schenken,
Jean Wactawski-Wende
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ABSTRACT: By contrast with many observational studies, women in the Women's Health Initiative (WHI) trial who were randomly allocated to receive oestrogen alone had a lower incidence of invasive breast cancer than did those who received placebo. We aimed to assess the influence of oestrogen use on longer term breast cancer incidence and mortality in extended follow-up of this cohort.
Between 1993 and 1998, the WHI enrolled 10,739 postmenopausal women from 40 US clinical centres into a randomised, double-masked, placebo-controlled trial. Women aged 50-79 years who had undergone hysterectomy and had expected 3-year survival and mammography clearance were randomly allocated by a computerised, permuted block algorithm, stratified by age group and centre, to receive oral conjugated equine oestrogen (0·625 mg per day; n=5310) or matched placebo (n=5429). The trial intervention was terminated early on Feb 29, 2004, because of an adverse effect on stroke. Follow-up continued until planned termination (March 31, 2005). Consent was sought for extended surveillance from the 9786 living participants in active follow-up, of whom 7645 agreed. Using data from this extended follow-up (to Aug 14, 2009), we assessed long-term effects of oestrogen use on invasive breast cancer incidence, tumour characteristics, and mortality. We used Cox regression models to estimate hazard ratios (HRs) in the intention-to-treat population. This study is registered with ClinicalTrials.gov, number NCT00000611.
After a median follow-up of 11·8 years (IQR 9·1-12·9), the use of oestrogen for a median of 5·9 years (2·5-7·3) was associated with lower incidence of invasive breast cancer (151 cases, 0·27% per year) compared with placebo (199 cases, 0·35% per year; HR 0·77, 95% CI 0·62-0·95; p=0·02) with no difference (p=0·76) between intervention phase (0·79, 0·61-1·02) and post-intervention phase effects (0·75, 0·51-1·09). In subgroup analyses, we noted breast cancer risk reduction with oestrogen use was concentrated in women without benign breast disease (p=0·01) or a family history of breast cancer (p=0·02). In the oestrogen group, fewer women died from breast cancer (six deaths, 0·009% per year) compared with controls (16 deaths, 0·024% per year; HR 0·37, 95% CI 0·13-0·91; p=0·03). Fewer women in the oestrogen group died from any cause after a breast cancer diagnosis (30 deaths, 0·046% per year) than did controls (50 deaths, 0·076%; HR 0·62, 95% CI 0·39-0·97; p=0·04).
Our findings provide reassurance for women with hysterectomy seeking relief of climacteric symptoms in terms of the effects of oestrogen use for about 5 years on breast cancer incidence and mortality. However, our data do not support use of oestrogen for breast cancer risk reduction because any noted benefit probably does not apply to populations at increased risk of such cancer.
US National Heart, Lung, and Blood Institute; Wyeth.
The lancet oncology 03/2012; 13(5):476-86. · 14.47 Impact Factor
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ABSTRACT: Retrospective studies of archived human specimens, with known clinical follow-up, are used to identify predictive and prognostic molecular markers of disease. Due to biochemical differences, however, formalin-fixed paraffin-embedded (FFPE) DNA and RNA have generally been extracted separately from either different tissue sections or from the same section by dividing the digested tissue. The former limits accurate correlation whilst the latter is impractical when utilizing rare or limited archived specimens.
For effective recovery of genomic DNA and total RNA from a single FFPE specimen, without splitting the proteinase-K digested tissue solution, we optimized a co-extraction method by using TRIzol and purifying DNA from the lower aqueous and RNA from the upper organic phases. Using a series of seven different archived specimens, we evaluated the total amounts of genomic DNA and total RNA recovered by our TRIzol-based co-extraction method and compared our results with those from two commercial kits, the Qiagen AllPrep DNA/RNA FFPE kit, for co-extraction, and the Ambion RecoverAll™ Total Nucleic Acid Isolation kit, for separate extraction of FFPE-DNA and -RNA. Then, to accurately assess the quality of DNA and RNA co-extracted from a single FFPE specimen, we used qRT-PCR, gene expression profiling and methylation assays to analyze microRNAs, mRNAs, and genomic DNA recovered from matched fresh and FFPE MCF10A cells. These experiments show that the TRIzol-based co-extraction method provides larger amounts of FFPE-DNA and -RNA than the two other methods, and particularly provides higher quality microRNAs and genomic DNA for subsequent molecular analyses.
We determined that co-extraction of genomic DNA and total RNA from a single FFPE specimen is an effective recovery approach to obtain high-quality material for parallel molecular and high-throughput analyses. Our optimized approach provides the option of collecting DNA, which would otherwise be discarded or degraded, for additional or subsequent studies.
PLoS ONE 01/2012; 7(4):e34683. · 4.09 Impact Factor
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Orsi Giricz,
Paul A Reynolds,
Andrew Ramnauth,
Christina Liu,
Tao Wang,
Lesley Stead,
Geoffrey Childs, Thomas Rohan,
Nella Shapiro,
Susan Fineberg,
Paraic A Kenny,
Olivier Loudig
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ABSTRACT: Invasive lobular carcinoma (ILC) of the breast, characterized by loss of E-cadherin expression, accounts for 5-15% of invasive breast cancers and it is believed to arise via a linear histological progression. Genomic studies have identified a clonal relationship between ILC and concurrent lobular carcinoma in situ (LCIS) lesions, suggesting that LCIS may be a precursor lesion. It has been shown that an LCIS diagnosis confers a 15-20% risk of progression to ILC over a lifetime. Currently no molecular test or markers can identify LCIS lesions likely to progress to ILC. Since microRNA (miRNA) expression changes have been detected in a number of other cancer types, we explored whether their dysregulation might be detected during progression from LCIS to ILC. Using the Illumina miRNA profiling platform, designed for simultaneous analysis of 470 mature miRNAs, we analysed the profiles of archived normal breast epithelium, LCIS lesions found alone, LCIS lesions concurrent with ILC, and the concurrent ILCs as a model of linear histological progression towards ILC. We identified two sets of differentially expressed miRNAs, the first set highly expressed in normal epithelium, including hsa-miR-224, -139, -10b, -450, 140, and -365, and the second set up-regulated during lobular neoplasia progression, including hsa-miR-375, -203, -425-5p, -183, -565, and -182. Using quantitative RT-PCR, we validated a trend of increasing expression for hsa-miR-375, hsa-miR-182, and hsa-miR-183 correlating with ILC progression. As we detected increased expression of hsa-miR-375 in LCIS lesions synchronous with ILC, we sought to determine whether hsa-miR-375 might induce phenotypes reminiscent of lobular neoplasia by expressing it in the MCF-10A 3D culture model of mammary acinar morphogenesis. Increased expression of hsa-miR-375 resulted in loss of cellular organization and acquisition of a hyperplastic phenotype. These data suggest that dysregulated miRNA expression contributes to lobular neoplastic progression.
The Journal of Pathology 08/2011; 226(1):108-19. · 6.32 Impact Factor
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Ying Huang,
Dennis G Ballinger,
James Y Dai,
Ulrike Peters,
David A Hinds,
David R Cox,
Erica Beilharz,
Rowan T Chlebowski,
Jacques E Rossouw,
Anne McTiernan, Thomas Rohan,
Ross L Prentice
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ABSTRACT: Genome-wide association studies have identified several genomic regions that are associated with breast cancer risk, but these provide an explanation for only a small fraction of familial breast cancer aggregation. Genotype by environment interactions may contribute further to such explanation, and may help to refine the genomic regions of interest.
We examined genotypes for 4,988 SNPs, selected from recent genome-wide studies, and four randomized hormonal and dietary interventions among 2,166 women who developed invasive breast cancer during the intervention phase of the Women's Health Initiative (WHI) clinical trial (1993 to 2005), and one-to-one matched controls. These SNPs derive from 3,224 genomic regions having pairwise squared correlation (r2) between adjacent regions less than 0.2. Breast cancer and SNP associations were identified using a test statistic that combined evidence of overall association with evidence for SNPs by intervention interaction.
The combined 'main effect' and interaction test led to a focus on two genomic regions, the fibroblast growth factor receptor two (FGFR2) and the mitochondrial ribosomal protein S30 (MRPS30) regions. The ranking of SNPs by significance level, based on this combined test, was rather different from that based on the main effect alone, and drew attention to the vicinities of rs3750817 in FGFR2 and rs7705343 in MRPS30. Specifically, rs7705343 was included with several FGFR2 SNPs in a group of SNPs having an estimated false discovery rate < 0.05. In further analyses, there were suggestions (nominal P < 0.05) that hormonal and dietary intervention hazard ratios varied with the number of minor alleles of rs7705343.
Genotype by environment interaction information may help to define genomic regions relevant to disease risk. Combined main effect and intervention interaction analyses raise novel hypotheses concerning the MRPS30 genomic region and the effects of hormonal and dietary exposures on postmenopausal breast cancer risk.
Genome Medicine 06/2011; 3(6):42.
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ABSTRACT: Examination of cancer rates in a single Hispanic subgroup-Puerto Ricans- and comparison of incidence rates among mainland Puerto Ricans living in the United States, island Puerto Ricans in Puerto Rico, and U.S. non-Hispanic whites to reveal ethnic-specific cancer patterns and disparities in Puerto Ricans.
Incidence data were obtained from the cancer registries of Puerto Rico and three U.S. northeastern states (New York, New Jersey, and Connecticut) with a high density of mainland Puerto Ricans. Age-adjusted rates were compared by standardized rate ratios (SRRs).
Total cancer incidence was the lowest in island Puerto Ricans, intermediate for mainland Puerto Ricans, and highest in U.S. non-Hispanic whites. Compared to mainland Puerto Ricans, islanders had significantly lower rates (p<0.05) for major cancers-lung (SRRs=0.36 in males and 0.29 in females), prostate (SRR=0.71), female breast (SRR=0.73), and colon-rectum (SRRs=0.74 in males and 0.65 in females)-as well as several less common cancers (urinary bladder; non-Hodgkin lymphoma; liver; kidney and renal pelvis; pancreas; thyroid; leukemia; and skin melanoma). Overall cancer rates in mainland Puerto Ricans were modestly lower than those in U.S. non-Hispanic whites, but mainland Puerto Ricans had the highest rates for stomach, liver, and cervical cancers among the three populations.
Despite socioeconomic disadvantages, island Puerto Ricans have relatively low cancer incidence. Identifying contributing factors would be informative for cancer research, and understanding the reasons for increased cancer risk in their mainland counterparts would facilitate the development of ethnic-specific intervention programs.
Revista Panamericana de Salud Pública 05/2009; 25(5):394-400. · 0.85 Impact Factor
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ABSTRACT: Experimental evidence provides strong support for anti-carcinogenic effects of calcium and vitamin D with respect to breast cancer. Observational epidemiologic data also provide some support for inverse associations with risk. We tested the effect of calcium plus vitamin D supplementation on risk of benign proliferative breast disease, a condition which is associated with increased risk of breast cancer. We used the Women's Health Initiative randomized controlled trial. The 36,282 participants were randomized either to 500 mg of elemental calcium as calcium carbonate plus 200 IU of vitamin D(3) (GlaxoSmithKline) twice daily (n = 18,176) or to placebo (n = 18,106). Regular mammograms and clinical breast exams were performed. We identified women who had had a biopsy for benign breast disease and subjected histologic sections from the biopsies to standardized review. After an average follow-up period of 6.8 years, 915 incident cases of benign proliferative breast disease had been ascertained, with 450 in the intervention group and 465 in the placebo group. Calcium plus vitamin D supplementation was not associated with altered risk of benign proliferative breast disease overall (hazard ratio = 0.99, 95% confidence interval = 0.86-1.13), or by histologic subtype. Risk varied significantly by levels of age at baseline, but not by levels of other variables. Daily use of 1,000 mg of elemental calcium as calcium carbonate plus 400 IU of vitamin D(3) for almost 7 years by postmenopausal women did not alter the overall risk of benign proliferative breast disease.
Breast Cancer Research and Treatment 11/2008; 116(2):339-50. · 4.43 Impact Factor
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ABSTRACT: Menstrual and reproductive history and postmenopausal hormone use are well-established risk factors for breast cancer. However, previous studies that have assessed these factors in association with risk of benign proliferative epithelial disorders (BPED) of the breast, putative precursors of breast cancer, have yielded inconsistent findings. To investigate these associations, we conducted a cohort study among 68,132 postmenopausal women enrolled in the Women's Health Initiative randomized clinical trials. Women were prospectively followed and those reporting an open surgical biopsy or a core needle biopsy had histological sections obtained for centralized pathology review. Over an average of 7.8 years of follow-up, we identified 1,792 women with BPED of the breast. We used Cox proportional hazards models to estimate hazard ratios (HRs) and 95% confidence limits (CLs) for the associations of interest. Menstrual and reproductive histories were not associated with risk of BPED of the breast, overall or by histological subtype. Women who had used postmenopausal hormones for 15 years or more had a two-fold increase in risk of BPED of the breast compared to women who had never used postmenopausal hormones (HR = 2.03 95% CL = 1.73, 2.38) and the increase in risk was observed for both BPED of the breast without atypia and for atypical hyperplasia. Furthermore, the risk of BPED of the breast decreased with time since cessation of use so that there was essentially no increase in risk 5 or more years after ending use (HR for stopping >or=5 years earlier = 0.96, 95%CL = 0.79, 1.16; HR for stopping <5 years earlier = 1.32, 95% CL = 1.08,1.61).
Breast Cancer Research and Treatment 04/2008; 114(1):113-20. · 4.43 Impact Factor
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ABSTRACT: In postmenopausal women, levels of estrogens, androgens, and perhaps prolactin have been related to risk of breast and other hormonal cancers in women. However, the determinants of these hormone concentrations have not been firmly established. Associations among various demographic, menstrual, and reproductive factors, medication use and endogenous sex hormone concentrations (estradiol, free estradiol, estrone, estrone sulfate, testosterone, free testosterone, sex hormone binding globulin, androstenedione, dehydroepiandrosterone (DHEA), DHEA sulfate (DHEAS), dihydrotestosterone, and prolactin) were evaluated in a cross-sectional analysis from a simple random sample of 274 postmenopausal women selected from the Women's Health Initiative Dietary Modification Trial. In multiple regression analyses on log-transformed hormones, the concentrations of DHEA, and DHEAS were negatively and statistically significantly associated with age (both beta=-0.03, P<0.001, respectively). Estradiol, estrone, DHEA, and free testosterone concentrations were higher in African-American than in non-Hispanic White women, but after multivariate adjustment the associations were statistically significant only for free testosterone (beta=0.38, P=0.01). Women who had a history of bilateral oophorectomy had a mean 35% lower testosterone concentration compared with women with at least one ovary remaining (beta=-0.43, P=0.002), and lower free testosterone (beta=-0.42, P=0.04) after multivariate adjustment. Women who reported regular use of NSAIDs had higher DHEA concentrations (beta=0.20, P=0.04) and lower prolactin concentrations (beta=-0.18, P=0.02) compared with non-users. These results suggest that while age, oophorectomy status, and NSAID use may be associated with selected sex hormone concentrations, few menstrual or reproductive factors affect endogenous sex hormones in the postmenopausal period.
Breast Cancer Research and Treatment 03/2008; 108(2):217-31. · 4.43 Impact Factor
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ABSTRACT: Strategies for estrogen receptor (ER)-positive breast cancer risk reduction in postmenopausal women require screening of large populations to identify those with potential benefit. We evaluated and attempted to improve the performance of the Breast Cancer Risk Assessment Tool (i.e., the Gail model) for estimating invasive breast cancer risk by receptor status in postmenopausal women.
In The Women's Health Initiative cohort, breast cancer risk estimates from the Gail model and models incorporating additional or fewer risk factors and 5-year incidence of ER-positive and ER-negative invasive breast cancers were determined and compared by use of receiver operating characteristics and area under the curve (AUC) statistics. All statistical tests were two-sided.
Among 147,916 eligible women, 3236 were diagnosed with invasive breast cancer. The overall AUC for the Gail model was 0.58 (95% confidence interval [CI]=0.56 to 0.60). The Gail model underestimated 5-year invasive breast cancer incidence by approximately 20% (P<.001), mostly among those with a low estimated risk. Discriminatory performance was better for the risk of ER-positive cancer (AUC = 0.60, 95% CI = 0.58 to 0.62) than for the risk of ER-negative cancer (AUC = 0.50, 95% CI = 0.45 to 0.54). Age and age at menopause were statistically significantly associated with ER-positive but not ER-negative cancers (P=.05 and P=.04 for heterogeneity, respectively). For ER-positive cancers, no additional risk factors substantially improved the Gail model prediction. However, a simpler model that included only age, breast cancer in first-degree relatives, and previous breast biopsy examination performed similarly for ER-positive breast cancer prediction (AUC=0.58, 95% CI= 0.56 to 0.60); postmenopausal women who were 55 years or older with either a previous breast biopsy examination or a family history of breast cancer had a 5-year breast cancer risk of 1.8% or higher.
In postmenopausal women, the Gail model identified populations at increased risk for ER-positive but not ER-negative breast cancers. A model with fewer variables appears to provide a simpler approach for screening for breast cancer risk.
CancerSpectrum Knowledge Environment 11/2007; 99(22):1695-705. · 14.07 Impact Factor
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Thomas Rohan
Nutrition Reviews 09/2007; 65(8 Pt 2):S80-3. · 4.47 Impact Factor
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ABSTRACT: Gene expression profiling of formalin-fixed and paraffin-embedded (FFPE) specimens, banked from completed clinical trials and routine clinical care, has the potential to yield valuable information implicating and linking genes with clinical parameters. In order to prepare high-quality cDNA from highly fragmented FFPE-RNA, previously precluded from high-throughput analyses, we have designed a novel strategy based on the nucleic acid restoration of incomplete cDNA sequences prior to T7 in vitro transcription (IVT) amplification. We describe this strategy as complementary-template reverse-transcription (CT-RT) because short single-stranded T7-oligo-dT24-VN-DNA sequences, obtained from FFPE-RNA, are used as primers for the RT of complementary RNA templates contained in a sense-RNA library. We validated our assay by determining the correlation between expression profiles of a matched 10-year-old frozen and FFPE breast cancer sample. We show that T7 IVT-amplification of cDNA transcripts restored by CT-RT is a specific and reliable process that allows recovery of transcriptional features undetectable by direct T7 IVT-amplification of FFPE-RNA. Furthermore, CT-RT restored 35-41% of the transcripts from archived breast and cervical specimens when compared to matched frozen tissue; and profiles included tissue-specific transcripts. Our results indicate that CT-RT allows microarray profiling of severely degraded RNA that could not be analyzed by previous methods.
Nucleic Acids Research 02/2007; 35(15):e94. · 8.03 Impact Factor
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Jules J Berman,
Jorge Albores-Saavedra,
David Bostwick,
Ronald Delellis,
John Eble,
Stanley R Hamilton,
Ralph H Hruban,
George L Mutter,
David Page, Thomas Rohan,
William Travis,
Donald E Henson
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ABSTRACT: Precancers are lesions that precede the appearance of invasive cancers. The successful prevention or treatment of precancers has the potential to eliminate deaths due to cancer.
A National Cancer Institute-sponsored Conference on Precancer was convened on November 8-9, 2004, at The George Washington University Medical Center, Washington, DC. A definition of precancers was developed over 2 days of Conference discussions.
The following five criteria define a precancer: (1) evidence must exist that the precancer is associated with an increased risk of cancer; (2) when a precancer progresses to cancer, the resulting cancer arises from cells within the precancer; (3) a precancer differs from the normal tissue from which it arises; (4) a precancer differs from the cancer into which it develops, although it has some, but not all, of the molecular and phenotypic properties that characterize the cancer; (5) there is a method by which the precancer can be diagnosed.
The Conference participants developed a general definition for precancers that would provide a consistent and clinically useful way of distinguishing precancers from all other types of lesions. It was recognized that many precancerous lesions may not meet this strict definition, but the group felt it was necessary to define criteria that will help standardize clinical and biological studies. Furthermore, a set of defining criteria for putative precancer lesions will permit pathologists to build a diagnostically useful taxonomy of precancers based on specified clinical and biological properties. Precancers thus characterized can be classified into clinically relevant sub-groups based on shared properties (i.e. biomarkers, oncogenes, common metabolic pathways, responses to therapy, etc.). Publications that introduce newly described precancer entities should describe how each of the five defining criteria apply. This manuscript reviews the proposed definition of precancers and suggests how pathologists, oncologists and cancer researchers may determine when these criteria are satisfied.
Cancer Detection and Prevention 02/2006; 30(5):387-94. · 2.52 Impact Factor
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Rowan T Chlebowski,
Zhao Chen,
Garnet L Anderson, Thomas Rohan,
Aaron Aragaki,
Dorothy Lane,
Nancy C Dolan,
Electra D Paskett,
Anne McTiernan,
F Alan Hubbell,
Lucile L Adams-Campbell,
Ross Prentice
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ABSTRACT: The lower breast cancer incidence in minority women and the higher breast cancer mortality in African American women than in white women are largely unexplained. The influence of breast cancer risk factors on these differences has received little attention.
Racial/ethnic differences in breast cancer incidence and outcome were examined in 156,570 postmenopausal women participating in the Women's Health Initiative. Detailed information on breast cancer risk factors including mammography was collected, and participants were followed prospectively for breast cancer incidence, pathological breast cancer characteristics, and breast cancer mortality. Comparisons of breast cancer incidence and mortality across racial/ethnic groups were estimated as hazard ratios (HRs) and 95% confidence intervals (CIs) from Cox proportional hazard models. Tumor characteristics were compared as odds ratios (ORs) and 95% confidence intervals in logistic regression models.
After median follow-up of 6.3 years, 3938 breast cancers were diagnosed. Age-adjusted incidences for all minority groups (i.e., African American, Hispanic, American Indian/Alaskan Native, and Asian/Pacific Islander) were lower than for white women, but adjustment for breast cancer risk factors accounted for the differences for all but African Americans (HR = 0.75, 95% CI = 0.61 to 0.92) corresponding to 29 cases and 44 cases per 10,000 person years for African American and white women, respectively. Breast cancers in African American women had unfavorable characteristics; 32% of those in African Americans but only 10% in whites were both high grade and estrogen receptor negative (adjusted OR = 4.70, 95% CI = 3.12 to 7.09). Moreover, after adjustment for prognostic factors, African American women had higher mortality after breast cancer than white women (HR = 1.79, 95% CI = 1.05 to 3.05) corresponding to nine and six deaths per 10 000 person-years from diagnosis in African American and white women, respectively.
Differences in breast cancer incidence rates between most racial/ethnic groups were largely explained by risk factor distribution except in African Americans. However, breast cancers in African American women more commonly had characteristics of poor prognosis, which may contribute to their increased mortality after diagnosis.
CancerSpectrum Knowledge Environment 04/2005; 97(6):439-48. · 14.07 Impact Factor
