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David A Brown,
Kenneth W Hance,
Connie J Rogers, Leah B Sansbury,
Paul S Albert,
Gwen Murphy,
Adeyinka O Laiyemo,
Zhuoqiao Wang,
Amanda J Cross,
Arthur Schatzkin,
Mark Danta,
Preeyaporn Srasuebkul,
Janaki Amin,
Matthew Law,
Samuel N Breit,
Elaine Lanza
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ABSTRACT: Macrophage inhibitory cytokine-1 (MIC-1/GDF15) mediates nonsteroidal anti-inflammatory drug (NSAID) protection from colonic polyps in mice and is linked to the development of colorectal carcinoma in humans. Therefore, changes in serum MIC-1/GDF15 levels could predict the presence of premalignant colonic polyposis and assist in population screening strategies.
Serum MIC-1/GDF15 levels were measured in subjects in the Polyp Prevention Trial, in which NSAID use and colon cancer risk factors were defined. Subjects had an initial adenoma removed, a repeat colonoscopy removing previously unidentified polyps, and serum MIC-1/GDF15 estimation. Three years later recurrent adenomas were identified and serum MIC-1/GDF15 levels reestimated. The relationship between serum MIC-1/GDF15 levels and adenoma presence or recurrence was examined.
Serum MIC-1/GDF15 levels differed by adenoma status and were significantly related to colon cancer risk factors. In addition, mean serum MIC-1/GDF15 levels rose with increasing numbers of adenomas present and high-risk adenoma recurrence. NSAID users had higher serum MIC-1/GDF15 concentrations, which were related to protection from adenoma recurrence. Furthermore, adjusted serum MIC-1/GDF15 levels at final follow-up were related to adenoma recurrence (highest quartile MIC-1/GDF15; OR = 14.7, 95% CI: 3.0-73).
These data suggest that MIC-1/GDF15 mediates at least some of the protection afforded by NSAIDs against human colonic polyposis. Furthermore, serum MIC-1/GDF15 levels vary with the development of adnenomatous colonic polyps. Impact: Serum MIC-1/GDF15 determination may hold promise as the first serum screening test to assist the detection of premalignant adenomatous colonic polyposis.
Cancer Epidemiology Biomarkers & Prevention 12/2011; 21(2):337-46. · 4.12 Impact Factor
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Brigette L Tippin,
A Joan Levine,
Alicia M Materi,
Wen-Liang Song,
Temitope O Keku,
Julie E Goodman, Leah B Sansbury,
Sudipto Das,
Aihua Dai,
Alan M Kwong, [......],
R Michael Garavito,
Tsuyoshi Inoue,
Wonhwa Cho,
John A Lawson,
Shiv Kapoor,
Laurence N Kolonel,
Loïc Le Marchand,
Robert W Haile,
Robert S Sandler,
Henry J Lin
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ABSTRACT: Intestinal tumors in Apc(Min/+) mice are suppressed by over-production of HPGDS, which is a glutathione transferase that forms prostaglandin D(2) (PGD(2)). We characterized naturally occurring HPGDS isoenzymes, to see if HPGDS variation is associated with human colorectal cancer risk. We used DNA heteroduplex analysis and sequencing to identify HPGDS variants among healthy individuals. HPGDS isoenzymes were produced in bacteria, and their catalytic activities were tested. To determine in vivo effects, we conducted pooled case-control analyses to assess whether there is an association of the isoenzyme with colorectal cancer. Roughly 8% of African Americans and 2% of Caucasians had a highly stable Val187lle isoenzyme (with isoleucine instead of valine at position 187). At 37°C, the wild-type enzyme lost 15% of its activity in 1h, whereas the Val187Ile form remained >95% active. At 50°C, the half life of native HPGDS was 9min, compared to 42 min for Val187Ile. The odds ratio for colorectal cancer among African Americans with Val187Ile was 1.10 (95% CI, 0.75-1.62; 533 cases, 795 controls). Thus, the Val187Ile HPGDS isoenzyme common among African Americans is not associated with colorectal cancer risk. Other approaches will be needed to establish a role for HPGDS in occurrence of human intestinal tumors, as indicated by a mouse model.
Prostaglandins & other lipid mediators 07/2011; 97(1-2):22-8. · 2.70 Impact Factor
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ABSTRACT: Lignans and proanthocyanidins are plant polyphenols that have shown protective properties against colorectal neoplasms in some human studies. Using logistic regression, we estimated odds ratios (ORs) and 95% confidence intervals (CIs) to prospectively evaluate the association between lignan and proanthocyanidin intake, estimated from databases linked to a food frequency questionnaire, and adenoma recurrence in 1,859 participants of the Polyp Prevention Trial. Overall, individual or total lignans or proanthocyanidins were not associated with colorectal adenoma recurrence. However, in sex-specific analyses, total lignan intake was positively associated with any adenoma recurrence in women (highest vs. lowest lignan intake quartile OR = 2.07, 95% CI: 1.22-3.52, p trend = 0.004) but not in men (p interaction = 0.04). To conclude, dietary lignan and proanthocyanidin consumption were not generally related to colorectal adenoma recurrence; however, high lignan intake may increase the risk of adenoma recurrence in women.
International Journal of Cancer 05/2011; 130(7):1649-59. · 5.44 Impact Factor
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ABSTRACT: Chemopreventive dietary compounds, such as flavonols, may inhibit colorectal carcinogenesis partly by altering cytokine expression and attenuating inflammation. Single nucleotide polymorphisms (SNPs) in the promoter regions of genes encoding cytokines may influence flavonol-induced changes in cytokine expression and consequently cancer risk. Using logistic regression, we estimated odds ratios (OR) and 95% confidence intervals (CI) for the association between SNPs of interleukin (IL)-1β, 6, 8, and 10 alone or combined with flavonol intake or serum IL concentration changes, and adenoma recurrence in 808 participants from the intervention arm of the Polyp Prevention Trial, a 4-year intervention study evaluating the effectiveness of a low-fat, high-fiber, high-fruit and vegetable diet on adenoma recurrence. Overall, SNPs in genes encoding IL-1β, 6, 8, and 10 were not associated with their corresponding serum concentrations or adenoma recurrence. However, individuals homozygous for IL-10 -592 C (OR=2.23, 95% CI: 1.07-4.66, P(interaction)=0.03) orIL-10 -819 C (OR=2.18, 95% CI: 1.05-4.51, P(interaction)=0.05) had an elevated risk of high-risk adenoma recurrence when their serum IL-10 concentrations increased during the trial. In addition, IL-6 -174 GG in combination with above median flavonol intake (OR=0.14, 95% CI: 0.03-0.66) or with decreased IL-6 concentrations (OR=0.14, 95% CI: 0.03-0.65) reduced the risk of advanced adenoma recurrence, although the interaction term was not statistically significant. In conclusion, our results suggest that IL SNPs, in combination with a flavonol-rich diet or decreased serum IL, may lower the risk of adenoma recurrence.
European journal of cancer prevention: the official journal of the European Cancer Prevention Organisation (ECP) 03/2011; 20(2):86-95. · 2.21 Impact Factor
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Andrew N Freedman, Leah B Sansbury,
William D Figg,
Arnold L Potosky,
Sheila R Weiss Smith,
Muin J Khoury,
Stefanie A Nelson,
Richard M Weinshilboum,
Mark J Ratain,
Howard L McLeod, [......],
Issam Zineh,
Gurvaneet Randhawa,
Christine B Ambrosone,
Mary V Relling,
Nat Rothman,
Heng Xie,
Margaret R Spitz,
Rachel Ballard-Barbash,
James H Doroshow,
Lori M Minasian
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ABSTRACT: Recent advances in genomic research have demonstrated a substantial role for genomic factors in predicting response to cancer therapies. Researchers in the fields of cancer pharmacogenomics and pharmacoepidemiology seek to understand why individuals respond differently to drug therapy, in terms of both adverse effects and treatment efficacy. To identify research priorities as well as the resources and infrastructure needed to advance these fields, the National Cancer Institute (NCI) sponsored a workshop titled "Cancer Pharmacogenomics: Setting a Research Agenda to Accelerate Translation" on July 21, 2009, in Bethesda, MD. In this commentary, we summarize and discuss five science-based recommendations and four infrastructure-based recommendations that were identified as a result of discussions held during this workshop. Key recommendations include 1) supporting the routine collection of germline and tumor biospecimens in NCI-sponsored clinical trials and in some observational and population-based studies; 2) incorporating pharmacogenomic markers into clinical trials; 3) addressing the ethical, legal, social, and biospecimen- and data-sharing implications of pharmacogenomic and pharmacoepidemiologic research; and 4) establishing partnerships across NCI, with other federal agencies, and with industry. Together, these recommendations will facilitate the discovery and validation of clinical, sociodemographic, lifestyle, and genomic markers related to cancer treatment response and adverse events, and they will improve both the speed and efficiency by which new pharmacogenomic and pharmacoepidemiologic information is translated into clinical practice.
CancerSpectrum Knowledge Environment 10/2010; 102(22):1698-705. · 14.07 Impact Factor
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ABSTRACT: Serum interleukin-6 (IL-6), a proinflammatory cytokine, is considered an indicator of inflammation and may be an indicator of colorectal carcinogenesis given that inflammation can promote carcinogenesis. Flavonols, which can be found in fruits and vegetables, may inhibit colorectal carcinogenesis partly by inhibiting inflammation. We estimated odds ratios and 95% confidence intervals (95% CI) to determine whether serum IL-6 was associated with colorectal adenoma recurrence and flavonol intake and thus may serve as a risk indicator and as a response indicator to dietary flavonols. Serum IL-6 concentrations at baseline, year 1, and year 3 were measured in 872 participants from the intervention arm of the Polyp Prevention Trial, a 4-year trial that examined the effectiveness of a low-fat, high-fiber, high-fruit and vegetable diet on adenoma recurrence. Intake of flavonols, especially of isorhamnetin, kaempferol, and quercetin, was inversely associated with serum IL-6 concentrations (highest versus lowest flavonol intake quartile, 1.80 versus 2.20 pg/mL) and high-risk (OR, 0.51; 95% CI, 0.26-0.98) and advanced adenoma recurrence (OR, 0.17; 95% CI, 0.06-0.50). A decrease in IL-6 concentration during the trial was inversely associated with high-risk (OR, 0.44; 95% CI, 0.23-0.84) and advanced adenoma recurrence (OR, 0.47; 95% CI, 0.19-1.18). Individuals with above median flavonol intake and equal or below median IL-6 change after baseline had the lowest risk of recurrence of high-risk and advanced adenoma. Our results suggest that serum IL-6 may serve as a risk indicator and as a response indicator to dietary flavonols for colorectal cancer prevention.
Cancer Prevention Research 06/2010; 3(6):764-75. · 4.91 Impact Factor
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ABSTRACT: Serum adiponectin, leptin, C-peptide, and homocysteine are indicators for obesity, hyperinsulinemia, and chronic inflammation, which have all been associated with colorectal cancer.
To determine whether serum adiponectin, leptin, C-peptide, and homocysteine are associated with fat, fiber, fruit and vegetable, flavonol, or dry bean intake and colorectal adenoma recurrence.
Using logistic regression, we estimated odds ratios (OR) and 95% confidence intervals (95% CI) for adenoma recurrence in 627 participants from the control arm of the Polyp Prevention Trial, a 4-year trial that examined the effectiveness of a low-fat, high-fiber, high-fruit and vegetable diet on adenoma recurrence.
Serum concentrations of C-peptide and homocysteine were inversely related to fiber, fruit and vegetable, and flavonol intake and positively related to percentage of calories from fat (all P(trend) < or = 0.01). High homocysteine concentrations were associated with any (4th versus 1st quartile: OR, 2.26; 95% CI, 1.30-3.94) and more than one adenoma recurrence (OR, 2.11; 95% CI, 1.01-4.40). Individuals in the highest, versus lowest, tertile of serum leptin concentration had a decreased risk of advanced adenoma recurrence (OR, 0.22; 95% CI, 0.06-0.79).
Our results suggest that serum homocysteine may serve as an indicator of dietary exposure, including a low-fat and high-fiber, high-fruit and vegetable, and high-flavonol diet, as well as colorectal adenoma recurrence.
Discovering biomarkers that are both modifiable and can predict cancer risk is critical. We identified serum homocysteine as a novel indicator that is modified by diet and predicts risk of adenoma recurrence.
Cancer Epidemiology Biomarkers & Prevention 06/2010; 19(6):1441-52. · 4.12 Impact Factor
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Elizabeth L Barry, Leah B Sansbury,
Maria V Grau,
Iqbal U Ali,
Shirley Tsang,
David J Munroe,
Dennis J Ahnen,
Robert S Sandler,
Fred Saibil,
Jiang Gui,
Robert S Bresalier,
Gail E McKeown-Eyssen,
Carol Burke,
John A Baron
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ABSTRACT: Cyclooxygenase-2 (COX-2) catalyzes the rate-limiting step in the production of prostaglandins, potent mediators of inflammation. Chronic inflammation plays an important role in the development and progression of colorectal cancer. Aspirin inhibits COX-2 activity and lowers the risk for colorectal adenomas and cancer. We investigated whether common genetic variation in COX-2 influenced risk for colorectal adenoma recurrence among 979 participants in the Aspirin/Folate Polyp Prevention Study who were randomly assigned to placebo or aspirin and followed for 3 years for the occurrence of new adenomas. Of these participants, 44.2% developed at least one new adenoma during follow-up. Adjusted relative risks and 95% confidence intervals (95% CI) were calculated to test the association between genetic variation at six COX-2 single-nucleotide polymorphisms and adenoma occurrence and interaction with aspirin treatment. Two single-nucleotide polymorphisms were significantly associated with increased adenoma recurrence: for rs5277, homozygous carriers of the minor C allele had a 51% increased risk compared with GG homozygotes (relative risk, 1.51; 95% CI, 1.01-2.25), and for rs4648310, heterozygous carriers of the minor G allele had a 37% increased risk compared with AA homozygotes (relative risk, 1.37; 95% CI, 1.05-1.79). (There were no minor allele homozygotes.) In stratified analyses, there was suggestive evidence that rs4648319 modified the effect of aspirin. These results support the hypothesis that COX-2 plays a role in the etiology of colon cancer and may be a target for aspirin chemoprevention and warrant further investigation in other colorectal adenoma and cancer populations.
Cancer Epidemiology Biomarkers & Prevention 09/2009; 18(10):2726-33. · 4.12 Impact Factor
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Pharmacogenomics 03/2009; 10(2):165-169. · 3.97 Impact Factor
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ABSTRACT: Recent studies have suggested that some hyperplastic polyps may be associated with an increased risk of colorectal cancer. Prospective information on the risk of adenoma recurrence associated with hyperplastic polyps is limited. We sought to investigate whether the coexistence of hyperplastic polyps with adenomas increases the risk of adenoma recurrence.
We used unconditional logistic regression models to examine the association between baseline hyperplastic polyps and subsequent adenoma recurrence during a 3-year follow-up evaluation, among 1637 participants in the Polyp Prevention Trial.
A total of 437 participants (26.7%) had hyperplastic polyps coexisting with adenomas at baseline. Of these, 132 (30.2%) had at least one hyperplastic polyp in the proximal colon, whereas 305 (69.8%) had only distal hyperplastic polyps. When compared with subjects without any hyperplastic polyps at baseline, there was no statistically significant association between the presence of baseline hyperplastic polyps and recurrence of any adenoma (odds ratio [OR], 1.19; 95% confidence interval [CI], 0.94-1.51) or advanced adenoma (OR, 1.25; 95% CI, 0.78-2.03). Also, there was no association between hyperplastic polyp location and adenoma recurrence (OR, 1.01; 95% CI, 0.69-1.48) for any proximal hyperplastic polyp (OR, 1.26; 95% CI, 0.96-1.65) and for distal hyperplastic polyps.
The coexistence of hyperplastic polyps with adenomas, irrespective of location, does not confer an increased risk of adenoma recurrence beyond that of adenomas alone within 3 years of follow-up evaluation. Prospective long-term studies on adenoma recurrence risk associated with hyperplastic polyps in screening populations are needed.
Clinical gastroenterology and hepatology: the official clinical practice journal of the American Gastroenterological Association 10/2008; 7(2):192-7. · 5.64 Impact Factor
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Gerd Bobe, Leah B Sansbury,
Paul S Albert,
Amanda J Cross,
Lisa Kahle,
Jason Ashby,
Martha L Slattery,
Bette Caan,
Electra Paskett,
Frank Iber,
James Walter Kikendall,
Peter Lance,
Cassandra Daston,
James R Marshall,
Arthur Schatzkin,
Elaine Lanza
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ABSTRACT: Two recent case-control studies suggested that some flavonoid subgroups may play a role in preventing colorectal cancer. Previous prospective cohort studies generally reported no association; however, only a small subset of flavonoids was evaluated and partial flavonoid databases were used. We used the newly constructed U.S. Department of Agriculture flavonoid database to examine the association between consumption of total flavonoids, 6 flavonoid subgroups, and 29 individual flavonoids with adenomatous polyp recurrence in the Polyp Prevention Trial. The Polyp Prevention Trial was a randomized dietary intervention trial, which examined the effectiveness of a low-fat, high-fiber, high-fruit, and high-vegetable diet on adenoma recurrence. Intakes of flavonoids were estimated from a food frequency questionnaire. Multivariate logistic regression models (adjusted for age, body mass index, sex, regular non-steroidal anti-inflammatory use, and dietary fiber intake) were used to estimate odds ratios and 95% confidence intervals for both any and advanced adenoma recurrence within quartiles of energy-adjusted flavonoid intake (baseline, during the trial, and change during the trial). Total flavonoid intake was not associated with any or advanced adenoma recurrence. However, high intake of flavonols, which are at greater concentrations in beans, onions, apples, and tea, was associated with decreased risk of advanced adenoma recurrence (4th versus 1st quartile during the trial; odds ratio, 0.24; 95% confidence interval, 0.11, 0.53; P(trend) = 0.0006). Similar inverse associations were observed to a smaller extent for isoflavonoids, the flavonol kaempferol, and the isoflavonoids genistein and formononetin. Our data suggest that a flavonol-rich diet may decrease the risk of advanced adenoma recurrence.
Cancer Epidemiology Biomarkers & Prevention 07/2008; 17(6):1344-53. · 4.12 Impact Factor
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Adeyinka O Laiyemo,
Gwen Murphy,
Paul S Albert, Leah B Sansbury,
Zhuoqiao Wang,
Amanda J Cross,
Pamela M Marcus,
Bette Caan,
James R Marshall,
Peter Lance,
Electra D Paskett,
Joel Weissfeld,
Martha L Slattery,
Randall Burt,
Frank Iber,
Moshe Shike,
J Walter Kikendall,
Elaine Lanza,
Arthur Schatzkin
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ABSTRACT: Lack of confidence in postpolypectomy surveillance guidelines may be a factor in the observed low adherence rates among providers.
To assess the 2006 postpolypectomy colonoscopy surveillance guidelines, which recommend 3-year follow-up colonoscopy for individuals with high-risk adenomas (defined as > or =3 adenomas or any advanced adenomas) and 5- to 10-year follow-up for patients with 2 or fewer nonadvanced adenomas, who are considered to be at low risk.
Analysis of prospective data from the Polyp Prevention Trial.
United States.
1905 patients who had colorectal adenomas removed at baseline screening or diagnostic colonoscopy and completed the trial.
Baseline adenoma characteristics, risk-stratified according to definitions used in the guidelines, were examined as predictors for advanced adenoma recurrence.
125 patients (6.6%) had advanced and 629 (33.0%) had nonadvanced adenoma recurrence; 1151 (60.4%) had no recurrence within 4 years of follow-up. The probability of advanced adenoma recurrence was 0.09 (95% CI, 0.07 to 0.11) among patients with high-risk adenomas at baseline and 0.05 (CI, 0.04 to 0.06) among those with low-risk adenomas at baseline. The relative risk for advanced adenoma recurrence for patients with high-risk adenomas versus those with low-risk adenomas at baseline was 1.68 (CI, 1.19 to 2.38) when advanced adenoma recurrence was compared with no advanced adenoma recurrence and 1.76 (CI, 1.26 to 2.46) when advanced adenoma recurrence was compared with no adenoma recurrence. The c-statistics for these 2 comparisons were 0.68 and 0.72, respectively. Limitation: Participants were self-selected and had restrictions on the degree of obesity.
Although the risk for recurrence of advanced adenoma within 4 years is greater for patients with high-risk adenomas at baseline than for those with low-risk adenomas, the discrimination of this risk stratification scheme is relatively low.
Annals of internal medicine 03/2008; 148(6):419-26. · 16.73 Impact Factor
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ABSTRACT: The inducible Cyclooxygenase (COX)-2 enzyme plays an important role in inflammation and carcinogenesis. Recent reports suggest that single nucleotide polymorphisms (SNPs) in the COX-2 gene may alter enzyme function and in turn modify an individual's risk of colon cancer. We explored the association between the COX-2 Val511Ala SNP and risk of colon cancer among 240 African American cases and 326 African American controls in a population-based, case-control study in North Carolina.
We used unconditional logistic regression models to determine the odds ratios (ORs) for genotype and risk of colon cancer.
We observed a non-statistically significant inverse association between any Ala COX-2 genotype and risk of colon cancer (OR = 0.62, 95% CI: 0.33, 1.16) among African Americans. The inverse association was present among non-regular NSAID users, use < or = 3 times/week, (OR = 0.66; 95% CI: 0.32, 1.37) and regular NSAID users, use > or =3 times/week for > or =3 months, (OR = 0.41; 95% CI: 0.11, 1.54).
Our results suggest that the COX-2 Val511Ala SNP does not antagonize the effect of NSAIDs on colon cancer risk and provides support that NSAID use and the COX-2 Val511Ala SNP may contribute to a reduced risk of colon cancer among African Americans.
Cancer Causes and Control 04/2006; 17(3):257-66. · 2.88 Impact Factor
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Leah B Sansbury,
Andrew W Bergen,
Kay L Wanke,
Binbing Yu,
Neil E Caporaso,
Nilanjan Chatterjee,
Luke Ratnasinghe,
Arthur Schatzkin,
Teresa A Lehman,
Aravind Kalidindi,
Ramakrishna Modali,
Elaine Lanza
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ABSTRACT: Pro- and anti-inflammatory cytokine genes may be important in the maintenance and progression of colorectal cancer. It is possible that single-nucleotide polymorphisms in inflammatory genes may play a role in chronic colonic inflammation and development of colorectal adenomas. Furthermore, common variants in cytokine genes may modify the anti-inflammatory effect of nonsteroidal anti-inflammatory drugs (NSAIDs) in the prevention of colorectal cancer.
We examined the association between cytokine gene polymorphisms and risk of recurrent adenomas among 1,723 participants in the Polyp Prevention Trial. We used logistic regression to calculate odds ratios (OR) for the association between genotype, NSAID use, and risk of adenoma recurrence.
Cytokine gene polymorphisms were not statistically significantly associated with risk of adenoma recurrence in our study. We observed statistically significant interactions between NSAID use, IL-10 -1082 G>A genotype, and risk of adenoma recurrence (P = 0.01) and multiple adenoma recurrence (P = 0.01). Carriers of the IL-10 -1082 G>A variant allele who were non-NSAID users had a statistically significant decreased risk of multiple adenoma recurrence (OR, 0.43; 95% confidence interval, 0.24-0.77) as well as a nonsignificant 30% decreased risk of any adenoma recurrence. In contrast, NSAID users who were carriers of the IL-10 -1082 G>A variant allele were at an increased risk of any adenoma recurrence (OR, 1.55; 95% confidence interval, 1.00-2.43).
These findings suggest that individuals who are carriers of the IL-10 -1082 G>A variant allele may not benefit from the chemoprotective effect of NSAIDs on adenoma polyp recurrence.
Cancer Epidemiology Biomarkers & Prevention 04/2006; 15(3):494-501. · 4.12 Impact Factor
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Nestle Nutrition workshop series. Paediatric programme 02/2006; 57:153-202.
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ABSTRACT: African Americans have the highest colon cancer incidence and mortality rates among all US ethnic groups. Epidemiologic studies suggest that use of nonsteroidal antiinflammatory drugs (NSAIDs) is associated with a reduced risk of colon cancer, but no study to date with adequate sample size has reported on the association among African Americans. The authors examined the association between NSAID use and risk of colon cancer in a population-based, case-control study in North Carolina that enrolled 731 African-American (294 cases, 437 controls) and 960 White (349 cases, 611 controls) participants between 1996 and 2000. Odds ratios were calculated using unconditional logistic regression for categories of NSAIDs and colon cancer risk. Inverse associations between regular NSAID use and colon cancer were similar for African Americans (odds ratio = 0.41, 95% confidence interval: 0.22, 0.77) and Whites (odds ratio = 0.48, 95% confidence interval: 0.28, 0.83) but stronger for women than men. Inverse associations were slightly weaker for occasional versus regular NSAID use, but they were similar for aspirin and nonaspirin NSAID use. These results add new knowledge suggesting that the protective effect of NSAIDs against colon cancer is similar among African Americans and Whites.
American Journal of Epidemiology 10/2005; 162(6):548-58. · 5.22 Impact Factor
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ABSTRACT: Data on the involvement of nonphysician healthcare providers in colorectal cancer (CRC) screening delivery are sparse. This article describes physicians' use of nurse practitioners and physician assistants to provide CRC screening with the fecal occult blood test (FOBT), flexible sigmoidoscopy, and colonoscopy, as well as physicians' attitudes toward using these providers to perform flexible sigmoidoscopy.
Nationally representative samples of primary care physicians, gastroenterologists, and general surgeons were surveyed in 1999-2000. Descriptive statistics and logistic regression were used to estimate the prevalence and predictors of physicians' use of nurse practitioners and physician assistants for CRC screening and to assess physicians' attitudes toward their use in providing CRC screening with flexible sigmoidoscopy.
Overall, 24% of primary care physicians reported using a nurse practitioner or physician assistant to provide CRC screening with FOBT. However, only 3% of all physicians surveyed used nurse practitioners and physician assistants for CRC screening with flexible sigmoidoscopy, and less than 1% of gastroenterologists and general surgeons reported using these providers to perform CRC screening with colonoscopy. Approximately 15% of general surgeons, 40% of primary care physicians, and 60% of gastroenterologists who do not currently use nurse practitioners or physician assistants to perform CRC screening with flexible sigmoidoscopy agreed that these providers could effectively perform the procedure.
These results show current involvement of nurse practitioners and physician assistants in the delivery of CRC screening to be limited. Use of nonphysician healthcare providers for CRC screening with FOBT and flexible sigmoidoscopy is one possible solution to the challenge of boosting low screening rates. However, physician beliefs about the ability of nurse practitioners and physician assistants to perform flexible sigmoidoscopy are a potential barrier to increasing the involvement of nonphysician providers in CRC screening delivery.
American Journal of Preventive Medicine 11/2003; 25(3):179-86. · 4.04 Impact Factor
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ABSTRACT: Individual differences in dietary intake are thought to account for substantial variation in cancer incidence. However, there has been a consistent lack of effect for low-fat, high-fiber dietary interventions and risk of colorectal cancer. These inconsistencies may reflect the multistage process of cancer as well as the range and timing of dietary change. Another potential reason for the lack of effect is poor dietary adherence among participants in these trials. The authors examined the effect of strict adherence to a low-fat, high-fiber, high-fruit and -vegetable intervention over 4 years among participants ( n = 1,905) in the US Polyp Prevention Trial (1991–1998) on colorectal adenoma recurrence. There was a wide range of individual variation in the level of compliance among intervention participants. The most adherent participants, defined as “super compliers” ( n = 210), consistently reported that they met or exceeded each of the 3 dietary goals at all 4 annual visits. Multivariate logistic regression models were used to estimate the association between dietary adherence and adenoma recurrence. The authors observed a 35% reduced odds of adenoma recurrence among super compliers compared with controls (odds ratio = 0.65, 95% confidence interval: 0.47, 0.92). Findings suggest that high compliance with a low-fat, high-fiber diet is associated with reduced risk of adenoma recurrence.
