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Detection rates of premalignant polyps during screening colonoscopy: time to revise quality standards?
Ross, WA, Thirumurthi, S, Lynch, PM, Rashid, A, Pande, M, Shafi, MA, Lee, JH, Raju, GS
Gastrointestinal endoscopy. 2015;(3):567-74
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Abstract
BACKGROUND Standards for the detection of adenomas during screening colonoscopy are widely used to measure examination quality. No such standards exist for sessile serrated adenomas (SSAs). OBJECTIVE To measure both the adenoma detection rate (ADR) and SSA detection rate (SSADR) during screening colonoscopy before and after quality improvement/financial incentive measures. DESIGN Retrospective determination of baseline ADR/SSADR by the endoscopist, followed by prospective collection of data after informing physicians of baseline detection rates. SETTING Tertiary cancer center with a large cancer screening program. PATIENTS A total of 2833 average-risk colorectal cancer screening patients 50 to 75 years of age undergoing initial colonoscopy. DATA COLLECTION Electronic medical records for indication and demographics, endoscopy report, and pathology report. MAIN OUTCOME MEASUREMENTS Detection rates of adenomas and SSAs by sex. RESULTS The overall ADR in male and female patients was 50.6% and 36.6%, respectively. The overall detection rate of advanced adenomas in male and female patients was 12.4% and 6.5%, respectively. The overall SSADR in male and female patients was 10.1% and 7.1%, respectively. In 108 patients (3.8% of entire group), SSAs were the only premalignant lesions found. Detection rates of both types of premalignant polyps improved over time but did not reach statistical significance. LIMITATIONS Single-center experience with limited sample size and small group of endoscopists. CONCLUSION ADRs far in excess of current standards are achievable. Cecal withdrawal time is associated with the ADR. Prevalence of SSA rivals that of advanced adenomas and is greater than current medical literature suggests. The combination of monitoring and financial incentives did not result in statistically significant improvement in ADRs.
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Relationship between detection of adenomas by flexible sigmoidoscopy and interval distal colorectal cancer.
Rogal, SS, Pinsky, PF, Schoen, RE
Clinical gastroenterology and hepatology : the official clinical practice journal of the American Gastroenterological Association. 2013;(1):73-8
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BACKGROUND & AIMS Low rates of adenoma detection by colonoscopy have been associated with increased rates of interval colorectal cancer. We evaluated the relationship between the rate of adenoma detection by flexible sigmoidoscopy and interval distal colorectal cancer. METHODS We analyzed data from the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer screening trial, which used flexible sigmoidoscopy as a colorectal cancer screening modality (46,835 subjects; 66,711 examinations by 93 examiners). An adenoma detection rate was defined for each examiner as the number of examinations that identified adenomas (confirmed by pathology analysis) divided by the total number of screening examinations. Interval cancers were defined as cancers presumed detectable but not detected, which was based on the stage at diagnosis and the elapsed time from screening to diagnosis. RESULTS The Prostate, Lung, Colorectal, and Ovarian Cancer study identified 32 interval distal cancers. The incidence of interval cancer for individuals screened by examiners in the lowest quartile of distal adenoma detection (2.0%-7.2%) was 9.0/10,000 examinations, whereas the incidence of interval cancers was lower among individuals whose examiners were in higher quartiles of adenoma detection, ranging from 3.0 to 5.4/10,000 examinations. The odds of interval distal cancer were significantly increased for patients of examiners in the lowest quartile of distal adenoma detection (<7.2%), with an adjusted odds ratio of 2.4 (95% confidence interval, 1.1-5.0; P = .02). CONCLUSIONS Lower levels of adenoma detection by flexible sigmoidoscopy increase the risk for interval distal cancer. Detection of distal adenomas is a marker of the performance quality of flexible sigmoidoscopy.
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Design and baseline characteristics of participants in a phase III randomized trial of celecoxib and selenium for colorectal adenoma prevention.
Thompson, P, Roe, DJ, Fales, L, Buckmeier, J, Wang, F, Hamilton, SR, Bhattacharyya, A, Green, S, Hsu, CH, Chow, HH, et al
Cancer prevention research (Philadelphia, Pa.). 2012;(12):1381-93
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COX inhibitors reduce colorectal adenoma recurrence by up to 45% and selenium supplementation may prevent colorectal cancer. Following colonoscopic adenoma resection, 1,600 men and women, ages 40 to 80 years, were randomized to celecoxib (400 mg daily), a selective COX-2 inhibitor, and/or selenium (200 μg daily as selenized yeast), or double placebo. The trial was initiated in November 2001. The primary trial endpoint is adenoma recurrence in each intervention group compared with placebo, as determined by surveillance colonoscopy conducted three to five years after baseline. Randomization was stratified by use of low-dose aspirin (81 mg) and clinic site. Following reports of cardiovascular toxicity associated with COX-2 inhibitors, the celecoxib arm was discontinued in December 2004 when 824 participants had been randomized. Accrual continued with randomization to selenium alone or placebo. Randomization of the originally planned cohort (n = 1,621) was completed in November 2008. A further 200 patients with one or more advanced adenomas (denoting increased risk for colorectal cancer) were accrued to enhance statistical power for determining intervention efficacy in this higher-risk subgroup. Accrual of the total cohort (n = 1,824) was completed in January 2011. Baseline cohort characteristics include: mean age 62.9 years; 65% male; body mass index (BMI) 29.1 ± 5.1; 47% taking low-dose aspirin while on trial; 20% with three or more adenomas; and 38% with advanced adenomas. Intervention effects on adenoma recurrence will be determined, and their modification by genetic background and baseline selenium level. The effect of selenium supplementation on risk for type II diabetes will also be reported.
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Iron homeostasis and distal colorectal adenoma risk in the prostate, lung, colorectal, and ovarian cancer screening trial.
Cross, AJ, Sinha, R, Wood, RJ, Xue, X, Huang, WY, Yeager, M, Hayes, RB, Gunter, MJ
Cancer prevention research (Philadelphia, Pa.). 2011;(9):1465-75
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Red meat consumption has been positively associated with colorectal cancer; however, the biological mechanism underlying this relationship is not understood. Red meat is a major source of iron, which may play a role in colorectal carcinogenesis via increased crypt cell proliferation, cytotoxicity, and endogenous N-nitrosation. In a nested case-control study within the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial, we prospectively evaluated multiple iron exposure parameters, including dietary intake and serum measures of iron, ferritin, transferrin, total iron binding capacity (TIBC), and unsaturated iron binding capacity (UIBC) in relation to incident colorectal adenoma in 356 cases and 396 matched polyp-free controls. We also investigated variation in eight key genes involved in iron homeostasis in relation to colorectal adenoma in an additional series totaling 1,126 cases and 1,173 matched controls. We observed a positive association between red meat intake and colorectal adenoma [OR comparing extreme quartiles (OR(q4-q1)) = 1.59, 95% CI = 1.02-2.49, P(trend) = 0.03]. Serum TIBC and UIBC were inversely associated with colorectal adenoma (OR(q4-q1) = 0.57, 95% CI = 0.37-0.88, P(trend) = 0.03; and OR(q4-q1) = 0.62, 95% CI = 0.40-0.95, P(trend) = 0.04, respectively). Colorectal adenoma was not associated with serum ferritin, iron, or transferrin saturation or with polymorphisms in genes involved in iron homeostasis. Serum TIBC and UIBC, parameters that have a reciprocal relationship with overall iron load, were inversely related to colorectal adenoma, suggesting that individuals with lower iron status have a reduced risk of developing colorectal adenoma.
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Effect of folic acid supplementation on genomic DNA methylation in patients with colorectal adenoma.
Pufulete, M, Al-Ghnaniem, R, Khushal, A, Appleby, P, Harris, N, Gout, S, Emery, PW, Sanders, TA
Gut. 2005;(5):648-53
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BACKGROUND AND AIMS A low dietary folate intake can cause genomic DNA hypomethylation and may increase the risk of colorectal neoplasia. The hypothesis that folic acid supplementation increases DNA methylation in leucocytes and colorectal mucosa was tested in 31 patients with histologically confirmed colorectal adenoma using a randomised, double blind, placebo controlled, parallel design. METHODS Subjects were randomised to receive either 400 microg/day folic acid supplement (n = 15) or placebo (n = 16) for 10 weeks. Genomic DNA methylation, serum and erythrocyte folate, and plasma homocysteine concentrations were measured at baseline and post intervention. RESULTS Folic acid supplementation increased serum and erythrocyte folate concentrations by 81% (95% confidence interval (CI) 57-104%; p<0.001 v placebo) and 57% (95% CI 40-74%; p<0.001 v placebo), respectively, and decreased plasma homocysteine concentration by 12% (95% CI 4-20%; p = 0.01 v placebo). Folic acid supplementation resulted in increases in DNA methylation of 31% (95% CI 16-47%; p = 0.05 v placebo) in leucocytes and 25% (95% CI 11-39%; p = 0.09 v placebo) in colonic mucosa. CONCLUSIONS These results suggest that DNA hypomethylation can be reversed by physiological intakes of folic acid.