Incidence Of Distal Colorectal Cancer Research Articles

Risk-stratified screening and colorectal cancer incidence and mortality: A retrospective study from the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial

ObjectiveTo determine whether risk stratification can optimize the benefits of flexible sigmoidoscopy (FSG) screening. MethodsThe Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial was conducted from 1993 to 2001 in the United States. A colorectal cancer (CRC) risk stratification tool was developed in the control arm (n = 64,207) from the PLCO cohort and validated in the UK Biobank (n = 270,726). PLCO participants (n = 130,021) were classified into low-, medium-, and high-risk groups. Cumulative incidence and mortality were estimated using the Kaplan-Meier method. Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for the associations between screening and CRC incidence and mortality. ResultsThe CRC risk stratification tool was based on age, gender, body mass index, smoking status, family history of CRC, diabetes, regular use of aspirin, and CRC screening history. Compared with the control arm, FSG screening was significantly associated with a reduction in mortality in both the medium-risk (HR = 0.76, 95% CI = 0.63–0.92) and high-risk groups (0.58, 0.46–0.73), but not in the low-risk group (0.85, 0.61–1.19). FSG screening also reduced distal CRC incidence and mortality in the medium-risk and high-risk groups. Furthermore, it was associated with a reduction in incidence (0.74, 0.59–0.92) and mortality (0.59, 0.40–0.87) of proximal colon cancer in the high-risk group. ConclusionsFSG screening yielded more benefits for the high-risk group than for the low-risk and medium-risk groups, supporting the development of a risk-stratified CRC screening strategy.

The impact of endoscopist performance and patient factors on distal adenoma detection and colorectal cancer incidence

BackgroundHigh quality endoscopy is key for detecting and removing precursor lesions to colorectal cancer (CRC). Adenoma detection rates (ADRs) measure endoscopist performance. Improving other components of examinations could increase adenoma detection.AimsTo investigate how endoscopist performance at flexible sigmoidoscopy (FS) affects adenoma detection and CRC incidence.MethodsAmong 34,139 participants receiving FS screening by the main endoscopist at one of 13 centres in the UK FS Screening Trial, median follow-up was 17 years. Factors examined included family history of CRC, bowel preparation quality, insertion and withdrawal time, bowel segment reached, patient pain and ADR. Odds ratios (OR) for distal adenoma detection were estimated by logistic regression. Hazard ratios (HR) for distal CRC incidence were estimated by Cox regression.ResultsAt screening, 4,104 participants had distal adenomas detected and 168 participants developed distal CRC during follow-up. In multivariable models, a family history of CRC (yes vs. no: OR 1.40, 95%CI 1.21–1.62), good or adequate bowel preparation quality (vs. excellent: OR 0.84, 95%CI 0.74–0.95; OR 0.56, 95%CI 0.49–0.65, respectively) and longer insertion and withdrawal times (≥ 4.00 vs. < 2.00 min: OR 1.96, 95%CI 1.68–2.29; OR 32.79, 95%CI 28.22–38.11, respectively) were associated with adenoma detection. Being screened by endoscopists with low or intermediate ADRs, compared to high ADRs, was positively associated with CRC incidence (multivariable: HR 4.71, 95%CI 2.65–8.38; HR 2.16, 95%CI 1.22–3.81, respectively).ConclusionsBowel preparation quality and longer insertion and withdrawal time are key for improving distal adenoma detection. Higher ADRs were associated with a lower risk of distal CRC.

The Sulfur Microbial Diet and Risk of Colorectal Cancer by Molecular Subtypes and Intratumoral Microbial Species in Adult Men.

INTRODUCTION:We recently described the sulfur microbial diet, a pattern of intake associated with increased gut sulfur-metabolizing bacteria and incidence of distal colorectal cancer (CRC). We assessed whether this risk differed by CRC molecular subtypes or presence of intratumoral microbes involved in CRC pathogenesis (Fusobacterium nucleatum and Bifidobacterium spp.).METHODS:We performed Cox proportional hazards modeling to examine the association between the sulfur microbial diet and incidence of overall and distal CRC by molecular and microbial subtype in the Health Professionals Follow-Up Study (1986–2012).RESULTS:We documented 1,264 incident CRC cases among 48,246 men, approximately 40% of whom had available tissue data. After accounting for multiple hypothesis testing, the relationship between the sulfur microbial diet and CRC incidence did not differ by subtype. However, there was a suggestion of an association by prostaglandin synthase 2 (PTGS2) status with a multivariable adjusted hazard ratio for highest vs lowest tertile of sulfur microbial diet scores of 1.31 (95% confidence interval: 0.99–1.74, Ptrend = 0.07, Pheterogeneity = 0.04) for PTGS2-high CRC. The association of the sulfur microbial diet with distal CRC seemed to differ by the presence of intratumoral Bifidobacterium spp. with an adjusted hazard ratio for highest vs lowest tertile of sulfur microbial diet scores of 1.65 (95% confidence interval: 1.14–2.39, Ptrend = 0.01, Pheterogeneity = 0.03) for Bifidobacterium-negative distal CRC. We observed no apparent heterogeneity by other tested molecular markers.DISCUSSION:Greater long-term adherence to the sulfur microbial diet could be associated with PTGS2-high and Bifidobacterium-negative distal CRC in men. Additional studies are needed to further characterize the role of gut microbial sulfur metabolism and CRC.

Incidence and Mortality of Proximal and Distal Colorectal Cancer in Germany—Trends in the Era of Screening Colonoscopy.

The use of colonoscopy has increased and colorectal cancer (CRC) incidence has decreased after the introduction of screening colonoscopy in Germany. However, it remains unknown to what extent progress has been achieved in the prevention of cancer in the proximal colon, distal colon, and rectum. We analyzed trends in CRC incidence (2000-2016) and mortality (2000-2018) in Germany by sex, age, and tumor location. The age-standardized incidence of CRC declined by 22.4% (from 65.3 to 50.7 per 100 000) in men and by 25.5% (from 42.7 to 31.8 per 100 000) in women. CRC mortality declined by 35.8% (from 29.6 to 19.0 per 100 000) in men and by 40.5% (19.0 to 11.3 per 100 000) in women. Despite demographic changes, the annual numbers of CRC cases and deaths still decreased from about 60 400 to 58 300 and from around 28 700 to 24 200, respectively. The decline in incidence was greatest in groups aged ≥ 55 years. While the incidence of cancer in the distal colon and rectum decreased by 34.5% and 26.2%, respectively, in men and by 41.0% and 27.9% in women, the incidence of proximal colon cancer remained stable in men and decreased by only 7.0% in women. However, a major shift towards earlier stages was observed for the proximal cancers. The results support the assumption that the increased use of colo - noscopy has contributed to substantial reductions in the incidence of distal CRC incidence and the mortality from cancers in the entire colon and rectum.

Higher Adenoma Detection Rates at Screening Associated With Lower Long-Term Colorectal Cancer Incidence and Mortality

Background & AimsDetection and removal of adenomas reduces colorectal cancer (CRC) risk. The impact of adenoma detection rates (ADRs) on long-term CRC incidence and mortality is unknown. We investigated this using data from the UK Flexible Sigmoidoscopy Screening Trial.MethodsOf 167,882 UK Flexible Sigmoidoscopy Screening Trial participants, 40,085 were in the intervention arm and underwent flexible sigmoidoscopy screening at 13 trial centers. The median follow-up time was 17 years. At each center, 1 endoscopist performed most flexible sigmoidoscopies. Multivariable logistic regression was used to classify centers into high-, intermediate-, and low-detector groups based on their main endoscopist’s ADR. We calculated the incidence and mortality of distal and all-site CRC, and estimated hazard ratios (HRs) with 95% CIs using Cox regression.ResultsFive, 4, and 4 centers, respectively, were classified into the high-detector, intermediate-detector, and low-detector groups. The average ADRs in each respective group were 15%, 12%, and 9%. Distal CRC incidence and mortality were reduced among those screened compared with controls in all groups, and effects of screening varied significantly by detector ranking, with larger reductions in incidence and mortality seen in the high-detector group (incidence: HR, 0.34; 95% CI, 0.27–0.42; mortality: HR, 0.22, 95% CI, 0.13–0.37) than in the low-detector group (incidence: HR, 0.55; 95% CI, 0.44–0.68; mortality: HR, 0.54; 95% CI, 0.34–0.86). Similar results were observed for all-site CRC, with larger effects seen in the high-detector (incidence: HR, 0.58; 95% CI, 0.50–0.67; mortality: HR, 0.52; 95% CI, 0.39–0.69) than in the low-detector group (incidence: HR, 0.72; 95% CI, 0.61–0.85; mortality: HR, 0.68; 95% CI, 0.51–0.92), although the heterogeneity was not statistically significant.ConclusionsHigher ADRs at screening provide greater long-term protection against CRC incidence and mortality. Isrctn.org, number: ISRCTN28352761.

Screening colonoscopy and flexible sigmoidoscopy for reduction of colorectal cancer incidence: A case-control study.

BackgroundFlexible sigmoidoscopy and colonoscopy are both recommended colorectal cancer screening options, but their relative effectiveness needs clarification. The aim of this study was to compare the effectiveness of colonoscopy and flexible sigmoidoscopy for reduction of colorectal cancer incidence.MethodsWe conducted a case-control study within the linked Surveillance, Epidemiology, and End Results (SEER)-Medicare database. Cases were subjects age 70–85 years in the SEER-Medicare database diagnosed with CRC during 2004–2013. Up to 3 controls were matched to each case by birth year, sex, race, and SEER region. Receipt of screening colonoscopy or flexible sigmoidoscopy was ascertained from Medicare claims. Conditional logistic regression models were developed to estimate the odds ratios (ORs) and 95% confidence intervals (CI) for a history of screening in cases vs. controls. We conducted secondary analyses by sex, race, endoscopist characteristics, and with varying timing and duration of the look-back period.ResultsReceipt of screening colonoscopy and sigmoidoscopy was associated with a 59% (OR 0.41, 95%CI 0.39, 0.43) and 22% reduction (OR 0.78, 95%CI 0.67, 0.92) in colorectal cancer incidence, respectively. Colonoscopy was associated with greater reduction in the distal colorectal cancer incidence (OR 0.22, 95%CI 0.20, 0.24) than proximal colorectal cancer incidence (OR 0.62, 95%CI 0.59, 0.66). Sigmoidoscopy was associated with a 52% reduction in distal colorectal cancer incidence (OR 0.48, 95%CI 0.37, 0.63), but with no reduction in proximal colorectal cancer incidence. These associations were stronger in men than in women. No differences by race or endoscopist characteristics were observed.ConclusionBoth screening colonoscopy and sigmoidoscopy were associated with reductions in overall colorectal cancer incidence, with a greater magnitude of reduction observed with colonoscopy.

Modeling in Colorectal Cancer Screening: Assessing External and Predictive Validity of MISCAN-Colon Microsimulation Model Using NORCCAP Trial Results.

Microsimulation models are increasingly being used to inform colorectal cancer (CRC) screening recommendations. MISCAN-Colon is an example of such a model, used to inform the Dutch CRC screening program and US Preventive Services Task Force guidelines. Assessing the validity of these models is essential to provide transparency regarding their performance. In this study, we tested the external and predictive validity of MISCAN-Colon. We validated MISCAN-Colon using the Norwegian Colorectal Cancer Prevention (NORCCAP) trial, a randomized controlled trial that examined the effectiveness of once-only flexible sigmoidoscopy (FS) screening. We simulated the study population and design of the NORCCAP trial in MISCAN-Colon and compared 10- to 12-year model-predicted hazard ratios (HRs) for overall and distal CRC incidence and mortality to those observed. In addition, we compared the numbers of screen-detected neoplasia. Finally, we predicted the trial's future results to allow for the assessment of predictive validity. MISCAN-Colon predicted an HR for overall CRC incidence (0.85), distal CRC incidence (0.82), overall CRC mortality (0.68), and distal CRC mortality (0.62). These were within the limits of the 95% confidence intervals of the NORCCAP trial results. Similar results were observed for the number of screen-detected cancers. The model significantly underestimated the number of screen-detected adenomas. Model-predicted HRs for CRC incidence and mortality up to 15- to 17-year follow-up were 0.84 and 0.72, respectively. Although the underestimation of screen-detected adenomas requires further investigation, MISCAN-Colon is able to make a valid replication of the CRC incidence and mortality reduction of an FS screening trial, which suggests that it can be considered a useful tool to support decision making on CRC screening.

Incidence Rates of Colorectal Cancer in South Asians, Other Asian Groups, and Non-Hispanic Whites in California

Introduction: The incidence of colorectal cancer (CRC) varies by race and region. South Asians constitute a fast-growing group in the U.S. and are concentrated in California. We studied the most recent incidence rates and trends of CRC in South Asians in comparison to other Asian groups and Non-Hispanic Whites in California. Methods: Using the California Cancer Registry SEER*Stat database, we calculated age-adjusted CRC incidence rates between 2011-2015 for South Asians, other Asian groups, and Non-Hispanic Whites. We defined South Asians as Asian Indians, Pakistanis, Bangladeshis, Sri Lankans, Nepalis, Bhutanese, and Maldivians. We also studied the annual percentage change (APC) in CRC incidence rates in South Asians, other Asian groups, and Non-Hispanic Whites between 1988-2014. Results: South Asians had a significantly lower incidence of colon, rectal, and rectosigmoid cancer than other Asian groups and non-Hispanic Whites, among both males and females (Table 1). Males in other Asian groups had higher CRC rates than Whites. Both proximal and distal CRC incidence rates in South Asians were lower than other Asians and Whites. Distal CRC rates were higher in other Asian groups than in Whites. Whites had the highest CRC incidence in the <50-year age group. No significant change was noted in the incidence rates of CRC in South Asians between 1988-2014 (Table 2, p<0.05). There was a significant decrease in the rates of colon (proximal and distal) and rectal carcinoma in other Asians in both males and females between 2000-2014 (Table 2, p<0.05), and in Whites (proximal and distal) in both males and females between 1988-2014 (Table 2, p<0.05). CRC rates in the <50-year age group increased significantly in Whites between 1992-2014, and non-significantly in South Asians and other Asians (Table 2, p<0.05). Conclusion: In this study, we found that South Asians had a significantly lower incidence of CRC in comparison to other Asian groups and Non-Hispanic Whites. CRC rates in other Asians is approaching that of Whites. CRC incidence trends show a significant decrease in other Asian groups and in Non-Hispanic Whites between 1988-2014, but not in South Asians. CRC rates are increasing in the <50-year age group across all racial groups. Continued efforts are needed to reduce the incidence of CRC in Asian populations, and to further investigate the etiologies of younger onset CRC.256_A Figure 1. Age adjusted incidence rates of CRC in South Asians, other Asian groups, and Non-Hispanic Whites in California between 2011-2015.256_B Figure 2. Trend in CRC incidence rates in South Asians, other Asian groups, and Non-Hispanic Whites in California between 1988-2014.

Ten-year incidence of colorectal cancer following a negative screening sigmoidoscopy: an update from the Colorectal Cancer Prevention (CoCaP) programme

ObjectiveTo examine the rates of colorectal cancer (CRC) following a negative screening sigmoidoscopy.DesignCohort study.SettingAn integrated healthcare delivery organisation in California, USA.Participants72 483 men and women aged 50 years and above...

Lower Endoscopy and Prevention of Colon Cancer

Lower Endoscopy and Prevention of Colon Cancer

Effect of screening sigmoidoscopy and screening colonoscopy on colorectal cancer incidence and mortality: systematic review and meta-analysis of randomised controlled trials and observational studies

Objectives To review, summarise, and compare the evidence for effectiveness of screening sigmoidoscopy and screening colonoscopy in the prevention of colorectal cancer occurrence and deaths.Design Systematic review and meta-analysis of...

Reduced incidence and mortality from colorectal cancer with flexible-sigmoidoscopy screening: a meta-analysis.

To conduct a systematic review and meta-analysis of published population-based randomized controlled trials (RCTs). RCTs evaluating the difference in mortality and incidence of colorectal cancer (CRC) between a screening flexible sigmoidoscopy (FS) group and control group (not assigned to screening FS) with a minimum 5 years median follow-up were identified by a search of MEDLINE and EMBASE databases and the Cochrane Central Register for Controlled Trials through August 2013. Random effects model was used for meta-analysis. Four RCTs with a total of 165659 patients in the FS group and 249707 patients in the control group were included in meta-analysis. Intention-to-treat analysis showed that there was a 22% risk reduction in total incidence of CRC (RR = 0.78, 95%CI: 0.74-0.83), 31% in distal CRC incidence (RR = 0.69, 95%CI: 0.63-0.75), and 9% in proximal CRC incidence (RR = 0.91, 95%CI: 0.83-0.99). Those who underwent screening FS were 18% less likely to be diagnosed with advanced CRC (OR = 0.82, 95%CI: 0.71-0.94). There was a 28% risk reduction in overall CRC mortality (RR = 0.72, 95%CI: 0.65-0.80) and 43% in distal CRC mortality (RR = 0.57, 95%CI: 0.45-0.72). This meta-analysis suggests that screening FS can reduce the incidence of proximal and distal CRC and mortality from distal CRC along with reduction in diagnosis of advanced CRC.

Comparative Effectiveness and Cost-effectiveness of Screening Colonoscopy vs. Sigmoidoscopy and Alternative Strategies: 2011 ACG Presidential Poster

Purpose: Colonoscopy for colorectal cancer (CRC) screening was championed initially based on the belief that examining the entire colon would yield better outcomes than screening the left colon with sigmoidoscopy. The demonstration in the U.K. Flexible Sigmoidoscopy Trial that sigmoidoscopy decreases distal CRC incidence and mortality, combined with observational data that question colonoscopy's power to prevent proximal CRC, rekindled the debate about the merits of screening colonoscopy. Our aims were to explore the comparative effectiveness and cost-effectiveness of screening colonoscopy and sigmoidoscopy vs. alternative CRC screening strategies, considering the most recent data that high quality colonoscopy is associated with protection against both distal and proximal CRC. Methods: We adapted our validated U.S. CRC screening Markov model and conducted a contemporary cost-utility analysis of screening colonoscopy every 10 years (COLO) vs. alternative strategies including annual fecal occult blood testing, annual fecal immunochemical testing (FIT), flexible sigmoidoscopy every 5 years (FS), and flexible sigmoidoscopy every 5 years and FIT every 3 years. We examined an average-risk screening population in the U.S. Results: In the base case, yearly FIT dominated other strategies, but its advantages over FS and COLO were contingent upon rates of FIT uptake (>85% relative to lower endoscopy) and adherence (>50% per cycle) that are well above current U.S. rates (Table 1). With optimal uptake and adherence, COLO cost $56,800/quality-adjusted life-year (QALY) gained vs. FS. Given a COLO uptake rate of 75% and a FS uptake rate of 50%, COLO cost $11,200/QALY gained vs. FS. Given a per-cycle adherence rate of 75% with COLO and 50% with FS, COLO cost $17,700/QALY gained vs. FS. COLO cost <$100,000/QALY gained vs. FS when COLO yielded a reduction in overall CRC incidence of ≥71%, and <$50,000/QALY gained when COLO yielded a reduction in overall CRC incidence of >73%. As CRC care costs or CRC risk increased, COLO became progressively more cost-effective compared with FS. In probabilistic analyses, COLO vs. FS cost ≤$50,000/QALY gained in 52% of iterations and ≤$100,000/QALY gained in 84% of iterations. On average, COLO required 3.8 colonoscopies and FS required 4.4 sigmoidoscopies and 1.7 colonoscopies over a lifetime.Table 1: Base case clinical and economic results assuming optimal screening uptake, adherence and follow-up for a cohort of 100,000 average risk persons from age 50 to 100 yearsaConclusion: Screening colonoscopy may be cost-effective compared with alternative CRC screening strategies, depending on the relative rates of screening uptake and adherence. The viability of screening colonoscopy depends on the ability to provide high quality colonoscopy.

Cribado del cáncer colorrectal

Colorectal cancer is the most frequent neoplasm in the Western countries and the second cause of death from cancer. This situation is due to the underuse of screening or early detection strategies. In the American Gastroenterological Association's congress, several studies reported major advances in the efficacy and efficiency of diverse approaches. Notable among these was evaluation of new fecal occult blood tests through immunological methods, especially with regard to the number of determinations, the cut-off point for positivity, age range of the target population and periodicity. One of the main contributions to the congress were the results of a UK controlled randomized trial showing the benefit of a single sigmoidoscopy performed in persons aged approximately 60 years on reducing the incidence of distal colorectal cancer and colorectal cancer overall and associated mortality. In this trial, the protective effect of sigmoidoscopy was maintained for a minimum of 10 years.

Once-only flexible sigmoidoscopy screening in prevention of colorectal cancer: a multicentre randomised controlled trial

Colorectal cancer is the third most common cancer worldwide and has a high mortality rate. We tested the hypothesis that only one flexible sigmoidoscopy screening between 55 and 64 years of age can substantially reduce colorectal cancer incidence and mortality. This randomised controlled trial was undertaken in 14 UK centres. 170 432 eligible men and women, who had indicated on a previous questionnaire that they would accept an invitation for screening, were randomly allocated to the intervention group (offered flexible sigmoidoscopy screening) or the control group (not contacted). Randomisation by sequential number generation was done centrally in blocks of 12, with stratification by trial centre, general practice, and household type. The primary outcomes were the incidence of colorectal cancer, including prevalent cases detected at screening, and mortality from colorectal cancer. Analyses were intention to treat and per protocol. The trial is registered, number ISRCTN28352761. 113 195 people were assigned to the control group and 57 237 to the intervention group, of whom 112 939 and 57 099, respectively, were included in the final analyses. 40 674 (71%) people underwent flexible sigmoidoscopy. During screening and median follow-up of 11.2 years (IQR 10.7-11.9), 2524 participants were diagnosed with colorectal cancer (1818 in control group vs 706 in intervention group) and 20 543 died (13 768 vs 6775; 727 certified from colorectal cancer [538 vs 189]). In intention-to-treat analyses, colorectal cancer incidence in the intervention group was reduced by 23% (hazard ratio 0.77, 95% CI 0.70-0.84) and mortality by 31% (0.69, 0.59-0.82). In per-protocol analyses, adjusting for self-selection bias in the intervention group, incidence of colorectal cancer in people attending screening was reduced by 33% (0.67, 0.60-0.76) and mortality by 43% (0.57, 0.45-0.72). Incidence of distal colorectal cancer (rectum and sigmoid colon) was reduced by 50% (0.50, 0.42-0.59; secondary outcome). The numbers needed to be screened to prevent one colorectal cancer diagnosis or death, by the end of the study period, were 191 (95% CI 145-277) and 489 (343-852), respectively. Flexible sigmoidoscopy is a safe and practical test and, when offered only once between ages 55 and 64 years, confers a substantial and longlasting benefit. Medical Research Council, National Health Service R&D, Cancer Research UK, KeyMed.

285 The European Achalasia Trial: A Randomized Multi-Centre Trial Comparing Endoscopic Pneumodilation and Laparoscopic Myotomy as Primary Treatment of Idiopathic Achalasia

Introduction A once-only flexible sigmoidoscopy (FS) screening at age around 60 has been proposed as a cost-effective and acceptable method of reducing colorectal cancer (CRC) incidence and mortality. We undertook a large randomised controlled trial in a general population sample to compare CRC incidence and mortality rates following a single FS screen. Methods and baseline results Between 1994 and 1999, we sent a questionnaire to 375 744 men and women, aged 55 to 64 years, in 14 UK centres, asking whether they would have the FS screening if invited. Those who responded ‘yes definitely' or ‘yes probably' and were found to be eligible (n = 170 432) were randomised to the control or intervention arms of the trial in a 2:1 ratio. Of 57 254 people invited, 40 674 (71%) were screened. Following screening, 38 525 (95%) had either no pathology or only low-risk adenomas and were discharged and 2051 had high risk adenomas detected and underwent colonoscopy. Biannual updates on status (emigration, cancer diagnoses or deaths) were obtained by matching with the National Health Service Central Register, Office of National Statistics, UK cancer registries, and Hospitals Episodes Statistics records. Results of follow-up The median follow-up time to death, emigration or 31st December 2008 is currently 11 years. A total of 2491 participants developed CRC during 1.85 million person years of follow-up: 1523 developed a distal cancer (rectum or sigmoid colon), 894 developed cancer in the proximal colon, 34 developed cancer in both sites, and in 40 cases the site was not known. On an intent-to-treat analysis, a significant reduction in incidence of total and distal CRC was observed among those invited for screening. A greater reduction was seen among those who attended for screening. Colorectal cancer mortality rates were also reduced significantly. Adjustment for self-selection bias in attenders using Cuzick et al's method (Stat Med 1997;16:1017-29) made little difference to the rate ratios or significance. Conclusion By 11 years, total and distal colorectal cancer incidence rates were reduced significantly among people offered a single flexible sigmoidoscopy screen between ages 55 and 64 years, and so far no attenuation of effect has been observed. Detailed results will be presented.

283 UK Flexible Sigmoidoscopy Screening Trial: Colorectal Cancer Incidence and Mortality Rates at 11 Years After a Single Screening Examination

Introduction A once-only flexible sigmoidoscopy (FS) screening at age around 60 has been proposed as a cost-effective and acceptable method of reducing colorectal cancer (CRC) incidence and mortality. We undertook a large randomised controlled trial in a general population sample to compare CRC incidence and mortality rates following a single FS screen. Methods and baseline results Between 1994 and 1999, we sent a questionnaire to 375 744 men and women, aged 55 to 64 years, in 14 UK centres, asking whether they would have the FS screening if invited. Those who responded ‘yes definitely' or ‘yes probably' and were found to be eligible (n = 170 432) were randomised to the control or intervention arms of the trial in a 2:1 ratio. Of 57 254 people invited, 40 674 (71%) were screened. Following screening, 38 525 (95%) had either no pathology or only low-risk adenomas and were discharged and 2051 had high risk adenomas detected and underwent colonoscopy. Biannual updates on status (emigration, cancer diagnoses or deaths) were obtained by matching with the National Health Service Central Register, Office of National Statistics, UK cancer registries, and Hospitals Episodes Statistics records. Results of follow-up The median follow-up time to death, emigration or 31st December 2008 is currently 11 years. A total of 2491 participants developed CRC during 1.85 million person years of follow-up: 1523 developed a distal cancer (rectum or sigmoid colon), 894 developed cancer in the proximal colon, 34 developed cancer in both sites, and in 40 cases the site was not known. On an intent-to-treat analysis, a significant reduction in incidence of total and distal CRC was observed among those invited for screening. A greater reduction was seen among those who attended for screening. Colorectal cancer mortality rates were also reduced significantly. Adjustment for self-selection bias in attenders using Cuzick et al's method (Stat Med 1997;16:1017-29) made little difference to the rate ratios or significance. Conclusion By 11 years, total and distal colorectal cancer incidence rates were reduced significantly among people offered a single flexible sigmoidoscopy screen between ages 55 and 64 years, and so far no attenuation of effect has been observed. Detailed results will be presented.

284 Laparoscopic Antireflux Surgery vs Long-Term Esomeprazole Treatment for Chronic GERD. Final Results After 5 Yrs of Follow up in the Lotus Study

Introduction A once-only flexible sigmoidoscopy (FS) screening at age around 60 has been proposed as a cost-effective and acceptable method of reducing colorectal cancer (CRC) incidence and mortality. We undertook a large randomised controlled trial in a general population sample to compare CRC incidence and mortality rates following a single FS screen. Methods and baseline results Between 1994 and 1999, we sent a questionnaire to 375 744 men and women, aged 55 to 64 years, in 14 UK centres, asking whether they would have the FS screening if invited. Those who responded ‘yes definitely' or ‘yes probably' and were found to be eligible (n = 170 432) were randomised to the control or intervention arms of the trial in a 2:1 ratio. Of 57 254 people invited, 40 674 (71%) were screened. Following screening, 38 525 (95%) had either no pathology or only low-risk adenomas and were discharged and 2051 had high risk adenomas detected and underwent colonoscopy. Biannual updates on status (emigration, cancer diagnoses or deaths) were obtained by matching with the National Health Service Central Register, Office of National Statistics, UK cancer registries, and Hospitals Episodes Statistics records. Results of follow-up The median follow-up time to death, emigration or 31st December 2008 is currently 11 years. A total of 2491 participants developed CRC during 1.85 million person years of follow-up: 1523 developed a distal cancer (rectum or sigmoid colon), 894 developed cancer in the proximal colon, 34 developed cancer in both sites, and in 40 cases the site was not known. On an intent-to-treat analysis, a significant reduction in incidence of total and distal CRC was observed among those invited for screening. A greater reduction was seen among those who attended for screening. Colorectal cancer mortality rates were also reduced significantly. Adjustment for self-selection bias in attenders using Cuzick et al's method (Stat Med 1997;16:1017-29) made little difference to the rate ratios or significance. Conclusion By 11 years, total and distal colorectal cancer incidence rates were reduced significantly among people offered a single flexible sigmoidoscopy screen between ages 55 and 64 years, and so far no attenuation of effect has been observed. Detailed results will be presented.

The incidence of colorectal cancer following a negative screening sigmoidoscopy: Implications for screening interval

Current guidelines recommend a 5-year interval for colorectal cancer (CRC) screening by sigmoidoscopy. However, the optimal screening interval is uncertain. We estimated the annual incidence of distal and proximal CRC in the first 5 years following a negative sigmoidoscopy examination to gauge the potential benefit of rescreening in <5 years. A cohort of 72,483 participants in the Colon Cancer Prevention program of Kaiser Permanente of Northern California (KP) was defined using computerized databases. Men and women aged 50 years and older who had a negative screening flexible sigmoidoscopy examination between 1994 and 1996 and were considered not to be at high risk for developing CRC were included. Subjects were censored at the time of diagnosis (for cases), death, termination of KP membership, or subsequent colon examination. Thirty cases of distal and 80 cases of proximal CRC occurred. Age-adjusted incidence rates of distal CRC ranged from a low of 2.8 per 100,000 person-years in the first year of follow-up to a high of 13.0 per 100,000 in the fourth year (rate difference, 10.2; 95% confidence interval, 1.1-19.3). However, for the entire follow-up period, incidence of distal CRC remained much lower than age-adjusted rates of 70.6 in the general population (Surveillance, Epidemiology, and End Results registry). The incidence of proximal CRC was also decreased modestly over population rates of disease. Screening by sigmoidoscopy more frequently than every 5 years would likely lead, at best, to only modest improvements as compared with a 5-year screening interval.

Is there a true “shift” to the right colon in the incidence of colorectal cancer?

Objective Previous studies have reported a migration in the occurrence of colorectal cancer (CRC) toward a proximal colonic location. To assess the potential impact of this, we evaluated recent temporal trends in the United States. Methods Using the nine population-based cancer registries that constitute the Surveillance, Epidemiology, and End Results Program of the National Cancer Institute, we identified primary CRCs diagnosed between 1978 and 1998. Temporal changes were evaluated for 3-yr time periods. Age-adjusted incidence rates and the proportions of new diagnoses of CRC were calculated by site and by race. Results We identified 243,861 individuals with CRC during 1978–1998, 51.1% of whom were men. In whites and in blacks, the proportions of new diagnoses of right CRC rose significantly, from 34% and 37% to 40% and 44%, respectively. In contrast, the proportions of left CRC (in whites and blacks) and of rectosigmoid CRC (in whites) decreased significantly over time. For whites and blacks, the age-adjusted incidence rates for right CRC remained unchanged (in whites) or showed a small increase (in blacks), whereas the age-adjusted incidence rates for left CRC (in whites and blacks) and for rectosigmoid CRC (in whites) declined. During 1996–1998, right CRC was the most common site in the oldest age groups (70–79, 80 yr, and older) in whites and in blacks. Conclusions The proximal migration of CRC over time is not attributed to a true increase in the incidence of right CRC. It is explained by a decrease in the incidence of distal CRC coupled with the aging of the population. Older individuals, in whom the burden of CRC is greatest, and in whom right CRC is the most common site, would be the most adversely affected from CRC screening methods that do not assess the total colon.