Surveillance endoscopy does not improve survival for patients with local and regional stage colorectal cancer

BACKGROUND. Endoscopic surveillance is recommended and widely practiced after definitive treatment for colorectal cancer, yet to the authors' knowledge there is little evidence supporting its benefit. The purpose of the current study was to estimate the impact of endoscopic surveillance on colorectal cancer-specific survival for persons with localized or regional colorectal cancer. The population included Medicare patients (age >= 65 years) who were diagnosed with local or regional stage colorectal cancer between 1986 and 1996. METHODS. The current study was a retrospective case-control study. Cases were defined as those individuals who died of colorectal cancer and controls were defined as those with colorectal cancer who did not die of colorectal cancer; controls were frequency matched to cases. Surveillance was defined as the use of colonoscopy, flexible sigmoidoscopy, or barium enema >= 6 months after diagnosis. Logistic regression was used to control for endoscopic procedure, race, comorbidity index at the time of diagnosis, and types of initial treatments after surgery. RESULTS. The analysis group contained 8130 cases (29%) and 20,079 controls (71%). The average time to first bowel surveillance for those with at least 1 surveillance examination was 15.9 months after the diagnosis (median, 13 months). In the regression analysis, surveillance endoscopy was not found to be associated with improved colorectal cancer-specific survival (odds ratio of 1.01; 95% confidence interval, 0.95-1.06 [P = 0.85]). Setting the surveillance interval to 12 months and 15 months rather than 6 months after diagnosis did not appear to influence the results. CONCLUSIONS. Surveillance endoscopy does not appear to influence colorectal cancer-specific mortality in patients age >= 65 years who are diagnosed with localized or regional stage colorectal cancer.