Colorectal cancer screening: A community case-control study of proctosigmoidoscopy, barium enema radiography, and fecal occult blood test efficacy

Objective: To examine the effectiveness of screening proctosigmoidoscopy, b arium enema radiography, and the fecal occult blood test (FOBT) in decreasi ng colorectal cancer mortality in a community setting. Patients and Methods: In this population-based case-control study, cases co mprised 218 Rochester, Minn, residents who died of colorectal cancer betwee n 1970 and 1993, Controls were 435 age- and sex-matched residents who did n ot have a diagnosis of colorectal cancer. Screening proctosigmoidoscopy, ba rium enema radiography, and FOBT results were documented for the 10 years p rior to and including the date of diagnosis of fatal colorectal cancer in c ases and for the same period in matched controls. History of general medica l examinations and hospitalizations was also recorded. Results: Within the 10 years prior to diagnosis, the percentages of cases v s controls with at least 1 screening proctosigmoidoscopy were 23 (10.6%) of 218 cases vs 43 (9.9%) of 435 controls; at least 1 screening barium enema radiographic study was done in 12 (5.5%) of 218 vs 25 (5.7%) of 435, Within 3 years prior to diagnosis, the percentages of cases vs controls with at l east 1 screening FOBT were 27 (12.4%) of 218 vs 44 (10.1%) of 435, Adjusted odds ratios were 1.04 (95% confidence interval [CI], 0.21-5.13) for procto sigmoidoscopy (distal rectosigmoid cancers only), 0.67 (95% CI, 0.31-1.48) for barium enema radiography, and 0.83 (95% CI, 0.45-1.52) for FOBT over th e above time periods, Conclusion: In this case-control study within a community setting, a colore ctal cancer-specific mortality benefit could not be demonstrated for screen ing by FOBT, proctosigmoidoscopy, or barium enema radiography. Screening fr equency was low, which may have contributed to the lack of measurable effec ts.