Colorectal cancer screening through detection of fecal occult blood in a controlled health zone

AIM: to determine the viability and utility of fecal occult blood (FOB) scr eening (Hemoccult Ii) as a method for the early diagnosis of colorectal can cer in a well-controlled health area. METHODS: between February 1994 and September 1996, personal. letters were s ent to all persons in the Casas Ibanez health area (Albacete) aged between 50 and 75 years (4986 persons). All the tests were read by the same team me mber. A clinical history was taken of persons with positive test results, a nd they were offered colonoscopy. If a growth was found which was suitable for endoscopic resection, this was done. If the growth was totally resected an annual check-up was advised. Malignant and partially resected premalign ant growths were referred for surgical treatment. We analyzed percent parti cipation, attendance for testing, negative and positive tests, growths diag nosed, false-positive tests and positive predictive value. RESULTS: the a participation rate was 56.25%. In the 157 colonoscopies perf ormed, 39 neoplasic polyps and 9 cancers were found (7 of which were Dukes stage A and 2 of which were Dukes stage C-D). Sensitivity was 97% and speci ficity was 96%. The positive predictive value was 30.37%. The positivity ra te was 6.08%, while the predictive,value for cancer was 5.38% and the predi ctive value for adenoma was 23.35%. CONCLUSIONS: FOB screening, in our setting, proved to have a high recruitme nt capacity with a positive predictive value for colorectal carcinoma which was slightly higher than the value obtained in other countries of similar socioeconomic status. Furthermore, we found a significant improvement in th e diagnostic stage of colorectal carcinoma at the time of resection.