Progress report on controlled trial of fecal occult blood testing for the detection of colorectal neoplasia.

Our controlled trial of screening for colorectal cancer has now been in progress for almost five years. Screening is accomplished by rigid sigmoidoscopy in control and study groups and, in addition, by fecal occult blood testing in the study group. Patients screened are men and women age 40 and older, mostly at average risk. Fecal occult blood testing is with Hemoccult slides with patients on a meat-free, high-bulk diet without hydration, and with a four-day storage interval between slide preparation and testing. Patients with positive slides undergo diagnostic investigation that includes both colonoscopy and double-contrast barium enema and, in some, an upper gastrointestinal series. Preliminary results to date include: patient baseline statistics and subgroup comparability, rate of positive slides of 1-4%, predictive value for neoplasia of 44-50%, false-positives of 0.5-2.1%, favorable Dukes' staging of cancers in the study group, and high patient compliance. Considerably more follow-up is need in our study and control population, and issues such as mortality and cost need to be addressed. Additional time will be necessary to provide firm conclusions.