Objective— To compare the costs of colorectal cancer (CRC) screening by two faecal occult blood tests (FOBT)—namely, Hemoccult (guaiac based) and reversed passive haemagglutination (RPHA) tests. RPHA was interpreted according to two positivity thresholds (+ or +/-). Methods— Attenders performed both tests. Subjects with a positive FOBT test were invited to have a complete exploration of the colon. The total costs for every 10 000 screened subjects and costs for each unit of result (screened subject, or patient with adenoma/s or cancer detected) were calculated for both tests. Results— 8353 subjects were enrolled. A total of 2109 repeated screening after two years. RPHA(+ and +/-) showed the highest and RPHA(+) the lowest positivity rate at first screening. The Hemoccult positivity rate was highest at repeat screening. Total costs of screening by RPHA(+ and +/-) were highest as this method had the highest recall rate. Screening by RPHA(+) was the least costly. Costs for each screened subject were highest for RPHA(+ and +/-) and lowest for RPHA(+). Costs for each cancer detected were lowest for RPHA(+) and highest for Hemoccult or RPHA(+ and +/-) in subjects aged > 49 or < 50, respectively. Costs for subjects with detected adenoma/s of > 9 mm were lowest for RPHA(+ and +/-) and highest for Hemoccult. At repeat screening total costs of RPHA(+ and +/-) were lower than at first screening, whereas for each subject with cancer or adenoma/s costs were increased. Conclusions— Our data confirm that screening by RPHA is more cost effective than by Hemoccult.
Immunochemical faecal occult blood tests in primary care and the risk of delay in the diagnosis of colorectal cancer