RANDOMIZED STUDY OF SCREENING FOR COLORECTAL-CANCER WITH FECAL-OCCULT-BLOOD TEST

Background Case-control studies and a voluntary-based follow-up study have suggested that repeated screening with faecal-occult-blood (FOE) tests can lead to a reduction in mortality from colorectal cancer (CRC ). The aim of this randomised study was to compare mortality rates aft er FOE tests every 2 years during a 10-year period with those of unscr eened similar controls. Methods 140 000 people aged 45-75 years lived in Funen, Denmark, in August, 1985, and were considered for inclusion in our study. Before randomisation we excluded individuals who had CRC or precursor adenomas and those who had taken part in a previous pilo t study. Randomisation of 137 485 people in blocks of 14 allocated thr ee per 14 to the screening group (30 967), three per 14 to the control group (30 966), and eight not to be enrolled in the study (75 552). C ontrols were not told about the study and continued to use health-care facilities as normal. Hemoccult-II blood tests (with dietary restrict ions but without rehydration) were sent to screening-group participant s. Only those participants who completed the first screening round wer e invited for further screening-five rounds of screening during a 10-y ear period. Participants with positive tests were asked to attend a fu ll examination and were offered colonoscopy whenever possible. The pri mary endpoint was death from CRC. Findings Of the 30 967 screening-gro up participants, 20 672 (67%) completed the first screening round and were invited for further screening; more than 90% accepted repeated sc reenings. During the 10-year study, 481 people in the screening group had a diagnosis of CRC, compared with 483 unscreened controls. There w ere 205 deaths attributable to CRC in the screening group, compared wi th 249 deaths in controls. CRC mortality, including deaths attributabl e to complications from CRC treatment, was significantly lower in the screening group than in controls (mortality ratio 0.82 [95% Cl 0.68-0. 99]) p=0.03). Interpretation Our findings indicate that biennial scree ning by FOE tests can reduce CRC mortality. This study is being contin ued to improve its statistical power and to assess the effect of the r emoval of more precursor adenomas in the screening-group participants than in controls on CRC incidence.