Baseline findings of the Italian multicenter randomized controlled trial of "once-only sigmoidoscopy"--SCORE

A single sigmoidoscopy examination at around age 60 years has been proposed as a cost-effective strategy to prevent colorectal cancer. A multicenter randomized controlled trial, the SCORE trial, is in progress in Italy to estimate the impact of this strategy on colorectal cancer incidence and mortality and the duration of the protective effect. We present the baseline screening outcomes.

A questionnaire was mailed to a random sample of 236 568 people aged 55-64 years to assess their eligibility for and interest in screening. Those reporting a history of colorectal cancer, adenomas, inflammatory bowel disease, recent colorectal endoscopy, or two first-degree relatives with colorectal cancer were excluded. Eligible, interested respondents were assigned randomly to the control group (no further contact) or the intervention group (invitation to undergo sigmoidoscopy). Screenees with colorectal cancer, polyps larger than 5 mm, three or more adenomas, adenomas 5 mm or smaller with a villous component of more than 20%, or severe dysplasia were referred for colonoscopy.

Of the 56 532 respondents (23.9% of those invited), 34 292 were enrolled and 17 148 were assigned to the screening group. Of those, 9999 attended and 9911 were actually examined by sigmoidoscopy. Distal adenomas were detected in 1070 subjects (10.8%). Proximal adenomas were detected in 116 of 747 (15.5%) subjects without cancer at sigmoidoscopy who then underwent colonoscopy. A total of 54 subjects was found to have colorectal cancer, a rate of 5.4 per 1000 (54% of which were Dukes' A). The procedures were relatively safe, with two perforations (one in 9911 sigmoidoscopy exams and one in 775 colonoscopies) and one hemorrhage requiring hospitalization after polypectomy during colonoscopy. The pain associated with sigmoidoscopy was described as mild or less than expected by 83.3% of the screenees.

Sigmoidoscopy screening is generally acceptable to recipients and safe. The high yield of advanced adenomas is consistent with the projected impact of sigmoidoscopy screening on colorectal cancer incidence.