Screening for colorectal cancer by once only sigmoidoscopy: a feasibility study in Turin, Italy.

Objectives: To assess the impact on compliance of three invitation methods, as well as the acceptability and efficacy of two bowel preparation regimens, for endoscopic screening in the general population.
Methods: 1170 subjects (men and women aged 55 to 59, in the rosters of a sample of general practitioners (GPs) in Turin), were randomly allocated to one of three invitation groups (A: personal letter, signed by GP, with a pre-fixed appointment; B: same as for A + letter supporting the study by a well known scientist; C: letter signed by the study coordinator, NS) and two preparation regimens (i: one enema, self administered at home two hours before the test; ii: two enemas, administered the night before and two hours before the test). A postal reminder was mailed to non-attenders. A sample of non-responders was contacted for a telephone interview by a trained nurse. Written consent was obtained from all subjects undergoing the test.
Results: A total of 278 subjects attended for sigmoidoscopic screening. An invitation from the GP alone produced the highest response rate (compliance: A = 29.3%; B = 24.9%; C = 26.8%). A single enema was as effective as two enemas in achieving satisfactory preparation for the test: the proportion of subjects invited to repeat the test was 8.1% in the single enema group, and 9.6% in the group receiving two enemas.
Conclusions: Compliance with this screening procedure tends to be low. One enema, self administered two hours before sigmoidoscopy, can ensure a satisfactory bowel preparation.