Growth of colorectal polyps: design of a prospective, randomized, placebo-controlled intervention study in patients with colorectal polyps.

One hundred and sixteen patients were included, during 18 months, in a double-blind placebo-controlled intervention study, with calcium, vitamins A, C, E and selenium (in a cocktail) or placebo against growth of colonic polyps. Patients were randomized within three arms, according to diameter of the largest polyp, < 5 mm, 5-9 mm or > 9 mm. Polyps > 9 mm were resected, the others were left to be measured annually before resection after 3 years. The protocol (performed in all of the patients) included registration of demographic data, family and personal history, measurement of polyps, collection of blood specimens, stools and biopsy samples. Registration of nutritional status, diet history and 5-day prospective food consumption, was performed in 108 patients. The patient compliance was registered every third month by the hospital pharmacist, with concomitant delivery of new boxes of capsules. Additionally, stool collections were performed from all of the patients for the measurement of faecal calcium, bile salts and fat. Inclusion rate of 37, 41 and 38 patients in each of the three 6-month periods was uniform. The group with the largest polyps measuring 5-9 mm comprised 44% of the material. The sex ratio corresponded to that in overall referrals for colonoscopy. The age relationship of size and multiplicity of polyps and the distribution of polyps in the large bowel corresponded to previous experience in polyp-bearing individuals of the same age.(ABSTRACT TRUNCATED AT 250 WORDS)