Supplemental calcium and colorectal adenomas in individuals with resected colorectal carcinomas (CRC): Results from a SWOG feasibility study.

B143

Background : Calcium taken orally in the dose range of 1250 mg daily decreases new colorectal adenoma formation in individuals with a previous adenoma. Polyp eradication endoscopically is associated with decreased rates of CRC. Resected CRC patients have high rates of adenoma formation and were chosen as the patient population to conduct a prospective placebo controlled feasibility study of calcium intervention in the Southwest Oncology Group. Methods : 220 patients with CRC, stages I and II, were randomized after a 3 month run-in period on placebo, to five years of calcium carbonate 1800 mg per day versus placebo. Colonoscopies were performed at enrollment, 3 years, and 5 years. Results : Females: males was 2:3, 60% had a synchronous polyp. Median age was 68 years. Endpoint results are shown below. ADENOMA RECURRENCE BY TREATMENT ARM OVERALL: Calcium 44% (42/99) vs Placebo 63% (22/99) SA: absent Calcium 29% (10/35) vs Placebo 50% (20/40) present Calcium 53% (32/60) vs Placebo 79% (42/59) 4 or more Calcium 75% (9/12) vs Placebo 88% (14/16) FEMALES: Calcium 45% (17/38) vs Placebo 62% (21/34) MALES: Calcium 44% (25/57) vs Placebo 63% (41/65) SA=synchronous adenoma, p=0.01 for all arms Conclusions : Calcium 1800 mg daily for 5 years lowers adenoma recurrence risks in CRC survivors. In addition, the increased risks of adenoma recurrence, particularly, if SA is present, have not been previously recognized and proper surveillance colonoscopy should be adhered to.