Cholecalciferol and Calcium Carbonate in Treating Patients With Colon Cancer That Has Been Removed by Surgery

RATIONALE: The use of cholecalciferol and calcium carbonate may keep colon cancer from coming back in patients with colon cancer that has been removed by surgery.
PURPOSE: This randomized clinical trial is studying two different doses of cholecalciferol to compare how well they work when given together with calcium carbonate in treating patients with colon cancer that has been removed by surgery.