While taking calcium supplements can decrease the risk of all types of colorectal polyps, research led by Dartmouth Medical School shows calcium had the greatest effect on advanced colorectal adenomas, considered to be most strongly associated with invasive colorectal cancer.
The multi-center study, reported in the June 16 issue of the Journal of the National Cancer Institute, builds on prior Dartmouth research and provides more evidence that calcium supplementation appears to be a relatively safe and inexpensive way to reduce the risk of the most serious types of colorectal polyps.
"Our results suggest that calcium supplementation may have a more protective effect on advanced adenomas than on other types of colorectal polyps," said Kristin Wallace, a Dartmouth Medical School (DMS) graduate student who was the lead author on the study. "These findings highlight the need to consider 'polyp type' when assessing the efficacy of a given treatment."
John Baron, MD, professor of medicine and of community and family medicine at DMS and an investigator at Norris Cotton Cancer Center at Dartmouth-Hitchcock Medical Center, has done numerous studies on the effects of aspirin and calcium on colon cancer and led the project . "Previous studies have demonstrated an association between calcium intake and moderate decreases in the risk of precancerous colorectal tumors, but this is the first randomized trial to evaluate the effect of calcium on different types of colorectal lesions," he said.
Colorectal polyps, or adenomas, are bumps or fleshy tumors that occur on the inside lining of the colon that may become cancerous over time. By decreasing the size of the polyps and their number, there is less potential for colorectal cancer.