Indication: Colorectal cancer

Source: NEJM, February 16, 2006;354:684-696.

Research: Randomized trial evidence that calcium in combination with vitamin D supplementation is beneficial in the primary prevention of colorectal cancer is lacking, so researchers conducted additional analyses of postmenopausal woman participating in the Women’s Health Initiative (WHI) study. The incidence of pathologically confirmed colorectal cancer was the designated secondary outcome.

Results: Invasive colorectal cancer developed in 168 women assigned to calcium plus vitamin D supplementation and in 154 women assigned to placebo. Tumor characteristics, frequency of colorectal-cancer screening, and abdominal symptoms were similar in both groups. There were no significant treatment interactions with baseline characteristics. Researchers pointed out that daily supplementation of calcium with vitamin D for seven years had no effect on the incidence of colorectal cancer among postmenopausal wo-men. However, they also said the long latency period associated with the development of colorectal cancer, along with the seven-year duration of the trial, may have contributed to this null finding. Ongoing follow-up will assess the longer-term effect of this intervention.