Vitamin D May Promote Colon Cancer Survival

By Steven Reinberg
HealthDay Reporter
Friday, June 20, 2008; 3:00 AM

Copyright © 2008 ScoutNews, LLC. All rights reserved.

THURSDAY, June 19 (HealthDay News) -- Colon cancer patients with high blood levels of vitamin D boost their survival odds by 48 percent, a new study suggests.

Previous studies have indicated that high levels of vitamin D may reduce the risk of getting colon cancer by 51 percent, although other studies dispute that claim. But until now, no studies have looked at whether vitamin D could improve survival among people who already had the disease.

"Vitamin D has been studied for many years, and there is a lot of data that it could be implicated in cancer pathogenesis," explained lead researcher Dr. Kimmie Ng, from the Dana-Farber Cancer Institute in Boston. "Vitamin D is involved a lot of things that can go wrong in cancer," she noted.

According to Ng, the vitamin may improve survival in colon cancer patients by slowing the growth of tumor cells. It may also be involved in killing cancer cells and inhibiting the growth of blood vessels in tumors.

The report is published in the June 20 edition of the Journal of Clinical Oncology.

In the study, Ng's team collected data on 304 patients diagnosed with colon cancer between 1991 and 2002. These patients participated in either the Nurses Health Study or the Health Professionals Follow-Up Study.

All those in the study had their vitamin D levels measured at least two years before being diagnosed with colon cancer.

The patients' health was tracked until they died, or until 2005, whichever came first. During the follow-up period, 123 patients died, 96 of them from colon or rectal cancer, the researchers report.

The team found that patients with the highest levels of vitamin D were 48 percent less likely to die from colon cancer or any other cause, compared with those with the lowest levels.

For colon cancer alone, those with the highest vitamin D levels were 39 percent less likely to die, compared with those with the lowest levels of vitamin D, Ng's group found.

Ng doesn't yet advocate vitamin D supplements as a means of preventing or treating cancer, however. "Definitive evidence that our results are due to vitamin D would require a randomized clinical trial," Ng said.