Their study, presented here at the 96th Annual Meeting of the American Association for Cancer Research, shows that patients with high vitamin D intake who had surgery in months with lots of sun were more than twice as likely to be alive five years after surgery, compared to patients with low vitamin D intake who had wintertime operations.
The mechanism behind the link between vitamin D and surgery outcome is not known, and the study needs to be validated, the researchers say, but they add that a number of other studies have hinted that vitamin D may work to inhibit a variety of different cancers.
"Animal studies have shown that treatment of cancer with vitamin D demonstrates both anti-proliferative and anti-invasive properties, but we don't know if that is true in humans with cancer," says the lead investigator, Wei Zhou, Ph.D., a research scientist at the Harvard School of Public Health. "So the best way we can make some sort of association is to look at differences in what happens after treatment of cancer between patients who use high levels of vitamin D through their diet and supplements, as well as through sunlight exposure, compared to patients who do not.
"This study in no way suggests that people should try to time their cancer surgeries for a particular season - that would obviously be impossible," Zhou adds. "But, if validated, it may mean that increasing a patient's use of vitamin D before such surgery could offer a survival benefit."
The research team, led by Prof. David Christiani, M.D., of Harvard University, included investigators from Massachusetts
Contact: Warren R. Froelich
American Association for Cancer Research