Newly diagnosed metastatic colorectal cancer patients with higher vitamin D levels had better outcomes after treatment with a combination of chemotherapy and targeted therapy. The results of this phase III trial were presented at the American Society of Clinical Oncology (ASCO) 2015 Gastrointestinal Cancers Symposium
While it is too early for clinicians to recommend vitamin D as a therapy for colon cancer, maintaining recommended vitamin D levels in general has been shown to benefit overall health.
“Metastatic colorectal cancer patients are frequently deficient in vitamin D. In this study, higher levels of vitamin D in the plasma are associated with both a higher overall survival and progression-free survival,” said lead study author Kimmie Ng, MD, MPH, assistant professor of medicine at Dana-Farber Cancer Institute, at a press conference.
Both epidemiologic and preclinical studies have shown that vitamin D has antitumor activity. Vitamin D has been shown to inhibit cell proliferation and angiogenesis, to induce cell differentiation and apoptosis. Vitamin D also has anti-inflammatory effects. Given to mouse models of colorectal cancer, vitamin D has been shown to result in a lower tumor burden. Additionally, higher vitamin D blood levels are linked to a decreased risk of colorectal cancer as well as improved survival for those diagnosed with the disease.
This is of great interest to patients with colorectal cancer who frequently want to know if there is anything that they can do to better their prognosis, said Smitha S. Krishnamurthi, MD, moderator of the press conference. The work suggests that high vitamin D levels may lead to a slower growing tumor or may enhance the effects of chemotherapy. Still, Krishnamurthi cautioned that these hypotheses need to be formally tested in clinical trials. In the meantime, patients should have their vitamin D levels checked, said Krishnamurthi.