Results from the SUNSHINE trial by researchers at the Dana-Farber Cancer Institute suggest that supplementing chemotherapy treatments with high doses of vitamin D may help delay the progression of metastatic colorectal cancer. The study’s initial findings were reported at the 2017 American Society of Clinical Oncology meeting and have since been published in JAMA. A larger trial at hundreds of sites across the United States is set to begin later this year.
The SUNSHINE trial tested the effects of different doses of vitamin D in 139 patients being treated with chemotherapy for colorectal cancer. One group of patients received 4,000 IU of vitamin D per day and the other group received 400 IU of vitamin D per day. The high-dose group had a median delay of 13 months before their disease progressed, and the low-dose group had a median delay of 11 months. Patients in the high-dose group were also 36% less likely to have disease progression or death during the follow up period of 22.9 months.
“The results of our trial suggest an improved outcome for patients who received vitamin D supplementation, and we look forward to launching a larger trial to confirm these exciting and provocative findings,” said Charles Fuchs, MD, MPH, formerly of Dana-Farber as senior author of the study and now Director of the Yale Cancer Center.
Vitamin D is necessary for bone health and is made by the body through a chemical reaction that depends on sun exposure and is also found in some foods. Laboratory studies have shown vitamin D to have anti-cancer properties, including triggering programmed cell death, inhibiting cancer cell growth and reducing metastatic potential.
Further analysis of the results found that the of high-doses of vitamin D were less beneficial to patients who were overweight or whose tumors contained a mutated KRAS gene. These findings suggest “that certain subsets of patients may need even higher doses of vitamin D for anti-tumor activity,” according to researchers.
Kimmie Ng, corresponding author of the SUNSHINE study, feels that the findings are important because “it identifies a cost-effective, safe, and easily accessible agent as a potential new treatment for metastatic colorectal cancer. This could therefore potentially have a large and wide-reaching impact globally, regardless of a patient’s socioeconomic status or a country’s resources.”