It always amazes me when, after a multi-million dollar study, the medical profession “declares an ah-ha moment” about something that alternative doctors have been touting for decades. This study on Vitamin D and cancer is another example. Initial data from the SUNSHINE trial were reported at a prior meeting of the American Society of Clinical Oncology, and the final data are now reported in JAMA.

This large-scale, clinical trial evaluating whether high-dose vitamin D3 supplementation could benefit patients with colorectal cancer (CRC) is being planned on the back of positive final data from a smaller-scale study, which found that high-dose vitamin D3 supplements can help to extend progression-free survival (PFS) in CRC patients undergoing chemotherapy. Newly published results from the Phase II SUNSHINE trial comparing the effects of low-dose and high-dose vitamin D3 showed that higher doses of the vitamin extended CRC PFS from 11 months to 13 months. Patients in the high-dose cohort were also 36% less likely to have disease progression or death during the 22.9 months follow up. The trial wasn’t powered to determine benefits of vitamin supplementation on overall survival.

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“To our knowledge, this study is the first completed randomized clinical trial of vitamin D supplementation for treatment of advanced or metastatic colorectal cancer,” said Kimmie Ng, MD, MPH, director of clinical research at the Dana-Farber Cancer Institute’s Gastrointestinal Cancer Center, and corresponding author. “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,” added Charles Fuchs, MD, MPH, formerly of Dana-Farber, and senior author of the study, who is now director of Yale Cancer Center.

The researchers report the SUNSHINE trial data in a paper titled, “Effect of high-dose vs standard-dose vitamin D3 supplementation on progression-free survival among patients with advanced or metastatic colorectal cancer. The SUNSHINE randomized clinical trial.”

Experimental evidence suggests that vitamin D has anti-neoplastic activity, and observational studies have indicated that high levels of vitamin D can reduce colorectal cancer risk and also improve survival among CRC patients, the authors stated. A prospective analysis of Phase III data from a trial evaluating more than 1000 patients with metastatic CRC enrolled in a Phase III trial evaluating chemotherapy plus biological agents also found that patients with higher blood levels of 25-hydroxyvitamin D—the best indicator of vitamin D status—had much better overall survival and PFS. “However, observational studies are not able to discern whether higher 25-hydroxyvitamin D levels play a causal role in improving survival, are simply a surrogate of better health, or a reflection of more favorable disease,” the researchers pointed out.

In a separate paper published in the same issue of JAMA (“Effects of vitamin D supplementation on relapse-free survival among patients with digestive tract cancers”), a research team headed by scientists at the Jikei University School of Japan, reported results from the AMATERASU trial, which found no benefit of postoperative vitamin D3 supplementation on the relapse-free survival of 417 patients with digestive tract cancers.

We have always recommended our cancer patients to try to keep their blood Vitamin D levels between 50-150 and to take a Vitamin D3 along with the other fat soluble vitamins (A, D, and K as MK7). See HERE for a product we use with 5000iu Vitamin D along with these other nutrients. Taking 1-2 capsules per day is usually adequate.