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No difference in GI cancer outcomes with vitamin D supplementation
Key clinical point: Vitamin D supplementation did not improve clinical outcomes in patients with gastrointestinal malignancy, according to results from two randomized clinical trials.
Major finding: The AMATERASU study showed no significant improvement in relapse-free survival (hazard ratio, 0.76; 95% CI, 0.50-1.14; P = .18). The SUNSHINE study showed a nonsignificant rise in median progression-free survival (13 vs. 11 months; P = .07) in patients given high-dose versus standard-dose vitamin D3.
Study details: The SUNSHINE study was a phase 2 randomized clinical trial of 139 patients with advanced or metastatic colorectal cancer. The AMATERASU study was a randomized clinical trial of 417 patients with digestive tract cancers.
Disclosures: The SUNSHINE clinical trial was supported by grant funding from the National Institutes of Health’s National Cancer Institute. Additional funding was provided by the Gloria Spivak Faculty Advancement Award, Friends of Dana-Farber Cancer Institute Award, Project P Fund, Consano, Pharmavite, and Genentech. The AMATERASU clinical trial was supported by funding from the Japan-Supported Program for the Strategic Research Foundation at Private Universities, the International University of Health and Welfare Hospital, and Jikei University. The authors of both studies reported multiple associations with pharmaceutical companies.
Ng K et al. JAMA. 2019 Apr 9. doi: 10.1001/jama.2019.2402; Urashima M et al. JAMA. 2019 Apr 9. doi: 10.1001/jama.2019.2210.
In recent decades, numerous observational studies have shown potential benefit of vitamin D supplementation in patients with various forms of cancer. As a result, several randomized trials are currently underway examining the use of the supplement in patients with colorectal cancer.
The SUNSHINE and AMATERASU randomized clinical trials evaluated the use of vitamin D3 supplementation in patients with advanced or metastatic colorectal cancer and gastrointestinal cancer, respectively. In contrast to observational data, both of these trials failed to show significant improvements in pertinent clinical endpoints, including progression-free and relapse-free survival.
However, many questions remain unanswered because of certain quantitative considerations in the studies, such as sample size and the use of one-sided versus two-sided statistical testing. Other potential contributing factors include patient or tumor parameters that could alter the effects of supplementation.
Another important consideration is that these findings may not reflect the potential benefits of supplementation in other forms of malignancy. Increased levels of vitamin D have been linked with significantly reduced morbidity and mortality among hospitalized patients with certain nonmalignant conditions, in addition to other types of cancer.
Additional confirmatory studies that include longer follow-up periods are needed to better understand these preliminary results.
Elizabeth L. Barry, PhD, and Michael N. Passarelli, PhD, are with the department of epidemiology at the Geisel School of Medicine at Dartmouth, Hanover, N.H. John A. Baron, MD, MS, MSc, is with the department of epidemiology at the University of North Carolina at Chapel Hill. No conflicts of interest were reported. These comments are adapted from her editorial (JAMA. 2019 Apr 9. doi: 10.1001/jama.2019.2589 ).