Vitamin D supplementation improves outcome in men with low-risk prostate cancer
Friday, December 21, 2012. An article published this year in the Journal of Clinical Endocrinology & Metabolism reports the findings of a trial conducted by researchers at the Medical University of South Carolina which revealed a benefit for supplementing with vitamin D among men whose prostate cancer was at low risk of progression into a more aggressive form. Men with low risk prostate cancer frequently receive regular monitoring, as opposed to undergoing surgery or radiation which can cause unwanted effects such as urinary incontinence.
The trial included 48 African-American and Caucasian men with low-risk prostate cancer who received 4,000 international units (IU) vitamin D3 for one year. Prostate biopsies were conducted before and after the treatment period. Nineteen men diagnosed with prostate cancer who underwent biopsies at a similar interval served as controls. Prostate-specific antigen (PSA), 25-hydroxyvitamin D and other factors were measured in treated subjects at the beginning of the trial and every two months through its conclusion.
Supplementation corrected all cases of vitamin D insufficiency of deficiency observed prior to treatment. Fifty-five percent of the vitamin D-treated subjects had fewer cancerous cores in their biopsied tissue or improved Gleason scores (which evaluate the prognosis of cancerous prostate tumors) at the end of the trial. In contrast, progression occurred in 63 percent of the men in the untreated control group. No significant change in PSA levels were noted.
"Increasing numbers of patients diagnosed with low-risk prostate cancer are electing active surveillance due to the relative indolent nature of the disease as well as the risks of side effects from definitive treatment (surgery or radiation therapy)," David T. Marshall and colleagues write. "The combination of active surveillance and vitamin D3 supplementation at 4000 IU/d resulted in a decreased number of positive cores at repeat biopsy in more than half of patients diagnosed with low-risk prostate cancer."
"Our next objective is to conduct a definitive, randomized trial to validate the effectiveness of vitamin D3 supplementation in active surveillance, using an intervention strategy that is extremely cost effective and easy to implement."
The trial's findings were included in a review article by the same authors which appeared online on December 7, 2012 in The Journal of Steroid Biochemistry and Molecular Biology. Bruce W. Hollis and coauthors note that a year of supplementation eliminated differences in circulating vitamin D levels observed between Caucasian and African American participants, and they suggest that vitamin D3 supplementation could reduce prostate cancer-related health disparities.
"Vitamin D3 supplementation may not only provide a significant addition to active surveillance, but also help us avoid the overtreatment of low-risk disease in subjects who respond to an intervention strategy that appears to be safe and is extremely cost-effective," they write. "At the same time, this non-toxic regimen would help us identify those patients (non-responders) who are affected by potentially aggressive disease and should consider definitive treatment."