Sufficient vitamin D levels may increase survival in patients with cancer

According to a new review from China, cancer patients who have high blood vitamin D concentrations when they are diagnosed tend to have better survival rates and remain in remission longer.

The meta-analysis evaluated the results of 25 studies that measured blood vitamin D levels of a total of 17,332 cancer patients at or near the time of diagnosis and measured survival rates (1). The data analysis found a 10 nmol/L increase in vitamin D levels was tied to a 4% increase in survival of the patients. The strongest link was found between vitamin D levels and survival in breast cancer, lymphoma and colorectal cancer. There was also a positive (but less strong) effect of vitamin D in participants with lung cancer, gastric cancer, prostate cancer, leukemia, melanoma or Merkel cell carcinoma.

The researchers commented that, as vitamin D levels may affect the prognosis of cancer patients, physicians need to pay close attention to vitamin D status in people who have been diagnosed with cancer. They said that as vitamin D deficiency is a widespread issue all over the world, it is important to ensure that everyone has sufficient levels of this nutrient. Several epidemiological studies have associated higher vitamin D levels (above 75 nmol/L) with significantly reduced mortality in patients with cancer (2, 3). Randomized controlled trials are needed to evaluate whether vitamin D supplementation can improve survival in cancer patients with low vitamin D status (below 50 nmol/L) at diagnosis and before treatment. Experimental studies have shown that 1,25-dihydroxyvitamin D, the bioactive form of vitamin D, may inhibit cancer cell proliferation and angiogenesis, and induce cancer cell maturation and apoptosis (4).

1. Li M. et al. Review: The Impacts of Circulating 25-Hydroxyvitamin D Levels on Cancer Patient Outcomes: A Systematic Review and Meta-Analysis. The Journal of Clinical Endocrinology & Metabolism. Published online April 2014.
   
2. Maalmi H. et al. Serum 25-hydroxyvitamin D levels and survival in colorectal and breast cancer patients: Systematic review and meta-analysis of prospective cohort studies. Eur J Cancer. 2014; 50(8):1510–1521.
   
3. Yin L. et al. Circulating 25-hydroxyvitamin D serum concentration and total cancer incidence and mortality: a systematic review and meta-analysis. Prev Med. 2013; 57:753–764.
   
4. Chiang K. C. and Chen T. C. The anti-cancer actions of vitamin D. Anticancer Agents Med Chem. 2013; 13:126–139.