NEW YORK (Reuters Health) – Patients with colorectal cancer with higher plasma 25-hydroxyvitamin D3 (25(OH)D) levels before their diagnosis appear to have a reduced overall mortality rate, according to researchers.

“Although our findings are premature and require further exploration,” lead investigator Dr. Kimmie Ng told Reuters Health, “they raise the possibility that vitamin D may have treatment benefits for colorectal cancer.”

Dr. Ng of the Dana-Farber Cancer Institute, Boston, and colleagues retrospectively examined data for 304 participants in a large health study. All had been diagnosed with colorectal cancer and had had blood samples taken at least 2 years prior to diagnosis.

Higher 25(OH)D levels were associated with a significant reduction in overall mortality, the researchers report in the June 20th issue of the Journal of Clinical Oncology. Compared with patients with the lowest levels, those with the highest had an adjusted hazard ratio of 0.52 for overall mortality. There was also a trend towards improved colorectal-cancer specific mortality (hazard ratio, 0.61).

Given these findings, Dr. Ng concludes that “vitamin D should be studied further in colorectal cancer, including in the context of a clinical trial.”

J Clin Oncol 2008;26:2984-2991.