[Vitamin D during cancer treatment]

Recent knowledge on vitamin D has shown that its active form not only regulates calcium and phosphate metabolism but also has significant antimitotic and cell differentiation effects. It can inhibit proliferation, angiogenesis and metastatic potential in cancer tissue. Insufficient vitamin D plasma levels are found in 20- 60% of cancer patients at dia-gnosis. By many authors, vitamin D deficiency is associated with higher aggressivity of tumor and shorter survival of patients. Even in the absence of clinical studies showing benefit of supplementation on outcome, clear recommendations are currently available for treatment of vitamin D deficiency. Owing to the high prevalence of vitamin D insufficiency in cancer patients and significant risks of its further decrease after antitumor therapy, it should become standard of care to examine 25- hydroxyvitamin D serum levels and correct vitamin D insufficiency in cancer patients.