Malignant Melanoma: Vitamin D Status as a Risk and Prognostic Factor - Meta-analyses and Systematic Review

Solar ultraviolet radiation represents the most important environmental risk factor for skin cancer. However, vitamin D synthesis from sun exposure has been reported to exert anti-carcinogenic effects on melanocytes in vitro. This justifies the ongoing debate whether vitamin D status can be considered a risk and prognostic for primary cutaneous malignant melanoma. The aim of this study was to assess the relevance of the vitamin D status for melanoma risk and prognosis.

A systematic review and meta-analyses were conducted using Medline (via PubMed) and ISI (Web of Science).

Nine meta-analyses were conducted to assess the association between vitamin D status and melanoma risk, as well as prognosis (Breslow thickness, mitotic rate, tumor stage, and ulceration status). Patients with melanoma had significantly lower mean 25(OH)D levels compared to healthy controls, and there was a non-significant trend toward an increased melanoma risk in patients with vitamin D deficiency (≤20 vs. >20 ng/ml). Subgroup analyses of Southern European studies showed significant results. Low serum levels were significantly associated with greater Breslow thickness, the presence of mitoses, and ulcerated primary tumors, but not with higher tumor stage. We observed significantly increased risks for thicker tumors, mitotic tumors, and higher tumor stages in vitamin D-deficient patients.

This study demonstrates an association between low vitamin D status and both increased melanoma risk and worsened prognosis, further contributing to the growing body of evidence supporting the tumor-protective role of vitamin D.