Vitamin D levels are a key determinant of the body's response to anti-cancer immunotherapy, especially in patients with advanced skin cancer, a new study suggests.

The findings, published online in the peer-reviewed journal Cancer (CANCER), suggest that for patients with advanced melanoma, it may be important to maintain normal vitamin D levels while receiving immune checkpoint inhibitors, an immunotherapy drug.

Vitamin D has many effects on the body, including regulating the immune system.

To see if vitamin D levels affect the effectiveness of immune checkpoint inhibitors, the team analyzed the blood of 200 patients with advanced melanoma before and every 12 weeks during immunotherapy.

In the group of patients with normal vitamin D levels at baseline or after vitamin D supplementation, 56.0% responded well to immune checkpoint inhibitors, compared with 36.2% in the group of patients with low vitamin D levels who were not supplemented with vitamin D.

Progression-free survival (time from treatment initiation to cancer progression) was 11.25 months and 5.75 months in the two groups, respectively.

"Of course, vitamin D is not an anti-cancer drug per se, but its normal serum levels are necessary for the normal functioning of the immune system, including the response produced by anti-cancer drugs such as immune checkpoint inhibitors," said lead author Lukasz Grus from the Medical University of Poznań, Poland.

In our opinion, the assessment of vitamin D levels and its supplementation could be considered for the treatment of melanoma after proper random confirmation of our results.

Melanoma is a disease in which malignant (cancerous) cells form in melanocytes (cells that give color to the skin). Melanoma can occur anywhere on the skin. Unusual moles, sun exposure and health history can all affect the risk of developing melanoma.

A study published in the Journal of Clinical Oncology in 2011 found that people with higher levels of vitamin D in their blood were less likely to develop melanoma. However, it's important to note that these studies don't prove that vitamin D supplementation directly prevents melanoma, and more research is needed to confirm these findings. Additionally, excessive sun exposure, particularly during childhood, is a known risk factor for melanoma, so it's important to practice sun safety measures like wearing protective clothing, seeking shade, and using sunscreen.