Vitamin D Effects on Immune Microenvironment of Nonmelanoma Skin Cancer After Photodynamic Therapy (PDT)

Description

This research study explores the effect of photodynamic therapy (PDT) on nonmelanoma skin cancers (NMSC). NMSC are made up of basal cell carcinoma (BCC) and squamous cell carcinoma (SCC). PDT is a treatment for NMSC that may be used instead of surgery. PDT uses light and a special chemical reaction to kill cancer cells on the skin’s surface. First, an agent called aminolevulinate (ALA) is put on the skin of the tumor. Then, a bright blue light is shined on the skin, which causes a chemical reaction to occur. This chemical reaction helps to damage and kill cancer cells.

NMSCs are common and can usually be cured with surgery. However, surgery can leave scars or result in disfigurement. This can be especially difficult for people who have tumors on their face or other visible or sensitive parts of the body. As an alternative to surgery, photodynamic therapy (PDT) is approved in Europe to treat BCC and SCC. However, because PDT does not work as well on thicker tumors, the U.S. FDA has not yet approved it for use on NMSC in this country. Investigators want to better understand how PDT damages and kills tumor cells, so that knowledge can be used to make the treatment more effective.

Vitamin D (VitD) is both a nutrient and a steroid-like hormone. Over 10+ years of research in investigators’ laboratory has shown that VitD works well with PDT to treat NMSC. When participants receive a high dose of VitD before PDT, the treatment is able to clear the tumor more effectively. This has been shown in studies with mice that had early skin cancer, as well as mice with thick skin cancer. It has also been shown to be effective in participants with BCC. One reason that VitD may help is because it increases the amount of photosensitizing agent that can accumulate within the tumor, which helps to effectively kill cancer cells with PDT when light is applied. However, VitD has another important effect, which is that it helps to attract immune cells into the tumor. This effect has been seen in mouse models of SCC. The primary purpose of this study is to further investigate this immune mechanism in humans.