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

This research study is for people who have been diagnosed with a nonmelanoma skin cancer (either basal cell carcinoma or squamous cell carcinoma) and are planning to receive either Mohs surgery or ED\&C (electrodessication \& curettage) as part of clinical care. The purpose of this study is to understand how photodynamic therapy (PDT) with or without Vitamin D can promote an immune response to skin cancer.

For this study, participants will be randomized (randomly assigned) and asked to take Vitamin D or placebo for 6 days and come to the clinic for a single PDT treatment 1-14 days prior to their surgery. At this visit, photographs of participant's skin cancer will be taken, and participants will undergo PDT treatment. The study team will also take photos on the day of Mohs surgery or ED\&C. There will be up to two blood draws for research.

If participants do not want to come in for a PDT treatment prior to their Mohs surgery or ED\&C, they will have the option to participate by only allowing the study team to collect data about their skin cancer and their tissue from Mohs surgery or ED\&C.