Measurement of the Partial Pressure of Oxygen in Cutaneous Tumors Using Electron Paramagnetic Resonance (EPR) Oximetry

All patients in this study will receive standard of care therapy for their cancer at the discretion of their treating physician(s). All subjects will be assigned to one of the four cohorts for which they qualify; there is no randomization and no stratification within the cohorts. Cohort 1 - Patients who will receive definitive surgery for a primary malignancy of the skin Cohort 2 - Patients who will receive definitive radiation (+/- concurrent systemic therapy) for a primary malignancy of the skin Cohort 3 - Patients who will receive palliative radiation (+/- concurrent systemic therapy) for any tumor involving the skin Cohort 4 - Patients who will receive systemic therapy alone (without radiation) for any tumor involving the skin All patients enrolled in this study will undergo two initial measurements of their tumor oxygen level. On the first day, a small metal disc (less than 1 cm in diameter) called a SPOTChip will be placed on the surface of the tumor, and held in place using an adhesive. The patient will then be positioned (lying down or sitting) between a set of two magnets that are used to measure the oxygen level in the tumor. A small plastic oxygen detector will be placed on the skin over the tumor. These devices will be used to take a measurement of the tumor's oxygen level at baseline, then while breathing oxygen through a clear plastic facemask, and then a final time after the oxygen facemask has been removed. After the measurements are taken, a small amount (20-50 microliters) of India ink will be injected into the tumor using a small (28-gauge) needle. The India ink will make a permanent, dark blue/black colored mark on the tumor. The ink leaves a permanent tattoo in the spot where it is injected, unless it is physically removed surgically. The patient will return for another measurement, at least 2 days later. This measurement will use the India ink that was previously injected (described above) and there will no longer be a need to use the SPOTChip. For the India ink tumor oxygen measurement a small piece of wire (called a loop resonator) will be placed over the tumor and held in place using medical honey and saran wrap or tape. The Investigator will first take a measurement of the tumor's oxygen level at baseline, then while breathing oxygen through a clear plastic facemask, and then the mask will be taken the tumor's oxygen level will be measured as it returns to baseline. Patients who have surgical excision of the tumor (cohort 1) will not have any further measurements after this point. Patients who are being treated with radiation therapy (cohorts 2 \& 3), will come back for weekly measurements of the tumor during treatment, followed by one additional measurement one month after they have completed the course of radiation therapy. Patients being treated with chemotherapy, immunotherapy, or other systemic therapies without radiation (cohort 4), will come back for measurements every 3-4 weeks around the time of their regular infusion, followed by one additional measurement one month after they complete the course of systemic therapy.