Cohort 4 for Skin Cancer

Oxygen has a critical role in the metabolism of tumors and normal tissues and is a key determinant of sensitivity of tissues to ionizing radiation. Knowledge of the relationship between the partial pressure of oxygen (pO2) and radiation sensitivity has been exploited in strategies to enhance oxygenation or to sensitize hypoxic cells to radiation. This study involves taking at least one measurement of the oxygen level in the patient's tumor before, during, and after breathing oxygen through a facemask. The goal of the measurements is to learn more about changes in tumor oxygen levels in response to breathing extra oxygen and standard treatments like chemotherapy and radiation therapy, so that in the future we have a better understanding of how to best use these treatments to improve their ability to fight cancer. By taking measurements of a variety of tumor types undergoing a variety of treatments, we will gain valuable information towards assessing our underlying hypothesis that repeated measurements of tissue oxygen levels can be used to optimize cancer therapy, especially radiation therapy, so that the therapy is applied in a way that maximizes the therapeutic ratio. All patients in this study will receive standard of care therapy for their cancer at the discretion of their treating physician(s).