The initial 6 patients will have the OxyChip placed for a short duration (up to 4 weeks) after which the OxyChip will be removed when the tumor mass is resected, prior to delivery of any further therapies. After the successful implantation, removal, and evaluation of the OxyChip in the first 6 Phase IA patients, enrollment will be opened to an additional 24 Phase IA patients and to 6 Phase IB patients who will either receive neoadjuvant radiotherapy or systemic therapy (chemotherapy, biologic therapy, or endocrine therapy) while the OxyChip is in place. After the successful implantation, removal, and evaluation of the OxyChip in the first 3 Phase IB patients receiving radiation therapy or systemic therapy, enrollment will be opened to an additional 24 Phase IB patients. Up to five oxygen measurements per week will be made during the course of radiation or systemic therapy. The OxyChips will be removed at surgery. Patients receiving radiation or systemic therapy will be evaluated at least weekly for assessment with respect to any adverse events for the primary objective and oximetry measurements will be taken periodically at least one day after implantation and up to its removal at the planned tumor excision to assess the secondary objective. Following resection, the tissue surrounding the OxyChip will be examined for any adverse events for the primary objective. For the exploratory objectives, the tissue will also be examined for biomarkers associated with hypoxia or growth.