Radiation + Pembrolizumab for Oral Cancer

This phase II trial compares the effect of adding proton spatially fractionated radiotherapy (SFRT) or photon stereotactic body radiotherapy (SBRT) to standard immunotherapy pembrolizumab before surgery (neoadjuvant) in treating patients with oral cavity squamous cell cancer that has spread to nearby tissue or lymph nodes (locally advanced) or that has come back where it first started (primary site) or near it (locoregionally recurrent) and have not had (naive) prior radiation. Radiation therapy uses high energy x-rays, particles, or radioactive seeds to kill tumor cells and shrink tumors. Proton SFRT is a type of external beam radiation treatment that uses streams of protons (tiny particles with a positive charge) to deliver different doses of radiation to different parts of the tumor in a grid like pattern. This type of radiation kills tumor cells but does not damage nearby tissues. SBRT is a type of external radiation therapy that uses special equipment to position a patient and precisely deliver radiation to tumors in the body (except the brain). The total dose of radiation is divided into smaller doses given over several days. This type of radiation therapy helps spare normal tissue. Immunotherapy with monoclonal antibodies, such as pembrolizumab, may help the body's immune system attack the tumor, and may interfere with the ability of tumor cells to grow and spread. Giving neoadjuvant proton SFRT or SBRT in combination with pembrolizumab may be safe and tolerable and may be an effective approach to shrink the tumor, reduce the extent of surgery and/or the need for further treatment in patients with locally advanced or locoregionally recurrent oral cavity squamous cell cancer.