PD1/PD-L1 inhibition as a potential radiosensitizer in head and neck squamous cell carcinoma: a case report

Background: Immunotherapy targeting the checkpoint PD1 (programmed cell death protein 1) or PDL1 (programmed death ligand 1) has led to advances in the treatment of melanoma and non-small cell lung cancer (NSCLC). The use of such therapies has also been introduced into the treatment of other malignancies, including head and neck cancer. The combined effects of checkpoint inhibitors and anti-PD1(L1) antibodies and radiation therapy have not yet been sufficiently investigated. Case presentation: We report a case of locally relapsed non-resectable oral cavity squamous cell carcinoma, with excellent local control after pembrolizumab (MK3475) followed by radiotherapy. Conclusion: T cell activation induced by checkpoint inhibition may dramatically improve tumor response to radiation. More data are needed to identify the toxicity and efficacy of sequential or concurrent checkpoint inhibitors and radiotherapy.