Neutron Radiation Therapy for Treatment of Refractory Merkel Cell Carcinoma.

We describe the first reported use of neutron radiation therapy for successful palliation of treatment refractory Merkel cell carcinoma. The patient was a 78-year-old man with Merkel cell carcinoma involving the scalp and bilateral cervical lymph nodes. The extensive coalescing scalp lesions were locally destructive, painful, and highly detrimental to his overall quality of life, and he had previously progressed through 3 courses of conventional x-ray-based radiation therapy and multiple immunotherapy regimens. We treated him with neutron radiation therapy, and he experienced a complete and durable local response with minimal toxicity. High linear energy transfer particle therapy approaches deserve consideration as a treatment option in cancers that are refractory to standard radiation therapy.