Pembrolizumab in Recurrent Squamous Cell Carcinoma of the Vulva: Case Report and Review of the Literature

Advanced vulvar cancer is associated with a very poor prognosis. Surgical resection is the mainstay of treatment, with radiation indicated for areas at high risk for recurrence. When surgical and radiation options have been exhausted, the effectiveness of systemic chemotherapy is poor. No biologic or targeted agents have been approved for the management of advanced or recurrent vulvar cancer. Pembrolizumab, a humanized monoclonal antibody against programmed death 1 (PD-1), has been successfully used as a target of tumor immune therapy in small cell lung cancer and melanoma. We present the first case in the literature of a patient with recurrent vulvar cancer who was treated successfully with pembrolizumab. Caris next-generation testing revealed a PD-L1 and PD-1 mutation (PD-L1 positive, 2+, 100%). She attained a complete clinical remission after 2 cycles, and a CT scan after 6 cycles revealed a significant response by RECIST criteria. After completing 10 cycles, treatment was stopped due to complications of severe malnutrition related to narcotic abuse. A CT scan 10 weeks after the final treatment revealed no adenopathy. Pembrolizumab is a safe and effective chemotherapeutic agent to treat recurrent vulvar carcinoma.