Duration of Anti-Programmed Death-1 Therapy in Advanced Melanoma: How Much of a Good Thing Is Enough?

The Oncology Grand Rounds series is designed to place original reports published in the Journal into clinical context. A case presentation is followed by a description of diagnostic and management challenges, a review of the relevant literature, and a summary of the authors' suggested management approaches. The goal of this series is to help readers better understand how to apply the results of key studies, including those published in Journal of Clinical Oncology, to patients seen in their own clinical practice. A 53-year-old healthy man presented with recurrent in-transit melanoma of the right lower extremity. Eight years prior he had undergone wide local excision and sentinel lymph node biopsy for invasive melanoma of the anteromedial aspect of the distal right thigh. Pathology revealed an ulcerated melanoma, Breslow depth 3.5 mm, and with one involved micrometastatic inguinal lymph node. Staging studies did not demonstrate distant metastases. Superficial inguinal node dissection was performed and did not identify any additional metastatic nodes of 14 retrieved for a final pathologic staging of T3bN1aM0 (stage IIIB) cutaneous melanoma. He received 12 months of adjuvant high-dose interferon alfa-2b. Two years later, he developed a 1.2-cm subcutaneous focus of in-transit recurrence approximately 4 cm proximal to the original melanoma site in the right thigh, which was treated with surgical resection followed by adjuvant radiotherapy. Over the next 4 years, he underwent six additional surgeries for isolated in-transit recurrences affecting the same limb. He was referred for therapeutic options at the time of his latest in-transit recurrence. Examination revealed three palpable subcutaneous nodules in the right thigh in the setting of lymphedema. A core biopsy confirmed recurrent melanoma (Fig 1). Whole-body fluorodeoxyglucose positron emission tomography imaging revealed at least 17 hypermetabolic cutaneous and subcutaneous nodules in the right thigh, four fluorodeoxyglucose-avid nodules below the right knee, but no distant metastases (Fig 2A). Brain magnetic resonance imaging was normal. His serum chemistry profile, including lactate dehydrogenase, was normal. Molecular analysis demonstrated presence of BRAF V600E mutation in the tumor. After multidisciplinary evaluation, an isolated limb infusion procedure of the right lower extremity was not believed to be feasible, secondary to the proximal extent of the recurrence. Therapy was initiated with pembrolizumab at 2 mg/kg intravenously every 3 weeks.