[Recurrent Postoperative Lung Cancer with Tumor Shrinkage after Discontinuation of Pembrolizumab-A Case Report].

Our patient was a 41-year-old man with non-small cell lung cancer of grade cT3N2M0 and clinical Stage ⅢA. After induction chemoradiotherapy(weekly CBDCA plus PTX[5 courses]and concurrent radiation of 50 Gy, left upper lobectomy with lymph node dissection(ND2a-1)was performed. The postoperative pathological findings were large cell carcinoma, ypT2aN2M0, Stage ⅢA, with complete resection; the PD-L1 tumor proportion score was 50 to 74%. Consolidation chemotherapy( triweekly CBDCA plus PTX, 1 course)followed. Twelve months after surgery, he developed mediastinal lymph node recurrence(#4L), and pembrolizumab was administered every 3 weeks as a first-line treatment. Complete response was evident after 3 courses; thus, we continued this monotherapy. After 35 courses(24 months)of pembrolizumab, we discontinued the regimen. Twenty-two months later, the disease has not progressed. The patient is being followed-up in our outpatient department. We report a case of recurrent postoperative lung cancer with continuous tumor shrinkage after discontinuation of pembrolizumab.