[A Case of Pathological Complete Response Induced by Preoperative Gemcitabine plus S-1 with Concurrent Radiation Therapy Followed by Gemcitabine plus S-1 Therapy in Borderline Resectable Pancreatic Cancer].

The patient was a 69-year-old man. He visited our hospital with a complaint of right back pain. An abdominal CT scan confirmed a hypovascular mass 35 mm in diameter in the pancreatic head. He was diagnosed with pancreatic head cancer (cT3, cN0, cM0, cStage ⅡA, borderline resectable-A). Gemcitabine plus S-1(GS)-based chemoradiation therapy(CRT) was performed, followed by 6 courses of GS therapy. Tumor markers were almost normalized, and subtotal stomach-preserving pancreaticoduodenectomy was performed. Histopathological examination of the resected specimen revealed highly atrophic pancreatic tissue with fibrosis and no evidence of residual cancer cells (pathological complete response). The patient remains disease-free 36 months after surgery. There are few reports of pancreatic cancer with pCR after GS-based chemoradiation therapy and subsequent GS therapy. We therefore report this case together with a review of the literature.