[A Resectable Case of TS-1 Therapy Useful in Distinguishing Primary Lung Cancer from Lung Metastases of Pancreatic Cancer].

We report a case of pneumonectomy followed by radical pancreatectomy after oral administration of TS-1 for pancreatic cancer with complications ofa lung tumor. The patient was a 66-year-old woman. A pancreatic tail tumor and 2 lung nodules were detected on CT scans, and were diagnosed as pancreatic cancer and metastatic lung cancer. During a total of1 1 courses ofTS -1 therapy, the pancreatic tumor tended to contract, but both pulmonary nodules remained unchanged. Due to differences in treatment effect, double cancers of the lung and pancreas were suspected, rather than metastatic lung cancers. We performed a VATS partial resection of the left lower lobe for diagnostic therapy. The pathological diagnosis revealed an inflammatory myofibroblastic tumor and a primary lung cancer. We diagnosed that a radical pancreatectomy was possible and performed distal pancreatectomy. Pathological diagnosis confirmed an invasive pancreatic ductal carcinoma. Oral administration ofTS -1 was performed as adjuvant chemotherapy after surgery. Liver metastasis was observed 10 months after pancreatectomy, and GEM therapy was initiated. Peritoneal dissemination was observed at 2 years following pancreatectomy, and the patient died at 2 years and 9 months. TS-1 therapy for synchronous lung tumors and pancreatic cancer with careful observation allowed for a definitive radical resection. This method was an effective treatment for lung nodules with pancreatic cancer.