[A case of successful R0 resection after neoadjuvant therapy for locally advanced unresectable pancreatic cancer].

Adjuvant surgery for initially unresectable pancreatic cancer with a favorable response to chemotherapy or chemoradiation therapy often contributes to a better prognosis than non-surgical treatment alone. We encountered a sexagenarian woman with cancer of the pancreatic body involving the celiac trunk, common hepatic artery, and gastroduodenal artery, which are normally indicative of an unresectable tumor. After systemic chemotherapy (gemcitabine plus S-1 following chemoradiation therapy [S-1 plus irradiation, total 56 Gy]), the level of carbohydrate antigen 19-9 (CA19-9) decreased to within the normal range and the radiological findings showed a slight regression of the tumor without evidence of metastases. Ten months after the initial treatment, distal pancreatectomy with celiac axis resection was performed. Histopathologically, the tumor was almost replaced by marked fibrosis, including the nerve plexus around the adjacent arteries. Viable cells were observed in a part of the nerve plexus of the common hepatic artery alone. S-1 was administered after the surgery, and the patient has survived without recurrence for 17 months since the initial therapy. Here, we report a case of successful R0 resection after chemoradiation therapy for locally advanced unresectable pancreatic cancer.