Successful Conversion Surgery for Locally Advanced Unresectable Anaplastic Pancreatic Carcinoma after Neoadjuvant S-1-Based Chemoradiotherapy

Anaplastic pancreatic cancer is a very rare type of invasive ductal carcinoma with poor prognosis. This is the first report on a successful curative conversion surgery for anaplastic pancreatic cancer after neoadjuvant chemoradiotherapy. The patient had a locally advanced unresectable pancreatic cancer which involved the celiac axis and the left side of the hepatoduodenal ligament. An endoscopic ultrasonography-guided needle biopsy of the tumor revealed anaplastic carcinoma. He underwent neoadjuvant S-1-based chemoradiotherapy, and subsequently the tumor reduced in size after completion of chemoradiotherapy. Aggressive surgery including total pancreatectomy, left hepatectomy and total gastrectomy was performed. Postoperative pathology revealed no residual tumor in resected specimens. After surgery the patient did not receive chemotherapy or radiotherapy. At 1.5 years after diagnosis and 1 year after surgery, the patient was in good health and free from recurrence. S-1-based chemoradiotherapy followed by aggressive conversion surgery is one of the promising treatment options for locally advanced unresectable anaplastic pancreatic cancer.