A Case of Locally Advanced, Unresectable Pancreatic Cancer with Superior Mesenteric Artery Invasion Treated with FOLFIRINOX plus Radiation Therapy, followed by Conversion Surgery

We report a case of a woman in her 70s who underwent conversion surgery after FOLFIRINOX, followed by radiation therapy for initially locally advanced unresectable pancreatic cancer. She visited her local doctor with a chief complaint of upper abdominal pain. Contrast-enhanced CT scan of the abdomen revealed an irregular mass invading the superior mesenteric artery, and the first and second jejunal arteries(>180°)in the pancreatic uncinate region. Based on imaging, she was diagnosed as UR-LA(sm), cT4N0M0, cStage Ⅲ pancreatic cancer, and underwent 5 courses of modified FOLFIRINOX. Radiation therapy of 50.4 Gy was added for local control, and CA19-9 decreased from 394.1 U/mL to 10.5 U/mL. The treatment effect was judged as RECIST: partial response. The tumor was considered to be potentially curative, and a subtotal stomach preserving pancreaticoduodenectomy was performed 8 months after the initial treatment. The tumor was found to be 3× 2 mm in size, pStage ⅠA, R0, and the response to preoperative chemotherapy: Evans Grade Ⅲ. The patient is alive at 5 months postoperatively without recurrence.