A case of pathological complete response with liposomal irinotecan + 5-FU/LV for unresectable locally advanced pancreatic cancer

BACKGROUND: Pancreatic cancer has one of the worst prognoses of any all cancers. 5-FU/leucovorin + irinotecan + oxaliplatin (FOLFIRINOX), gemcitabine (GEM) plus nab-paclitaxel regimens have been recognized as global-standard, first-line treatments for patients with advanced pancreatic cancer. The liposomal irinotecan (nal-IRI) + 5-FU/LV regimen is now included in treatment guidelines as a recommended and approved option for use in patients with metastatic pancreatic cancer that has progressed after GEM-based therapy and who have a suitable performance status and comorbidity profile. There is no report that nal-IRI + 5-FU/LV regimen was significantly effective, and we will report it because we experienced this time. CASE PRESENTATION: A 69-year-old man presented with epigastric pain, and a contrast computed tomography (CT) revealed an enhanced mass lesion measuring 33 × 27 mm on the pancreatic body with encasement of the common hepatic artery (CHA) and the splenic vein. An endoscopic ultrasound-guided fine needle aspiration was performed and demonstrated cytology consistent with adenocarcinoma. Therefore, we diagnosed the patient with unresectable locally advanced pancreatic cancer. The patient received the GEM and S-1 regimen; however, the adverse event was relatively severe. Then, 11 cycles of nal-IRI + 5-FU/LV regimen were administered. A CT scan revealed that the tumor had shrunk to 18 × 7 mm in diameter with encasement of the CHA. The encasement of the splenic vein had disappeared, without any distant metastases. From this post-chemotherapy evaluation and intraoperative frozen section of around the celiac artery, gastroduodenal artery and pancreas stump confirmed absence of tumor cells, we performed distal pancreatectomy with celiac axis resection. A histological examination of the surgical specimen revealed no evidence of residual adenocarcinoma, consistent with a pathological complete response to treatment. CONCLUSIONS: We present the first case of a pathological complete response with nal-IRI + 5-FU/LV for unresectable, locally advanced pancreatic cancer. In the future, nal-IRI may become a key drug for pancreatic cancer treatment.