Significance of Aggressive Surgery for an Invasive Carcinoma Derived from an Intraductal Papillary Mucinous Neoplasm Diagnosed Preoperatively as Borderline Resectable

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Purpose: We investigated the clinicopathological features of borderline resectable invasive carcinomas (BRICs) derived from intraductal papillary mucinous neoplasms (IPMNs) and examined the significance of the aggressive "surgery first" approach compared with the treatment of conventional borderline resectable pancreatic ductal adenocarcinomas (BRPDAs).
Patients and Methods: We retrospectively studied 7 patients with BRICs derived from IPMNs and 14 patients with conventional BRPDAs. Several factors were reviewed: initial symptoms, preoperative imaging, serum level of CA19-9, perioperative factors, pathological findings, adjuvant chemotherapy, and outcome.
Results: All BRICs derived from IPMN were huge tumors (more than 3 cm in diameter) suspected to involve <180° of the circumference of the vessel. Five patients (71%) underwent a modified Whipple procedure, and 2 (29%) underwent distal pancreatectomy. Only 3 patients (43%) required vascular resection. Curative resection was achieved in all 7 patients, who are alive with no evidence of recurrence. There were no severe postoperative complications. With regards to the pathological IPMN subtype, 2 tumors (29%) were gastric and 5 (71%) were intestinal. Only 2 patients (29%) had lymph node metastasis. The final stage was II in 4 (57%) cases and IVa in 3 cases (43%). The 3-year survival rate was 100%. Tumors of BRICs derived from IPMNs were larger than those of conventional BRPDAs (p<0.05). The BRICs derived from IPMN less frequently metastasized to lymph nodes (p<0.05) and were of an earlier stage (p<0.05) than were conventional BRPDAs. The 3-year survival rate was significantly higher for BRICs derived from IPMNs (100%) than for conventional BRPDAs (19%, p<0.001).
Conclusion: The BRICs derived from an intestinal or gastric IPMN are less aggressive than conventional BRPDAs and have a more favorable prognosis. In addition, aggressive "surgery first" approach may contribute to this better prognosis.