Pancreatic Cancer Frequently Infiltrates the TRIANGLE Compartment: A Surgical Option to Prevent Local Recurrence

Objective: To evaluate the presence of pancreatic cancer cells within the TRIANGLE compartment (area between mesenteric-portal axis, celiac trunk, and superior mesenteric artery) and to determine its potential role for locoregional recurrence. Background: Approximately 30% of patients develop locoregional recurrence after resection of pancreatic ductal adenocarcinoma (PDAC), most of them within the TRIANGLE compartment. The surgical approach to oncologically clean this compartment aims to improve local control by resecting the perineural, lymphatic and soft tissue around and in-between the celiac trunk, superior mesenteric artery, and mesenteric-portal axis, a region not typically addressed in standard pancreatic resections. Methods: Prospective study of patients who underwent a TRIANGLE compartment resection for PDAC between January 2023 and December 2024. Histopathological analyses were performed to assess cancer involvement in lymph nodes, perineural, adipose, and lymphovascular tissue. Cancer-positive (Tr+) and cancer-negative (Tr−) TRIANGLE patients were compared. Results: A total of 131 patients received a resection of the TRIANGLE compartment, 56 (43%) after neoadjuvant chemotherapy. The TRIANGLE compartment contained malignant cells in 41 patients (31%) with different tissue types affected. Stratified by tumor stage, 56% with locally advanced (n = 14/25), 40% with borderline resectable (n = 8/20), and 21% with resectable tumors (n = 15/72) harbored cancer cells within the TRIANGLE compartment. Conclusion: This study is the first to demonstrate that in 1 out of 3 patients with PDAC, the TRIANGLE compartment harbors cancer cells. This might explain the high rates of locoregional recurrence observed after standard pancreatic resection. By incorporating the TRIANGLE compartment into the standard surgical management of PDAC, surgeons might be able to improve local disease control.