Clinical significance of para-aortic lymph node metastasis for prognosis in patients with pancreaticobiliary cancer who underwent radical surgical resections.

Objective: To elucidate surgical strategies for patients undergoing radical resection, in cases where solitary distant lymph node metastasis is identified intraoperatively, we investigated the prognostic significance of para-aortic lymph node (PALN) metastases and other regional lymph node (RLN) metastases in pancreatic carcinomas (PC) and biliary duct cancers (BDC). Material and Methods: This study retrospectively analyzed data from 181 PC patients and 116 BDC patients who underwent radical resections at two institutions between 1994 and 2021. Results: Among PC patients, metastases were observed in RLN and PALN in 54% and 9% of cases, respectively. Similarly, RLN and PALN metastases were present among BDC patients in 39% and 9% of cases, respectively. Survival analysis revealed that patients with BDC and PALN metastases exhibited significantly reduced disease-free (DFS) and overall survival (OS) compared to those without PALN involvement. Multivariate analysis identified PALN metastasis as an independent predictor of OS in BDC patients (p<0.05), while RLN metastasis was independently associated with DFS (p<0.05). Additional clinicopathological factors associated with PALN and RLN metastases were also identified. Preoperative serum levels of Duke Pancreas II monoclonal antibody were significantly elevated in patients with PALN metastases. Histological findings of lymphatic or perineural infiltration and hepatic or pancreatic invasion were independently associated with RLN metastases. Conclusion: Based on these findings, radical resection may be considered for PC patients with isolated PALN metastases only in the absence of additional adverse prognostic factors. Prospective clinical trials are warranted to further refine the criteria for surgical intervention when solitary PALN metastases are detected intraoperatively.