Prognostic significance of pathologic nodal status in patients with resected pancreatic cancer

Background The purpose of this study was to evaluate the significance of pathologic nodal assessment and extent of nodal metastases on patient outcome in patients with pancreatic adenocarcinoma. Materials and Methods A prospectively maintained pancreatic cancer database was reviewed, and 696 consecutive patients were identified who underwent resection for pancreatic adenocarcinoma between 1995 and 2005. Overall survival was compared to lymph node (LN) status, absolute number of pathologically assessed LN, and LN ratio expressed as the number of positive LN to the total LN assessed. Results Of the 696 patients, 598 (86%) had pancreaticoduodenectomy (PD), and 96 (14%) had distal pancreatectomy (DP). For all patients, median follow-up was 13 months (range, 0-122 months), and estimated 5-year survival was 16%. A total of 243 (35%) patients were LN-negative (N0) and had a median survival of 27 months. When assessed as a continuous variable, the number of pathologically assessed LN did not correlate with survival for N0 patients undergoing either PD or DP. The median survival for the 453 patients with node-positive (N1) disease was 16 months. When analyzed as a continuous variable, the absolute number of positive LNs was a significant predictor of survival for N1 patients with a linear relationship up to eight positive LNs. LN ratio, as a continuous variable, also predicted survival with a linear relationship up to a ratio of 0.35. A ratio of 0.18 was associated with a 19-month median survival and served as the best cutoff, p < 0.01. Conclusions The absolute number of positive LNs and LN ratio are strong predictors of survival for patients with node-positive pancreatic adenocarcinoma. Inadequate surgical lymphadenectomy or pathologic LN assessment understages node-negative patients.