How many number of retrieved lymph nodes is required for accurate N-staging in resected pancreatic cancer?

Introduction: Although N stage is important factor in survival of resected pancreatic cancer, appropriate number of retrieved lymph nodes for accurate staging is still controversial. Methods: From 1993 to 2019, 446 patients underwent pancreatectomy for pancreatic cancer were included. The binomial probability law was applied to define the minimum number of examined LNs (minELN). The prognostic factors for overall survival were analyzed. Results: According to binomial probability law, 12 and 20 retrieved lymph nodes were found to be required accurate staging for pancreatic cancer. With node-positive disease, the median OS of patients with less than 12 ELNs was not significantly different to those with 12 or more ELNs (20 v. 18 months, p = 0.326). However, N stage determination (N1 v. N2) was accurate in stratifying oncologic outcomes even when finding fewer than 12 ELNs (26 v. 19 months, p = 0.04) and more than 12 ELNs (22 v. 18 months, p = 0.01). On the other hand, with node-positive disease, the median OS of patients with less than 20 ELNs was not significantly different to those with 20 or more ELNs (20 v. 20 months, p = 0.78). However, N stage determination (N1 v. N2) was accurate in stratifying oncologic outcomes in fewer than 20 ELNs (23 v. 17 months, p = 0.015), but SHOWED no significant IN MORE THAN 20 ELNs (22 v. 18 months, p = 0.07). Conclusions: AJCC (8TH) N-staging system in independent prognostic factor for long-term survival of resected pancreatic cancer.Retrieving 12 lymph nodes are appropriate for Nodal staging PDAC by using AJCC (8th) N stage.