Optimal Number of Lymph Nodes Retrieved to Lower the Risk of False N0 for Patients with Pancreatic Cancer Undergoing Curative Surgery.

BACKGROUND

Accurate LN examination is critical for staging and prognosis in pancreatic cancer. However, the ideal number of LNs required for precise staging and improved survival remains unclear. This study aimed to determine the optimal number of lymph nodes (LNs) to retrieve during pancreatectomy for pancreatic cancer to minimize false node-negative (false N0) rates and assess its impact on survival outcomes.

METHODS

This retrospective cohort study analyzed data from patients undergoing curative-intent upfront surgery for pancreatic cancer at two tertiary centers in South Korea (2010-2021). An exploration cohort of 808 patients was used to identify LN retrieval thresholds, and the results were validated in an independent cohort of 444 patients. The study excluded patients who received neoadjuvant therapy or had fewer than two retrieved LNs. False N0 rates and 5 year overall survival were analyzed.

RESULTS

In the exploration cohort, examining 16 LNs reduced the false N0 rate to 18.9%, whereas in the validation cohort, retrieving 12 LNs resulted in a false N0 rate of 19.5%. Among the node-negative (N0) patients, retrieving up to 21 LNs was associated with improved 5 year overall survival. Differences in cutoff values between cohorts were attributed to demographic variations and inclusion of fewer LNs retrieved but higher detection of metastatic nodes in the validation cohort.

CONCLUSIONS

Retrieving a sufficient number of LNs during pancreatectomy is essential to reducing false N0 rates and improving survival outcomes for pancreatic cancer patients. These findings highlight the need for standardized LN evaluation protocols and support further prospective, multi-center studies to optimize staging accuracy.