Optimal Lymph Node Count for Colorectal Cancer Surgery: A Cohort Study Utilizing Real-World Data

Colorectal cancer is a leading global malignant tumor, and adequate lymph node (LN) examination is essential for its management.

This retrospective study, conducted from January 2018 to December 2023 at the First Medical Center of the Chinese PLA General Hospital, aimed to develop a statistical model for assessing LN count adequacy. To calculate false-negative probabilities, a new statistical model based on the β-binomial distribution and maximum likelihood method in R software was used.

Among 4429 screened colorectal cancer patients, there were 2314 with colon cancer and 2115 with rectal cancer. For colon cancer, the excision of 7 LNs for pT1 and 11 LNs for pT2 was associated with a likelihood of encountering occult positive LNs remained below 5%. For pT3 and pT4, after the removal of 16 LNs and 20 LNs, respectively, the likelihood of overlooking a positive node was below 10%. For rectal cancer, the excision of 7 LNs for pT1 and 12 LNs for pT2 was associated with a likelihood of encountering occult positive LNs remained below 5%. For pT3 and pT4, after removing 15 LNs and 19 LNs, the likelihood of overlooking a positive node was below 10%.

Our study establishes a novel quantitative framework that links LN harvest thresholds to the risk of false-negative metastasis in colorectal cancer, supporting adopting a more personalized approach.