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

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

[METHODS] 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.

[RESULTS] 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%.

[CONCLUSIONS] 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.