Prognostic value of the lymph node ratio in surgically treated stage III colorectal cancer patients with high numbers of harvested lymph nodes

Abstract

Background The lymph node ratio (LNR), defined as the number of positive lymph nodes (LN) divided by the total number of harvested LN, has been demonstrated to be an independent factor in the prognosis of surgically treated colorectal cancer (CRC) patients. This study aims to establish the prognostic value of LNR in stage III CRC patients with high numbers of LN removed. Methods Stage III CRC patients who underwent curative resections over an 8-year period were included to the study. Demographics, clinicopathological features, surgical as well as recurrence and survival outcomes were recorded and statistically analyzed. Calculations for LNR were carried out as a function of percentage rates and Cox proportional hazards regression analyses were performed to determine its effect on disease-free and overall survival. Results Among a total of 493 surgically treated CRC cases, 104 patients were included to the study consisting of 68 (65.4%) men and 36 (34.6%) women with a median age of 64 (inter-quartile range: 55-74) years. The mean number of harvested LN was 31.6 +/- 21.0 (range: 12-103). Multivariate Cox regression analyses proved LNR to be a significant factor in both disease-free and overall survival (p = 0.007 and p = 0.003, respectively). Forward elimination analyses showed that a 1% increase in LNR resulted with a 2% increase in both the risks of recurrence and mortality. Conclusions The LNR may be assessed as an adjunct to the current staging systems for the prediction of oncological outcomes and survival of surgically treated stage III CRC patients.