The prognostic value of different lymph node classification systems in stage III colorectal cancer patients

Abstract

AIM: Prognostic significance assessment of different lymph node classification systems in stage III colorectal cancer patients.

MATERIAL AND METHODS: A total of 85 stage III colorectal cancer patients, who had undergone surgery between January 2013 and December 2018, were divided into 3 different groups comprising of lymph node ratios (LNR) and log odds of positive lymph nodes (LODDS) as per the cutoff values of 25 and 75 percentile threshold values. They were accordingly classified as: LNR1 <0.069, LNR2 0.069-0.24, LNR3 >0.24 and LODDS1 <-0.99; -0.99≥ LODDS2 <-0.47; LODDS3 ≥-0.47. Further the LNR was assessed according to the cutoff values proposed by Berger et al The pN statuses of all patients were also categorized as pN1 and pN2 in line with the AJCC 8th Edition. The Kaplan-Meier test and Cox regression analysis were performed to analyze the relationship among the LNR, LODDS, pN and overall survival.

RESULTS: While 55 patients included in the study had tumors in their colons, the localization of the tumors of 30 patients was the rectum. The means for survival time was 63.3 months +/- 3.6 [95% CI(56.2-70.4)]. When univariate analyses were conducted for the factors affecting 3 and 5-year survival of the patients, it was ascertained that there was a significant relationship only between perineural invasion (PNI) and survival. Accordingly, the 3-year survival of those with PNI was found to be 31.4% in comparison to 56% of those without PNI (p=0.025), while the figure was 5.7% for the 5-year survival of the former group and 22% for the latter (p=0.040). When the relation between the survival time of the patients and the LNR classification conducted according to the staging system developed by Berger et al was studied, no significant relationship could be found (p>0.05). Similarly, and 0.321 respectively.

CONCLUSION: Although numerous studies have shown that there was a significant relationship between high LNR and increased survival, as opposed to the results of our study, the greatest obstacle before LNR’s survival prediction is the absence of a consensus for standard cutoff values.