Screening and validation of a novel T stage-lymph node ratio classification for operable colon cancer.

Abstract

BackgroundLymph node ratio (LNR) has advantages in predicting prognosis compared with American Joint Committee on Cancer (AJCC) pathological N stage. However, the prognostic value of a novel T stage-lymph node ratio (TLNR) classification for colon cancer combining LNR and pathological primary tumor stage (T stage) is currently unknown.MethodsWe included 62,294 patients with stage I–III colon cancer from the Surveillance, Epidemiology, and End Results Program as a training cohort. External validation was performed in 3,327 additional patients. A novel LNR stage was established and combined with T stage in a novel TLNR classification. Patients with similar survival were grouped according to T and LNR stages, with T1LNR1 as a reference.ResultsWe developed a novel TLNR classification as follows: stages I (T1LNR1-2, T1LNR4), IIA (T1LNR3, T2LNR1-2, T3LNR1), IIB (T1LNR5, T2LNR3-4, T3LNR2, T4aLNR1), IIC (T2LNR5, T3LNR3-4, T4aLNR2, T4bLNR1), IIIA (T3LNR5, T4aLNR3-4, T4bLNR2), IIIB (T4aLNR5, T4bLNR3-4), and IIIC (T4bLNR5). In the training cohort, the novel TLNR classification had better prognostic discrimination (area under receiver operating characteristic curve, 0.621 vs. 0.608, two-sided P<0.001), superior model-fitting ability for predicting overall survival (Akaike information criteria, 561,129 vs. 562,052), and better net benefits compared with the AJCC 8th tumor/node/metastasis classification. Similar results were found in the validation cohort for predicting both overall and disease-free survival.ConclusionsThis novel TLNR classification may provide better prognostic discrimination, model-fitting ability, and net benefits than the AJCC 8th TNM classification, for potentially better stratification of patients with operable stage I–III colon cancer; however, further studies are required to validate the novel TLNR classification.