Realignment of NSCLC staging from 8 to 9 TNM edition: Impact on survival in Stage IIA to IIIB disease

PurposeThe ninth edition TNM staging of non-small-cell lung cancer (NSCLC) was introduced in 2023 with changes that may impact neoadjuvant and adjuvant chemotherapy use. This study evaluates the changes to overall survival (OS) and disease-free survival (DFS) prognosis in our mixed Asian population with this realignment.MethodsWe reviewed 634 lung cancer patients who underwent lung resection between 1 January 2015 and 30 June 2023. About 152 stage IIA to IIIB NSCLC patients were included, further stratified according to TNM subgroups and adjuvant chemotherapy uptake for survival analysis.ResultsStage IIB patients derived OS benefit with adjuvant chemotherapy use, which was not observed in Stage IIA patients. Among the subgroups comprising Stage IIB (eighth edition), T3N0 patients observed a significant prognostic OS benefit from adjuvant chemotherapy, but not in downstaged T1N1 patients (Stage IIA, ninth edition). In patients who did not receive neoadjuvant chemotherapy prior to surgery, OS and DFS in downstaged T1N2a disease were not significantly worse compared to Stage IIB patients (eighth edition), while T2N2a patients (Stage IIIA, eighth and ninth edition) had significantly lower DFS prognosis.ConclusionOur study ascertained the impact of the ninth edition NSCLC TNM staging on current clinical practice. Upfront resection can be considered in T1N2a disease, in concordance with its downstaging to Stage IIB. Adjuvant chemotherapy use in Stage IIA patients and N1 disease can be further evaluated in the ninth edition. In the future, we expect there to be more evidence for further validation of the new staging system.