Impact of pathological stage and histological subtype on clinical outcome of adjuvant chemotherapy of paclitaxel plus carboplatin versus oral uracil–tegafur for non-small cell lung cancer: subanalysis of SLCG0401 trial

Background: Pathological stage (pStage) and histological subtype are strong determinants of the treatment strategy for non-small cell lung cancer (NSCLC). Setouchi Lung Cancer study Group (SLCG) recently reported the results of a multicenter trial (SLCG0401) indicating that paclitaxel plus carboplatin (CBDCA/PTX) as adjuvant chemotherapy does not yield better survival than uracil–tegafur (UFT) in NSCLC patients with pStage IB–IIIA disease, while stratified analyses considering the pStage and histological subtype have not been performed. Methods: We reanalyzed the overall survival (OS) and relapse-free survival (RFS) in 402 patients who had been randomly assigned to receive CBDCA/PTX or UFT by multivariate analysis with adjustments for the pStage and histological subtype. Results: There were no significant differences in the OS or RFS between the two treatment settings either in the entire cohort (n = 402) and in some of subsets: pStage IB (n = 228), pStage II (n = 117), adenocarcinoma (AD, n = 265), and squamous cell carcinoma (SQ, n = 101). In pStage IIIA patients (n = 57), CBDCA/PTX yielded superior RFS to UFT [hazard ratio (HR) 0.44; P = 0.016]. Among the patients with non-AD and non-SQ histology (n = 36), UFT yielded both superior OS and RFS to CBDCA/PTX (HRs 0.16 and 0.23; P = 0.046 and 0.011, respectively). Conclusions: There are subsets of patients in which one or the other between UFT and CBDCA/PTX is significantly more effective. Selection of adjuvant therapy for NSCLC patients needs to be made taking into consideration the pStage and histological subtype.