Influence of adjuvant chemotherapy on survival for patients with stage IB and IIA non-small cell lung cancer

Background: The role of adjuvant chemotherapy (ACT) for patients with stage IB–IIA non-small cell lung cancer (NSCLC) according to the eighth edition of the AJCC TNM staging system remains controversial. Methods: Data were collected from patients with NSCLC stage IB–IIA according to the eighth edition of the AJCC TNM staging system who underwent surgical resection from 2008 to 2015. The relationship between ACT and overall survival (OS) or disease-free survival (DFS) was analyzed using the Kaplan–Meier method and Cox proportional hazards model. Results: The study included 648 patients with completely resected NSCLC stage IB–IIA; 312 underwent ACT after surgical resection and 336 were placed under observation. After propensity score matching, 247 pairs of patients were matched and the five-year OS was 88.08% and 83.12% (P = 0.13) in ACT and non-ACT settings, respectively. Subgroup analyses demonstrated that ACT treatment was correlated with an improved five-year OS in patients with visceral pleural invasion (VPI) in the 3 < tumor ≤ 4 cm subgroup (93.98% and 68.93%, P < 0.01). Conclusions: ACT was not significantly associated with improved five-year OS in stage IB–IIA NSCLC patients. However, further subgroup analysis showed that patients with VPI in the 3 < tumor ≤ 4 cm (T2aN0M0, stage IB) subgroup might benefit more from ACT. Further studies are required to validate the findings and better systemic strategies need to be developed in these patients. Key points: Significant findings of the study: For patients with stage IB–IIA NSCLC according to the eighth edition of the AJCC TNM staging system, the effect of ACT remains unclear. ACT was not significantly associated with improved five-year OS in stage IB–IIA NSCLC patients. However, it was correlated with better DFS before or after PSM. Patients with VPI in the 3 < tumor ≤ 4 cm subgroup may benefit from ACT. What this study adds: ACT was not significantly associated with improved five-year OS in stage IB–IIA NSCLC patients. However, it was correlated with better DFS before or after PSM. Patients with VPI in the 3 < tumor ≤ 4 cm subgroup may benefit from ACT.