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.