Abstract:

Objective

To estimate the impact of adjuvant chemotherapy on survival in T2bN0M0 nonsmall cell lung cancer（NSCLC）patients.

Methods

The clinicopathological data of patients with stage T2bN0M0 NSCLC who underwent lobectomy and mediastinal lymph node dissection between 2010 and 2015 were retrospectively analyzed in the Surveillance，Epidemiology，and End Results（SEER）database.The risk factors were identified by Cox regression.Propensity score matching（PSM）analysis and Kaplan-Meier curves were used to compare the cancerspecific survival（CSS）and overall survival（OS）of T2bN0M0 NSCLC patients between the non-adjuvant chemotherapy and adjuvant chemotherapy groups.

Results

A total of 538 patients with completely resected stage T2bN0M0 NSCLC were enrolled in this study，including 285 males and 253 females，with a median age of 69（62-75）years.Patients with younger，grade III-IV were more likely to receive chemotherapy（P＜0.05）.In Cox regression，adjuvant chemotherapy was significantly associated with OS in completely resected stage T2N0M0 NSCLC（hazard ratio =0.52，95% confidence interval 0.36-0.74，P＜0.05）.In the total population，patients treated with adjuvant chemotherapy had a better OS than those not treated with adjuvant chemotherapy before and after PSM（P＜0.05）.In addition，adjuvant chemotherapy can bring a survival benefit for patients ＜70 years old，but does not improve OS for patients≥70 years old.Similarly，for poor-to-undifferentiated patients，adjuvant chemotherapy can improve the OS of patients，but for moderate-to-well differentiated patients，adjuvant chemotherapy cannot bring survival benefit.

Conclusion

Adjuvant chemotherapy contribute to a survival benefit in completely resected stage T2bN0M0 NSCLC patients，especially in patients ＜70 years and poor-to-undifferentiated NSCLC patients.Adjuvant chemotherapy should be considered in completely resected stage T2bN0M0 NSCLC patients.

Key words: Non-small cell lung cancer, Adjuvant chemotherapy, Overall survival, Tumor diameter, Propensity score matching