Efficacy of adjuvant chemotherapy for completely resected stage IB non-small cell lung cancer: A retrospective study

Background: Lung cancer is being increasingly detected in the early stages, highlighting the importance of lung cancer screening. However, there is no consensus on the post-operative management of stage IB nonsmall cell lung cancer (NSCLC). Therefore, this study aimed to identify the predictive factors for prognosis of stage IB NSCLC and determine the efficacy of adjuvant chemotherapy on recurrence and survival. Methods: We enrolled 89 patients with stage IB NSCLC who underwent complete resection surgery at Gangnam Severance Hospital from Jan 2008 to Dec 2014. As per the National Comprehensive Cancer Network guidelines, patients were considered to be at high risk when they showed poorly differentiated tumors, lymphovascular invasion, tumor size > 4 cm, and visceral pleural invasion (VPI). Results: Among the 89 patients, 27 underwent adjuvant chemotherapy. Young patients or patients with squamous cell lung cancer received adjuvant chemotherapy frequently. Adjuvant chemotherapy was not a significant factor for disease-free survival and overall survival. Adjuvant chemotherapy did not show a significant protective effect for survival, even for high-risk patients. However, VPI was a significant risk factor for disease-free survival [hazard ratio (HR): 7.051; 95% confidence interval (CI): 1.570-31.659; P=0.011] and overall survival (HR: 8.289; 95% CI: 1.036-66.307; P=0.046), even after adjustment for various factors. Conclusions: Adjuvant chemotherapy does not affect the prognosis of stage IB NSCLC, even in high-risk patients. Additionally, VPI is a strong prognostic factor of stage IB NSCLC.