Conditional survival rate estimates of lobectomy, segmentectomy and wedge resection for stage IA1 non-small cell lung cancer: A population-based study.

Conditional survival rate (CSR) is defined as the dynamic possibility of survival, considering the changes in the survival risk over time. The present study aimed to compare the CSR of the surgical procedures for stage IA1 non-small cell lung cancer (NSCLC). Overall, data for 2,535 patients with stage IA1 NSCLC after lobectomy, segmentectomy or wedge resection were obtained from the Surveillance, Epidemiology and End Results database, and the overall survival (OS) rates were subsequently compared. CSR estimates, the possibility of patients who had already survived × years, to survive further y years, was calculated as CSR=S(x+y)/S(x), where S is the survival rate at a particular point in time. A Cox regression model and propensity-score matching were used to adjust confounding factors. There were no statistical differences in the OS among the three surgical procedures, except that OS of patients who underwent a lobectomy was improved compared with the wedge resection. The CSR of surviving to the 5th year after operation improved gradually over time. The 3-year CSR of lobectomy or segmentectomy was higher compared with that of the wedge resection. Moreover, the 3-year CSR of segmentectomy was higher compared with that of lobectomy from the 3rd year after surgery, particularly in some specific situations, such as female sex, patients ≥66 years old, patients with squamous cell carcinoma or patients with poor tumor differentiation. The present study is the first report to compare CSR following lobectomy, segmentectomy and wedge resection for patients with stage IA1 NSCLC, to the best of our knowledge. These findings indicated that lobectomy is the most conservative surgical procedure for stage IA1 NSCLC and raises questions regarding improved long-term prognosis of segmentectomy in some subsets of patients.