Survival comparison of right and left side non-small cell lung cancer in stage I–IIIA patients: A Surveillance Epidemiology and End Results (SEER) analysis

Abstract

Background: Primary tumors located in the right and left side have distinctive prognoses, but the details have not been fully identified in non-small cell lung cancer (NSCLC). This study investigated the impact of primary tumor side on long-term survival in NSCLC patients. Methods: Data of 90 407 patients from the Surveillance, Epidemiology, and End Results (SEER) Program were analyzed. To avoid bias between groups, we used innovative propensity score matching (PSM) analysis. Results: There was no significant distinction in overall survival (OS) between right (n = 53 496) and left (n = 36 911) side tumors (hazard ratio [HR] 0.993, 95% confidence interval [CI] 0.9756–1.011; P = 0.432). Left side was associated with superior five-year cancer-specific survival (CSS) compared to right side NSCLC (HR 0.977, 95% CI 0.9574–0.9969; P = 0.024). No significant difference was observed in OS (P = 0.689) or CSS (P = 0.288) after PSM analysis. In the 51 319 patients who underwent surgery, left side (n = 21 245) was associated with poor OS compared to right side (n = 30 074) NSCLC (HR 1.039, 95% CI 1.011–1.067; P = 0.006), while CSS was similar (HR 1.031, 95% CI 0.997–1.065; P = 0.069). In patients who underwent surgery, there was also no significant difference in OS (P = 0.986) or CSS (P = 0.979) after PSM analysis. Conclusion: The prognosis between right and left side NSCLC in stage I–IIIA was similar regardless of whether patients underwent surgery. Primary tumor side cannot be considered a prognostic factor when choosing appropriate treatment.