PLNR≤20% may be a benefit from PORT for patients with IIIA-N2 NSCLC: a large population-based study

Abstract

PurposeOur study was to evaluate the influence of positive lymph nodes ratio (PLNR) on survival for patients with pathological stage IIIA-N2 non-small cell lung cancer (NSCLC) after receiving postoperative radiotherapy (PORT).Patients and methodsThe chi-squared test was used to compare the patient baseline characteristics. Cox proportional hazard model was used to analyze the influence of different variables on overall survival (OS). X-tile model was applied to determine the cutoff values of PLNR. Kaplan–Meier method and log-rank test were used to compare survival differences. Based on different cutoff values of PLNR, Cox proportional hazard model was also used to analyze the influence factors on OS.ResultsMultivariate Cox regression analysis showed that PLNR (P=0.001) and PORT (HR=1.283; 95% CI 1.154–1.426; P<0.001) were significant independent prognostic factors for OS in patients with resected IIIA-N2 NSCLC. The X-tile model was used to screen three different cutoff values including PLNR≤20%, 20%<PLNR≤40%, PLNR>40%. Based on these different cutoff values, we found that patients with PLNR≤20% receiving PORT have a better OS (P=0.007). Further multivariable analysis showed that PORT is an independent prognostic factor of OS only for patients with PLNR≤20% (HR=1.328; 95% CI 1.139–1.549; P<0.001). Conclusion: PLNR≤20% may be a prognostic factor for patients with IIIA-N2 NSCLC receiving PORT.