Overall Survival Following Salvage Thoracic Radiotherapy for Locoregional Recurrence in Patients with Completely Resected PIIIA-N2 NSCLC

Abstract

Locoregional recurrence is a common failure pattern for patients with completely resected pIIIA-N2 NSCLC. The salvage thoracic radiotherapy is administered in some pIIIA-N2 NSCLC patients despite postoperative radiotherapy (PORT). Salvage thoracic radiotherapy could be well tolerated and might improve survival from several small sample retrospective studies, while the high-level clinical evidence is presently lacking. We conducted this retrospective case control study to demonstrate the efficacy of salvage thoracic radiotherapy for completely resected pIIIA-N2 NSCLC patients with locoregional recurrence. Between January 2003 and June 2019, patients who had undergone lobectomy or pneumonectomy plus mediastinal lymph node dissection or systematic sampling in our single institution were retrospectively reviewed. Those with pⅢA-N2 NSCLC that did not receive PORT and suffered locoregional recurrence being the first treatment failure were enrolled. The log-rank test was used to analyze differences between the groups, and the Kaplan-Meier method was used for survival analysis. Univariate and multivariate analyses using Cox proportional hazards regression models were performed to evaluate potential prognostic factors for survival. Statistically significant difference was set as p<0.05. Of all the patients with pⅢA-N2 NSCLC reviewed, 105 suffered locoregional recurrence as the first treatment failure and didn't receive PORT. Among these patients, 51 (48.6%) received salvage thoracic radiotherapy and 54 (51.4%) did not. The median OS was 47.7 months of all patients. Survival analysis showed that the median OS in salvage thoracic radiotherapy group (69.0 months) was significantly longer than that in non-salvage thoracic radiotherapy group (37.7 months) (p = 0.029). For patients of EGFR wild type, salvage thoracic radiotherapy group had significantly longer median OS of 69.0 months compared with non-salvage thoracic radiotherapy group of 31.3 months (p = 0.004). When assessed by histological types, salvage thoracic radiotherapy significantly improved the survival of patients with lung squamous cell carcinoma with median OS not reached compared with non-salvage thoracic radiotherapy group of 31.3 months (p<0.001), while in patients with non-squamous cell carcinoma, this survival benefit was not observed (p = 0.829). Salvage thoracic radiotherapy is an effective treatment for completely resected pIIIA-N2 NSCLC patients that have not received PORT and suffered post-operative locoregional recurrence.