Improved Survival With Increased Time-To-Radiation and Sequential Chemotherapy After Surgery for pN2 Non-Small-cell Lung Cancer.

BACKGROUND: Currently, the ideal timing for postoperative radiotherapy (PORT) and chemotherapy is unknown. The present study evaluated their relative timing on overall survival (OS) using the National Cancer Database (NCDB).

MATERIALS AND METHODS: The NCDB was queried for patients from 2004 to 2012 with resected non-small-cell lung cancer (NSCLC), pathologically involved N2 (pN2) nodes, and negative margins. All patients underwent adjuvant chemotherapy and external beam radiotherapy. The time to radiation (TTR) was determined from the date of surgery to the start of PORT, with the exclusion of those receiving PORT < 4 weeks or > 24 weeks postoperatively. Early and late TTR was dichotomized at 8 weeks after receiver operating characteristic analysis. Multivariate Cox regression analysis was conducted to predict the variables significantly associated with survival.

RESULTS: A total of 1629 patients were eligible for analysis. Of the 1629 patients, 703 had received PORT < 8 weeks and 926 had received PORT ≥ 8 weeks postoperatively. The receipt of PORT after 8 weeks was associated with better OS (P = .0044). No significant differences were found in survival in the concurrent group comparing early and later TTR (P = .9119). However, a significant OS benefit was found for sequential chemotherapy with an increased TTR (P = .0045). Older age, male sex, shorter distance traveled, increased nodal positivity, larger tumor size, higher Charlson/Deyo comorbidity score, and early TTR were associated with inferior survival on multivariate analysis.

CONCLUSION: A TTR of ≥ 8 weeks with sequential chemotherapy in the setting of PORT was associated with improved survival in patients with NSCLC with pN2 nodes.