Prognostic factors in neoadjuvant treatment followed by surgery in stage IIIA-N2 non-small cell lung cancer: a multi-institutional study by the Oncologic Group for the Study of Lung Cancer (Spanish Radiation Oncology Society).

Purpose: To evaluate the prognostic factors associated with survival in patients treated with neoadjuvant treatment [chemoradiotherapy (CRT) or chemotherapy] followed by surgery (CRTS) in patients with stage IIIA-N2 non-small cell lung cancer (NSCLC).

Methods: A retrospective study was conducted of 118 patients diagnosed with stage T1-T3N2M0 NSCLC and treated with CRTS at 14 hospitals in Spain between January 2005 and December 2014. Overall survival (OS) and progression-free survival (PFS) were estimated using the Kaplan-Meier method and compared using the log-rank test. Cox regression analysis was performed.

Results: Surgery consisted of lobectomy (74.5% of cases), pneumectomy (17.8%), or bilobectomy (7.6%). Neoadjuvant treatment was CRT in 62 patients (52.5%) and chemotherapy alone in 56 patients (47.5%). Median follow-up was 42.5 months (5-128 months). 5-year OS and PFS were 51.1% and 49.4%, respectively. The following variables were independently associated with worse OS and PFS: pneumonectomy (vs. lobectomy); advanced pathologic T stage (pT3 vs. pT0-pT2); and presence of persistent N2 disease (vs. ypN0-1) in the surgical specimen.

Conclusions: In this sample of patients with stage IIIA-N2 NSCLC treated with CRTS, 5-year survival (both OS and PFS) was approximately 50%. After CRTS, the patients with the best prognosis were those whose primary tumour and/or mediastinal nodal metastases were downstaged after induction therapy and those who underwent lobectomy. These findings provide further support for neoadjuvant therapy followed by surgery in selected patients.