Outcome of Patients With pN2 "Potentially Resectable" Non-Small Cell Lung Cancer Who Underwent Surgery After Induction Chemotherapy

Patients with stage IIIA-ipsilateral mediastinal lymph node involvement (N2) non-small cell lung cancer (NSCLC) represent a heterogeneous group with different clinical presentation. The aim of this study was to analyze a series of patients with "potentially resectable" stage IIIA-pathologically proven N2 (pN2) NSCLC undergoing induction chemotherapy followed by surgery to evaluate their long-term outcomes and to identify prognostic factors. Out of 287 patients who underwent induction chemotherapy for NSCLC with ipsilateral mediastinal lymph node involvement pathologically proven, we retrospectively evaluated 141 (49%) patients with no clinical evidence of progression after induction chemotherapy and candidates for surgery. Most of them (73%) underwent at least 3 cycles of cisplatin-based chemotherapy. We used the Kaplan-Meier method to plot survival and the log-rank test to assess the survival difference between groups. Multivariable analysis was performed using Cox proportional hazards regression. A total of 15 (10.6%) patients underwent explorative thoracotomy; 126 patients underwent surgical anatomical resection after a median 27 days (range: 21-30) from the last cycle of chemotherapy. A total of 113 (89.7%) patients had a radical resection. A total of 22 (17.5%) patients had a complete pathologic lymph node downstaging (pN0), and 8 (6.3%) patients had a complete pathological response (pT0N0). The median overall survival was 24 months, with a 5-year overall survival of 30%. At multivariable analysis, downstaging and number of cycles of chemotherapy were independent prognostic factors (P = 0.006); downstaging benefit was mostly because of complete pathological response (hazards ratio = 0.23, 95% CI: 0.07-0.76). In conclusion, more than 3 cycles of chemotherapy and pathological downstaging could significantly improve 5-year survival in selected patients with "potentially resectable" pathologically proven N2 disease.