Mediastinal downstaging after induction treatment is not a significant prognostic factor to select patients who would benefit from surgery: the clinical value of the lymph node ratio

OBJECTIVES: Multimodal management of N2 non-small-cell lung cancer is still a matter of debate. In particular, the place of surgery for persistent N2 after induction treatment is controversial and surgery is usually reserved for patients experiencing a mediastinal downstaging (pN1 and pN0). We aimed to evaluate whether there might exist subgroups of pN2 according to the lymph node ratio (LNR). METHODS: Between 1996 and 2012, we retrospectively reviewed the data from 152 potentially resectable cN2 patients who underwent an induction treatment before surgery. RESULTS: The median follow-up time was 32 months (2–112). The average age at the time of diagnosis was 58.52 ± 10.47 years. In univariate analysis, overall survival (OS) was significantly influenced by extracapsular spread (32 ± 5.33 vs 24 ± 12.73 months, P= 0.01), pN after surgery (65 ± 2.45 months for pN0, 44 ± 2.14 months for pN1 and 19 ± 1.72 months for pN2, P