Perspectives on the effect of nodal downstaging and its implication of the role of surgery in stage IIIA (N2) non-small cell lung cancer

Patients with persistent N2 disease after induction have poor survival. Many of these patients may have had mediastinoscopy before induction therapy, making reassessment of the mediastinum by repeat mediastinoscopy hazardous and inaccurate. The sensitivity and specificity of endobronchial ultrasonography and nodal fine-needle aspiration in this setting is unclear. In this study, we sought to identify the clinical predictors of persistent N2 disease after induction therapy, which may help in selecting the patients most likely to benefit from surgical resection.A retrospective review of a prospective database (1990 to 2014) was performed to identify patients who had surgical resection after induction therapy for clinical stage IIIA-N2 non-small cell lung cancer. Multivariable logistic regression analysis was performed to determine independent predictors of persistent N2 disease.203 patients (56% female; median age 64 years) underwent potentially curative lung resection after induction therapy. Ninety-seven patients (48%) had pathologic nodal downstaging (pN0/N1), which was associated with significantly better overall survival compared with patients with persistent N2 disease (5 years, 56% versus 35%, p = 0.047). Univariate and multivariate analysis showed that upper or middle lobe location and less than 60% reduction of N2 SUVmax were independent predictors of persistent N2 disease.Patients with upper lobe tumors and less than 60% reduction in N2 SUVmax are more likely to have persistent N2 disease, which is often associated with poor survival rates. These clinical prognostic criteria may help surgeons in stratifying patients and properly selecting optimal surgical candidates.