PUB032 Surgical Management of cN1 Non-Small Cell Lung Cancer: Histological Impact on Nodal Status and Survival Outcomes

Abstract

Surgical resection is employed as a standard treatment for cN1 non-small cell lung cancer (NSCLC). In the resected cases, not a small population of unfavorable prognosis including pN2 cases is observed. Invasive mediastinal evaluations using endobronchial ultrasonography and/or mediastinoscopy are suggested for patients with radiological cN1 NSCLC in the several guidelines. However, practical benefits of those modalities remain unclear due to its heterogeneous population. We retrospectively reviewed clinicopathological factors of 161 patients who underwent surgical resection for radiologically diagnosed cN1 NSCLC treated from 2001 to 2013 in our institute. The patients without preoperative invasive mediastinal evaluation and induction treatment were enrolled. To identify the population who can benefit from invasive mediastinal staging, we analyzed predictive factors of pN2 status. Furthermore, disease free survival (DFS), overall survival (OS) and factors affecting them were also investigated. One hundred nineteen patients (73.9%) with pN0-1 and 42 patients (26.1%) of pN2 were identified. More patients of female sex, high serum CEA and adenocarcinoma (AD) histology were included in the pN2 group (p=0.044, 0.028 and 0.024, respectively). The univariate analyses showed that higher age and AD histology were potential predictor for pN2 status (p=0.048 and 0.01, respectively) and the multivariate analysis demonstrated AD histology was a significant predictor for pN2 status (HR: 2.445, p=0.015). Five-year OS rate of the pN0-1 and pN2 AD patients were 56.8% and 34.0%, respectively (p=0.46), those of non-AD patients were 70.2% and 64.9%, respectively (p=0.94). In AD patients, five-year DFS rate of the pN0-1 was 50.2%, which was significantly better than that of pN2 patients, 5.8% (p<0.001), while those of non-AD patients were not different, demonstrating 55.4% and 73.9%, respectively (p=0.48). Out of 26 AD patients with pN2 disease, 24 patients (92.6%) experienced recurrence. Twenty-one patients (80.8%) of them were accompanied with non-local disease. AD histology was the independent predictor for pN2 status in resected cN1 NSCLC. Surgical outcomes of cN1/pN2 AD patients were poor and the efficacies of surgery is considered to be limited for them. While those of non-AD patients was favorable being identical with pN1-0 patients. Mediastinal evaluation of invasive modalities may be more beneficial for AD patients in terms of prognostic distinction and decision of treatment strategies.