Postoperative Radiotherapy for Patients With Completely Resected Pathologic N2 Non-Small-Cell Lung Cancer: A Retrospective Analysis

BACKGROUND: Adjuvant radiotherapy in non-small-cell lung cancer (NSCLC) is still controversial. The purpose of this retrospective study was to evaluate the role of postoperative radiotherapy (PORT) in terms of local control and survival in pathologic N2 NSCLC. PATIENTS AND METHODS: From January 2003 to December 2008, 66 patients with pathologic N2 NSCLC received PORT. Mediastinal lymph node metastases were classified into single (12 patients) or multiple (54 patients) stations. All patients received conformal radiation therapy, with a median total dose of 50.4 Gy. Target volumes included the bronchial stump, ipsilateral hilum, all pathologically involved lymph node regions, and all the lymph nodes between 2 noncontiguous pathologic nodal stations. The pattern of failure was considered as locoregional or systemic, or a combination of both. Locoregional failure was defined as in field or out of field. RESULTS: Median follow-up time was 34.9 months (range 3.5-62.8 months). Local control was 80% at 12 months, 77.2% at both 24 and 36 months, and 72.1% at 60 months. The pattern of failure was locoregional in 3 patients (1 out of field and 2 in field) and systemic in 25 patients, with 12 patients presenting both locoregional and distant disease. Overall survival at 12, 36, and 60 months was 77%, 44%, and 37%, respectively. Median survival time was 34 months. The number of pathologically involved lymph node stations was a prognostic factor for local control (P = .05), cancer-specific survival (CSS) (P = .04), and disease-free survival (DFS) (P = .04). CONCLUSION: Despite the limitations of the present study, mainly represented by its retrospective nature, our data support the role of PORT in terms of locoregional control and overall survival benefit; the number of involved mediastinal lymph nodes represents a significant prognostic factor in patients with pathologic N2 NSCLC.