Abstract: Background and purpose: The prognosis of completely resected stage Ⅲ_A(N₂) non-small cell lung cancer (NSCLC) remains a significant concern. The 5-year overall survival (OS) rates range from 10% to 30%. This study aimed to analyze the patterns of first failure in completely resected stage Ⅲ_A(N₂) NSCLC and to assess the actuarial risk of developing metastasis at different sites and to guild standard clinical practice. Methods: Patients with Ⅲ_A(N₂) NSCLC who had undergone radical surgery in our hospital from Jan. 2005 to Jul. 2012 were retrospectively reviewed. The progression-free survival (PFS), the OS, patterns of first failure, the actuarial risk were analyzed. The cumulative incidence of first failure was determined using the Kaplan-Meier analysis. Results: Among 357 patients who met the eligibility criteria with completely resected stage Ⅲ_A(N₂) NSCLC, 5-year OS was 36.9%. There were 284 (77.6%) patients experiencing disease failure: 61 with local failure, 197 with local and distant failures, and 26 patients with local recurrence as the first failure. Brain, bone and lung were the main sites of distant failure as the first failure, while brain was the most common site. There were 67 patients developing brain metastases (BM) as the first site of failure. The median time of local failure as the first site of failure was 13.6 months, and the time to develop distant recurrence was 15.1 months. 92.5% BM developed in 3 years after the complete resection. Conclusion: As the first failure, the rate of distant failure was much higher than that of local failure in completely resected stage Ⅲ_A(N₂) NSCLC. Brain was the most common site of distant failure as the first failure. These results can be helpful in  guiding standard clinical practice and evaluating the outcome of comprehensive treatment.

Key words: Non-small cell lung cancer, Stage Ⅲ_A(N₂), Patterns of first failure, Distant failure, Brain metastases