Prognostic Factors in Stage IIB Non-Small Cell Lung Cancer according to the 8th Edition of TNM Staging System

BACKGROUND: The purposes of this study were to evaluate the appropriateness of the stage migration of stage IIA non-small cell lung cancer (NSCLC) in the seventh edition of the tumor, node, and metastasis classification for lung cancer to stage IIB lung cancer in the eighth edition, and to identify prognostic factors in patients with eighth-edition stage IIB disease. METHODS: Patients with eighth-edition stage IIB disease were subclassified into those with seventh-edition stage IIA disease and those with seventh-edition stage IIB disease, and their recurrence-free survival and disease-specific survival rates were compared. Risk factors for recurrence after curative resection were identified in all included patients. RESULTS: Of 122 patients with eighth-edition stage IIB NSCLC, 101 (82.8%) had seventh-edition stage IIA disease and 21 (17.2%) had seventh-edition stage IIB disease. Nonsignificant differences were observed in the 5-year recurrence-free survival rate and the 5-year disease-specific survival rate between the patients with seventh-edition stage IIA disease and those with seventh-edition stage IIB disease. Visceral pleural invasion was a significant risk factor for recurrence in patients with eighth-edition stage IIB NSCLC. CONCLUSION: The stage migration from seventh-edition stage IIA NSCLC to eighth-edition stage IIB NSCLC was appropriate in terms of oncological outcomes. Visceral pleural invasion was the only prognostic factor in patients with eighth-edition stage IIB NSCLC.