Surgical-pathologic factors affect long-term outcomes in stage IB (pT2 N0 M0) non-small cell lung cancer: A heterogeneous disease

Objectives: Our objective was to identify surgical-pathologic factors affecting prognosis in stage IB non-small cell lung cancers. Methods: Between 1997 and 2006, a cohort of 272 cases of pT2 N0 M0 stage lung cancer were retrospectively analyzed. The patients included 70 women and 202 men with a mean age of 67.0 years. The surgical resections included pneumonectomy in 4, bilobectomy or lobectomy in 217, and limited resections in another 51. The impact of surgical-pathologic characteristics on survival, including cell type, tumor differentiation, tumor size, depth of visceral pleural invasion, type of surgical resection, and extent of lymphadenectomy on patient survival, was compared accordingly. Results: Tumor types included adenocarcinoma/bronchioloalveolar carcinoma in 142, squamous cell carcinoma in 100, and others in 30. Cell differentiations were classified as well, moderately, and poorly differentiated in 23, 151, and 92 cases, respectively. The mean tumor size was 3.9 cm in diameter, and the average resected lymph node number was 14.3. Direct visceral pleural or subpleural invasions (<1 mm) were found in 134 and 42 cases, respectively. Angiolymphatic invasions were seen in 26 cases, and positive tumor margins were found in 14 cases. The overall 5-year and 10-year survivals were 59.5% and 41.3%, respectively. Good prognostic factors using univariate analysis included female gender, nonlimited resection, well-differentiated tumor, no angiolymphatic invasion, smaller size (<= 3 cm), and numbers of nodes retrieved (>14 nodes). However, the Cox proportional hazard model revealed female gender, well-differentiated tumor, no pleural involvement, no angiolymphatic invasion, and more than 14 nodes retrieved as independent good prognostic factors. Conclusions: Stage IB lung cancer can be treated by standard pulmonary resection accompanied by adequate mediastinal lymphadenectomy. Owing to the heterogeneity of stage IB lung cancer and the fact that prognosis can be affected by many surgical-pathologic factors, refinement of the current TNM staging criteria may be needed.