Prognostic prediction of clinical stage IA lung cancer presenting as a pure solid nodule

BACKGROUND: Clinical stage IA lung cancer presenting as a ground glass opacity (GGO) on imaging is known to be associated with a good prognosis. Conversely, the prognosis of lung cancer presenting as a pure solid nodule is less favorable. The purpose of this study was to identify the predictive factors affecting prognosis in pure solid nodule lung cancer. METHODS: A total of 328 consecutive patients undergoing curative resection of clinical stage IA pure solid nodule lung cancer were reviewed retrospectively. Recurrence, survival and risk factors for nodal upstaging were analyzed. RESULTS: Of the 328 patients, 277 patients (84.6%) underwent lobectomy (or greater) and 51 patients (15.6%) underwent sublobar resection. Mediastinal lymph node dissection or sampling was performed in 278 patients (84.8%). The 5-year recurrence-free survival rate was 70.0% and the disease-specific survival rate was 86.5%. Intraoperative mediastinal lymph node dissection was the only significant related factor for recurrence and cancer-related death in a multivariate analysis [hazard ratio (HR) =0.485, P=0.020; HR =0.342, P=0.014]. A total of 217 patients underwent lobectomy with mediastinal lymph node dissection and nodal upstaging occurred in 36 patients (16.6%). There were no significant predictive factors for nodal upstaging in a multivariate analysis. Visceral pleural invasion, lymphovascular invasion, and small cell carcinoma histology were the only identified risk factors for nodal upstaging (HR =3.858, P=0.006; HR =8.792, P<0.001; HR =45.908, P=0.017). CONCLUSIONS: There were no definite factors predictive of prognosis in clinical stage IA pure solid nodule lung cancer. Only accurate pathologic staging and adequate intraoperative lymph node dissection were shown to be related to prognosis.