Pathologic N(0) Status in Clinical T(1)N(0)M(0) Lung Adenocarcinoma is Predictable by the Solid Component Proportion with Quantitative CT Number Analysis

Correctly predicting pathologic regional node-negative (pN(0)) disease in patients with lung cancer before operation may avoid unnecessary mediastinal lymph node dissection (MLND). In this study, we analyze the value of the radiographic and histopathological features of primary tumors for predicting pN(0) status in cT(1)N(0)M(0) lung adenocarcinoma and to establish an optimal surgical strategy for avoiding MLND in cT(1)N(0)M(0) lung adenocarcinoma patients. We retrospectively investigated the histopathological and radiographic data of 348 surgically resected cT(1)N(0)M(0) lung adenocarcinoma patients with systematic lymph node dissection from January 2005 to December 2012. Histopathological features and radiographic features were analyzed. Multivariable analysis was used to identify significant predictors of pN(0) disease. Our results showed that pN(0) disease was detected in 306 patients (87.9%) among the 348 patients with cT(1)N(0)M(0) lung adenocarcinoma. A decreasing trend of the pN(0) disease proportion was observed with both increasing histological grade and decreased differentiation (P < 0.001). In multivariable analysis, the solid component proportion was a significant predictor of pN(0) disease. Among 110 patients with a solid component proportion of no more than 21.3%, mediastinal lymph node involvement was not observed. Patients who meet this criterion may be successfully managed with lung resection without MLND.