OBJECTIVETo analyze the prognostic value of the new classification (proposed by International Association for the Study of Lung Cancer/American Thoracic Society/European Respiratory Society) in stage I pulmonary adenocarcinoma.

METHODSPathological slides of 328 cases of stage I pulmonary invasive adenocarcinoma were reviewed according to the new classification. The patients received operation in Department of Thoracic Surgery of Zhongshan Hospital affiliated to Fudan University from January 2005 to December 2009. There were 145 male and 183 female patients with an average age of (59 ± 10) years (ranging from 34 to 82 years). Clinical, pathological, and survival data were retrospectively analyzed. Kaplan-Meier method was used for analysis of survival, and Cox regression analysis was used for finding out prognostic factors.

RESULTSFive-year progression-free survival rate and overall survival rate of lepidic-predominant subtype were both 100%. Five-year progression-free survival rate of patients with micropapillary component (49.3%) was significantly lower than that of patients without micropapillary component (75.4%, χ² = 8.154, P = 0.004). Regression analysis showed that tumor size is an independent prognostic factor of death (HR = 1.967, 95% CI: 1.507 to 2.567, P = 0.000) and recurrence (HR = 1.796, 95% CI: 1.469 to 2.198, P = 0.000). In subgroup analysis, the presence of solid component (HR = 1.985, 95% CI: 1.013 to 3.888, P = 0.046) and tumor size (HR = 1.941, 95% CI: 1.455 to 2.589, P = 0.000) were independent prognostic factors of recurrence for stage IB pulmonary adenocarcinoma.

CONCLUSIONSThe new classification of adenocarcinoma is of prognostic value in stage I pulmonary adenocarcinoma. The presence of solid or micropapillary component impacts on survival. Detailed record of each component in tumor is necessary.