Prognostic significance of histologic subtype in pStage I lung adenocarcinoma

The International Association for the Study of Lung Cancer, the American Thoracic Society, and the European Respiratory Society (IASLC/ATS/ERS) proposed a new histologic classification of lung adenocarcinoma in 2011. While several studies have already validated the prognostic value of this new classification of lung adenocarcinoma, we conducted own investigation in the present study. This study included 197 patients with invasive lung adenocarcinoma who underwent complete resection. Pathologic diagnoses were made in accordance with the new IASLC/ATS/ERS classification for lung adenocarcinoma. The lepidic/acinar/papillary group had a significantly better prognosis than the micropapillary/solid/invasive mucinous adenocarcinoma group (5-year recurrence-free survival [RFS] 73 vs. 21%: p < 0.01, 5-year overall survival 85 vs. 52%: p < 0.01). Age (hazard ratio [HR], 1.898; p = 0.03), CEA (HR, 1.873; p = 0.03), pStage (HR, 6.149; p < 0.01), and histologic subtype (HR, 2.342; p = 0.01) were independent prognostic factors for the RFS. Furthermore, age (HR, 3.242; p = 0.04), CEA (HR, 3.405; p = 0.03) and histologic subtype (HR, 11.108; p < 0.01) were independent prognostic factors for the progression-free survival in pStage I. The histologic subtype correlated with the prognosis of pStage I of lung adenocarcinoma. Patients in the high-grade group of lung adenocarcinoma, which included solid, micropapillary and invasive mucinous adenocarcinoma with pStage I, should be considered candidates for postoperative adjuvant therapy.