Prognostic Factors in Completely Resected Node-Negative Lung Adenocarcinoma of 3 cm or Smaller

Introduction The role of adjuvant chemotherapy for patients with stage I NSCLC remains unknown. The prognostic value of histological subtypes in resected node-negative small lung adenocarcinoma has not been widely investigated. This study investigated the prognostic factors in patients with node-negative lung adenocarcinoma 3 cm or smaller to find potential candidates for adjuvant chemotherapy. Methods A total of 726 patients with completely resected node-negative lung adenocarcinoma 3 cm or smaller were included in the study. Prognostic factors for overall survival or probability of freedom from recurrence (FFR) were investigated. Results During follow-up, recurrence developed in 59 patients (8.1%). Univariate analysis showed that the micropapillary/solid predominant pattern group was associated with a significantly lower probability of FFR (p = 0.001) in node-negative lung adenocarcinoma 3 cm or smaller. Those with greater tumor size (p = 0.001) and the micropapillary/solid predominant pattern group (p = 0.035) had a significantly lower probability of FFR in multivariate analysis. For tumors 2 cm or smaller, the micropapillary/solid predominant pattern group had a trend toward a lower probability of FFR (p = 0.053) in multivariate analysis. Presence of the solid pattern was a prognostic factor for lower probability of FFR (p = 0.001) in multivariate analysis. Conclusions The new adenocarcinoma classification has significant impact on recurrence in node-negative lung adenocarcinoma 3 cm or smaller. Patients with the micropapillary/solid predominant pattern have a significantly higher risk for recurrence. For tumors 2 cm or smaller, presence of the solid pattern was a prognostic factor for higher probability of recurrence. This information is useful for patient stratification for adjuvant therapy.