P1.16-60 A High Risk of Recurrence After the Resection of Lower Lobe Adenocarcinoma

Abstract

According to previous reports, non-small cell lung cancers arising in the lower lobe are associated with a worse prognosis than those arising in the upper lobe; however, the reason remains to be elucidated. Thus, we attempted to identify high-risk population in patients with lower lobe disease, that may substantially cause poor prognosis of lower lobe disease. We retrospectively reviewed a consecutive series of 400 patients with completely resected lung adenocarcinoma who were treated between January 2006 and December 2015. All patients underwent major lung resection and lymph node dissection. The clinicopathological factors that were investigated included the solid component size, the pathological subtype (pre-invasive, minimally invasive/invasive), the epidermal growth factor receptor (EGFR) mutation status, and some other characteristics (TNM 8th edition). The proportion of never-smokers among patients with lower lobe disease was significantly higher than that among those with upper lobe disease. According to a multivariate proportional hazards analysis, primary site (upper/lower) was an independent predictor of early recurrence, along with the solid component size, pleural lavage cytology results, pathological pleural invasion, and pathological lymph node metastasis. However, although lower lobe disease was associated with early recurrence in never smokers (Fig 1A), it was not in smokers (Fig 1B). Furthermore, although lower lobe disease was associated with early recurrence in never smokers with EGFR wild-type tumors (Fig 1C), it was not in never smokers with EGFR mutant tumors (Fig 1D). EGFR wild-type tumors were more frequently detected in patients with lower lobe disease than in those with upper lobe disease when the analysis was restricted to never smokers. Patients with lower lobe cancer, particularly those without a smoking history or those with EGFR wild-type tumors, showed a higher risk of recurrence than their counterparts with upper lobe disease. Further studies that include the molecular profiling of such aggressive lesions, are warranted.