P1.08-032 Impact of the Oncogenic Status on the Mode of Recurrence in Resected Non-Small Cell Lung Cancer

Abstract

Surgical resection is employed in patients with resectable non-small cell lung cancer (NSCLC). Despite complete resection, recurrence is sometimes observed. Oncogenic mutations promote initiation and progression of lung cancer, and mutation status predicts treatment outcome of advanced NSCLC; however, their impact on the recurrence patterns remain poorly understood. We retrospectively studied 401 patients showing recurrence after complete resection of NSCLC. Clinicopathological factors were reviewed for time to recurrence (TTR), and recurrence patterns were compared according to oncogenic status and examined according to EGFR mutational subtype. Among 401 patients, 185 with EGFR mutation, 46 with KRAS mutation, 15 with ALK rearrangement, and 155 with triple negative mutation (TN) were identified. Multivariate analysis following univariate analyses showed that younger age, well–moderately differentiated histology, earlier pathologic stage, and presence of EGFR or ALK mutation were favorable prognostic factors for TTR. Locoregional recurrence was observed in 53.3% of ALK-positive patients, being significantly common in these patients than in EGFR- and KRAS-positive patients. EGFR-positive patients mostly experienced pleural recurrence, the incidence of which was significantly higher in TN patients. Adrenal recurrence was observed in 7.2% of TN patients, but it was rarely identified in EGFR-positive patients. (Figure) Among EGFR-positive patients, the incidence of brain metastases was significantly higher in L858R cohort than in Del Ex19 cohort. In resected NSCLC, younger age, well–moderately differentiated histology, earlier pathologic stage, and presence of EGFR or ALK mutation were favorable factors for TTR, and distinct recurrence patterns were revealed according to oncogenic mutation status and mutational EGFR subtype. Our results may provide suggestions for developing a strategy for follow-up and adjuvant therapies after resection.