P1.01-51 Micropapillary Predominant and Pathologic Stage Were Risk Factors for Postoperative Brain Metastasis in Lung Adenocarcinoma

Abstract

Brain metastasis from non-small cell lung cancer following curative resection is a significant issue because it often causes critical symptoms and may require different therapeutic approaches from other recurrence. On this background, we aimed to investigate correlation between clinicopathological variables and brain metastasis in resected lung adenocarcinoma. Clinicopathological data of 358 patients who had undergone complete resection for lung adenocarcinoma at Saiseikai Utsunomiya Hospital between 2002 and 2015 were retrospectively reviewed. Brain metastasis-free survival was calculated from the date of surgery to the date when brain metastasis was diagnosed or the date of last follow-up by using Kaplan-Meier method. We analyzed the risk factors of postoperative brain metastasis by log-rank analysis and Cox regression analysis. The median follow-up period was 60.4 months (range, 1.0 - 195.6 months). Thirty-six patients developed brain metastasis after complete resection of lung adenocarcinoma during follow-up. Thirty-three patients were diagnosed as brain metastasis by contrast-enhanced brain MRI and the others were diagnosed by contrast-enhanced brain CT. Five-year brain metastasis-free survival rate was 91.4%. Log-rank analysis demonstrated that pathologic stage IB or higher (p <0.001), lymphovascular invasion (p <0.001), presence of spread through alveolar spaces (p < 0.001) and micropapillary predominant pattern (p <0.001) were significantly associated with recurrence of brain metastasis. Cox regression analysis demonstrated that pathologic stage IB or higher (p = 0.004) and micropapillary predominant pattern (p = 0.007) were independent risk factors for brain metastasis. Our findings suggest that careful follow-up may be required for patients with higher pathologic stage as well as micropapillary predominant lung adenocarcinoma after complete resection. It may also emphasize clinical significance of micropapillary subtype in resected lung adenocarcinoma.