P2.01-61 Multiple Primary Carcinomas (MPC) in Patients with Non Small Cell Lung Cancer (NSCLC)

Abstract

data of patient characteristics, histology, performance status (PS), stage, metastatic sites, smoking history, driver mutation, PD-L1 expression, treatment line from medical records. Progression-free survival(PFS) of pembrolizumab and Overall survival(OS) was calculated using Kaplan-Meier method. We compared PFS according to PD-L1 expression using log rank test and Cox model was used to assess the effect of PD-L1 expression on PFS. Patients were stratified into 2 PD-L1 groups based on PD-L1 expression: medium-high expression (TPS 50-74%), and very high expression (TPS 75-100%). Result: The median age was 74 years (range: 43-86) and 15% of patients were women. The metastatic sites were brain (17%), pleural effusion (27%), bone (39%), liver (7%). The 22% of patients previously treated with chemotherapy and 78% of patients was treatment-naive. Median PFS of all patients was 7.0 months (CI95%. 4.2-16 months) and, median OS of all patients was not reached, respectively. In log-lank test, sex, smoking history, brain metastasis, pleural effusion, driver mutation, and PD-L1 expression were associated with PFS. In multivariate analysis using Cox model, only PD-L1 very high expression was associated with good prognosis (HR: 0.37, CI95%: 0.14-1.00). Conclusion: Even in cohort of PD-L1 TPS of 50% or greater, PD-L1 very high expression was predictive marker of pembrolizumab monotherapy.