137PD Prognostic factors in oligometastatic non-small-cell lung cancer (OM-NSCLC)

Abstract

Background: OM-NSCLC represents a distinct prognostic group within stage IV lung cancer. An increase in overall survival (OS) has been suggested with ablative (surgery or radiotherapy) therapy. We performed an analysis of clinical factors influencing outcome in a series of patients ( pts) with OM-NSCLC treated in a tertiary hospital. Methods: OM-NSCLC pts (defined as ≤3 metastatic lesions at diagnosis) diagnosed between Jan-2012 and Dec-2016 were included in the analysis. Median OS was calculated with the Kaplan-Meier method. The association between clinical and pathological factors and OS was determined using uni-(UV) and multivariable (MV) Cox regression models. Variables with a p-value <0.01 in UV analysis were included in the MV model. Results: 84 pts were identified: 25 pts squamous histology (29.8%), 58 adenocarcinoma (58%) and 1 (1.2%) undifferentiated carcinoma. 11 pts (13%) were EGFR-mutation positive. Most patients presented with one (78.3%) or two (20.5%) metastatic sites: CNS (39.2%), bone (29.8%), lung (17.9%), adrenal (11.9%) and liver (10.7%). 57 pts (67.9%) underwent local treatment (8.8% surgery, 70.2% radiotherapy, both 21.2%) before (68.2%) or during (49.1%) chemotherapy. Median follow-up was 10.5 months with a median OS of 15.8 months (95CI%:8.9-22.7). In MV OS analysis, only T-stage ( p = 0.012) and histology ( p = 0.006) were significantly associated with OS (Table).