351P Management of brain metastasis of NSCLC oncogene addicted: A delphi consensus process of the Italian association of radiotherapy and clinical oncology (AIRO)

Background: Lung adenocarcinoma is the most common subtype of non-small cell lung cancer, and liver metastases accounts for approximately one fifth of metastatic sites.Although clinical trials suggest that immune checkpoint inhibitors offer advantages over chemotherapy, the real-world magnitude of this benefit remains uncertain.Using the SEER database, we evaluated whether the transition to the immunotherapy era has translated into meaningful survival improvements in this high-risk population.Methods: Using the SEER database, we identified patients with lung adenocarcinoma and liver metastases and stratified them into pre-immunotherapy (2010-2014) and immunotherapy-era (2015-2021) cohorts.Primary endpoints were overall survival (OS) and cancer-specific survival (CSS).Survival was analyzed using Kaplan-Meier methods and multivariable Cox regression adjusting for age, sex, race, rural/urban status, and chemotherapy use.Analyses were conducted in Jamovi (v2.6).Results: A total of 16,535 patients were included, with 6,494 being in the 2010-2014 era and 10,041 in the 2015-2021 era.The majority were aged >50 years (94.6%) and white (76.9%).Median survival improved significantly from 3 months [95% CI: 3-3] in the pre-immunotherapy era to 4 months [95% CI: 3-4] in the immunotherapy era.The 1,3,5 year OS rates increased from 18.55%, 4.59%, and 1.94% (2010-2014) to 26.10%, 9.86%, and 5.27% (2015-2021), respectively.On multivariable analysis, diagnosis in 2015-2021 was independently associated with improved OS (HR 0.79, 95% CI 0.76-0.81)and CSS (HR 0.76, 95% CI 0.73-0.79;both p<0.001).Chemotherapy receipt was the strongest predictor of survival (HR 0.33), while older age, male sex, and nonmetropolitan residence were associated with higher mortality. Conclusions:The immunotherapy era is associated with a statistically significant improvement in survival outcomes for patients with lung adenocarcinoma and liver metastasis.While 1 & 3-year survival rates have notably increased, liver metastasis remains a significant prognostic challenge.The persistence of geographic disparities and the dominant role of chemotherapy highlight the need for optimized combination strategies and improved access to care in this high-risk population.