Population-based impacts of new therapies on outcomes for stage IV non-small cell lung cancer.

Abstract

9120 Background: Over 15 years, diagnostic and therapeutic algorithms for Stage IV non-small cell lung cancer (NSCLC) have dramatically progressed. While clinical trials demonstrate overall survival (OS) advantages, population level impact remains uncertain. Here we evaluate real world, population-based outcomes for Stage IV NSCLC to assess impact of changing therapies on referral, treatment patterns and OS, which may help explain ongoing stigma/nihilism. Methods: A retrospective cohort analysis was completed to evaluate de novo Stage IV NSCLC diagnosed in Manitoba from 2006 to 2015. We evaluated treatment received (not seen by specialist, saw a specialist but did not receive therapy, radiation therapy (RT) only, and systemic therapy (mutation unknown and known)) and treatment era of diagnosis (2006-2009, 2010-2013 and 2014-2015). Multivariable logistic regression assessed systemic therapy predictors. Kaplan-Meier curve and Cox proportional hazard models evaluated OS. Results: 3,601 patients were diagnosed with Stage IV NSCLC, 53% male. Only 21% received systemic therapy, mean age of 62. Within the cohort, 973 (27%) patients did not see a specialist, 610 (17%) saw a specialist but did not receive therapy, 1248 (35%) only received RT, and 771 (21%) received systemic therapy (17% mutation status unknown and 4% known). Younger patients and those with confirmed histology were more likely to see a specialist and receive treatment, each (p < 0.001). Patients who received systemic therapy had lower comorbidity and higher income quintile, each (p < 0.001). Median OS did not differ between treatment era with median OS of 3.0, 2.9 and 2.8 months for 2006-2009, 2010-2013 and 2014-2015 respectively, p = 0.082. When survival analysis was restricted to patients who received systemic therapy, median OS improved by era to 10.9, 11.2 and 15.6 months respectively, p = 0.001. Variables found to be independently associated with survival included treatment type, age, sex and comorbidity. Conclusions: Improved systemic therapy and molecular testing has improved OS for patients who receive systemic therapy. However, due to the large proportion of Stage IV NSCLC patients who never receive systemic therapy we do not see improved survival at a population level between treatment eras.