1842P Molecular testing in older patients treated for an advanced or metastatic non-squamous non-small cell lung cancer

Abstract

Background: With an aging population, global cancer burden continues to rise. Increased age is an independent risk factor for not receiving aggressive therapy and is associated with shorter overall survival (OS). However, the interplay between age, cancer therapy and other factors has not been explored in depth. Here we explore the impact of and interaction between age, comorbidity and polypharmacy on OS in advanced malignancies.Methods: A retrospective cohort study was conducted including patients 18 years diagnosed with advanced breast, lung, colorectal, prostate or ovarian cancer diagnosed between 2004 and 2015 in Manitoba, Canada. Cancer stages were included if standard therapy included systemic therapy (ST). Clinical and administrative health data were used to determine demographics, oncologic characteristics, treatment, comorbidity (Charlson Comorbidity Index (CCI) and Resource Utilization Band (RUB)), polypharmacy (6 medications) and OS. Kaplan-Meier curves and multivariable Cox proportional hazards models were produced to evaluate associations with OS.Results: 15,252 patients were diagnosed with advanced or incurable solid tumors of whom 48% received ST. Patients who did not receive ST were older, had increased comorbidity, health care usage and polypharmacy. In treated patients, OS declined with increased age with median OS of 8.9, 6.1, 4.1, 3.5, 2.5, 1.9 and 1.7 years for patients aged <40, 40-49, 50-59, 60-69, 70-79, 80-89 and 90 respectively. OS differed by cancer type; breast cancer had the longest and lung cancer had the shortest OS. OS was 2.3 years for patients taking 6 medications compared to 3.9 years in those taking <6 medications. OS was the longest for individuals with low comorbidity (RUB¼ 2, CCI¼ 0). Age at diagnosis, cancer type, stage, medication count, RUB and year of diagnosis were independently associated with OS. Interactions were found between age and cancer type (p<0.001) and age with stage (p¼0.019). Conclusions:In this population-based study, age, RUB and polypharmacy each independently impacted OS in treated patients. CCI was not independently associated with OS. Polypharmacy was found to be an independent predictor of OS. Age interacted with both cancer type and stage in association with OS.