EPID-31. Days alive and at home in glioblastoma patients across age groups: a population-based study in Ontario, Canada

Abstract The optimal management of glioblastoma (GBM) in older adults remains uncertain, with limited evidence to inform treatment decisions in this population. Older patients are consistently underrepresented in clinical trials, and conventional endpoints such as overall survival may not fully capture outcomes that align with patient’s values and priorities. “Days spent alive and at home” (DAAH) is a novel, patient-centered measure that reflects both survival and functional independence. We conducted a population-based retrospective cohort study to examine the association between age and DAAH following surgery for GBM. Using linked administrative databases from Ontario, Canada between 2006 – 2022, we identified adults (≥18 years) with a new diagnosis of glioblastoma who underwent either biopsy or surgical resection. Patients were stratified into four age groups: ≤50, 51-65, 66-75, 76-85, and >85. The primary outcome was DAAH in the first 365 days post-surgery. Secondary outcomes included overall survival, post-operative complications, and length of stay during index surgery. Multivariable regression models adjusted for sex, surgery type, frailty status, resource utilization band, tumor location, year of treatment, and neighborhood material deprivation and rurality indices. A total of 6,847 patients met inclusion criteria (mean age 63.6; 59% male). Median DAAH within 365 days was 355 (IQR 263-362) for patients ≤ 50 years, 308 days (IQR 126-359) for those 51-65, 171 days (IQR 61–336) for 66-75, 91 days (IQR 27-227) for 76-85, and 61 days (IQR 9-123) for those >85. Increasing age was independently associated with fewer DAAH (p<0.001), shorter overall survival (p<0.001), higher post-operative complication rates (p=0.015), and longer hospital stays during index surgery (p<0.001) in multivariable regression models. Older age is strongly associated with reduced DAAH following surgery for GBM. DAAH may offer a more relevant and patient-centered metric to guide treatment planning and shared decision-making in this understudied patient population.