Radiation therapy utilization in older adults with high-risk prostate cancer: A SEER-based analysis.

178 Background: Radiation therapy (RT) is a cornerstone of curative treatment for high-risk prostate cancer. However, older adults are often undertreated, potentially due to concerns about comorbidities, life expectancy, or treatment-related toxicity. This study aimed to examine age-based trends in RT use in a large, population-based cohort to better understand potential disparities in care. Methods: We conducted a retrospective cohort study using SEER 22 data from 2012 to 2020. Men aged 60 years and older diagnosed with high-risk prostate cancer, poorly differentiated, Grade III and undifferentiated, anaplastic, Grade IV were included. Patients were categorized into age groups: 60–64, 65–69, 70–74, 75–79, 80–84, and ≥85 years. The primary outcome was receipt of RT, defined by the SEER "Radiation Recode" variable. Descriptive statistics were used to determine RT receipt by age group, and a Chi-square test was performed to assess statistical significance. Results: Among 507,964 eligible patients, the overall rate of RT receipt was 33.9%. However, RT use varied markedly by age. RT was administered to 31.3% of men aged 60–64, 37.1% of those 65–69, 45.9% of those 70–74, and 46.4% of men aged 75–79. Usage declined significantly in the oldest groups, with 32.4% of those aged 80–84 and only 13.0% of those aged ≥85 receiving RT. The association between age and RT receipt was statistically significant (Chi-square p < 0.001). Due to data limitations in SEER, patients with 'None/Unknown' radiation status were grouped as not having received documented radiation. This may include patients with incomplete records. Conclusions: In this large national cohort, radiation therapy use declined substantially with increasing age, particularly among men aged 85 and older. While some variation may be attributable to clinical factors such as frailty or competing health risks, the steep drop in RT receipt suggests that age may be an independent barrier to treatment. These findings raise important concerns about age-related disparities in prostate cancer care and highlight the need for patient-centered, individualized decision-making to ensure equitable access to evidence-based therapies. RT rates in pts with prostate cancer based on age. Age Radiation Received Unknown if Radiation Received Sample Size Percentage 60-64 28031 61489 89520 31% 65-69 38877 65997 104874 37% 70-74 40609 47902 88511 46% 75-79 30820 35517 66337 46% 80-84 12570 26208 38778 32% 85+ 2877 19182 22059 13%