Abstract 2302: Overall survival and treatment patterns in elderly patients with stage IV colorectal cancer in the United States: SEER-medicare analysis, 2007-2020

Introduction: Traditional therapeutic options in metastatic colorectal cancer (mCRC) are limited and associated with severe toxicity. This limitation may be greater in populations where cancer treatment disparities have been reported. To better understand survival outcomes and patterns of treatment in these populations, we conducted an observational study to examine overall survival (OS) and lines of therapy (LOT) by sex, age, and race/ethnicity in elderly patients with stage IV CRC in the United States using the Surveillance, Epidemiology, and End Results (SEER) Medicare database. Methods: Patients aged ≥65 years with stage IV CRC were identified in the SEER-Medicare database between January 1, 2007, and December 31, 2020. The frequency of the first, second, and third LOT (1L-3L) and the regimens within each line were calculated. Kaplan-Meier curves were generated to examine OS. All analyses were conducted for the total population and by sex, age group, and race/ethnicity. Results: There were 9,042 CRC cases identified with a median age of 76 years. Most patients were female (55.0%), non-Hispanic White (72.5%), and had a proximal site of initial diagnosis (44.8%). Overall, the median OS was 7.8 months (95% CI, 7.5-8.2). Older age (≥85 years), female, and non-Hispanic Black and non-Hispanic American Indian/Alaska Native (AI/AN) patients had worse OS compared with younger age groups, male, and other racial/ethnic patients, respectively. Of the 9,042 patients, 4923 (54.4%), 2761 (30.5%), and 1556 (17.2%) patients received 1L, 2L, and 3L, respectively. The most common regimens were FOLFOX ± anti-VEGF (47.7%) for 1L, FOLFIRI ± anti-VEGF (27.0%) for 2L, and FOLFIRI ± anti-VEGF (18.7%) and other (17.5%) for 3L. The most common regimens by LOT were similar by sex and race/ethnicity. However, different treatment patterns were observed by age group. Compared with younger age groups, older age groups received fewer 2L and 3L and more capecitabine-based regimens or anti-VEGF monotherapy. As for OS, compared to patients aged 65-74 years, worse OS was observed for patients aged 75-84 years within each LOT and patients aged ≥85 years within 1L (P values < 0.01). Compared to non-Hispanic White patients, worse OS was observed for non-Hispanic Black patients within each LOT and non-Hispanic AI/AN patients within 3L (P values < 0.01). OS was similar between male and female patients within each LOT. Conclusion: Compared with younger patients, older patients received fewer 2L and 3L, received less intensive therapy regimens, and had worse OS. Although therapy regimens across LOT were comparable by sex and race/ethnicity, worse OS was observed in female, non-Hispanic Black, and non-Hispanic AI/AN. This study may provide insight on identifying needed treatment among patients with mCRC. Citation Format: Alicia C. McDonald, Xinyue Liu, Ruixuan Jiang, Jae Min, Pierre Leconte, Anne C. Deitz, Changxia Shao. Overall survival and treatment patterns in elderly patients with stage IV colorectal cancer in the United States: SEER-medicare analysis, 2007-2020 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 2302.