Abstract A023: Influence of pre-diagnosis obesity and post-diagnosis aspirin use on survival from stage IV colorectal cancer

Background: The relationship between obesity and colorectal cancer (CRC) outcome is poorly understood in late-stage patients. Increased body mass may negate aspirin use for cancer prevention, but the influence of body mass index (BMI) on post-diagnosis aspirin use is unclear. This study aims to evaluate impacts of pre-diagnosis BMI and post-diagnosis aspirin use on overall survival in late-stage CRC patients on the Assessment of Targeted Therapies Against Colorectal Cancer (ATTACC) clinical protocol. Methods: Patients with metastatic or treatment refractory disease were consented on the ATTACC protocol at MD Anderson Cancer Center and invited to complete a survey on risk factors relevant to CRC etiology. Using survey data, BMI was calculated from the decade prior to initial CRC diagnosis for 656 patients. Survival was measured from stage IV diagnosis until death or last follow-up. Cox Proportional Hazards models were constructed to estimate associations of pre-diagnosis obesity and post-diagnosis aspirin use with overall survival. Results: Controlling for age, sex, race, stage at initial diagnosis, and weight change between pre-diagnosis and survey date, patients with pre-diagnosis obesity had significantly higher likelihood of death (HR 1.45, 95% CI: 1.11, 1.91) compared to those with normal pre-diagnosis BMI. Further, only patients with normal weight pre-diagnosis experienced a survival benefit with post-diagnosis aspirin use (HR 0.59, 95% CI: 0.39, 0.90). Conclusions: Our findings suggest potentially differential tumor development resulting from the long-term physiologic host environment, here obesity. Confirmation and further evaluation are needed to determine whether pre-diagnosis BMI may predict benefit from post-diagnosis aspirin use. Citation Format: Jennifer S. Davis, Janelle C. Chavez, Melissa Kok, Yazmin San Miguel, Hwa Young Lee, Henry Henderson, Michael J. Overman, Van Karlyle Morris, Bryan Kee, David Fogelman, Shailesh M. Advani, Benny Johnson, Christine Parseghian, John Paul Shen, Arvind Dasari, Kenna R. Shaw, Eduardo Vilar, Kanwal P. Raghav, Imad Shureiqi, Robert A. Wolff, Funda Meric-Bernstam, Dipen Maru, David G. Menter, Scott Kopetz, Shine Chang. Influence of pre-diagnosis obesity and post-diagnosis aspirin use on survival from stage IV colorectal cancer [abstract]. In: Proceedings of the AACR Special Conference on Colorectal Cancer; 2022 Oct 1-4; Portland, OR. Philadelphia (PA): AACR; Cancer Res 2022;82(23 Suppl_1):Abstract nr A023.