Obesity Before Colorectal Cancer Diagnosis, Aspirin Use Linked to Worse Survival Outcomes

Obesity history may be useful in anticipating benefit from postdiagnosis aspirin use in tumor biology and survival outcomes.

Having obesity before a diagnosis of colorectal cancer (CRC) is associated with significantly worse overall survival, and adjuvant aspirin use is associated with improved survival outcomes in individuals with a normal body weight before diagnosis. These study results were published in JAMA Network Open.

The cross-sectional study enrolled participants from the Assessment of Targeted Therapies Against Colorectal Cancer protocol who were treated at a cancer center from 2010 through 2018. The patients were aged 18 years and older and had prior failed treatment with systemic chemotherapy for metastatic CRC.

Study participants reported regular use of aspirin or nonaspirin nonsteroidal anti-inflammatory drugs, and the number of pills taken daily, weekly, monthly, or yearly, as well as years used. Patients also provided their weight history within the past year and for the following ages: 14 to 19 years, mid-20s, mid-30s, mid-40s, mid-50s, mid-60s, and 70 years and older.

Researchers evaluated the association of regular, adjuvant aspirin use and prediagnosis obesity as combined factors with overall survival. Survival time was measured from stage IV diagnosis until death or the last follow-up date. Body mass index (BMI) was classified as normal weight (≤24.9 kg/m2), overweight (25.0 to 29.9 kg/m2), or obese (≥30.0 kg/m2).

Importantly, our findings suggest prediagnosis BMI may be useful in identifying patients who may benefit from postdiagnosis aspirin use, even in the setting of metastatic CRC.

Among 656 participants, 38.3%, 36.3%, and 25.4% had normal, overweight, and obese prediagnosis BMI, respectively. The majority of patients (63.1%) were between ages 45 and 65 years at initial diagnosis, 42.7% were women, 76.4% were non-Hispanic White, 60.7% had never smoked, and 14.2% had diabetes.

Individuals with an obese prediagnosis BMI had an increased likelihood of death vs those with a normal prediagnosis BMI (hazard ratio [HR], 1.45; 95% CI, 1.11-1.91), after adjustment for age category, sex, race, diagnosis stage, and weight change. Those who had 10% or more weight gain had a reduced likelihood of death compared with those who had no change (HR, 0.75; 95% CI, 0.60-0.95).

Participants who had an overweight or obese prediagnosis BMI had an increased likelihood of death vs individuals with normal prediagnosis BMI, which was partially mediated by weight change (overweight: HR, 1.04; 95% CI, 1.00-1.08; obese: HR, 1.11; 95% CI, 1.02-1.21).

Aspirin users had a reduced likelihood of death vs nonusers (HR, 0.59; 95% CI, 0.48-0.90), with a significant interaction between prediagnosis BMI and aspirin use. Individuals with a normal BMI prediagnosis had significantly improved survival with postdiagnosis aspirin use (HR, 0.59; 95% CI, 0.39-0.90), and those with an overweight BMI did not. Participants with an obese prediagnosis BMI had a nonsignificant survival benefit with postdiagnosis aspirin use (HR, 0.79; 95% CI, 0.48-1.08).

Study limitations include analyzing data from patients who were initially diagnosed at stage IV and patients diagnosed at earlier stages who then progressed. Also, the inability to account for variations in treatment may have resulted in an overestimation of association for prediagnosis obesity and postdiagnosis aspirin use. Furthermore, complete data were lacking for all participants, weight history was self-reported, and waist circumference measurements were not available.

“This study provides intriguing evidence supporting the association of obesity with CRC biology during carcinogenesis,” the study authors wrote. “Importantly, our findings suggest prediagnosis BMI may be useful in identifying patients who may benefit from postdiagnosis aspirin use, even in the setting of metastatic CRC.”

Disclosure: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.

This article originally appeared on Gastroenterology Advisor

References:

Davis JS, Chavez JC, Kok M, et al. Association of prediagnosis obesity and postdiagnosis aspirin with survival from stage IV colorectal cancer. JAMA Netw Open. 2022;5(10):e2236357. doi:10.1001/jamanetworkopen.2022.36357