ASPO Abstracts
Pre-diagnostic obesity and post-diagnostic aspirin use influence survival in stage IV colorectal cancer patients
Category: Lifestyles Behavior, Energy Balance & Chemoprevention
Conference Year: 2020
Abstract Body:
Purpose: To evaluate effects of pre-diagnostic obesity and post-diagnostic aspirin use on s
survival in stage IV colorectal cancer patients.
Methods: Patients consented on the ATTACC protocol (Assessment of Targeted
Therapies Against Colorectal Cancer) at MD Anderson Cancer center were invited to
complete a twenty page environmental survey, including data on current, regular aspirin
use, and weight history. Pre-diagnostic obesity status was determined from self-reported
weight data by age decade. Patients were followed from the time of stage IV diagnosis
until death or date of last follow-up, which was censored. Survival was compared by BMI
category: obesity (≥30), overweight (25-30) and normal/underweight (<25). Cox
proportional hazards models were used to assess the effects of pre-diagnostic obesity
and post-diagnostic aspirin use on survival, adjusting for age at initial diagnosis, stage at
initial diagnosis, race/ethnicity and sex. Aspirin models were additionally adjusted for BMI
changes between pre-diagnosis and survey completion. Adjusted survival curves were
generated using the ‘DIRECTADJUST’ option. We included 682 patients with available,
non-missing data for pre-diagnostic obesity and regular aspirin use.
Results: Compared to patients with normal/underweight, those who were overweight or o
obese in the decade prior to diagnosis had significantly worse overall survival following s
stage IV diagnosis with Hazard Ratios (HR) of 1.28 (95% CI: 1.02, 1.61) and 1.66 (95% C
CI: 1.29, 2.13), respectively. We stratified by BMI category to evaluate the effect of a
aspirin use, finding significant survival benefit for patients who were normal/underweight (
(HR: 0.59, 95% CI: 0.39, 0.91) and patients who were obese (HR: 0.59, 95% CI: 0.38, 0
0.92), but not patients who were overweight (HR: 1.01, 95% CI: 0.71, 1.45) in the decade p
prior to diagnosis.
Conclusions: Pre-diagnostic BMI predicted survival in a stage IV population suggesting
persistent effects of pre-diagnostic weight status on tumor/patient biology. These findings
suggest persistent effects of the pre-diagnostic environment and may help to identify
subsets of patients who are more likely to benefit from post-diagnostic aspirin use.
Keywords: Colorectal Cancer Obesity Survival Aspirin