Abstract 3704: Demographics of colorectal cancer patients vary by aspirin use
Authors: Davis Jennifer S. , Advani Shailesh , Banfield Emilyn , Overman Michael , Jiang Zhi-Qin , Manuel Shanequa , Daniel Carrie , Chang Shine , Kopetz Scott 
Published: August 2015

Abstract
Purpose: Regular NSAID (Non-Steroidal Anti-Inflammatory Drug) use results in an overall reduction in colorectal cancer (CRC) risk; however, this reduction may vary among molecularly defined subsets of CRC. Characterization of patients by regular NSAID use and molecular subtype will provide unique insight into the biology of NSAID-based CRC prevention.
Methods: A sample of patients was selected from the Assessment of Targeted Therapies Against Colorectal Cancer (ATTACC) protocol, which is designed to molecularly profile tumors of patients with refractory metastatic CRC. Demographic data and NSAID use were collected from a risk-factor survey. Demographic characteristics were compared between 106 non-NSAID users, 75 regular aspirin users and 78 regular non-aspirin NSAID users. Chi-square analysis was used to compare categorical variables and ANOVA was used for continuous variables. Logistic regression was used to assess predictors of aspirin or non-aspirin NSAID use compared to non-use.
Results: Preliminary results indicate that aspirin users tend to be older, male and more frequently engage in vigorous physical activity compared to non-users and users of non-aspirin NSAIDs (Table I). In univariate analyses, patients who are older or engage in more frequent vigorous physical activity are at increased odds of using aspirin. When controlling for other variables, only age at diagnosis predicts aspirin use.
Table 1.Description and AssociationsNo NSAID useAspirin useNon-Aspirin usep valueN1067578Age at Stage IV Diagnosis, Mean (SE)55.2 (1.0)59.5 (1.1)53.1 (1.3)0.0006Gender, N (%)11884810.0251Male72 (61.0)59 (72.8)44 (52.4)Female46 (39.0)22 (27.2)40 (47.6)Vigorous Physical Activity, N (%)11780840.0214Little or none50 (42.7)18 (22.5)34 (40.5)Once/week10 (8.6)14 (17.5)13 (15.5)Twice/week or more57 (48.7)48 (60.0)37 (44.1)Logistic RegressionUnadjusted Odds of Aspirin UseAdjusted Odds of Aspirin Use*OR (95% CI)p valueOR (95% CI)p valueAge at Stage IV Diagnosis1.047 (1.013, 1.081)0.00571.049 (1.014, 1.085)0.0055Gender (Female)0.584 (0.316, 1.078)0.08550.701 (0.356, 1.379)0.3032Vigorous Physical Activity (overall effect)0.00850.0486Little or none (Ref)1.001.00Once/week3.889 (1.468, 10.300)0.03692.481 (0.892, 6.906)0.2997Twice/week or more2.339 (1.207, 4.533)0.58952.305 (1.137, 4.673)0.2662*Each variable is adjusted for the other variables in the table
Conclusions: These preliminary data indicate that we will be able to distinguish aspirin users from non-NSAID users in a sample of late-stage CRC patients. Going forward, we will combine these demographic data with tumor molecular classification to determine the subtypes of CRC that are more or less prevalent in aspirin/NSAID users. Use of NSAIDs and overall survival will also be evaluated among different molecular subtypes of CRC. This data, combined with analysis of risk factors for each molecular subtype will provide unique insight into the biology of NSAID-based CRC prevention.
Citation Format: Jennifer S. Davis, Shailesh Advani, Emilyn Banfield, Michael Overman, Zhi-Qin Jiang, Shanequa Manuel, Carrie Daniel, Shine Chang, Scott Kopetz. Demographics of colorectal cancer patients vary by aspirin use. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3704. doi:10.1158/1538-7445.AM2015-3704