Aspirin negatively interacts with PCa hormone therapy

Baby aspirin appeared to interfere with the ability to deliver a full course of hormone therapy in 206 men with localized but high- or intermediate-risk prostate cancers who were enrolled in a study comparing radiation therapy alone with radiation therapy plus hormone therapy. In a letter to the editor of the New England Journal of Medicine (2007; 357:2737-8), Anthony V. D’Amico, MD, PhD, and Philip W. Kantoff, MD, of the Dana–Farber Cancer Institute, Boston, discussed the effects of low-dose aspirin on liver function tests.

Hormone therapy consisted of 6 months of a luteinizing hormone–releasing hormone agonist and the antiandrogen flutamide (Eulexin). A logistic-regression multivariable analysis was used to assess whether an association existed between commonly used drugs (aspirin or atorvastatin [Lipitor]) and the discontinuation of flutamide due to elevated values on liver function tests. The use of baby aspirin was significantly associated with abnormal liver function tests (p=.02), whereas the use of atorvastatin was not (p=.13).

Flutamide was prematurely discontinued in 37% of aspirin users compared with 16% of nonusers because of abnormal liver function tests. Moreover, after a median follow-up of 7.6 years and adjustment for known prognostic factors and interactions, and with men who completed 6 months of hormone therapy with both the LHRH agonist and flutamide as the comparison group, the risk of death was 3.5 times as high among men who completed 6 months of the LHRH agonist but discontinued flutamide early (p=.04) and 6.1 times as high among men treated with radiation therapy alone (p<.001). These data show that a commonly used drug can alter the tolerability of anticancer therapy.