About 215,000 men are diagnosed with prostate cancer annually in the United States, and about 28,500 die from the disease. Older men are at highest risk and are also likely to be using cardioprotective aspirin, as recommended by the US Public Health Service. In the August 27, 2012, issue of the Journal of Clinical Oncology, researchers led by Kevin S. Choe, MD, of the University of Texas Southwestern Medical Center, report that antithrombotic therapy, particularly with aspirin, reduces mortality associated with prostate cancer over a mean follow-up period of 70 months.
Dr Choe and colleagues investigated long-term outcomes of men with biopsy-proven prostate cancer who were included in a longitudinal, observational study called Cancer of the Prostate Strategic Urologic Research Endeavor (CaPSURE). A total of 5,995 men were enrolled, of whom 4,028 were treated with radical prostatectomy and 1,927 were treated with radiotherapy (27% with androgen deprivation therapy). Within the group, 37% (n=2,175) used antithrombotic medications, predominantly aspirin (n=1,897). Gleason scores and T-stage distributions were similar between the groups receiving or not receiving antithrombotics, and similar percentages required salvage therapy. A smaller proportion of men in the antithrombotic therapy group had high-risk disease, had lower mean PSA scores, were older with longer follow up, and were more likely to have received radiotherapy (each, P<0.01).
During follow up, 193 men died from prostate cancer. The 10-year risk of prostate-cancer specific mortality (PCSM) was significantly lower (P<0.01) among men using antithrombotics than among men not using them, 3% vs. 8%. The benefit of antithrombotic use was most evident among men with high-risk disease (4% vs. 19%; P<0.01); a lesser benefit was seen for those with intermediate-risk disease, and the difference among men with low-risk disease was not significant. An analysis by antithrombotic type showed a clear benefit for aspirin, with a hazard ratio versus no aspirin of 0.28 (95% CI: 0.19, 0.41; P<0.01). Non-aspirin antithrombotic use lowered PCSM, but to a lesser extent (P=0.06). In multivariable analysis, aspirin use emerged as an independent variable associated with lower PCSM (P=0.02), whereas non-aspirin antithrombotic use had no significant association.
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There is substantial evidence for aspirin’s efficacy in cancer prevention and in reducing mortality associated with colorectal cancer and lymphomas (see “Aspirin Use in Cancer Prevention,” published in ChemotherapyAdvisor.com on July 26, 2012). This study extends that evidence to prostate cancer, with significant reductions in mortality. As an observational study, it has limitations related to the researchers’ ability to control for confounding variables, such as the dosage or duration of aspirin use, comorbidities, or concomitant medication use, and the authors suggest a randomized study to confirm their results. In the meantime, the findings present another compelling reason for clinicians and patients to ensure that recommended preventive medications are being used.
Questions for Readers
-Are you prescribing aspirin to your patients as a form of cancer prevention or to reduce cancer mortality?
-Or, do you think that aspirin use for cancer prevention/to reduce cancer mortality is overrated?
Readers: We’d love to hear from you in the comments section below! If you have a case study or a more extended response to this subject, click here to submit an item for us to publish.
References
Centers for Disease Control and Prevention. Prostate Cancer Risk by Age. http://www.cdc.gov/cancer/prostate/statistics/age.htm. Updated August 13, 2010. Accessed September 5, 2012.
Centers for Disease Control and Prevention. Prostate Cancer Statistics. http://www.cdc.gov/cancer/prostate/statistics/. Updated April 30, 2012. Accessed September 5, 2012.
Choe KS, Cowan JE, Chan JM, et al. Aspirin use and the risk of prostate cancer mortality in men treated with prostatectomy or radiotherapy. J Clin Oncol. Published online ahead of print
US Preventive Services Task Force. Aspirin for the Prevention of Cardiovascular Disease. Recommendation Statement. http://www.uspreventiveservicestaskforce.org/uspstf09/aspirincvd/aspcvdrs.htm. Published March 2009. Accessed September 5, 2012.
