Could a drug as simple and inexpensive as aspirin be used as a treatment for prostate cancer? A number of studies conducted over the past few years have suggested that aspirin may have a role in prostate cancer treatment. Here is a brief look at what researchers have discovered about aspirin and prostate cancer.
Prostate Cancer, Aspirin and Radiation Therapy
A study published in 2011 by researchers at Fox Chase reported on the effect of aspirin in 2,041 men who underwent radiation for treatment of prostate cancer. The men were followed-up ten years after they completed radiation treatment.
Overall, the 761 men who took aspirin had a lower risk of cancer recurrence (as indicated by a rise in PSA levels) than the 1,380 men who did not take aspirin. Specifically, 31% of men taking aspirin had a recurrence of prostate cancer compared with 39% of men who did not take aspirin.
According to Mark Buyyounouski, MD, MS, a radiation oncologist at Fox Chase and the team’s leader, “it’s a little premature to say that men need to start taking aspirin if they have a history of prostate cancer.” He also noted that while researchers are uncertain how aspirin worked to help the men in the study or what the optimal dose, timing, or length of aspirin therapy should be, “It’s possible aspirin therapy is making the radiation more effective or preventing the cancer from spreading.”
In another study one year earlier, researchers presented study results indicating that men who take aspirin or other anticoagulants when undergoing radiation treatment or surgery for prostate cancer may reduce their risk of dying of the disease by more than 50%.
All of the 5,275 men in this particular study had localized cancer and had been treated with surgery or radiation. A total of 1,982 were taking anticoagulants, including aspirin, clopidogrel, enoxaparin, and/or warfarin.
At 10 years after treatment, the authors found that
- Use of anticoagulants reduced the risk of dying from prostate cancer from 10% to 4%
- The reduced risk of dying was greater among patients who had high-risk prostate cancer
- The risk of the cancer spreading to the bones was also reduced
- Aspirin was more beneficial than the other anticoagulants
The lead author of the study, radiation oncologist Kevin Choe, MD, PhD, of the University of Texas Southwestern Medical School in Dallas, noted that “findings from this study are promising, however, further studies are necessary before the addition of aspirin to prostate cancer therapy becomes standard treatment.”
Aspirin and PSA Levels
Can aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs) lower PSA levels? Some studies suggest they can. At the University of Rochester Medical Center (URMC), a research team studied data from 1,319 cancer-free men older than 40 who had participated in the 2001-2002 National Health and Nutrition Examination Survey (NHANES) and documented their PSA levels and their use of aspirin, other NSAIDs, and acetaminophen.
According to first author Eric A. Singer, MD, MA, urology resident at URMC, men who regularly used aspirin and other NSAIDS had a PSA level that was about 10% lower than men who did not use the drugs.
However, Singer also warned that “there’s not enough data to say that men who took the medications were less likely to get prostate cancer,” and the researchers did not track to see how many of the men ever got prostate cancer.
The lower PSA levels may also be related to other factors. For example:
- A lowered PSA may reflect a reduction in inflammation (which aspirin and other NSAIDs treat) without having an impact on a man’s risk of prostate cancer
- A PSA level that is reduced by taking aspirin and other NSAIDs might artificially mask a man’s risk of developing prostate cancer
- Several other factors may cause a low PSA level, including obesity and use of statins
An important take-home message from this study, according to Singer, is “the importance for doctors to know what medications their patients are on.” Therefore if you are using aspirin or other NSAIDs, you should tell your doctor when undergoing a PSA test for prostate cancer screening.
This recommendation echoes one made in an earlier study from the University of Arizona, Tucson, published in Prostate in 2010. The 140 men in this study had prostate cancer and were part of a trial of selenium to prevent prostate cancer progression.
The investigators also looked at use of aspirin, other NSAIDs, and statins and their effect on PSA levels and PSA velocity (rate of PSA change over time). Overall, baseline PSA levels were significantly lower in men who took aspirin compared with those who did not. But among men who never smoked versus those who did smoke, PSA levels among aspirin users were reduced more.
The authors concluded their findings supported evidence that aspirin has an impact on PSA, especially among men who had never smoked. However, “they do not suggest a protect effect on the disease and support previous findings that aspirin may mask accurate measurement of PSA,” which supports doctors asking patients to stop taking aspirin for a period prior to PSA testing.
So, can aspirin treat prostate cancer? Study results indicate it is still too early to tell. However, it is apparent aspirin use is one thing to avoid before a PSA test, and the drug may also have a positive effect on prostate cancer. Men who have prostate cancer as well as those who schedule a PSA test should talk to their healthcare providers about their use of aspirin and other NSAIDs.
Sources
Algotar AM et al. Effect of aspirin, other NSAIDs, and statins on PSA and PSA velocity. Prostate 2010 Jun 1; 70(8): 883-88
Singer EA et al. PSA levels in relation to NSAID and acetaminophen consumption: results from the 2001-2002 National Health and Nutrition Examination Surveys. Cancer online 2008 Sep 8
Study presented at the 52nd Annual Meeting of the American Society for Radiation Oncology in San Diego, Nov. 3, 2010
