Should medications be used for primary prevention of disease?
There may be drugs that help prevent disease. As physicians, we want to do what is best and right — and easiest — for our patients. In an ideal world, we could prescribe a pill to drastically reduce the risk of chronic disease. In our zeal, we have to tread cautiously, though, and remember the adage from the Hippocratic Oath: first, do no harm.
More drugs are being evaluated for primary prevention, meaning stopping disease from occurring in the first place. Doesn’t it seem paradoxical that we would give “healthy” people medications? However, there are several recent trials with seemingly impressive results that looked at preventing cancer and its metastases, prostate cancer, high blood pressure, diabetes, strokes and even heart attacks.
Preventing cancer and its metastases
There has been much discussion over the years about using aspirin for the prevention of colorectal cancer. I was at a lecture a month ago where the lecturer said the results were so convincing he might even consider taking aspirin. There are three new studies investigating aspirin’s potential role in cancer and its distant metastases — tumors in other parts of the body.
One of the trials was a meta-analysis (group of 34 trials) of over 69,000 participants that was published in The Lancet online on March 21. The results showed a 15 percent reduction in the risk of deaths from cancer when taking aspirin on a daily basis compared to no aspirin. This means we should all be taking aspirin, right? Not so fast.
This trial had several limitations (The Lancet editorial online, March 21). First, there was a significant risk of bleeding in the first three years of taking the drug, after which time the bleed risk diminished and the cancer benefit continued. Second, these trials were designed for cardiovascular disease, so there was no initial assessment for cancer.
Third, two very large, randomized clinical trials, the Women’s Health Study and the Physicians’ Health Study, were excluded from the analysis, because they gave aspirin every other day. However, neither of these trials showed any cancer reduction benefit. Therefore, in order to benefit, it would seem that people would have to be diligent about taking medication every day, even without symptoms. We all know how well that works.
Another meta-analysis (group of five studies) showed a significant reduction in distant metastases — 36 percent. For those who developed cancer, there was a 70 percent reduction in distant metastases (The Lancet online, March 21). These results are impressive. However, yet again, the analyses were of trials designed for cardiovascular disease, not cancer.
In a third meta-analyses using aspirin, there were conflicting results. Five studies showed a reduction in disease metastases of 31 percent, while seven studies did not show this effect (The Lancet Oncology online, March 21). We may need studies focused on preventing cancer deaths as their primary endpoints in order to make definitive statements about using aspirin in healthy patients.
Prevention of prostate cancer
Avodart (dutasteride) is a drug used for the treatment of enlarged prostate: BPH. In a randomized controlled trial called the REDUCE trial, results showed that Avodart could reduce the risk of prostate cancer by almost 23 percent over four years with healthy men who were at high risk of the disease (N Engl J Med. 2010;363;1192-1202). These positive results were due mainly to a reduction in low-risk benign tumors.
However, beyond the drug’s common side effect of impotence, it also has a twofold increased risk of metastatic prostate cancer. Therefore, the FDA not only rejected the drug for prevention, but also issued a warning about the risk of high-grade prostate cancer risk. These drugs also appear to suppress PSA levels, giving patients a false sense of security.
Prevention of strokes and heart attacks
In last week’s article on the role of statins, I wrote that the JUPITER trial showed statins may be beneficial for primary prevention (N Engl J Med 2008; 359). The FDA approved a statin, Crestor (rosuvastatin) for primary prevention of heart disease in patients without high cholesterol but a slightly elevated inflammatory factor, hsCRP, in February 2010. However, a Cochrane meta-analysis of 14 studies refuted this claim (Cochrane Database Syst Rev 2011; 1: CD004816).
Unfortunately, there is not a panacea. With many, if not all, drugs come side effects. One of the big problems with drugs is that they throw off our bodies’ homeostasis (equilibrium), making them hard to justify for primary prevention. However, we control our own fates, and lifestyle changes play a tremendous role in shaping our futures. All of the diseases mentioned above are impacted substantially by the choices we make every day: our environment, exercise and the food we eat.
Dr. Dunaief is a speaker, author and local lifestyle medicine physician focusing on the integration of medicine, nutrition, fitness and stress management. For further information, go to the website www.medicalcompassmd.com and/or consult your personal physician.