The use of complementary and alternative medicine is a well-known phenomenon among cancer patients, and prostate cancer patients are no exception. The review article by Drs. Das and Kaplan nicely summarizes most of the data available on the use of PC-SPES, selenium(Drug information on selenium), and vitamin E(Drug information on vitamin e) by prostate cancer patients. These three agents are probably the most widely used complementary approaches in prostate cancer, and they are the ones that have been studied most extensively. However, true data on efficacy, careful toxicity analyses, dose-response analysis, or pharmacokinetic analyses of these agents are extremely limited.
Perhaps the article’s first lesson is that the use of complementary and alternative medicine among prostate cancer patients is increasing. It is hard to know exactly what percentage of patients use these therapies, although the exact percentage probably depends on the sample surveyed. Support groups, urology practices, and tertiary referral centers may include a larger proportion of patients who have explored the use of complementary medicine.
In any case, this article points out that it behooves us to take a careful medical history from our patients because published series suggest that one-third or more of prostate cancer patients use some form of complementary medicine. At our institution, for example, we no longer ask patients, "What medicines are you taking?" We ask specifically, "Are you taking any supplements, vitamins, herbal products, or other over-the-counter compounds?" A comprehensive questionnaire listing the most commonly used agents is useful to this end.
Why should we care what over-the-counter products our patients take? First, we should not assume that these compounds are benign. (And even if they have not caused any adverse events as single agents, they essentially represent black boxes that may interact with other prescribed or nonprescribed medications.) Second, as we evaluate the efficacy of novel therapeutics for patients, we need to know if any confounding variables exist.
For example, we now know that PC-SPES is capable of modulating the expression of prostate-specific antigen (PSA) in virtually all patients with hormone-sensitive disease and a majority of patients with hormone-refractory or androgen-independent disease. If use of a novel agent is initiated and we are unaware that the patient has also recently started taking PC-SPES, we and our patients are blinded as to which agent or combination of agents is, in fact, providing clinical benefit.
This article provides physicians with a useful tool for discussing with their patients what is known about the use of PC-SPES, vitamin E, and selenium. In addition to the authors’ conclusion that it is extremely important that physicians and other health-care professionals understand the potential role and side effects of these therapies, the importance of relaying this information to patients as nonjudgmentally and objectively as possible also needs to be emphasized.