Bernstein and Grasso present a survey
of the use of complementary and alternative medicine (CAM) by cancer patients.
Like many such surveys, they report a high prevalence of CAM use. What is of
concern in their findings, however, is the widespread use of modalities that may
interact with conventional cytotoxic therapy. This observation is particularly
worrisome given that the surveyed patients were largely in the first year after
diagnosis, and thus were likely to have been using CAM therapies concurrently
with conventional treatment.
Interactions Between CAM and Conventional Treatment
Nearly half of the patients surveyed by Bernstein and Grasso
were using herbal (or "botanical") medicine. Botanical agents are
pharmacologically active, particularly with respect to liver metabolism. When a
botanical slows or speeds the metabolism of a chemotherapeutic agent, increased
toxicity or lowered efficacy may result. St. John’s wort is the best known of
several botanical treatments that interact with enzymes in the cytochrome P450
family, in particular, CYP3A4. Experimental data show reduced concentrations
of indinavir (Crixivan) resulting from the use of St. John’s wort.
Decreased levels of chemotherapy agents metabolized by CYP3A4, such as the
taxanes, have not been demonstrated empirically but remain a possible concern.
It has also been shown that pretreatment of cancer cells with
botanical agents may lower their sensitivity to chemotherapy. For example,
pretreatment of colon cancer lines with berberine markedly reduces paclitaxel (Taxol)-induced
apoptosis and cell-cycle effects. The apparent mechanism of action is
upregulation of the multidrug-resistance transporter, pgp-170. Berberine is
the main constituent of huanglian, a botanical medicine with in vitro
antiproliferative activity against tumor lines.
A further mechanism of interactions between CAM and
conventional cancer treatment concerns antioxidants. The activity of
radiotherapy and of many chemotherapy drugsincluding the alkylating agents,
anthracyclines, and podophyllum agentsdepends, at least in part, on the
production of free radicals. Many dietary supplements (such as vitamin C) are
strong antioxidants, and some botanicalsfor example, garlic and ginsenghave
marked antioxidant properties. Concurrent administration of antioxidant
supplements or botanical products may reduce the efficacy of radiotherapy and of
chemotherapy agents that act by producing oxidative damage.
In looking at the tables in the Bernstein/Grasso article, it
seems likely that more than half of the cancer patients surveyed were using a
CAM therapy that, in theory at least, could either reduce the effectiveness or
increase the toxicity of conventional therapy. This possibility is clearly of
great concern. There is a need for greater public and professional awareness of
the risks associated with the use of botanical and dietary supplements by cancer
patients. Research to identify and define such risks more precisely is also
The Problem of Alternative Medicine
Bernstein and Grasso explicitly surveyed respondents’ use
of several "alternative" cancer treatments, including Gerson therapy
and the Hoxsey method. It is not surprising that no respondent appeared to have
used these modalities. Alternative therapies are, by definition, used instead of
conventional medicine. For example, the "Gonzalez" regimen involves
diet, vitamins, enzymes, and enemas to treat cancer. An unusual form of hair
analysis is used to guide treatment. The originator of the technique has stated
that "You don’t do chemotherapy and Gonzalez. You do one or the
Any survey (such as the one described in the article) that
interviews patients who present to a conventional cancer center will fail to
identify those who have turned to alternative medicine. The only methods capable
of identifying such patients involve sampling directly from alternative cancer
practices (see, for example, the seminal study by Cassileth et al) or sending
questionnaires to the homes of patients identified through cancer registries
(see the study by Rees et al). These methods have not been applied in the
United States recently. The number of patients currently leaving conventional
care to subscribe solely to alternative cancer treatments is not well
Complementary Therapies and Supportive Care
Bernstein and Grasso report that a significant proportion of
cancer patients use complementary therapies such as massage (1 in 5 respondents)
and relaxation techniques (1 in 3 respondents). These modalities are popular
among cancer patients because they address the psychological and physical
symptoms, such as anxiety and pain, that commonly result from cancer and its
Complementary therapies are increasingly available as part of
the supportive services offered at conventional cancer centers. For example, a
support program offered at the Carol Franc Buck Breast Care Center of the
University of California, San Francisco/Mt. Zion, includes meditation and yoga.
At Memorial Sloan-Kettering Cancer Center, acupuncture, massage, and relaxation
therapies are available both on the inpatient wards and at a special outpatient
It may be time for surveys of CAM in cancer to separate
"complementary" from "alternative" medicine. Is taking shark
cartilage to cure cancer really the same sort of behavior as having a massage to
treat pain and anxiety? Probably not, and surveys should avoid treating them as
such. In terms of cost, avoidance of proven treatment, side effects, and
interactions with conventional medicine, alternative cancer therapy is vastly
more problematic than complementary therapy. Further sociologic research should
therefore focus on the problem of alternative medicine. Research that relies on
patients visiting conventional cancer centers will not include patients who have
abandoned conventional care to seek alternative cures. Researchers need to find
creative ways to identify such patients and describe their behavior.
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