Despite decades of searching, scientists are still struggling to find a cure for cancer. And though some conventional treatments can slow the spread of the disease, many are highly toxic and have harsh side effects. So it's no surprise that six of 10 people with the disease try some form of alternative (also called complementary) therapy, according to a survey by scientists at the National Institutes of Health (NIH) which was published in the May 2000 issue of the journal Oncology Nursing Forum. Partly because so many patients are turning to alternative approaches, mainstream researchers are beginning to put these unproven therapies to the test in carefully controlled studies. Here are some of the most popular.
What it is: A mixture of eight Chinese herbs purported to treat prostate cancer.
Summary: The "natural" mixture was shown to be contaminated with synthetic drugs.
The evidence: In the Sept. 4, 2002, issue of the Journal of the National Cancer Institute, researchers analyzed eight lots of PC-SPES produced between 1996-2001. All lots contained various concentrations of the drugs Coumadin, Indocin, and DES. Coumadin is a blood thinner, and Indocin and DES have shown cancer-fighting properties.
Side effects and cautions: In a study reported in The New England Journal of Medicine on September 17, 1998, all men who tried PC-SPES experienced some breast tenderness and loss of libido. The synthetic drugs in PC-SPES could interfere with other drugs being taken.
What they are: Support groups, relaxation therapies, visual imagery, stress reduction techniques, and other approaches used to help patients relax and focus their minds on easing the symptoms of cancer and chemotherapies. Some researchers believe these techniques can even help patients fight the disease.
Summary: There's strong evidence that mind-body techniques ease symptoms, and preliminary evidence that they can also increase survival time.
The evidence: In a landmark study published in the Oct. 14, 1989, issue of The Lancet, Stanford University psychiatrist David Spiegel, MD, found that women with breast cancer who took part in weekly support groups in addition to their regular treatments lived twice as long, on average, as women who received only conventional therapy. In a follow-up trial, reported in 1999 in the journal Psycho-oncology, Spiegel studied 111 patients with breast cancer. Patients taking part in support groups experienced a 40% decrease in their scores on a scale that measures degree of mood disturbance and a similar drop on a scale that measures anxiety and depression in hospital patients. A wide variety of mind-body techniques are currently being tested at the NIH and at research centers around the country.
Side effects and cautions: The only worry is that some patients may choose mind-body techniques as a substitute for conventional therapy, rather than opting for both. The real benefits of these techniques, most researchers agree, are seen when they are used as a complement to more mainstream treatment.
What it is: A powder or extract made from the connective tissue of sharks, which is purported to contain substances that can shrink tumors.
Summary: There is no solid evidence that shark cartilage fights cancer, and several studies that show it's worthless.
The evidence: According to research published in the November-December 1998 issue of the journal Anticancer Research, scientists in Taiwan identified potent substances in shark cartilage that can block the formation of blood vessels to tumors. A dose of 200 micrograms of shark cartilage extract given to mice was enough to suppress the growth of melanomas, the researchers reported. Unfortunately, those promising findings haven't been repeated by other scientists.
Dutch researchers found no evidence that shark cartilage slowed the growth or reduced the size of tumors in mice, according to a report in the journal Acta Oncologia in 1998. What's more, research published in the Journal of Clinical Oncology in November 1998, found no evidence of tumor regression in any of 47 patients given shark cartilage. More clinical trials are under way.
Side effects and cautions: In the Journal of Clinical Oncology report, five patients had to be taken off shark cartilage treatment because they experienced nausea, vomiting, or constipation. Many cancer doctors worry that patients will use this unproven treatment in lieu of standard therapy. Environmentalists worry that the use of shark cartilage could endanger shark populations.
The Gonzalez Protocol
What it is: A complicated regimen that includes taking oral pancreatic enzymes, coffee enemas, and more than 150 pills daily, including vitamins, minerals, papaya extract, and animal glandular extracts. It is purported to treat pancreatic cancer.
Summary: One very small study shows promise. This approach requires strict physician supervision.
The evidence: In a preliminary study of just 11 patients, Nicholas Gonzalez, MD, reported that five patients survived more than two years on the regimen -- nearly three times longer than most patients with this rapidly fatal form of cancer. Pancreatic enzymes are believed by some researchers to have cancer-killing properties, although the evidence is far from complete. The NIH is conducting a five-year clinical study of the Gonzalez protocol.
Side effects and cautions: The Gonzalez protocol is a very demanding regimen which should only be undertaken under a doctor's strict supervision, because of the potentially toxic effects of combining many different supplements.
Summary: Preliminary findings show real promise. Be sure to check with your doctor about dosage.
The evidence: In findings published in the May 1998 issue of the British Journal of Urology, 974 men with prostate cancer were given either 200 micrograms of selenium supplements or placebo pills daily for a period of about 4.5 years. Men in the supplement group had a 63% reduction in the incidence of new prostate tumors. They were also significantly less likely to die from all forms of cancer within the 6.5 years that researchers tracked them. Three large randomized trials funded by the National Cancer Institute found that taking vitamin E and selenium significantly lowered lung cancer risk.
Side effects and cautions: At high doses, selenium can be extremely toxic. Ingesting vitamin E at doses higher than 1,000 IUs can thin the blood and cause internal bleeding. Experts caution against taking very high doses of either of these supplements without consulting a doctor.
What it is: A strict diet that eliminates meat and dairy products and derives 50% to 60% of its calories from whole grains, 25% to 30% from vegetables, and the rest from beans, seaweed, and other plant sources.
Summary: There is strong evidence that plant-based diets can help prevent cancer. The effectiveness of these diets as a treatment remains controversial.
The evidence: Although there is no direct evidence yet that a macrobiotic diet will prevent or slow the growth of tumors, there is plenty of evidence that its components are potent cancer-fighters. In a report in the journal Nutrition and Cancer in August 1998, epidemiologist Larry Kushi, PhD, and his colleagues showed that a diet very rich in whole-grain foods can protect against a variety of cancers. Hundreds of studies have found an association between vegetable consumption and a lower risk of many forms of the disease, including colon, lung, prostate, and breast cancers, according to epidemiologist John Potter, PhD, of the Fred Hutchison Cancer Research Center in Seattle. More clinical trials are under way.
Side effects and cautions: Although a macrobiotic diet is very rich in vitamins and minerals, it is low in protein compared with the average American diet. Patients are advised to talk to their doctors before beginning any strict diet regimen.
Peter Jaret is a freelance writer based in Petaluma, Calif. His work has appeared in Health, Hippocrates, National Geographic, and many other publications.
Originally published July 24, 2000.
Medically updated April 9, 2003.