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By Alan R. Gaby, MD
Healthnotes Newswire (March 6, 2003)—A team of researchers has developed a set of guidelines to help doctors advise their patients about the safety and efficacy of various treatments for cancer. Their report, published in the Annals of Internal Medicine (2002:137:889–903), evaluates a wide range of therapies, including dietary modifications, nutritional supplements, herbs, acupuncture, massage therapy, and exercise.
Massage therapy may help relieve anxiety associated with cancer. A specific massage technique, called manual lymph drainage, was found to be beneficial for women with chronic swelling and pain in the arm (lymphedema) after surgery for breast cancer. Several precautions were suggested in relation to the use of massage in cancer patients. The therapist should avoid the area directly over known tumors (in order to minimize the possibility of spreading the tumor), should not massage over areas of bone that might be affected by the cancer (in order to reduce the risk of fracture), and should avoid deep massage in people who are prone to bleeding.
According to the report, acupuncture can help control chemotherapy-related nausea and may also be useful for the treatment of cancer-related pain.
Of the nutritional supplements evaluated, vitamin E in relatively small amounts (approximately three times the Recommended Dietary Allowance) was found to reduce the risk of prostate cancer. Vitamin A and beta-carotene, on the other hand, showed little evidence of benefit; in fact, taking beta-carotene actually increased the risk of lung cancer in smokers. Vitamin C was judged to be ineffective as a treatment for cancer; moreover, taking large amounts of this vitamin could potentially increase the risk of bleeding. Consequently, it was recommended that the use of vitamin C as a treatment for cancer be discouraged. No evidence was found to indicate that shark cartilage is an effective treatment for cancer.
The authors of the report reached their conclusions after reviewing a large body of published research. They relied mainly on randomized clinical trials, when they were available, and gave less weight to intervention trials that lacked a control group and to observational (epidemiological) studies.
While this report will help practitioners and the public to make wiser and better-informed choices regarding the prevention and treatment of cancer, its recommendations are by no means the final word. Many cancer treatments have not been well studied, and recommendations concerning their use will be updated as additional research is done. Furthermore, some of the conclusions reached in this report appear to have been based on a superficial analysis of the evidence.
For example, one study suggested that taking large amounts of vitamin C (10 grams per day) can prolong the lives of terminal cancer patients by more than five-fold. In that study, 8 of 100 terminal patients experienced dramatic improvement, and were still alive an average of 3.5 years after starting vitamin C supplementation. That study was not considered in the new report because it was not a randomized trial. However, the negative research that was reviewed had serious flaws. In the most widely publicized negative study, vitamin C supplementation was given only for a few months, rather than for the rest of the patients' lives, as in the positive study. Second, vitamin C therapy was abruptly withdrawn during the study, and the patients were immediately put on chemotherapy. Abruptly discontinuing vitamin C may result in "rebound" vitamin C deficiency, and giving chemotherapy in the face of acute vitamin C deficiency could increase the toxicity of the drugs. Third, there was evidence that the patients assigned to placebo were able to identify which treatment they were receiving, and that some patients in the placebo group were taking large amounts of vitamin C on the sly.
Concerning the alleged risk of bleeding from high-dose vitamin C, that side effect has never been reported to occur, even in people taking enormous quantities of vitamin C.
Despite its weaknesses, this report provides a great deal of useful information regarding the prevention and treatment of cancer. However, it also underscores the fact that a great deal remains unknown and that additional research is urgently needed.
Alan R. Gaby, MD, an expert in nutritional therapies, testified to the White House Commission on CAM upon request in December 2001. Dr. Gaby served as a member of the Ad-Hoc Advisory Panel of the National Institutes of Health Office of Alternative Medicine. He is the author of Preventing and Reversing Osteoporosis (Prima, 1994), and co-author of The Natural Pharmacy, 2nd Edition (Healthnotes, Prima, 1999), the A–Z Guide to Drug-Herb-Vitamin Interactions (Healthnotes, Prima, 1999), Clinical Essentials Volume 1 and 2 (Healthnotes, 2000), and The Patient’s Book of Natural Healing (Prima, 1999). A former professor at Bastyr University of Natural Health Sciences, in Kenmore, WA, where he served as the Endowed Professor of Nutrition, Dr. Gaby is the Chief Medical Editor for Healthnotes, Inc.
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