The findings are cause for some concern, since some vitamins and herbs may cause harmful interactions with cancer drugs, so it is important for patients and doctors to discuss openly complementary and alternative medicine, according to the study's authors.

"Whether we call these approaches medicines, alternatives, unconventional or complementary approaches, or natural herbal remedies, interest in them is here to stay," states a team of researchers led by Dr. Mary Ann Richardson, who was at the University of Texas-Houston School of Public Health at the time of the study.

Physicians need to "improve communication and drop the don't ask, don't tell' approach," Richardson, who is now at the National Center for Complementary and Alternative Medicine, in Bethesda, Maryland, told Reuters Health. According to Richardson, about 75% of patients in the survey wanted more information about complementary and alternative medicine, and about half of those would like to get this information from their physicians. She also noted that it is important to catalog the use of complementary and alternative treatments, particularly vitamins and high-dose antioxidants, since they may interfere with medical treatment.

Richardson and her colleagues surveyed the use of unconventional medicine by 453 people who were undergoing outpatient treatment for cancer at one of eight clinics at The University of Texas M.D. Anderson Cancer Center, in Houston. More than 99% of the patients had heard of complementary and alternative medicine, and about 83% had tried at least one approach, the researchers report in the July issue of the Journal of Clinical Oncology. The most commonly used alternatives included spiritual practices like prayer, vitamins and herbs.

Even when the researchers excluded spiritual practices, psychotherapy and support groups, more than two-thirds reported using at least one unconventional therapy. Of these patients, 38% had used herbs like essiac tea, mistletoe and Ayurveda, while about 60% had used vitamins, including melatonin and shark cartilage.

Women, younger people, those who had undergone cancer surgery or who were poor were more likely to use alternative treatments. People provided a range of reasons for choosing unconventional therapy, including a desire to improve quality of life, to boost the immune system and to prolong life. A substantial proportion of people had higher hopes for alternative treatment, with almost 38% reporting that they hoped it would cure their cancer.

Many doctors remained in the dark about their patients' use of complementary and alternative medicine, according to the report. About 60% of participants said that they had not discussed the topic of alternative and complementary medicine with a physician. But when the researchers asked about specific alternative treatments, about 38% of patients said that they had not told a physician.

The study does not appear to be an isolated case, since another study appearing in the same journal also indicates that many cancer patients use alternative and complementary therapy without informing a physician.

In the study, which included 411 breast cancer survivors living in Ontario, Canada, about two-thirds said that they had used some sort of unconventional treatment, but just under half had told a physician.

SOURCE: Journal of Clinical Oncology 2000;18:2505-2521.