Many in cancer drug trials use herbs, supplements

NEW YORK (Reuters Health) - The use of herbal medicine is common among patients with advanced cancer who are participating in early-stage clinical trials (phase I) of experimental drugs, according to a new study.

Based on these findings, physicians who are running these trials should question patients "intensively (yet sensitively)" about their use of complementary and alternative medicines, Dr. Christopher K. Daugherty of the University of Chicago and colleagues recommend.

Phase I trials, are conducted to test drugs for toxicity and determine the best dosage, they add, and certain herbs and supplements could interfere with the results.

Little is known about complementary and alternative medicine use among patients in cancer clinical trials, Daugherty and his team note in the Journal of Clinical Oncology. To investigate, they surveyed 212 patients with advanced cancer who had recently consented to participate in phase I trials. All of the patients were interviewed about a week before the trial began.

Thirty-four percent said they used some type of biologically based alternative medicine, such as an herbal drug, a supplement, vitamins or minerals. About half used herbal drugs, and about half said they used vitamins or minerals.

The patients who reported alternative medicine use were younger, with an average age of 55 years compared with an average age of 62 years among those who didn't report using these medicines.

Study participants who said they believed they would die within the year were also more likely to report using alternative medicines. Users of alternative medicines, which are not regulated by the Food and Drug Association, reported a worse quality of life than non-users.

Daugherty and his colleagues note that some patients took high-dose vitamin C or St. John's wort, both of which have been shown to interact with chemotherapy drugs. Using such medicines "could result in an investigational agent's toxicity to be overestimated or underestimated." This could lead to future trial participants being given too much or too little of the drug, they add.

The researchers conclude: "Physician-investigators need to be fully aware of their patients' complementary and alternative medicine use to both effectively care for patients and conduct scientifically sound clinical trials."

SOURCE: Journal of Clinical Oncology, February 10, 2007.