Many children undergoing treatment for cancer use herbal remedies, vitamins or other types of alternative therapies, a new research review suggests.

The review, of 28 studies involving 3,500 children, found that anywhere from 6 percent to 91 percent of study participants used some form of alternative or complementary medicine at some point during their cancer treatment. In half of the studies, the rate ranged between 20 percent and 60 percent.

It is not clear from the studies whether some children were receiving alternative therapies instead of a particular standard cancer treatment, or whether they were only being used in addition to conventional medicine, according to lead researcher Dr. Felicity Bishop, of the University of Southampton School of Medicine in the UK.

What the studies do indicate, she told Reuters Health by email, is that “a substantial proportion of pediatric cancer patients use complementary and alternative medicine at some point in their treatment.”

The bottom line for parents, according to Bishop, is that they should discuss any use of such therapies with their child’s doctor.

She and her colleagues report their findings in the journal Pediatrics.

The public often perceives alternative therapies as “natural” and safe. But while some approaches are unlikely to cause harm - like relaxation therapies to reduce stress - other alternative treatments may present a risk to cancer patients. Research has found, for example, that high-dose vitamin C, St. John’s wort and green tea compounds may interact with certain cancer drugs and lessen their effectiveness.

And few alternative therapies promoted for cancer patients have been subject to rigorous clinical trials to test their effectiveness.

Some recent studies have had promising results; for example, a clinical trial last year found that the herb milk thistle may help limit liver inflammation as a side effect of chemotherapy in children with acute lymphoblastic leukemia. Another found that adding flaxseed to the diets of men scheduled to undergo surgery for prostate cancer seemed to slow the cancer’s growth in some patients.

However, researchers caution that these are the first well-controlled clinical trials to evaluate those therapies, and more studies are needed before recommendations can be made.

In their review, Bishop and her colleagues found that herbal remedies were the most commonly reported alternative therapies, though use varied widely across the studies - with anywhere from 2 percent to 48 percent of children using herbs.

Between 3 percent and 47 percent of children used special diets or other nutritional therapies, while 3 percent to 30 percent used prayer or other forms of “faith-healing.” Other forms of alternative therapy included high-dose vitamins, mind-body therapies like meditation and relaxation techniques, and homeopathy.

In studies that asked parents why they had turned to alternative therapies, the most common reasons were “to cure or help fight the child’s cancer,” to help ease symptoms and to counter the side effects of conventional cancer treatment.

According to the U.S. National Cancer Institute, patients considering alternative therapy should speak with their doctors first to make sure it fits safely into their overall care. Doctors or staff at a patient’s cancer center may also be able to recommend an alternative-medicine practitioner. Some cancer centers now offer alternative- and complementary-medicine programs that can be integrated into standard care.

SOURCE: Pediatrics, April 2010.