"I recommend mistletoe as a Christmas decoration and for kissing under, but not as an anticancer drug," writes Edzard Ernst, MD, PhD, FRCP, FRCPEd, in BMJ (formerly called British Medical Journal).
Ernst directs the complementary medicine department at the University of Exeter and Plymouth's medical school in England.
He points out that in Europe many cancer patients take mistletoe preparations and that Germany's insurance system covers mistletoe treatment.
In the U.S., the FDA hasn't approved any mistletoe cancer drugs.
Mistletoe studies have yielded mixed results and have often been "methodologically weak," Ernst says.
BMJ includes a report about a woman in Wales with inflammation under the skin where she had given herself mistletoe extract injections over the past year.
The 61-year-old woman previously had a type of cancer called lymphoma. With her cancer in remission, she began giving herself three weekly injections of mistletoe extract in her belly.
Ten months later, she had a breast tumor surgically removed. At a follow-up appointment, she complained that she had a mass in her abdomen.
Doctors removed the abdominal mass, which wasn't cancerous.
The mistletoe extract may have caused inflammation that led to the mass, which was located near the injection site, write University Hospital of Wales' Alison Finall and colleagues.
Finall's team didn't prove the mistletoe extract caused the mass; and they don't link the mistletoe extract to the woman's breast tumor. They didn't study mistletoe extract in any other patients.
The Welsh group calls for "rigorous" trials to get conclusive data about mistletoe as a treatment for cancer.
Such a trial may already be under way.
In the U.S., the National Center on Complementary and Alternative Medicine (NCCAM) is studying mistletoe's use with a chemotherapy drug in treating certain advanced cancers.
Those studies aren't focusing on the mistletoe used to deck the halls during the holidays.
Instead, the NCCAM is studying European mistletoe, a different species that has been used for centuries as a remedy for a wide variety of health problems, according to the NCCAM's web site.
Meanwhile, Finall and colleagues urge patients to tell their doctor about any use of complementary treatments.
SOURCES: Finall, A. BMJ, Dec. 23-30, 2006; vol 333: pp 1293-1294. Ernst, E. BMJ, Dec. 23-30, 2006; vol 333: pp 1282-1283. National Center for Complementary and Alternative Medicine: "Mistletoe for Treatment of Cancer." National Center for Complementary and Alternative Medicine: "Frequently Asked Questions About the Mistletoe-Gemcitabine Study." News release, BMJ.
By Miranda Hitti
Reviewed by Louise Chang