Chinese Herb Tied to Cancer

Oncology

New research demonstrates a link between a Chinese herb and a type of cancer. Meanwhile, the Food and Drug Administration (FDA) has warned doctors and health-food suppliers about the herb, and is moving to block its importation into the United States.

In the June 8 issue of The New England Journal of Medicine, a team of Belgian and German researchers, led by Joelle L. Nortier, M.D., Ph.D., from Universite Libre de Bruxelles in Belgium, report that a high percentage of patients who several years ago took diet drugs that contained a Chinese herb called Aristolochia fangchi went on to develop cancer of the urinary tract.

In Belgium in the early 1990s, doctors prescribed weight-loss pills for patients that contained a Chinese herb called Stephania tetrandra. But after these patients began to develop kidney failure, it was discovered the herb had been inadvertently replaced with Aristolochia fangchi, which, when broken down in the body into its component aristolochic acid, is known to lead to kidney damage.

"The Chinese names [for both herbs] sound similar and can be confused, resulting in misidentification," wrote David L. Kessler, M.D., dean of the Yale University School of Medicine and a former FDA commissioner, in an accompanying editorial.

Many of these patients required kidney transplants, the researches reported, and their doctors later detected neoplastic lesions -- precancerous changes -- in the urinary tracts of some of them.

One of the patients developed urothelial cancer, Nortier wrote, and this prompted the team to inform the remaining 43 patients being treated for herb-linked kidney damage. Of this group, 39 agreed to have their kidneys and ureters (the pair of tubes that carry urine from the kidneys to the bladder) removed as a preventive measure. One patient was found to have a bladder tumor, and 17 others had cancer of the ureter or renal pelvis, or both.

Based on previous cell and animal research that linked herbs in the aristolochia family to cancer, the authors recommend that doctors ask patients about their intake of herbal medicine when they have kidney disease or urothelial cancer that cannot be explained.

Communication between patients taking herbal or natural products and their health care providers is essential, said Georgia M. Decker, R.N., A.O.C.N., founder and nurse-practitioner at Integrative Care in Albany, N.Y. "The public as a whole has got to take responsibility for themselves and work in partnership with their doctors," she said. "[All] herbs are medicine and should be treated as medicine."

Kessler says the FDA should ban this specific family of herbs, which he said he was able to buy in capsule form when he sought to determine its availability.

"The data in animals alone justify restricting the use of herbs that contain aristolochic acid," he wrote. "The finding of an association of [Aristolochia fangchi] with human urothelial tumors, even though not perfect, adds urgency to the need to reach a decision that should already have been obvious."

The FDA has reached a similar conclusion.

On May 16, the agency sent a letter to the herbal industry noting that Canada and England have issued public warnings because of findings of aristolochic acid in botanical products marketed as traditional medicines, and kidney damage, as was seen in Belgium, linked to ingestion of these compounds. The FDA urged manufacturers to screen their products for the presence of any plants from the aristolochia family.

In a separate letter, the FDA also advised doctors to be on the lookout for any adverse reactions in patients taking dietary supplements. The agency included a list of herbs suspected of containing or known to contain aristolochic acid.

Even though there have been no reported cases of kidney damage or cancer linked to the herb in the United States, the FDA, which is limited in its power to regulate the natural medicine industry, is preparing to block import of the herb.

Kessler believes the widespread and growing use of herbs and dietary supplements underlines the need for regulating the quality and safety of these substances.

"Examples like that described by Nortier et al. should persuade Congress to change the law to ensure the safety and efficacy of dietary supplements before more people are harmed," he wrote.

Decker stopped short of supporting this view, instead reiterating the need for patients to be aware of what exactly they're taking, and keeping their health care providers fully informed in case of possible harmful drug interactions.

"People are a little too quick to assume if it's herbal and natural, it's safe," she said. "All treatment has its consequences."

To see a complete list of the FDA's botanical ingredients of concern that may contain or be adulterated with aristolochic acid, visit http://vm.cfsan.fda.gov/~dms/ds-bot2.html

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