Milk thistle may limit liver damage from chemo

NEW YORK (Reuters Health) - An herb used since ancient times to treat liver ailments may help reduce the liver damage caused by some cancer drugs, a study published Monday suggests.

A bag used to hold chemotherapy drugs is pictured at a patient's home in Burbank,California March 16, 2009. REUTERS/Fred Prouser

In a study of 50 children undergoing chemotherapy for acute lymphoblastic leukemia (ALL), researchers found that an herb called milk thistle appeared to reduce treatment-related liver inflammation.

The study, published online in the journal Cancer, is the first clinical trial to test the herb in children undergoing chemotherapy, and the investigators caution that more research is still needed.

However, the findings are “promising” -- particularly since there is currently no way to help protect the liver from chemotherapy-induced damage, said senior researcher Dr. Kara M. Kelly, a pediatric oncologist at Columbia University Medical Center in New York.

Liver inflammation is common among children undergoing chemotherapy for ALL, Kelly told Reuters Health -- with about two-thirds developing liver toxicity at some point during treatment.

Traditionally, doctors have dealt with the side effect by lowering patients’ chemotherapy doses -- which, in turn, can lower the chances of seeing a complete remission. Kelly said that more recently, there has been a movement toward “accepting” the liver toxicity and sticking with the chemo regimen. But it’s not clear what the long-range consequences of that might be.

“So we still need an alternative option,” Kelly said.

That is where milk thistle comes in. The plant’s flowers and seeds have been used for more than 2,000 years to treat disorders of the liver and gallbladder. In recent years, lab research has found that the active substance in milk thistle -- an antioxidant called silybin

-- might help prevent body tissue damage by blocking toxins from breaching cell walls.

Several clinical trials have investigated milk thistle as a way to prevent or treat liver damage in people with hepatitis, an inflammation that can be caused by an infection, and in those with cirrhosis, a buildup of scar tissue in the liver often linked to alcoholism. The results of those studies have been mixed.

For the current study, Kelly and her colleagues randomly assigned 50 children with ALL to take either milk thistle capsules or placebo (inactive) capsules for one month while undergoing their “maintenance” round of chemotherapy.

Going into the study, all of the children had signs of liver inflammation from their previous round of treatment.

After one month, however, children taking milk thistle had lower levels of two liver enzymes than those in the placebo group -- a sign of lesser liver inflammation.

Children on milk thistle were also somewhat less likely to need their chemotherapy dose lowered at any point; 61 percent needed a dose adjustment, versus 72 percent of children taking the placebo. That difference, however, was not statistically significant, which means it could have been due to chance.

Kelly said that more research is needed to look at the longer-term effects of milk thistle on the liver, and to see whether it does in fact reduce the need to lower chemotherapy doses.

She added that the herb should also be studied for preventing liver damage from other chemotherapy regimens for other cancers.

But while milk thistle is available over the counter, Kelly cautioned chemotherapy patients against using it on their own. Anyone receiving cancer treatment, she said, should “absolutely” talk with his or her doctor before starting any supplements.

SOURCE: Cancer, online December 14, 2009.