Yew Tree Bark Cures for Prostate Cancer
By Doug Desjardins
The yew tree is native to the Pacific Northwest and its bark is the source of a powerful drug used to treat cancer. Most often known by the trademarked name Taxol, it is particularly effective in treating advanced cases of prostate cancer, according to the National Cancer Institute (NCI).
The benefits of yew tree bark were discovered in the early 1960s, when the NCI studied hundreds of plants in search of natural cancer treatments. One of those plants was the yew tree, and follow-up studies and animal tests showed that its bark contained an anti-cancer agent. The product was named “Taxol,” based on “Taxus,” the botanical name of the yew tree.
In 1991, pharmaceutical company Bristol-Myers signed an agreement to mass-produce Taxol. But finding an adequate source of bark was a problem, since it took an entire tree to create a single dose of the drug. Chemists at Bristol-Myers soon found that a smaller, more common relative of the yew tree contained a more abundant supply of an agent similar to Taxol, and it could be used to mass-produce the drug.
Taxol was introduced as a treatment for prostate cancer in the 1990s. It is typically reserved for cases where the cancer is advanced or has recurred, NCI reports. It is also used to fight hormone-refractory prostate cancer that does not respond to hormone-blocking drugs as a first line of treatment. Taxol is used sparingly because of its adverse side effects, which include near-total hair loss and neutropenia, a condition where white blood cells are depleted to the point where the body is unable to fight off even minor infections.
Two types of medications from yew tree bark are used to fight prostate cancer. The first is paclitaxel, a generic version of Taxol. The second is docetaxel—a synthetic form of Taxol sold under the brand name Taxotere—which tends to produce fewer negative side effects than its sister drug.
Taxol is often used in combination therapies with other drugs to treat prostate cancer. An ongoing study at the Sloan-Kettering Cancer Center in New York combining the breast cancer drug Herceptin with Taxol shows promise in treating recurrent and more advanced prostate cancer. Herceptin helps slow the growth of prostate cancer cells that are present in men when the disease is first diagnosed.