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Ovarian cancer vs. the spotted owl.

As health professionals, we know that the use of laboratory animals is absolutely essential to medical research, however repugnant it may be to some. But when there are those who seem to put an animal's welfare above that of thousands of dying ovarian cancer patients, we can only wonder how such individuals' priorities have gone so far awry ! In 1989, Dr. William McGuire of the Johns Hopkins University School of Medicine published the results of a study of 48 women whose advanced ovarian cancer had failed to respond to standard chemotherapy. With only months to live, they were given an experimental drug, taxol, and in 30 percent of these terminal patients the tumors shrank by more than half-and disappeared altogether in one patient. Encouraged by these and other results reported later from two other medical centers, the National Cancer Institute contracted with BristolMyers Squibb Company to make the drug and test it in patients.

The Institute has also initiated studies of taxol use in breast and other cancers. At the M.D. Anderson Cancer Center in Houston, taxol was given to 25 women with breast cancer that had metastasized throughout their bodies and did not respond to any other drug. In 13 of the patients, the tumors shrank by more than half and disappeared in three of them. Dr.

Gabriel Hortobagyi, who tested the women and who has used more than 20 other cancer drugs in the past 20 years, says, "I don't remember a single drug that has been this effective." Doctors at Johns Hopkins are also excited about the use of taxol in lung cancer. Given in combination with cisplatin, a standard drug for lung cancer, taxol produced some unusual responses. In one case, a tumor that occupied almost the entire right lung disappeared completely.

Although 10,000 women die of ovarian cancer each year, there is only enough taxol now available to treat one in 10. The problem lies in the fact that the Pacific yew, whose bark is the most available source of taxol, is the habitat of the spotted owl, protected under the Endangered Species Act. The tree grows sparsely in the forests of the Pacific Northwest. Because of this, and because six 100-year-old trees are required to make enough taxol to treat one patient, clear-cutting (removal of all trees and underbrush) of large areas is necessary to harvest the yew bark.

Some environmentalists are opposed to such massive deforesting. They accuse the National Cancer Institute of not trying hard enough to find other sources of taxol, such as the needles, rather than the bark. They argue further that not enough is being done to find a means of synthesizing the drug. In reply, the experts point out that there is too little taxol in the needles to warrant extraction of the drug. Also, it will be at least two or three years before a synthetic form of the drug can be commercially available.

Meanwhile, are we going to deprive tens of thousands of women the potential for prolonging life while we debate the merits of saving the yews and thus protecting the spotted owl? "This is the ultimate confrontation between medicine and the environment," says Dr. Bruce Chabner, director of the division of cancer treatment of the National Cancer Institute. "It's the spotted owl vs. people. I love the spotted owl, but I love people more."

Dr. Sam Broder, director of the Institute, says that taxol is the most important new cancer drug in 15 years. He is quick to point out, however, that it is not in itself a cure, that it's not a panacea, and that it does have side effects. "But we are definitely able to get responses in women with ovarian cancer and in breast cancer who have failed every other drug. For a single drug to do that, it's quite unusual."
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Title Annotation:using taxol in Pacific yew trees as cancer treatment also poses threat to endangered species
Publication:Medical Update
Date:Aug 1, 1991
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