SHRINKING THE RISK
September 3, 1998
An advisory board of the Food and Drug Administration has recommended the approval of Herceptin, a revolutionary new drug that shrinks breast cancer tumors. A second, more controversial recommendation suggests that some women use the drug Tamoxifen to prevent or delay the onset of the illness. Health correspondent Susan Dentzer reports on these new possible weapons in the war against cancer.
JIM LEHRER: The breast cancer story reported by Susan Dentzer of our health care unit, a partnership with the Henry J. Kaiser Family Foundation.
A RealAudio version of this segment is available.
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May 18, 1998:
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March 18, 1998:
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April 6, 1998:
A new study indicates that the drug Tamoxifen could reduce breast cancer rates by 45 percent.
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SUSAN DENTZER: There may soon be two promising new weapons in the war on breast cancer-- an illness that affects roughly 1.6 million women in the U.S. and kills nearly 44,000 each year.
SPOKESPERSON: It would appear from the preliminary research –
A drug that doesn't poison human cells.
SUSAN DENTZER: Yesterday an advisory board of the federal Food and Drug Administration recommended that the FDA approve a revolutionary new drug, Herceptin. The drug shrinks breast cancer tumors and slows progression of an especially deadly form of the disease. The green light for Herceptin heralds a new era. Conventional treatments for breast cancer include three basic techniques: surgery to remove a tumor or diseased breast, and radiation and chemotherapy that can kill both cancerous and healthy cells alike. These blunt approaches are sometimes described as "slash, burn and poison." But Herceptin, developed by researchers at the biotechnology company Genentech, takes a radically different approach-- zeroing directly in on breast cancer's most basic roots.
DR. SUSAN D. HELLMANN, Genentech: It's a breakthrough treatment because this is the first time that we've really had a cancer therapy that specifically targets a genetic problem at the level of the cancer cell.
SUSAN DENTZER: Nearly a third of women with breast cancer have tumor cells that contain too many copies of a gene called Her-2. In a healthy cell, Her-2 produces a protein that prompts normal cell growth. But in cells with too much Her-2, breast cells reproduce out of control and spread throughout the body. Physician Dennis Slamon played a key role in Her-2 research.
DR. DENNIS SLAMON: It turns out that women who had this alteration had a more aggressive form of the disease, and a shorter disease-free survival, in other words they relapsed more quickly, and unfortunately, they had a shorter overall survival; despite equivalent therapy, they died more quickly.
SUSAN DENTZER: Genentech's scientists found a way to block excess Her-2 with antibodies cloned from mice. The result was Herceptin. A major study has shown that the drug can slow or stop tumor growth -- sometimes in women for whom all other anti-cancer drugs have failed. Herceptin doesn't cure breast cancer but, in combination with chemotherapy, it slows or stops tumor growth in far more patients than in those who use just chemotherapy alone. Although expected to be very costly, the drug is likely to be the first of a wave of new medications.
DR. SUSAN D. HELLMANN: In the future, I think that you'll see more approaches where we look at the actual molecular biology, the genetic makeup of the tumor and think about and create new ways of treating patients with cancer by looking at the genetic abnormality.
SUSAN DENTZER: For the first time yesterday, the board also recommended that the FDA allow the use of a drug to prevent or at least delay the onset of breast cancer. It said that some women at high risk for the disease could use the longstanding anti-breast-cancer drug Tamoxifen in hope of keeping tumors from developing in the first place. Taken in pill form at a cost of about $100 a month, Tamoxifen has been used in breast cancer treatment for more than 20 years. It counteracts the effects of estrogen, the female hormone, in promoting the growth of breast cancer cells. One major study showed that Tamoxifen may have reduced the risk of developing breast cancer by nearly 45 percent in women who had a high risk of developing the disease. But other studies have suggested that the drug's effectiveness in preventing cancer is much less -- or even nonexistent. What's more, Tamoxifen can cause fatal blood clots and cancer of the uterine lining. The FDA panel's recommendation was controversial. Since little is know about the effects of long-term use of Tamoxifen, the panel recommended only short-term use. It also said it did not know which high-risk women should use the drug for prevention. Some patients and advocates were concerned.
Weighing the risk of Tamoxifen.
MARILYN McGREGOR, Cancer Survivor: Tamoxifen is a known carcinogen; it's not as if it's a benign thing; it's not Bayer aspirin. It's a carcinogen. It causes other kinds of cancers, in addition to a whole other range of issues. And so, as many of the people who criticized the trials said, well, is the benefit sufficient for those women to take the risk of taking the disease? It's not as if it's bland. It is a risk.
FRAN VISCO, President, National Breast Cancer Coalition: It's going to be difficult for women to make these decisions. And our concern is that doctors who don't understand and don't have the time to get all of this information to impart to their patients will simply prescribe it as a preventative for breast cancer.
SUSAN DENTZER: Despite the concerns, the FDA is expected to follow the advisory board's recommendations and approve use of both drugs.