Chemoprevention: A 21st century shell game?
Why do I think about shell games and chemoprevention? Chemoprevention is the healthy person's version of chemotherapy, a way to treat cancer with drugs in addition to, or instead of, surgery or radiation. It can cure a few cancers, such as early ovarian cancer and leukemia, and reduce the risk of recurrence for many other cancers, including breast cancer.
Over 15 years ago, cancer doctors started talking about testing tamoxifen in healthy women. They thought tamoxifen was so safe, compared to other kinds of chemotherapy, that it would be reasonable to use in healthy women. The National Cancer Institute (NCI) began a large study of tamoxifen in healthy women in 1992 and insisted that all women over age 60 were 'high risk' for breast cancer enough to consider taking part.
The Network thought differently, and pointed out that, even if tamoxifen reduced the risk of cancer in healthy women, it would cause so many new problems that women would substitute one disease for another. We got a lot of attention for our point of view (I even got to talk about tamoxifen with the Today Show's Katie Couric) but the NCI trial continued.
The first results were announced in 1998. Just as the chemoprevention enthusiasts predicted, women taking tamoxifen were less likely to develop breast cancer while taking the drug. And just as we predicted, healthy women developed new health problems: blood clots, endometrial cancer, strokes, uterine sarcomas, and even cataracts. That's when the shell game started to emerge. It seemed that those who were intellectually committed to the idea of chemoprevention divided women's bodies into different parts, and talked about the great success with one part (the breast) while downplaying problems caused in other parts of the body They ignored the fact that women are whole people, not parts that can be separated from each other and moved around the table, like shells in a game.
The Journal of the National Cancer Institute published an update of the tamoxifen chemoprevention study recently. * Seven years after the volunteers began taking their drugs, the reduction in breast cancer seems to be continuing, but the complications are growing, too. In fact, when the researchers did a (limited, by our perspective) risk/benefit calculation, they admitted that no healthy woman over 60 should consider taking tamoxifen because it causes many more problems than it prevents.
Sadly, the tamoxifen study spawned more chemoprevention trials; at least three are on-going now, testing raloxifene (first developed to treat osteoporosis) and newer breast cancer chemotherapy drugs anastrozole and exemestane. Like tamoxifen, these new drugs have safety problems, too. NWHN believes that true prevention isn't a shell game. Instead of women lifting up the shell and finding a prize (less breast cancer) they're just as likely to raise a shell and reveal a stroke, blood clot, or other kind of cancer. What kind of shell game is this? In addition to NWHN, several great groups that focus specifically on breast cancer have called for a different approach to prevention. See our website, www.nwhn.org for more resources.
* Fisher B, Costantino JP ,Wickerham DL et al. 'Tamoxifen for the prevention of breast cancer: current status of the NSAPB P-I study.' JNCI 2005; 97(22):1652-62.
by Cynthia Pearson, Executive Director
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|Publication:||Women's Health Activist|
|Date:||Jan 1, 2006|
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