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Prevention — Not Cure — of Breast Cancer
By Elizabeth M. Whelan, Sc.D., M.P.H.
There are organized marches nationwide to raise money to find a "cure" for breast cancer. Each day, the volume gets turned up on the debate over the usefulness of mammography for finding and "curing" cancer. Even the United States Post Office had a stamp advocating research to "cure" breast cancer.
Ironically, however, the real progress against breast cancer is taking place in another sphere: chemoprevention of this disease.
Each year in the United States, approximately 175,000 women are diagnosed with breast cancer and 43,000 will die of it. Among American women, breast cancer is the most common cancer and the second most common cause of death from cancer (after lung cancer). Thus, it is good news to learn that in the future, there may be a variety of drugs which women, particularly those at high risk, can take prophylactically to reduce the risk of developing breast cancer.
The drug tamoxifen (brand name Nolvadex) has been used for more than twenty years to treat breast cancer. Tamoxifen is one of a group of drugs called "selective estrogen-receptor modulators" or SERMs. Drugs of this type behave in some body tissues like the female hormone estrogen, but they block the effects of estrogens in other tissues, including the breast. In l998, the FDA approved tamoxifen for use in chemoprevention of breast cancer, the first agent ever approved for the prevention of cancer in healthy people. Studies suggest that tamoxifen can reduce the chances of getting breast cancer in high-risk women by as much as 50%. This benefit does not come without a downside: Women taking the drug were more likely to get endometrial cancer and blood clots.
Like tamoxifen, raloxifene (brand name Evista) is a selective estrogen-receptor modulator. While raloxifene has been approved by the FDA only for the treatment and prevention of osteoporosis (loss of bone density) in postmenopausal women, the evidence is mounting that raloxifene also significantly reduces breast cancer risk — by as much as 84% , apparently with fewer side effects than tamoxifene. The data on raloxifene and reduced breast cancer risk are "secondary" findings in studies that focused on the use of the drug among women who had osteoporosis. Studies designed specifically to measure breast cancer risk reduction are currently underway, but the results won't be available for four years.
So in this interim period, as more data comes in, the manufacturer of raloxifene (Lilly) cannot make even a suggestion about its products' role in cancer prevention. But among breast cancer specialists, the exciting news is out. As Dr. Larry Norton, medical director for breast cancer at New York's Memorial Sloan-Kettering Cancer Center, told the _Wall Street Journal_ recently, Evista "clearly reduces the risk of breast cancer."
While Lilly is not allowed to breathe a word to promote Evista as a preventive drug for breast cancer — nor for heart disease, where promising, protective effects are being identified and published — there are those who understandably argue that women at high risk of breast are being denied life-saving information. Carl Seiden, a J.P. Morgan medical analyst argues, "if I were giving advice to a loved one, this [Evista] looks like the best collection of attributes of anything on the market...[Evista is] a remarkably promising compound whose growth has been slowed down because it's promoted only for osteoporosis benefits."
Is the FDA, in its efforts to secure extensive and rigorous data to document Evista's efficacy in reducing breast cancer risk, actually contributing to the toll of breast cancer among women who might otherwise benefit from this drug? While pharmaceutical companies should be restricted from making baseless claims about the health benefits of drugs, the FDA might consider issuing a "preliminary approval" for use of a drug when, as in the case of Evista and breast cancer prevention, the early studies yield such dramatic, positive results.
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| Responses:
March 20, 2002
It is disappointing to see HealthFactsAndFears.com use supermarket tabloid presentation in discussing a drug such as raloxifene.
You should make clear to your readers that this drug has been in one of the biggest clinical research trials ever, since 1999, to research its effectiveness, safety, and best applications in breast cancer prevention. There are other trials and research for various applications that you can read about in the medical research literature. Certainly, the drug has been informally used in practice for some time by some doctors, as for example when a person has for one reason or another not been able to handle tamoxifen. See: http://www.cancer.gov/clinical_trials/doc.aspx?
viewid=31c9aeb5-0071-4dd8-8c4a-be2112ef8018#NCI+Materials
http://cis.nci.nih.gov/fact/4_19.htm
Many, many new drugs are partially released under controls as part of the late stages of clinical trials if their success has proven overwhelming, sometimes for compassionate use. Herceptin and Faslodex are examples, used for people whose cancer has metastasized. The reasons for waiting for the results and approval process are extremely serious, though, especially if the drug is to be widely used. These are powerful drugs, and their potential for serious damage and long-term side effects must be very carefully examined. I recommend this item about understanding the approval process for new cancer drugs: http://www.cancer.gov/clinical_trials/doc_header.aspx?
viewid=d94cbfac-e478-4704-9052-d8e8a3372b56 Understanding clinical trials: http://www.cancer.gov/clinical_trials/understanding/
—Nancy Miller
March 25, 2002
I am a breast cancer survivor. I am so tired of hearing about all the new drugs for treatment of breast cancer. I think more money should be used to find a cure for breast cancer. It is a chronic condition and women are constantly living with the fear of it reappearing. Instead of making the drug companies rich with all the new drugs, why aren't we concentrating on finding a cure?
—Mary
March 26, 2002
I have as much sympathy for breast cancer survivors as anyone else but must disagree with Mary on a few points.
Mary may be tired of hearing about new drugs for treating or preventing breast cancer, but the reason she's hearing about them so often is that that's where the greatest progress is being made.
She might prefer that money instead be used on a cure, but a complete cure may be less likely than effective treatment. It would be a mistake to divert valuable resources away from the places where they can do the most good. There are other disease research projects to consider, too. Would she like to see money taken away from AIDS research or children's health to pursue a cure that may not be found? Why not use money where it can most effectively save lives, through proven treatments and prevention? (As they say, an ounce of prevention...)
Profits — including the promise of new drugs "making drug companies rich" — are the most effective way of getting free people to put their money where it is doing the most good. The drug companies' ability to make returns on their investments is their biggest incentive for spending more research money on the fight against breast cancer, whether that fight takes the form of cure, treatment, or prevention.
—Jeff Stier, Esq.
Associate Director
American Council on Science and Health
July 15, 2002
I have had breast cancer three times. I started taking Evista three years ago to prevent osteoporosis. Nobody told me of the cancer protective effect. Why?
—Flo95 |
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