Becky Gannon, a 58-year-old nurse from Evans City, Pa., is balanced on the knife's edge between hoping for the best and trying to avert the worst. Her mother was diagnosed with breast cancer at 70 and died of a recurrence 10 years later. Her sister got a diagnosis of invasive breast cancer at 39.
When Allegheny General Hospital in Pittsburgh, where Gannon works, posted a notice seeking women with a high risk of breast cancer to participate in a study, she was intrigued. She got exhaustive briefings on the pros and cons of trying raloxifene or tamoxifen to reduce her risk.
But she has decided, for now, to hold off. She was troubled by her friend's experience with tamoxifen after a diagnosis of breast cancer, including many unpleasant side effects. She says she's more open to raloxifene, which her sister takes for osteoporosis.
But Gannon looks after her health — eats carefully, works out regularly, drinks alcohol rarely — and is an avowed optimist. She harbors the hope that breast cancer won't happen to her. Given that mindset, she says, it's hard to see taking a daily pill.
The "risk calculators" that are used to judge a woman's breast cancer vulnerability may also make people like Gannon skeptical about the need for preventive measures.
Medical professionals largely rely on the Breast Cancer Risk Assessment Tool — better known as the Gail model — which estimates a woman's risk of developing invasive breast cancer in the next five years. Because the disease is more likely to strike as women get older, a younger woman often greets her "Gail" number with relief, even if she shouldn't.
For instance, a 50-year-old woman who is told she stands a 1.7% chance of developing breast cancer in the next five years may perceive her risk as low. But in fact, such a woman is at higher-than-average risk and deemed a good candidate for preventive drug therapy.
Physicians are a factor too. Many primary care doctors and gynecologists shy from introducing new drug risks to women who seem healthy. They also have little time and are ill-equipped for the complex risk assessment and counseling the decision requires.
Nor do the public profiles of tamoxifen and raloxifene endear them to women. When women like Becky Gannon hear "tamoxifen," many recognize the name of a cancer drug their mother or aunt took. "The fact that it's a cancer drug … has some stigma," psychologist Angela Fagerlin says. "You think, 'I must be a sick person because I'm choosing to take this drug.'"
Raloxifene doesn't suffer from that problem: Since 1998, it has been widely recommended to many of the 12 million women who have osteoporosis and the roughly 40 million others thought to have low bone mass, or osteopenia.
The Food and Drug Administration gave Eli Lilly & Co. permission in 2007 to market the drug for breast cancer prevention too. But Lilly's approach is remarkably low-key: Its ads have merely billed raloxifene's effectiveness in driving down breast cancer risk as a bonus for women already taking it for their bones.
Finally, the mission of breast cancer prevention suffers from a major missing link: a clear way of showing doctor and patient that a woman's risk is dropping in response to drugs. It's a different situation than the one that exists for statins and blood pressure medications, for which improved cholesterol and blood pressure readings give everyone an accepted measure of whether a drug is working.
Researchers are focusing heavily on breast density as a possible risk indicator. A growing body of evidence has shown that women with less fatty, denser breasts are more likely to develop invasive breast cancer. But scientists still have much to learn about that. "The whole concept of chemoprevention of cancer is in its infancy, and it's not perfect," Wickerham says.
Still, he adds, "it wasn't all that long ago we were having the same discussion about heart disease. We're going to get better at this over time."