Better Odds Against Breast Cancer
The diagnosis of cancer is just about the scariest medical verdict a woman can hear. It shouldn't be. Greater progress has been made against breast cancer than against any other cancer in the past few years. It's true that some 212,000 women will be diagnosed with breast cancer in the U.S. this year, and 40,000 will die of the disease. But a huge international analysis released in mid-May found that for women in early stages of the disease, treatments now commonly used after surgery can lower the death rate from breast cancer within 15 years of diagnosis to 1 in 10 from 1 in 5.
Those odds are sure to get even better as treatments that have emerged in the past few years start having an impact on the data. An array of drugs are now available for use after surgery to prevent breast cancer from recurring. Since recurrences are usually far more deadly than the initial tumor, these so-called adjuvant therapies should cut the number of deaths by a third, says Dr. Gabriel Hortobagyi, director of breast medical oncology at M.D. Anderson Cancer Center in Houston.
Breast-cancer treatments themselves also no longer need be feared. Surgery, particularly when the tumor is caught early, can be minimally defacing, and new drug therapies are far more easily tolerated than the highly toxic chemotherapies that were common as recently as five years ago. Now, only 5% to 10% of breast-cancer patients receive high doses of chemotherapy. Doctors are also beginning to uncover evidence that aspirin, anticholesterol drugs called statins, and even exercise or a low-fat diet may help prevent breast cancer from occurring in the first place or recurring.
There is a catch however. The patient and her doctor must be well aware of what type of tumor she has, what risk factors are in her background, and the latest drugs available before deciding how to proceed. With this disease, being an educated patient is a must.
The American Cancer Society estimates that one in seven women in the U.S. will develop breast cancer in her lifetime. To figure out the chances of falling into that group, women can take the Gail Model Risk Assessment Tool, used by doctors to calculate a patient's five-year and lifetime risk for breast cancer. The model is based on a number of questions about a woman's family and personal medical history and lifestyle, with each factor given a separate numerical weight.
If breast cancer does develop, the tumor tissue is analyzed and classified as one of three types. About 60% to 70% of breast cancers are hormone-positive, meaning their growth is driven by excess amounts of estrogen or progesterone. Some 20% to 30% of women have particularly aggressive tumors caused by a mutation in the Her-2 gene, and about 10% have what are called triple-negative tumors, because they are not sensitive to hormones or Her-2. Medical researchers predict that in two to three years diagnostic tests will classify tumors even more precisely, making it easier to match a particular treatment to a patient.
Given the number of new drugs in development, such tests will make treatment decisions a lot easier, especially for patients with hormone-positive tumors. For two decades the gold standard for adjuvant treatment of hormone-positive tumors has been tamoxifen, which blocks the absorption of estrogen. Tamoxifen is widely prescribed as a daily treatment for at least five years after surgery to prevent recurrence, and is even taken to prevent breast cancer by high-risk women.
However, a new group of estrogen-blocking drugs called aromatase inhibitors is proving to be more effective and safer than tamoxifen in post-menopausal women.
A study released at the prestigious American Society of Clinical Oncology (ASCO) meeting in May comparing the aromatase inhibitor Femara with tamoxifen found that Femara was 19% more effective at preventing recurrences and 27% more effective at keeping tumors from spreading. "Tamoxifen is not obsolete, but its role in breast cancer treatment is likely to become more limited," said Dr. Beat Thuerlimann of the University of Basel in Switzerland. Two other aromatase inhibitors, Arimidex and Aromasin, appear to be interchangeable with Femara, breast cancer specialists say.
Women with Her/2-positive breast tumors are almost universally treated with Herceptin, a drug introduced in 1998 that blocks the genetic mutation causing their cancer. A new study has also found that Herceptin can cut tumor recurrences by a startling 52% when given as an adjuvant therapy, which is certain to boost survival odds.
The outlook is even improving for women who suffer recurrences. Avastin, a drug approved last year for colon cancer, was recently shown to almost double the length of time women in late stages of breast cancer survive when given with chemotherapy. Granted, those patients gained only 11 months, compared with six months when treated with chemo alone, but any life extension in such a sick patient group is considered a victory.
Ideally, researchers would like to prevent breast cancer from occurring altogether. For that reason a study showing that statins can lower the risk of breast cancer over a woman's lifetime by 50% got a lot of attention at ASCO, as did one that seemed to indicate that a low-fat diet can slightly lower the risk of recurrence. Also, a study published May 25 found that exercise improves survival for breast cancer patients. But researchers caution that these studies, which were based on patient responses to questionnaires, are far from definitive.
Right now, the best defense against breast cancer is to detect it early, treat it aggressively, and figure out how to lower the risk of recurrence. As more and better treatments come along, the chances of surviving the disease are sure to keep rising.
By Catherine Arnst