Researchers Finding New Ways to Prevent, Diagnose and Treat Breast Cancer

Tuesday, July 07, 2009

ROCHESTER, Minn. — Breast cancer is the most common cancer specific to women. An eight-page "Special Report" on breast cancer in the June issue of Mayo Clinic Health Letter covers recent advancements in prevention, detection and treatment.

Overall, breast cancer survival rates are among the highest of all cancers, and the number of deaths is declining. Nearly 89 percent of women diagnosed with breast cancer live for at least five years after treatment. Still, 40,000 Americans died from this cancer last year. Here are some advancements making a difference in breast cancer outcomes:

Prevention: Healthy lifestyles reduce the risk of breast cancer. Studies have shown that women who exercise about 30 minutes three or four times a week can decrease their breast cancer risk by about 26 percent. A study published in the Journal of the American Medical Association concluded that women who lost 22 pounds after menopause reduced their risk of developing breast cancer by 45 percent.

Other studies have shown that women who drink one to two alcoholic drinks a day increase their risk of breast cancer by 10 percent. That risk jumps to 30 percent when women consume three or more alcoholic beverages a day.

Screening: Mammography is still the standard of care for screening and remains the only screening test shown to decrease the chance of dying of breast cancer. But recently, several cancer organizations have recommended that women who are at very high risk of developing breast cancer also undergo magnetic resonance imaging (MRI) annually. This technique uses a magnet and radio waves to create detailed two-dimensional images. It's especially helpful in evaluating abnormalities in women with dense breast tissue and for those who have other risk factors, including:

— Known carriers of the gene mutation BRCA1 or BRCA2

— A lifetime risk of 20 percent or higher, based on family history of breast cancer and other health factors.

— Doctors work with women to determine this risk rating.

— Chest radiation before age 30 for other cancers

However, MRIs aren't for everyone and are not recommended for routine screening. They are expensive, require an intravenous injection of a contrast agent, and have a high rate of anxiety-producing false-positives.

Treatment: Testing the genetic makeup of a tumor can help determine which women are at the highest risk of recurrence and which of those are more likely to benefit from chemotherapy. Conversely, women at lower risk can avoid unneeded treatment.

Researchers are looking at changes in radiation, too. They are finding that shorter-course radiation may be effective for patients with early-stage cancer and no lymph node involvement.

Post-cancer treatment: For some breast tumors, patients typically take the estrogen blocker tamoxifen after treatment. It reduces the risk of recurrence by about 50 percent. But this therapy doesn't work well for 8 to 10 percent of women — those who have an inactive variant of the CYP2D6 enzyme. Now, genetic markers from the blood can determine which women most likely would — or wouldn't — benefit from tamoxifen. Other effective treatment options are available for women with the variant CYP2D6 enzyme.

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