March 6, 2008
US News

Breast Cancer: 3 Ways to Lower the Risk of Recurrence

A new study indicates that lower estrogen levels can help keep cancer from coming back

By Deborah Kotz

Many women diagnosed with breast cancer find the hardest thing about treatment is facing its end. After the harrowing chemotherapy, the radiation burns, and the hot flashes from anti-estrogen medications like tamoxifen or aromatase inhibitors, patients then are told there's nothing else they can do to prevent a recurrence; they just have to sit back, wait, and pray for no new breast lumps or painful twinges in their bones.

New research, though, suggests women may be able to lower their risk of recurrence by taking steps to reduce their estrogen levels. A study of more than 300 breast cancer patients found that those whose cancer came back within seven years had estrogen levels on average that were twice as high as those found in women who remained cancer free; this was true even for those taking tamoxifen. (The researchers controlled for other possible explanations such as age, cancer stage, body weight, and exercise habits.) Previous research has shown that women with excess estrogen, which fuels the growth of the most common breast cancers, have a greater likelihood of being diagnosed with breast cancer in the first place. Of course, estrogen levels are partly determined by genetics. But "based on what we now know, we recommend that patients do whatever they can to reduce their levels," says study leader Cheryl Rock, a professor of preventive medicine at the University of California-San Diego. She suggests the following:

1. Exercise as often as possible: Move fast enough to break into a sweat for 30 minutes on most days of the week. Studies have shown that regular, moderate exercise lowers levels of blood estrogens. Rock admits this can be very hard, especially for the 1 in 4 women who suffers from postchemotherapy fatigue. "It's counterintuitive to say this, but research shows that exercise can actually help reduce this exhaustion," she says. Once they get through the first 10 minutes of, say, brisk walking, she adds, the rest is usually a piece of cake.

2. Maintain a healthy weight: Body fat churns out estrogen, and excess fat around the abdomen causes hormonal changes that make breast tissue more vulnerable to estrogen's detrimental effects. Rock recommends aiming for a body mass index of below 25 (145 pounds for a 5-foot-4 woman) and a waist circumference of no more than 35 inches.

3. Increase dietary fiber: The role of fiber in reducing estrogen levels is somewhat less certain, says Rock, but it certainly can't hurt to get the government recommendation of 25 grams per day for women 50 and under and 21 grams for those over 50. Plus, that feeling of fullness you get from eating high-fiber foods can help you shed excess weight. Think whole-grain cereal for breakfast, replace white rice with brown rice, snack on raw vegetables, and top your pizza with broccoli and spinach.