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Breast Cancer Risk: Current Concepts

The last several years have seen improvements in detection and treatment of breast cancer.  Best of all, the death rate has decreased.  Even so, breast cancer is still the most common cancer in women and second only to lung cancer as a cause of cancer mortality.

Breast cancer is common enough to be of concern to almost every woman.  So many of us have friends, family members or coworkers who have had breast cancer; some of us have survived it ourselves.  Why one woman develops breast cancer and another doesn’t remains mostly mysterious.  Family history and genetic predisposition do seem to increase risk, but aren’t involved in the majority of cases.  And what can we do about them, anyway?  Neither are some of the other risk factors – age, early onset of menstrual cycles, having no children or having them later in life, and late menopause – amenable to interventions.

Nutritional factors such as dietary fat consumption, supplements, and eating fruits and vegetables, don’t seem to have a consistent protective effect as was once thought.   So a logical question is: what’s out there that might help?  Here are some suggestions from the January 2007 issue of Harvard Women’s Health Watch.


Manage your weight.  Studies suggest that weight gain after menopause is a risk factor.  The Nurses’ Health Study (NHS) found that losing 22 pounds or more after menopause decreased the risk of breast cancer.

Increase your activity level.  3 to 4 hours of exercise per week may reduce your risk by as much as 30%.  Even moderately intense activities such as brisk walking or yoga can help lower your risk.  Aim for 45-60 minutes on at least 5 out of 7 days every week.

Limit alcohol intake. No one knows why, but even a few drinks per week increase breast cancer risk.  The NHS indicates that this risk may be offset by adequate consumption of the B vitamin folic acid.  At least 600 mcg of folic acid per day is considered adequate.  Dark green leafy vegetables such as broccoli and chard are good sources.  Folic acid is now added to many cereals, flours and pasta products.  It’s also found in most multivitamin supplements—check the label of yours.

Vitamin D.  Getting plenty of the ‘sunshine’ vitamin may reduce risk by as much as 50%.  The recommended dose is 800-1000IU per day. Sun exposure and vitamin D-fortified dairy products are helpful but not usually sufficient.   Supplements are the most efficient way to increase your vitamin D intake.

Exposure to hormones.  Birth control pills and hormone replacement therapy, as well as diethylstilbestrol exposure (DES--a hormone used until the 1970s that was supposed to prevent miscarriage) have been associated with increased risk.  Be sure to discuss thoroughly the risks and benefits of hormonal medications before deciding to use them.

Breast density.  A dense breast has less fat and more glandular and connective tissue.  This is common in younger women, and is a risk factor exceeded in importance only by age and the presence of a BRCA1 or 2 gene mutations.  Digital mammography seems to work best for detection of cancers in women with dense breasts.

For more information:
www.health.harvard.edu/women
www.cancer.gov/bcrisktool -- is an online breast cancer risk assessment tool