ASK DR. BAUGHAN                                             November 13, 1998

BREAST CANCER RISKS AND PREVENTION

Lung cancer is the most common cancer in women who smoke.  For smokers, breast cancer is second most common cancer.  For all non-smokers, though, breast cancer is still number one in frequency.  Detection has improved, less devastating treatments have been developed, and survival is better.  Women can begin to shift from universal dread of breast cancer to careful assessment of their individual risk and reasonable belief in some preventive interventions.

Many women overestimate their risk of getting breast cancer, thinking if they have any risk factors that breast cancer is almost inevitable.  Let’s review the risk factors we know:

1.     Age at menarche (first menses) - if a women had her first period before she was 12 years old, she has a 30% higher risk than others.

2.     Age at menopause - if she did not have menopause until after 55 years old, her risk is 50% higher than average.

3.     Age at having first baby - if a woman never had a baby or did not have a baby until she was over 30, her risk is 90% higher.  NOTE:  This means she has almost TWICE the risk of other women, NOT that she has a 90% chance of having breast cancer.

4.     Other breast lumps - if a woman has had a breast biopsy, it depends on what was found.  If a benign lump was found, her risk still increases by 50%.  If proliferative disease was found, her risk doubles (100%).  If her biopsy showed atypical hyperplasia, her risk increases 4-fold (400%). 

5.     Family history - since breast cancer is the most common cancer in women, many women have relatives with breast cancer.  However, the risk only increases significantly if TWO first-degree relatives (sister, mother, or daughter) have breast cancer.  Then the risk is 5-fold (500%) increased.  This sounds like a whopping risk.  It is significant, but not inevitable.  If the life-long risk (living to 85 or so) is 1 in 8-11, then a 500% increase means the risk is 5 in 8-11, or around 50:50.  And that is if you live to 85 and don’t die of something else first.

A woman can’t do anything about these risk factors, though, except maybe decide when to have her first child.  There is more evidence accumulating, though, that some lifestyle factors make a difference.  It is hard to do studies that show that changing lifestyle makes an individual change, but the statistics are compelling.  The lifestyle issues sound a lot like those for heart disease.

1.     SMOKING - The risk of breast cancer is 60-80% higher in women who smoke.

2.     HIGH FAT DIET - It is very difficult to measure  the amount of fat someone eats in a research study on breast cancer.  What has been shown is that animals with breast cancer had their cancers grow more rapidly when fed a high-fat diet.  Asian woman, who generally have a lower fat diet than Americans, have lower breast cancer rates.  But if they move to America and begin eating the average American diet, their breast cancer rates go up.

3.     HIGH FIBER DIET - primarily animal studies have shown a decrease in breast cancer development if a high fiber diet is consumed.

4.     EXERCISE - Physically active people have less cancer of all types, including breast cancer.  Since obesity is a risk factor, hopefully exercise will help by reducing weight, also.

5.     ALCOHOL - In the Nurses Health Study, drinking more than one alcoholic beverage a day increased breast cancer risk by 2.5 (250%).

6.     SELENIUM - limited evidence suggests that 200 mcg (micrograms) of selenium added to a low-fat, high-fiber diet might have a beneficial effect.

The risk of breast cancer is there even without risk factors and with a low-risk lifestyle, so there is still no substitute for regular exams and mammograms.