Breast Cancer Risk Factors

We do not yet know exactly what causes breast cancer, but we do know that certain risk factors are linked to the disease. A risk factor is something that increases a person's chance of getting a disease. Different cancers have different risk factors. Some risk factors, such as smoking, can be controlled. Others, like a person's age or family history, can't be changed. While all women are at risk for breast cancer, the factors listed below can increase the chances of having the disease.

Causes

Medicine has identified changes in certain genes within breast cells that can be linked to a higher risk for breast cancer. Breast cells contain a variety of genes that normally work cooperatively with a woman?s natural hormones, diet, and environment to keep her breasts healthy. Certain genes routinely keep breast cells from dividing and growing out of control and forming tumors. When these genes become altered, changes occur and a cell no longer can grow correctly.

Genetic changes may be inherited from a parent or may accumulate throughout a person?s lifetime. Breast cancer usually begins in a single cell that changes from normal to malignant over a period of time. Presently, no one can predict exactly when cancer will occur or how it will progress. When breast cancer is diagnosed--even if detected at the earliest stage--it is not yet possible to predict which cancer cells will be treated successfully and which will continue to grow and spread quickly to other parts of the body.

Uncontrolled

Gender
Simply being a woman is the main risk factor for breast cancer. Men can get breast cancer, but this is fairly rare.

Age
The chance of getting breast cancer goes up as a woman gets older.

Genetic risk factors
Between 5% and 10% of breast cancers appear to be linked to changes in certain genes. Studies show that some breast cancer is linked to mutations or changes of the BRCA1 and BRCA2 genes. If a woman has inherited a mutated gene from either parent, she is more likely to develop breast cancer. About 50%-60% of women with these inherited mutations will develop breast cancer by the age of 70.

Family history
Breast cancer risk is higher among women whose close blood relatives have this disease. The relatives can be from either the mother's or father's side of the family. Having a mother, sister, or daughter with breast cancer almost doubles a woman's risk.

Personal history of breast cancer
A woman with cancer in one breast has a greater chance of developing a new cancer in the other breast. This is different from a recurrence of the first cancer.

Race
White women are slightly more likely to develop breast cancer than are African-American women. But African-Americans are more likely to die of this cancer. Asian and Hispanic women have a lower risk of developing breast cancer.

Earlier radiation treatment
Women who have had chest area radiation treatment as a child or young woman have a significantly increased risk of breast cancer.

Menstrual periods
Women who began having periods early (before 12 years of age) or who went through the change of life (menopause) after the age of 50 have a small increased risk of breast cancer. The same is true for women who have not had children or who had their first child after they were 30 years old.

Controllable

Birth control pills
It is still not clear what part birth control pills might play in breast cancer risk. It may be that women using birth control pills have a slightly greater risk of breast cancer. Women who stopped using the Pill more than ten years ago do not seem to have any increased risk. Women should discuss the risks and benefits of birth control pills with their doctor.

Estrogen replacement therapy (ERT)
Some studies suggest that long-term use (10 years or more) of estrogen replacement therapy, sometimes called hormone replacement therapy, for relief of menopause symptoms may slightly increase the risk of breast cancer. This risk applies only to current and recent users. A woman's breast cancer risk returns to that of the general population within 5 years of stopping ERT. Replacement therapy also lowers the risk of heart attacks and bone fractures; therefore, women should talk to their doctors about the pros and cons of using ERT.

Induced abortion
A large, recent study indicated that induced abortions do not increase the risk of breast cancer. Also, most studies also show no direct link between miscarriages and breast cancer.

Not breast feeding
Some studies suggest that breast feeding, if continued for 1 1/2 to two years, may slightly lower breast cancer risk. Other studies found no impact on breast cancer.

Alcohol
Use of alcohol is clearly linked to increased risk of developing breast cancer. Women who have one alcoholic drink a day have a very small increased risk. Those who have 2 to 5 drinks daily have about 1.5 times the risk of women who drink no alcohol. The American Cancer Society recommends limiting the amount you drink, if you drink at all.

Diet
There may be a link between being overweight and a higher risk of breast cancer, especially for women over 50 years of age. But the connection between weight and breast cancer risk is complex and is affected by whether a woman gained weight as an adult or has been overweight since childhood.

Studies of fat in the diet as it relates to breast cancer risk have often given conflicting results. Many studies of women in the United States have not found breast cancer risk to be related to fat in the diet. On the other hand, there is evidence that breast cancer is less common in countries where the typical diet is low in fat. More studies are needed to clarify the impact of fat intake and body weight on breast cancer risk. But, since diet and weight have been shown to affect the risk of developing several other types of cancer and heart disease, the American Cancer Society recommends maintaining a healthy weight and limiting your use of high-fat foods, especially those from animal sources.

Exercise
Exercise and cancer is a fairly new area of research. Some studies suggest that exercise in youth might give life-long protection against breast cancer. Even moderate physical activity as an adult could lower breast cancer risk. More research is underway to confirm these findings.

Smoking
While a direct link between smoking and breast cancer has not been found, smoking affects overall health and increases the risk for many other cancers, as well as heart disease. Women who smoke should make every attempt to quit.

Environment
Right now, research does not clearly show a link between breast cancer risk and exposure to pollutants such as pesticides. A great deal of research has been reported and more is under way in this area.

Recent internet e-mail rumors have suggested that underarm antiperspirants and underwire bras hamper lymph circulation and increase the risk of breast cancer. There is no evidence to support this idea.

Prevention

Medication

The drug tamoxifen has been used for many years as a treatment for some breast cancer. Recent studies show that women at high risk for breast cancer are less likely to develop the disease if they take tamoxifen.

Another drug, raloxifene, also blocks the effect of estrogen on breast tissue and some studies seem to show that it lowers the risk of breast cancer. But raloxifene has not yet been approved for this use.

Surgery

In some rare cases, women at very high risk might consider a preventive (prophylactic) mastectomy. This is an operation in which one or both breasts are removed before there is any known breast cancer. The reasons for considering this type of surgery need to be very strong. They would include one or more of the following: inherited mutated genes, an earlier breast cancer, a strong family history of breast cancer, and diagnosis of certain conditions such as lobular carcinoma in situ. While the operation reduces the risk of breast cancer, it does not guarantee that cancer won't develop in the small amount of breast tissue remaining after the operation.