Breast Cancer

Cancer occurs when cells in a part of the body begin to grow out of control. Normal cells divide and grow in an orderly fashion. But cancer cells continue to grow and crowd out normal cells. Although there are many kinds of cancer, they all have out-of-control cell growth in common. Breast cancer is a malignant (cancer) tumor that starts from breast cells. It is found mostly in women, but men can get breast cancer, too.

Breast cancer is the most common cancer among women in the United States, other than skin cancer. It is the second leading cause of cancer death in women, after lung cancer.

About 182,500 women in the United States will be found to have invasive breast cancer in 2008. About 40,500 women will die from the disease this year. There are about 2.5 million breast cancer survivors in the United States.

The chance of a woman having invasive breast cancer some time during her life is about 1 in 8. The chance of dying from breast cancer is about 1 in 35. Breast cancer death rates are going down as a result of early detection and improved treatment.

What are the Risk Factors for Breast Cancer?

Risk factors are behaviors or conditions that increase one’s chances of developing a disease. However, just because a person has a risk factor—or even more than one risk factor—does not mean that the person will get a disease. Some individuals have multiple risk factors and remain disease free. Others may have no risk factors and still develop cancer. The majority of cancers occur in women with no risk factors. 

We can put breast cancer risk factors into two main categories: Those that can’t be controlled, and those that can be controlled.

Uncontrollable Risk Factors

• Age. The chance of getting breast cancer goes up as a woman gets older. About 2 out of 3 women with invasive breast cancer are age 55 or older when the cancer is found.

• Dense breast tissue. Dense breast tissue means there is more glandular tissue and less fatty tissue. Women with denser breast tissue have a higher risk of breast cancer. Dense breast tissue can also make it harder for doctors to spot problems on mammograms.

• Family history. Breast cancer risk is high 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 doubles a woman's risk. It's important to remember that 80 percent of women who get breast cancer do not have a family history of this disease. 

• Gender. Simply being a woman is the main risk for breast cancer. While men also get the disease, it is about 100 times more common in women than in men.

• Genetic risk factors. Five percent to 10 percent of breast cancers are thought to be linked to inherited mutations (changes) in certain genes. The most common gene changes are those of the BRCA1 and BRCA2 genes. Women with these gene changes have up to an 80 percent chance of getting breast cancer during their lifetimes. Other gene changes may raise breast cancer risk, as well.

• Menstrual periods. Women who began having periods early (before age 12) or who went through the change of life (menopause) after the age of 55 have a slightly increased risk of breast cancer. They have had more menstrual periods and as a result have been exposed to more of the hormones estrogen and progesterone.

• Personal history of breast cancer. A woman with cancer in one breast has a greater chance of getting a new cancer in the other breast or in another part of the same breast. This is different from a return of the first cancer (which is called recurrence). 

• Previous breast radiation. Women who have had radiation treatment to the chest area (as treatment for another cancer) earlier in life have a greatly increased risk of breast cancer.

• Race. White women are slightly more likely than African-American women to get breast cancer, but African American women are more likely to die of breast cancer. One explanation may be that African-American women have faster growing (more aggressive) tumors. Asian, Hispanic, and American Indian women have a lower risk of getting breast cancer than African American women.

• Treatment with DES. In the past, some pregnant women were given the drug DES (diethylstilbestrol) because it was thought to lower their chances of miscarriage. Recent studies have shown that these women (and their daughters who were exposed to DES while in the womb) have a slightly increased risk of getting breast cancer.

Controllable Risk Factors

• Alcohol. Use of alcohol is clearly linked to an increased risk of getting breast cancer. Women who have one drink a day have a very small increased risk. Those who have 2 to 5 drinks daily have about 1½ times the risk of women who drink no alcohol. The American Cancer Society suggests limiting the amount you drink to one drink a day.

• Being overweight or obese. Being overweight or obese is linked to a higher risk of breast cancer, especially after menopause and if the weight gain took place during adulthood. Also, the risk seems to be higher if the extra fat is in the waist area. But the link between weight and breast cancer risk is complex, and studies of fat in the diet as it relates to breast cancer risk have often given conflicting results. The American Cancer Society recommends maintaining a healthy weight throughout life.

• Not breast-feeding. Some studies have shown that breast-feeding slightly lowers breast cancer risk, especially if the breast-feeding lasts 1½ to 2 years. This could be because breast-feeding lowers a woman's total number of menstrual periods, as does pregnancy.

• Not having children or having them later in life. Women who have had not had children, or who had their first child after age 30, have a slightly higher risk of breast cancer. Being pregnant more than once and at an early age reduces breast cancer risk. Pregnancy reduces a woman's total number of lifetime menstrual cycles, which may be the reason for this effect.

• Recent use of birth control pills. Studies have found that women who are using birth control pills have a slightly greater risk of breast cancer than women who have never used them. Women who have not used the pill for at least 10 years do not seem to have any increased risk. Women should talk to their doctors about the risks and benefits of birth control pills.

Symptoms of Breast Cancer

The widespread use of screening mammograms has increased the number of breast cancers found before they cause any symptoms, but some cancers are still missed. The most common sign of breast cancer is a new lump or mass. A lump that is painless, hard, and has uneven edges is more likely to be cancer. But some cancers are tender, soft, and rounded. Anything unusual should be checked by a doctor.

Other signs of breast cancer include the following:

• Breast pain
• Lump in the underarm area
• Nipple discharge other than breast milk
• Nipple pain or the nipple turning inward
• Redness, scaliness, or thickening of the nipple or breast skin
• Skin irritation or dimpling
• Swelling of all or part of the breast