Breast cancer is one of the most common cancers affecting American women, and is second only to lung cancer as a leading cause of cancer death in women. The number of breast cancer cases (incidence) has been on the rise during the past 20 years, while the death rate from breast cancer has decreased slightly.
The increase in cases is related, in part, to a greater emphasis on screening with routine breast exams and mammography. These screening tools often can detect breast cancer at an earlier -- and more treatable -- stage, which helps explain why the death rate has not increased significantly.
The exact cause of breast cancer has not been established, but there are risk factors that may play a role. A risk factor is a trait or behavior that increases a person's chance of developing a disease or makes a person susceptible to a certain condition. Risk factors for breast cancer include:
- Being female. Breast cancer can occur in men, but it is rare.
- Getting older. Your risk for breast cancer increases as you age. About 77% of women diagnosed with breast cancer each year are over age 50, and almost half are age 65 and older.
- Having a family history of breast cancer. Having a mother, sister, or daughter (a "first-degree relative") who has breast cancer puts you at higher risk for the disease. The risk is even greater if your relative developed breast cancer before menopause and had cancer in both breasts. Having one first-degree relative with breast cancer approximately doubles a woman's risk. Having two first-degree relatives with breast cancer increases her risk five-fold. Having a male blood relative with breast cancer may also increase a woman's risk of the disease. The risk of breast cancer is much less when the affected family members are distant relatives (such as aunts, grandmothers, and cousins).
- Having a personal history of cancer in one breast
- Having other breast lesions. These include multiple papillomatosis, atypical ductal hyperplasia, and lobular carcinoma in situ. These are not cancers, but are not normal cells either. Women with such history should discuss with their doctor whether medications to prevent breast cancer are right for them.
- Alcohol. The use of alcohol is linked to increased risk of developing breast cancer. Compared with nondrinkers, women who consume one alcoholic drink a day have a 10% increase in risk, and those who have two or three drinks daily have about 20% to 30% higher risk than women who drink no alcohol. Alcohol is also known to increase the risk of developing cancers of the mouth, throat, and esophagus.
- Reproductive history. Having your first child after age 30 or never having children can increase the chances of breast cancer. Getting your period early in life (before age 12) and reaching menopause after age 55 are also risk factors.
- A non-healthy lifestyle. Being overweight (especially in the upper body), and eating a diet high in calories and fat increase a woman’s chance of breast cancer. Luckily these are behaviors that can be changed.
- Being a carrier of a familial breast cancer gene, BRCA1 or BRCA2. Genes are the basic unit of heredity. They contain instructions for a cell's development and function, and are passed on from parents to children.
- Long-term postmenopausal hormone treatment. Studies suggest only formulations which include progestin or progesterone significantly contribute to breast cancer risk. Short-term use of hormone therapy (limited to 1-2 years), estrogen only hormone therapy, and premenopausal contraceptive dose hormones do not seem to increase the risk of breast cancer.
Does race or ethnicity affect breast cancer risk?
All women should be aware of their risk for breast cancer; it can affect women of every age, race, and ethnic group. However, the rates of developing and dying from breast cancer vary among various racial and ethnic groups.
According to the National Cancer Institute, white, non-Hispanic women have the highest overall incidence rate for breast cancer among U.S. racial/ethnic groups, while Korean-American women have the lowest rate. Among women ages 40 to 50, African-American women have a higher incidence of breast cancer than white women. African-American women also have the highest mortality (death) rate from breast cancer; Chinese-American women have the lowest death rate.
Several factors have been found to affect the breast cancer incidence and death rates among racial and ethnic groups. Differences in certain lifestyle behaviors -- such as diet, exercise, and acceptability of smoking and alcohol use -- can impact the risk of many diseases, including heart disease and breast cancer.
The higher death rate from breast cancer among African-American women has been linked to the stage, or extent, of the cancer at diagnosis. Studies show that African-American women tend to seek treatment when their cancer is in a more advanced, less treatable stage. Having a primary care provider increases the chance that a person will receive appropriate preventive care -- including routine check-ups and screenings -- that can detect disorders at an early stage.
There also are various factors that may contribute to the lower rates of routine and preventive health care among minority populations, including:
- Socioeconomic factors: These include income level, lack of transportation, and lack of access to health insurance or health care facilities, including screening programs.
- Language and communication barriers: These barriers can interfere with a person's ability to discuss health concerns and develop trust in a primary care physician.
- Education about or understanding of health care risks and symptoms: Women who are not aware of disease risks and symptoms are more likely to wait to seek treatment until they are in pain or their symptoms interfere with daily tasks.
- Cultural practices and expectations: Women of some cultures may turn to traditional or "folk" remedies before seeking treatment from a physician.
- Cultural and/or religious beliefs related to health and health care: Strong beliefs in healing and miracles, as well as distrust of the health care system, may keep some people from participating in routine preventive care.
There continues to be an enormous need for more education and resources to reach women — particularly minority women — with the message of breast cancer screening and prevention. Prevention and early detection of breast cancer are important for all women. For those who are at high risk, careful monitoring and follow-up care with a primary care provider or a breast specialist are especially important.
How can I protect myself from breast cancer?
- Talk to your doctor about when to start getting mammograms, and how often to get them.
- Have your breasts examined by a health care provider at least once a year.
- Become familiar with the way your breasts feel, and notify your provider of any changes.