Facts about Breast Cancer and Hormones

Introduction
Breast cancer is one of the most common cancers in women. About 183,000 women get breast cancer each year—most of them (80%) over age 50 years. A woman’s risk of getting breast cancer gradually rises as she gets older. Although breast cancer is among the leading cancers in women, the risk of getting breast cancer or dying from it is much lower than many women believe. Women in a study by the National Cancer Institute thought their risk of getting and dying from breast cancer was 25 times higher than it
actually was. In fact, less than 5% of US women will die from breast cancer, whereas about 50% will die from cardiovascular disease (heart attack and stroke). News reports often claim that one of every eight women (about 13%) will get breast cancer. However, this is only true for women who live to the age of 90. The chance of getting breast cancer is less for younger age groups. For example, only 2% of all women get breast cancer by age 50 years (see figure). Among women who live to the age of 80 years, about 10% will have had breast cancer.


Risk Factors
The reason why a woman gets breast cancer is unknown. However, research has shown that certain conditions may increase a woman’s risk:

• Personal history of breast cancer. Women who have had breast cancer are more likely to get it again.

• Family history. A woman’s risk for developing breast cancer increases if her mother, sister, daughter, or two or more other close relatives (such as cousins) have a history of breast cancer—especially at a young age.

• Genetic factors. Characteristics of certain genes make women more likely to get breast cancer. In families in which many women have had the disease, gene testing can show whether a woman has specific genetic factors known to increase the likelihood of breast cancer.

• Late childbearing/fewer children. Women who had their first baby after the age of 30 years have a slightly increased risk of developing breast cancer compared with women who had one or more children at a younger age.


Early Detection
Most breast cancer diagnosed today is not fatal. In fact, 50% more women die from lung cancer each year than from breast cancer, even though the number of women diagnosed with lung cancer is much lower. Better detection and treatment have caused the breast cancer death rate to go down in recent years. On average, more than 85% of women diagnosed with breast cancer today will be alive 5 years later. This number was less than 75% 20 years ago. Finding breast cancer early makes treatment much easier and increases
the chances of surviving the disease. Mammograms and clinical breast exams are common ways to find breast cancer early. A mammogram is an x-ray picture of the breast tissue. The pressure on the breast tissue can be uncomfortable, but the x-ray, itself, takes only a few moments. In a clinical breast exam, your health care provider will feel your breasts for lumps or other changes that might lead to cancer. The National Cancer Institute recommends that women between the ages of 20 and 40 years have clinical
breast exams at least once every 3 years. Women over age 40 years should have a clinical exam and a mammogram every 1 to 2 years. Doing so may reduce your chances of dying from breast cancer by 17% to 30%. Speak with your clinician about a mammogram schedule that is right for you. A breast self-exam is a way to check your own breasts at home. You should not rely upon self-exams instead of clinical breast exams, but they may help you find changes in your breasts between clinical exams. Report any changes to your clinician promptly. Ask your clinician for more information about how and when to
perform a breast self-exam.


Breast Cancer and Hormones
Many myths surround the use of hormones (estrogen and progestin) and their effect on breast cancer risk. Hormones are produced naturally in a woman’s body. They are also found in certain medications, such as birth control pills and hormone replacement therapy used by many women during menopause. Simply stated, hormones do not cause cancer. In some cases, they may cause preexisting hormone-sensitive tumors to grow. With regard to oral contraceptives (the birth control pill), experts have examined data from
dozens of studies performed all over the world. They found that use of the pill does not increase the longterm risk of breast cancer. Women currently using the pill had a very slightly increased risk of breast cancer being diagnosed, but that finding is likely due to more frequent and careful screening for women taking oral contraceptives. Dozens of studies have examined how menopausal hormone replacement therapy might affect breast cancer. Researchers recently looked at data from more than 50 studies and made a worst-case estimate that the yearly increase in breast cancer risk for women using menopausal hormones was 2%—roughly the same as the natural increase in risk that women face simply by getting older. In addition, any potential extra risk was gone 5 years after a woman stopped taking menopausal hormones.



For More Information
To learn more about breast cancer, contact the following organizations:

National Cancer Institute
31 Center Drive, MSC 2580
Bethesda, MD 20892
1-800-4-CANCER
www.nci.nih.gov


American Cancer Society
1599 Clifton Road, NE
Atlanta, GA 30329
1-800-ACS-2345
www.cancer.org


National Alliance of Breast
Cancer Organizations
9 E 37th Street, 10th Floor
New York, NY 10016
1-800-719-9154
www.nabco.org