Breast cancer screening

Breast cancer screening

Author
Suzanne W Fletcher, MD
Section Editor
Julie R Gralow, MD
Deputy Editor
H Nancy Sokol, MD

Disclosures

INTRODUCTION — Breast cancer screening includes tests to detect breast cancer at an early stage, before a woman discovers a lump. The chance of dying from breast cancer has declined by about a third over the past few decades. This is due, in part, to the use of breast cancer screening to find cancer at an earlier stage. Breast cancer is more likely to be cured when it is caught earlier.

This article discusses what breast cancer screening includes, when it should start, and how often it should be done. Women with a high risk of breast cancer, such as those with a genetic mutation in BRCA1 and BRCA2 and those who have multiple close relatives with breast cancer should review information about genetic testing and screening recommendations in higher risk individuals. (See “Patient information: Genetic testing for breast and ovarian cancer”.)

BREAST CANCER SCREENING METHODS — There are three main ways to screen for breast cancer: mammogram, breast exam with your doctor or nurse, and breast self-exam.

Mammogram — A mammogram is a breast x-ray. It is the best screening test for reducing the risk of dying from breast cancer. (See “Breast imaging: Mammography and ultrasonography”.)

Before the mammogram, you will be asked to undress from the waist up and wear a hospital gown. Each breast is x-rayed individually. The breast is flattened between two panels. This can be uncomfortable, but it only takes a few seconds. If possible, try to avoid scheduling your mammogram just before or during your menstrual period, when the breasts are more sensitive. Also, do not use underarm deodorant on the day of your appointment.

Mammogram results — A radiologist will review and interpret the mammogram. Sometimes the radiologist reviews the mammogram images while you wait. Some women will need to have more images taken. Needing more images is common and does not usually mean that you have cancer. These extra images help the radiologist to have the most accurate and clear view of your breast tissue.

If the radiologist does not review your mammogram immediately, you should get a phone call or letter with your results within 30 days. If you do not hear back about your results, call your doctor or nurse’s office. You should not assume that your mammogram was normal.

What if my mammogram is abnormal? — If your mammogram is abnormal, you will need further testing. In most cases, a woman with an abnormal mammogram does not have breast cancer. In 90 percent of women with an abnormal mammogram, breast cancer is not found.

Follow up testing after an abnormal mammogram is discussed separately. (See “Patient information: Common breast problems”, section on ‘Abnormal mammogram’.)

Breast exam by your doctor or nurse — Your doctor or nurse might perform a breast exam on a regular basis as part of breast cancer screening. During the exam, the doctor or nurse will look at the breasts and then carefully feel both breasts and the area under both arms.

Most expert groups recommend having a breast exam, along with a mammogram, starting at age 40 to 50.

Breast self-exam — Breast self-exam is a way of finding changes in your own breasts. No study has shown that breast self-exam reduces the risk of dying from breast cancer. Nevertheless, some women feel that doing breast self-exam on a regular basis improves their ability to find changes that would otherwise not have been noticed. Many expert groups encourage breast self-awareness, which includes education about risk factors for breast cancer and what to do if a breast abnormality is detected. Women who want to perform breast self-exams should still continue to get regular mammograms and breast exams by a doctor or nurse because they are better screening tests.

Instructions for performing a breast self-exam are provided here (table 1). The best time to perform breast self-exam is about one week after your menstrual period ends, when the breasts are least lumpy. If you do not have menstrual periods, you can pick one day each month.

Breast MRI — Magnetic resonance imaging (MRI) uses a strong magnet rather than x-rays to create a detailed image.

Compared to mammograms, breast MRI:

Has more “false positive” findings (changes that are not breast cancer)
May lead to more unnecessary biopsies in women who are not at high risk for breast cancer
Breast MRI may be recommended, in addition to mammography, to help find breast cancer in young women with a high risk for developing breast cancer (such as those with a very strong family history or a breast cancer gene) [1]. However, breast MRI is not recommended to screen for breast cancer in women who do not have a high risk of breast cancer.

BREAST CANCER SCREENING RECOMMENDATIONS

When to start mammograms — All expert groups agree that women age 50 and older should have screening for breast cancer (including a mammogram and a breast exam). There is controversy about use of mammograms among women in their 40s because on average, breast cancer is less common in the 40s while the chances of having an abnormal mammogram that must be worked up are higher.

Some expert groups recommend starting mammograms at age 40 [2].
Other groups recommend that women between ages 40 to 49 talk to their doctor or nurse about the risks and benefits of mammograms. Your decision to have or delay mammograms between ages 40 to 49 should be based on your individual preferences and risk of breast cancer [3].
How often to have a mammogram

Women who choose to have breast cancer screening beginning at age 40 are usually screened once per year until age 50.
After age 50, most expert groups recommend breast cancer screening every one to two years, depending on the woman’s individual risk of breast cancer.
When to stop mammograms — Most expert groups recommend that women continue to get routine mammograms and clinical breast exams as long as the woman is expected to live at least 10 years. This is because the risk of developing breast cancer increases as women age. (See “Patient information: Risk factors for breast cancer”.)

WHERE TO GET MORE INFORMATION — Your healthcare provider is the best source of information for questions and concerns related to your medical problem.

 

Related topics for patients, as well as selected articles written for healthcare professionals, are also available. Some of the most relevant are listed below.

Patient Level Information:

Patient information: Genetic testing for breast and ovarian cancer
Patient information: Common breast problems
Patient information: Risk factors for breast cancer

Professional Level Information:

Breast imaging: Mammography and ultrasonography
Breast lumps and other common breast problems
Epidemiology and risk factors for breast cancer
Genetic testing for hereditary breast and ovarian cancer syndrome
Characteristics of hereditary breast and ovarian cancer syndromes
Screening for breast cancer

The following organizations also provide reliable health information.

National Cancer Institute
1-800-4-CANCER
(www.cancer.gov/cancertopics/pdq/screening/breast/Patient)

National Library of Medicine
(www.nlm.nih.gov/medlineplus/mammography.html)

REFERENCES
Saslow D, Boetes C, Burke W, et al. American Cancer Society guidelines for breast screening with MRI as an adjunct to mammography. CA Cancer J Clin 2007; 57:75.
Smith RA, Cokkinides V, Brawley OW. Cancer screening in the United States, 2009: a review of current American Cancer Society guidelines and issues in cancer screening. CA Cancer J Clin 2009; 59:27.
Nelson HD, Tyne K, Naik A, et al. Screening for breast cancer: an update for the U.S. Preventive Services Task Force. Ann Intern Med 2009; 151:727.