Mammogram

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Mammogram

Test Overview

A mammogram is an X-ray test of the breasts (mammary glands) used to screen for breast problems, such as a lump, and whether a lump is fluid-filled (a cyst) or a solid mass.

A mammogram is done to help screen for or detect breast cancer. Many small tumours can be seen on a mammogram before they can be felt by a woman or her doctor. Cancer is most easily treated and cured when it is discovered in an early stage. Mammograms do not prevent breast cancer or reduce a woman's risk of developing cancer. But regular mammograms can reduce a woman's risk of dying from breast cancer by detecting a cancer when it is more easily treated.

Experts differ in their recommendations about when or how often women should have mammograms.

  • For women ages 50 to 69, regular mammograms (every 2 years) are recommended by the Canadian Cancer Society.
  • For women between the ages of 40 and 50, the benefits of regular mammograms are not clear. Women should discuss the benefits and harms of mammograms with their doctors. Talk with your doctor to decide when to start and how often to have a mammogram.
    • The Canadian Cancer Society and other experts recommend that for women younger than 50 years of age, the decision about when to start regular screening with mammograms every 2 years should be an individual one.1, 2 This decision should be based on her situation, her individual risk, and what she prefers.
  • Women age 70 and older may want to talk to their doctors about whether they need breast cancer screening.1

Your doctor may recommend testing at a younger age if you have risk factors for breast cancer.

Click here to view a Decision Point. Breast Cancer Screening: When Should I Start Having Mammograms?

A mammogram that appears to detect a cancer, when in fact a cancer is not present (false-positive results), can occur at any age but is more likely to occur in younger women. About 5% to 10% of screening mammograms will require more testing. This may include another mammogram of specific breast tissue or another test, such as an ultrasound. Most of these tests will show no cancer is present.

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Decision Points focus on key medical care decisions that are important to many health problems. Decision Points focus on key medical care decisions that are important to many health problems.
  Breast Cancer Screening: When Should I Start Having Mammograms?

Why It Is Done

A mammogram is done to:

  • Screen for breast cancer in women without symptoms.
  • Detect breast cancer in women with symptoms. Symptoms of breast cancer may include a lump or thickening in the breast, nipple discharge, or dimpling of the skin on one area of the breast.
  • Locate an area of suspicious breast tissue to remove for examination under a microscope (biopsy) when an abnormality is found.

How To Prepare

If you have previously had a mammogram done at another clinic, have the results sent or bring them with you to your examination.

Tell your doctor if you:

  • Are or might be pregnant. A mammogram is an X-ray test with exposure to low-dose radiation and is not done for routine screening during pregnancy.
  • Are breast-feeding. A mammogram may not provide clear results in breasts that contain milk.
  • Have breast implants. Breast implants require a modified mammogram method.
  • Have previously had a breast biopsy. Knowing the location of scar tissue will help the radiologist read your mammogram accurately.

On the day of the mammogram, do not use any deodorant, perfume, powders, or ointments on your breasts. The residue left on your skin by these substances may interfere with the X-rays.

If you are still having menstrual periods, you may want to have your mammogram done within 2 weeks after your menstrual period ends. The procedure will be more comfortable, especially if your breasts become tender before your period starts.

How It Is Done

A mammogram is done by a radiology technologist or mammogram technologist. The X-ray pictures (mammograms) are interpreted by a doctor who specializes in evaluating X-rays (radiologist).

You will need to remove any jewellery that might interfere with the X-ray picture. You will need to take off your clothes above the waist, and you will be given a cloth or paper gown to use during the test. If you are concerned about an area of your breast, show the technologist so that the area can be noted.

You usually stand during a mammogram. One at a time, your breasts will be placed on a flat plate that contains the X-ray film. Another plate is then pressed firmly against your breast to help flatten out the breast tissue. Very firm compression is needed to obtain high-quality pictures. You may be asked to lift your arm. For a few seconds while the X-ray picture is being taken, you will need to hold your breath. Usually at least two pictures are taken of each breast: one from the top and one from the side.

You may be in the mammogram clinic for up to an hour. The mammogram itself takes about 10 to 15 minutes. You will be asked to wait (usually about 5 minutes) until the X-rays are developed, in case repeat pictures need to be taken. In some clinics and hospitals, X-ray pictures can be viewed immediately on a computer screen (digitally).

How It Feels

A mammogram is often uncomfortable but rarely extremely painful. If you have sensitive or fragile skin, or a skin condition, let the technician know before you have your examination. If you have menstrual periods, the procedure is more comfortable when done within 2 weeks after your period has ended.

The X-ray plate will feel cold when you place your breast on it. Having your breasts flattened and squeezed is usually uncomfortable. But it is necessary to flatten out the breast tissue to obtain the best pictures.

Risks

A mammogram may appear to detect a cancer even when a cancer is not present (false-positive results). This can occur at any age but is more likely with younger women. False-positive results can lead to emotional distress and unneeded tests and treatments.

Also, a mammogram may detect abnormalities that will not develop into life-threatening cancer. Tests and treatment after this kind of discovery are not needed and can be harmful.

There is always a slight risk of damage to cells or tissue from being exposed to any radiation, including the very low levels of radiation used for this test. But the risk of damage from the X-rays is very low compared with the potential benefits of the test.

Results

A mammogram is an X-ray test of the breasts (mammary glands) that is used to screen for breast problems, such as a lump, and whether a lump is fluid-filled (a cyst) or a solid mass. Mammogram results are usually available within 10 days. It is not uncommon to be asked to return for another test so an additional view of an area in question can be obtained.

The results of a screening mammogram are sent directly to your family doctor's office. And in some provinces, they also will be sent directly to you. If the mammogram is done to diagnose a problem, the results will be sent to your family doctor, and he or she will discuss the results with you. If you have a mammogram that was not ordered by your doctor, a copy of the results will be sent to you.

Mammogram

Normal:

Breast tissue looks normal. No unusual growths, lumps, or other types of abnormal tissue are seen. The glands that produce milk for breast-feeding and the tubes (ducts) through which milk flows appear normal.

Abnormal:

An abnormal growth, lump, or other type of tissue may be seen. A cancerous (malignant) or non-cancerous (benign) tumour may be seen. One or more fluid-filled pockets (cysts) may be seen.

Bits of calcium (calcifications) may be seen. Tiny calcifications (microcalcifications) often occur in areas where cells are growing very rapidly (such as in a cancerous tumour). Larger calcifications (macrocalcifications) are usually normal and non-cancerous in women older than age 50.

Need more information:

A specific area needs to be looked at again. This is a very common result for many women and does not mean that the area is abnormal or cancerous.

Most abnormalities found during a mammogram are not breast cancer. But many women who have regular screening mammograms need more tests to investigate any abnormalities found during a mammogram. If an area of your breast tissue appears to be a concern during a mammogram, other tests may be done.

What Affects the Test

Reasons you may not be able to have the test or why the results may not be helpful include:

  • Deodorant, perfume, powders, or ointments applied to the breasts or under the arms before the test. They may interfere with the X-ray pictures.
  • Breast implants or scar tissue from previous breast surgery. This may make a mammogram harder to interpret.

A mammogram is not usually done if you are:

  • Pregnant, because the radiation could damage your developing baby (fetus). If a mammogram is absolutely necessary for diagnosing a problem, a lead apron will be placed over your abdomen to shield your baby from exposure to the X-rays.
  • Breast-feeding, because breasts that contain milk are very difficult to examine.

What To Think About

  • Most abnormalities found during a mammogram are not breast cancer. But many women who have regular screening mammograms need more tests to investigate any abnormalities found during a mammogram. If an area of your breast tissue appears to be a concern during a mammogram, other tests such as an ultrasound may be done.
  • Mammogram results are harder to interpret in women before menopause because breast tissue in younger women is denser than in older women. Mammograms may be less accurate in obese women.
  • A digital mammogram allows your doctor to view different parts of the breast without taking more images. Digital mammograms have the same overall accuracy as standard mammograms. The procedure in which a digital mammogram is done is the same as a standard mammogram—each procedure takes about the same amount of time, and breast compression is needed for both. Images from a digital mammogram can be magnified and stored electronically.
  • If you come from a family where women have had breast cancer earlier than age 40, talk to your doctor about what age to start screening. If you have a very strong family history of breast or ovarian cancer, you may want to have a breast cancer (BRCA) gene test. For more information, see the topic Breast Cancer (BRCA) Gene Test.

Other Places To Get Help

Organization

Canadian Cancer Society
10 Alcorn Avenue
Suite 200
Toronto, ON  M4V 3B1
Phone: (416) 961-7223
Fax: (416) 961-4189
Email: ccs@cancer.ca
Web Address: http://cancer.ca
 

The Canadian Cancer Society (CCS) is a national, community-based organization that provides information about cancer prevention, care, and treatment. The CCS also provides funding for cancer research.


References

Citations

  1. Canadian Cancer Society (2010). Breast cancer screening guidelines section of Breast cancer. Available online: http://www.cancer.ca/Canada-wide/Prevention/Getting%20checked/Breast%20cancer%20NEW.aspx?sc_lang=en.
  2. U.S. Preventive Services Task Force (2009). Screening for breast cancer. Available online: http://www.uspreventiveservicestaskforce.org/uspstf/uspsbrca.htm.

Other Works Consulted

  • American Cancer Society (2009). Prevention and Early Detection: American Cancer Society Guidelines for the Early Detection of Cancer. Atlanta: American Cancer Society. Available online: http://www.cancer.org/docroot/PED/content/ped_2_3X_ACS_Cancer_Detection_Guidelines_36.asp.
  • U.S. Preventive Services Task Force (2009). Screening for breast cancer. Available online: http://www.uspreventiveservicestaskforce.org/uspstf/uspsbrca.htm.

Credits

By Healthwise Staff
Primary Medical Reviewer Sarah Marshall, MD - Family Medicine
Primary Medical Reviewer Brian D. O'Brien, MD - Internal Medicine
Specialist Medical Reviewer Kirtly Jones, MD, MD - Obstetrics and Gynecology
Last Revised March 28, 2011

This information does not replace the advice of a doctor. Healthwise, Incorporated disclaims any warranty or liability for your use of this information.