Mammography is a specialised breast-imaging examination that uses low-dose X-rays to produce detailed two-dimensional images of the breasts. A mammogram may detect masses, calcifications, areas of tissue distortion and other changes that may be associated with breast cancer.
Standard digital mammography is used both to screen people without breast symptoms and to evaluate symptoms or abnormalities found during another examination. Although mammography is central to breast cancer detection, it does not identify every cancer and cannot confirm a diagnosis without further assessment.
An abnormal mammogram does not necessarily mean cancer. Additional mammographic views, ultrasound, digital breast tomosynthesis, contrast-enhanced mammography, breast MRI or biopsy may be recommended depending on the finding.
Role in Cancer Care
What to Expect
Before the Test
No fasting or medicine changes are usually required. If your breasts are particularly tender before your menstrual period, you may prefer to schedule routine screening when they are less sensitive, but a concerning symptom should not be left unevaluated for this reason.
Before the examination, inform the team if you:
Are pregnant or may be pregnant
Have a breast lump, nipple discharge, skin change, focal pain or another symptom
Have previously undergone breast surgery, biopsy or radiation therapy
Have breast implants
Have a personal or family history of breast or ovarian cancer
Are using hormone therapy
Have difficulty standing or moving your shoulders or arms
Have previous mammograms from another imaging centre
Bring previous mammograms and reports whenever possible. Comparing current and earlier images can help identify subtle changes and may reduce unnecessary additional testing.
Do not apply deodorant, antiperspirant, talcum powder, lotion or cream to the breasts or underarms on the day of the examination. These products can sometimes appear as spots on the images. Wearing a two-piece outfit may make it easier to undress from the waist up.
During the Test
You will stand in front of the mammography unit while a specially trained technologist positions one breast at a time on the imaging platform. The breast will be gradually compressed with a clear plastic paddle.
You will be asked to remain still and may need to hold your breath briefly while each image is taken. Two standard views are usually obtained of each breast during screening mammography. Diagnostic mammography may require additional, magnified or specially angled views.
Compression may feel tight or uncomfortable, but it lasts only a few seconds for each image. Tell the technologist if you experience significant pain. The degree of compression may be adjusted while still obtaining diagnostically useful images.
People with breast implants require specialised implant-displacement views in addition to standard images. Inform the imaging centre about the implants when scheduling the appointment so that sufficient time can be allowed.
The examination commonly takes approximately 20 to 30 minutes. A diagnostic mammogram may take longer if additional views are needed.
After the Test
No recovery period is required, and you can return to normal activities immediately. Temporary breast tenderness may occur but usually settles quickly.
For diagnostic examinations, you may be asked to wait while the radiologist reviews the images. Additional mammographic views or ultrasound may sometimes be performed during the same visit.
The report will describe the findings and breast density and usually assign a Breast Imaging Reporting and Data System, or BI-RADS, assessment category. The result may recommend routine screening, short-interval follow-up, additional imaging or biopsy.
Potential Benefits
- Early detection: Screening can identify some breast cancers before symptoms develop.
- Detection of calcifications: Mammography can show small calcifications that may be associated with early breast cancer.
- Assessment of symptoms: Diagnostic mammography can investigate a lump, nipple change, discharge or focal pain.
- Comparison over time: Previous and current images can be compared to detect subtle changes.
- Treatment follow-up: Mammography can monitor remaining breast tissue after breast-conserving treatment.
- Standardised reporting: BI-RADS categories help communicate findings and guide the next step.
- Low-dose imaging: Modern mammography uses a controlled, low radiation dose.
- Established screening role: Regular mammographic screening can reduce breast cancer mortality in appropriately screened populations.
