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What is a Mammogram?

Mammograms are x-rays of the breasts that are done in complete privacy by a specially-trained female technologist.

For more information about mammography, watch the animated video below.


Video available in EnglishCantoneseMandarin & Punjabi

Screening mammogram

A screening mammogram consists of four images (two of each breast) that look for hidden cancer in women who are healthy (no symptoms) and have never had breast cancer. BC Cancer Breast Screening offers screening mammograms to eligible women in BC.

Diagnostic mammogram

A diagnostic mammogram consists of additional images from several angles and is used for women who are experiencing breast symptoms (such as a lump, unusual nipple discharge or pain), women who have had breast cancer, and women with breast implants. Talk to your health care provider for a referral to a diagnostic imaging clinic. 

Your questions

Screening mammograms can find most types of breast cancer early, but like all screening tests, they aren't perfect. Some cancers can't be seen on an x-ray and some cancers can develop quickly between 2 year intervals. Learn more about the benefits and limitations of screening mammography.


Screening mammograms are for women with no symptoms of breast cancer (no apparent breast problems). Diagnostic mammograms are ordered by a doctor to look at an area of concern in the breast; which may lead to more tests; such as an ultrasound or a biopsy.

The effectiveness of screening mammography has been well established by several large clinical trials across the world. These trials have found a relative risk reduction of breast cancer deaths of between 15-25% for women aged 50-69. Of eight randomized control trials for screening mammography, seven showed that screening mammography is beneficial.

In February 2014, the British Medical Journal published 25-year follow-up results from the Canadian National Breast Screening Study- the only randomized control trial suggesting that annual screening in women age 40-59 does not reduce breast cancer mortality beyond that of physical examination (for the 50-59 year olds) or usual care (for 40-49 year olds). BC Cancer does not agree with the findings in this study, and other credible evidence does not correlate with the findings.

Tomosynthesis is a new technology available to improve investigation of breast problems. The quality of all mammograms in the BC Cancer Breast Screening program is of the highest standard. Further assessment is needed to determine the optimal use of breast tomosynthesis in breast health. Until more information is available, the primary use of this technology will remain in the diagnostic setting.


SOURCE: What is a Mammogram? ( )
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