Why have a mammogram

20% Complete

Benefits of Regular Mammograms
  • Mammography is the best way to find breast cancer early. 
    When breast cancer is found early, there are more treatment options available, a better chance for treatment success and reduced risk that the cancer will return.(1) 
  • Most women who have a mammogram will not have breast cancer and only a small number may need additional tests. 
    In Canada, about 1 out of 215 women who go for a mammogram as part of a provincial screening program will be diagnosed with breast cancer. (2) 
  • Regular mammograms may help you feel less worried. 
    Mammogram results that show breast cancer is not present may provide peace of mind.
  • Mammograms reduce a woman's risk of dying of breast cancer. 
    The goal of having mammograms at regular intervals as part of a screening program is to detect breast cancer early, when it is small and is less likely to have spread. (3)


Limitations of Regular Mammograms
  • Not every breast cancer that is found can be treated or cured.  
    Some cancers found through mammography cannot be cured. Finding out about a breast cancer that cannot be cured could cause stress and anxiety. 
  • Some breast cancers detected may not be life threatening, but may still lead to invasive treatment.  
    Mammograms may detect some breast cancers that will never become harmful, such as those that are slow growing and may never progress to produce symptoms or cause harm over a woman’s lifetime. It is difficult to determine which cancers will be harmful and which will not, so all are treated as possibly harmful. This may mean that women have surgery or treatment for breast cancer that would never have been life-threatening. For every breast cancer found, approximately 1-10% are non-life threatening.(4)  
  • Mammograms are not perfect and may not find a breast cancer that is present. Breast screening does not prevent breast cancer, but it can find it when it is already there. 
    No screening test is perfect and mammograms may miss some breast cancers. Breast cancer may develop before the first mammogram or in the time between screening appointments and this is one reason it is important to consider screening regularly.
  • Women are recalled for further testing for many reasons, and this can cause worry and stress. In most cases, breast cancer is not found.

What are the likely outcomes following 215 women after their mammogram?

This diagram represents the average outcome following screening of Canadian women ages 50-69 participating in provincial screening programs (a weighted average of both women screening for the first time and those participating in ongoing screening were included).(2) 

Are there other options?

Mammography is still the gold standard for breast cancer screening. You may have heard about other tests. Sometimes an MRI (Magnetic Resonance Imaging) scan or ultrasound is used in women at higher than average risk for breast cancer.
For more information on breast screening technologies, click here

While noticing how your breasts normally look and feel is important, breast self exams are not effective on their own. You may have heard it's important to do breast self-exams or have your health care provider to do a breast exam during your checkup.  Research has shown that self-exams are not considered effective at detecting breast cancer, especially compared to a mammogram that can detect cancer before you feel or see any breast changes.
It is still important for women to be breast aware – that is, knowing how your breasts normally look and feel, and taking note of any breast changes. Seek medical attention from a health care provider if you notice any of the following breast changes: 

alt text
Nipple changes
alt text
alt text
Nipple discharge
alt text
Lumps or thickening
alt text
Skin changes
alt text
Dimpling or puckering

Among women who are called back for further testing, many will have one or more diagnostic procedures. About 81% will have a second mammogram (diagnostic mammogram), 47% will have an ultrasound, and about 15-18% will have a biopsy done (where a tissue sample is taken for testing). (5)



Nelson HD, Fu R, Cantor A, Pappas M, Daeges M, Humphrey L. Effectiveness of breast cancer screening: systematic review and meta-analysis to update the 2009 U.S. Preventive Services Task Force Recommendation. Ann Intern Med 2016; 164(4): 244-55.


Canadian Partnership Against Cancer. Breast Cancer Screening in Canada: Monitoring and Evaluation of Quality Indicators – Results Report, January 2009 to December 2010. Toronto: Canadian Partnership Against Cancer; 2015.


The Canadian Task Force on Preventive Health Care. Recommendations on screening for breast cancer in average-risk women aged 40–74 years. CMAJ Can Med Assoc J. 2011 Nov 22;183(17):1991–2001. 


Lauby-Secretan B, Scoccianti C, Loomis D, Benbrahim-Tallaa L, Bouvard V, Bianchini F, et al. Breast-Cancer Screening — Viewpoint of the IARC Working Group. N Engl J Med. 2015 Jun 3;372(24):2353–8. 


Canadian Partnership Against Cancer. Breast Cancer Screening in Canada: Monitoring and Evaluation of Quality Indicators - Results Report, December 2009 - January 2010.  Toronto: Canadian Partnership Against Cancer; 2015.