A mammogram is an x-ray examination of the breast to discover and evaluate changes in the breast tissue.
Two to four screening mammograms out of every 1,000 result in a breast cancer diagnosis, according to the American Cancer Society.
Frequency of Mammogram Testing
There is a general consensus that mammograms are necessary and save lives, but there are differing opinions regarding how often mammogram screenings should be done. The American Cancer Society and the USPSTF offer different recommendations.
The U.S. Preventive Services Task Force (USPSTF) is a panel of healthcare providers, working under the auspices of the U.S. Department of Health and Human Services. They research and review the outcomes of different screening options. With regard to mammograms, the USPSTF recommends:
- Screening for the average-risk woman should begin at age 50
- The test should be repeated every two years
- Routine screening should end at age 74
- Self-breast exams have little value in reducing deaths from breast cancer
- The benefits of breast examination by a healthcare provider have yet to be determined
In contrast, the American Cancer Society (ACS) recommends:
- Screening should begin at age 40 for the general female population
- Testing should be repeated annually
The stated guidelines are for routine screening mammograms, not screenings for patients with a breast lump, other suspicious finding or those considered to be a high-risk. It is important to note that neither set of guidelines apply to women with risk factors such as rare BRCA mutations (in genes connected with hereditary breast-ovarian cancer syndrome) or a family history of breast cancer.
How it Works
A mammogram is done using low energy x-rays. The low energy does not penetrate through tissue as readily as routine x-rays.
The mammogram x-ray can be seen on sheets of film or as electronic images on a computer screen using a digital mammogram unit. Both types of mammogram are accurate, in most cases. Some studies report that the digital images have several distinct advantages including:
- Less frequent need for extra images to evaluate a questionable area on a mammogram
- Digital images can be enlarged and evaluated from different vantage points on the computer screen
- Higher accuracy in detecting cancer in two specific populations, women under 50 years old and women with dense breast tissue
Preparing for a Mammogram