A mammogram is a screening test for breast cancer. These types of screening tests play an important role in maintaining good health. While some tests can be done quickly during a regular doctor’s visit, a mammogram requires an additional appointment at a special facility. The test itself is also rather uncomfortable, not to mention the stress a potential cancer diagnosis can cause. The following will help you understand the benefits and risks of a mammogram so that you can make an informed decision about your options.
The Potential Benefits of a Mammogram
Screening tests can help identify illnesses and health problems before symptoms arise. For illnesses like cancer, early detection may allow for more treatment options and improve the prognosis.
Catch Breast Cancer Early
Mammograms may detect changes in the breast that could be cancerous up to 2 years before a lump can be felt. Ductal carcinoma in situ (DCIS), an early stage of a type of breast cancer, can also be found with mammography. An early start to treatment may also stop the cancer before it spreads to the rest of the breast tissue or to other organs.
The Potential Risks and Limitations of a Mammogram
As a screening test, a mammogram cannot actually diagnose breast cancer. To diagnose breast cancer, other tests or procedures will need to be done to closely examine the suspicious tissue. A mammogram simply suggests that cancer may or may not be present. Limits of the test can lead to false results. The test may suggest that cancer is present when it is not. This is called a false positive. The test may also suggest that cancer is not present when it does exist. This is called a false negative.
Sometimes, a mammogram may suggest that there is a cancerous change in breast tissue when there really is not. Benign (noncancerous) tissue can look suspicious on a mammogram. Follow-up tests to confirm what the tissue is may include additional mammograms, ultrasound exams, breast biopsies, and other medical tests. If the original mammogram was a false positive, which may happen 10% of the time, the additional medical tests and associated stress were unnecessary.
False Sense of Security
A normal mammogram does not guarantee that you are cancer free. One possibility is that the test result may be a false negative, meaning the mammogram was not able to show a cancer that was there. A clear test may also encourage a false sense of security, which may lead you to ignore symptoms that should be discussed with a doctor.
Radiation can cause cancer and is used during a mammogram. However, the mammogram uses small doses of radiation that are considered safe. Some have voiced concerns about long-term exposure with repeated mammograms. Research has not found a link between mammogram testing and cancer development. There appears to be little risk of harm from this radiation.
Can It Improve Your Health?
Some studies suggest that mammograms can decrease the rate of cancer death, while other studies have questioned these findings. What is agreed on is that the effectiveness of the mammogram may change based on the individual and the type of cancer. For example:
- Aggressive (fast growing) tumors—Younger women tend to have more aggressive cancerous breast tumors. By the time a mammogram finds an aggressive tumor, some cancer cells may have spread to another organ. Therefore, detection may be too late.
- Indolent (slow growing) tumors—These are more common in older women and make up half of all breast tumors. Regular mammograms may be able to detect this type of tumor.
- Inflammatory breast cancer—This can be very hard to detect by manual exam. A mammogram may be able to detect this type of cancer before symptoms appear.
- High risk groups—Women with a family history of breast cancer may undergo more aggressive screening, although changes in genetic testing may change recommendations in the future.
- Dense breast tissue—This makes it harder for mammograms to locate tumors. Young women and menopausal women on hormone therapy tend to have denser breast tissue. This can make a mammogram less effective for women in their 40’s and younger.
There are many professional, medical, and cancer groups that have their own set of mammography guidelines. The majority of guidelines agree that:
- Beginning at age 40, women with an average risk of breast cancers should have a mammogram every 1-2 years.
Women who are at higher than average risk of breast cancer should seek expert medical advice about:
- Whether they should begin screening before age 40
- How frequently they should be screened
The United States Preventive Services Task Force (USPSTF) has provided some added qualifications. The USPTF does not recommend regular mammograms for women 40-49 years of age with average risk of breast cancer. Instead, the task force suggested that each woman in this age group make an individual decision with their doctor based on her personal risks and benefits. Also, they recommend mammogram screening every 2 years for women 50-74 years of age, rather than every year.
Most guidelines do not have a recommended age to stop mammogram screening. The American Geriatric Society recommends mammography frequency changes to every 2-3 years after 75 years of age and the termination of screening if life expectancy is less than 4 years.
Putting the Pieces Together
Discuss these benefits and harms, as well as any risk factors you may have, with your doctor. This may help you make a decision on whether to have a mammography exam.
Awareness of your own health and periodic check-ins with your doctor will help identify signs of illness that need further testing, as well as ensure regular screenings. Contact your doctor if you notice a change in the look or feel of your breast.
The American Congress of Obstetricians and Gynecologists
National Cancer Institute
Canadian Breast Cancer Foundation
Canadian Cancer Society
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Last reviewed October 2017 by EBSCO Medical Review Board Michael Woods, MD, FAAP Last Updated: 11/5/2015