International Agency for Research on Cancer Releases Breast Cancer Screening Special Report
A special report from the IARC questions the value of screening mammograms for women ages 40 to 49.
Several large studies, including a review by the U.S. Preventive Services Task Force in 2009 and a study on the causes of death in the United Kingdom in 2013, have questioned the value of screening mammograms.
Doctors who question the value of mammograms say that while mammograms do save lives, for each breast cancer death prevented, three to four women are overdiagnosed. Overdiagnosis means either:
- a screening mammogram finds a suspicious area that would have been eventually diagnosed as cancer by other means, without any effect on prognosis
- a screening mammogram finds a suspicious area that never would have affected a woman’s health if it hadn’t been found or treated
False positive results from screening mammograms also have helped fuel the debate about the value of breast cancer screening. When a mammogram shows an abnormal area that looks like a cancer but turns out to be normal, it’s called a false positive. Ultimately the news is good: no breast cancer. But the suspicious area usually requires follow-up with more than one doctor, extra tests, and extra procedures, including a possible biopsy. There are psychological, physical, and economic costs that come with a false positive.
These studies and the resulting stories in the media have fueled an ongoing debate about the value of screening mammograms.
Since that time, the American Medical Association, the American College of Obstetricians and Gynecologists, the American College of Radiology, the American Cancer Society, the National Cancer Institute, and the National Comprehensive Cancer Network all have issued guidelines saying that all women should be eligible for screening mammograms starting at age 40.
Now the International Agency for Research on Cancer (IARC) has released a special report on breast cancer screening. After balancing the risk and benefits, the IARC said that there are benefits to screening women ages 50 to 74, but only limited benefits to screening women ages 40 to 49.
The special report was published in the June 3, 2015 issue of the New England Journal of Medicine. Read the abstract of “Breast-Cancer Screening -- Viewpoint of the IARC Working Group.”
The IARC is the specialized cancer agency of the World Health Organization and aims to promote international collaboration in cancer research.
The IARC working group that wrote the special report includes researchers from 16 countries. The researchers met in November 2014 to review and discuss studies that had been done on breast cancer screening. They cited the results of several studies in the special report, including:
- Women ages 50 to 69 who had screening mammograms have an estimated 40% lower risk of breast cancer compared to women who don’t have mammograms.
- Women ages 70 to 74 who have screening mammograms or are invited to participate in breast cancer screening programs also have a much lower risk of breast cancer compared to women who don’t have mammograms.
- For women ages 40 to 44 or 45 to 49, the evidence is limited and it isn’t clear how often these women should be screened.
- The estimated false positive risk is 20% for women who get 10 screening mammograms between age 50 and age 70.
- Estimates of how many women are overdiagnosed varies; the Euroscreen Working Group says about 6.5% of women are overdiagnosed but other estimates range from 4% to 11% or higher.
- Breast ultrasound may boost cancer detection, but it increases false positive rates.
At Breastcancer.org, we believe that if you're 40 or older and have an average risk of breast cancer, yearly screening mammograms should be part of your healthcare. If your breast cancer risk is higher than average, you may want to talk to your doctor about a more aggressive breast cancer screening plan that makes the most sense for your particular situation.
The Mayo Clinic, the American Medical Association, the American College of Obstetricians and Gynecologists, the American College of Radiology, the American Cancer Society, the National Cancer Institute, and the National Comprehensive Cancer Network all recommend that screening mammograms should start at age 40.
There's only one of you and you deserve the best care possible. Don't let any obstacles get in the way of your regular screening mammograms.
- If you're worried about cost, talk to your doctor, a local hospital social worker, or staff members at a mammogram center. Ask about free programs in your area.
- If you're having problems scheduling a mammogram, call the National Cancer Institute (800-4-CANCER) or the American College of Radiology (800-227-5463) to find certified mammogram providers near you.
- If you find mammograms painful, ask the mammography center staff members how the experience can be as easy and as comfortable as possible for you.
For more information on mammograms and other tests to detect and diagnose breast cancer, visit the Breastcancer.org Screening and Testing section.
— Last updated on February 22, 2022, 10:02 PM
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