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 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. In 2015, the American Cancer Society recommended that screening mammograms start at age 45.
Now the American College of Obstetricians and Gynecologists (ACOG) has released updated breast cancer screening guidelines that recommend that women at average risk be offered annual screening mammograms at age 40. The guidelines also say that if a woman doesn’t start having annual mammograms at age 40, regular screening should start at age 50. In all cases, the decision about when to start screening mammograms should be made individually by each woman after discussing the issue with her doctor.
The updated guidelines were published on the ACOG website. Read “ACOG Practice Bulletin: Breast Cancer Risk Assessment and Screening in Average-Risk Women.”
"Our new guidance considers each individual patient and her values," Christopher Zahn, M.D., ACOG vice president of practice activities, said in a statement. "Given the range of current recommendations, we have moved toward encouraging obstetrician-gynecologists to help their patients make personal screening choices from a range of reasonable options."
According to the guidelines, a woman and her obstetrician-gynecologist should discuss mammography and consider:
- the woman’s health history
- the benefits and harms of screening
- the woman's concerns, priorities, values, and preferences about mammograms
The guidelines recommend:
- Women at average risk of breast cancer should be offered screening mammograms starting at age 40. Women at average risk of breast cancer should start having screening mammography no earlier than age 40. If a woman hasn’t started having screening mammograms in her 40s, she should start having screening mammograms by age 50.
- The decision about the age to begin mammography screening should be made through a shared decision-making process between a woman and her obstetrician-gynecologist. This discussion should include information about the potential benefits and harms.
- Women at average risk of breast cancer should have a screening mammogram every 1 or 2 years based on an informed, shared decision-making process that includes a discussion of the benefits and harms of having screening every year or every 2 years and incorporates patient values and preferences. Having a screening mammogram every 2 years, particularly after age 55, is a reasonable option to reduce the frequency of harms, as long as patient counseling includes a discussion that with decreased screening comes some reduction in benefits.
- Women at average risk of breast cancer should continue having screening mammograms until at least age 75.
- Age alone should not be the basis to continue or stop screening mammograms. For women older than age 75, the decision to stop screening mammograms should be based on a shared decision-making process informed by the woman’s health status and longevity.
- The ACOG guidelines don’t recommend breast self-exam for average-risk women.
At Breastcancer.org, we believe that a woman’s best chance for early detection requires coordination of our current screening tools:
- high-quality mammography
- clinical breast exam
- breast self-exam
To not use all three tools are missed opportunities for early detection.
The reality is that every woman is at risk for breast cancer, and this risk tends to increase over time. It’s important to understand and regularly update your health information related to breast cancer risk throughout your life with your doctor. To get the conversation started, here are some points to talk to your doctor about:
- family history of breast or other related cancers (ovarian, melanoma)
- any test results for abnormal genes linked to a high risk of breast cancer
- results of past breast biopsies, even if they were benign
- personal history of being treated with radiation to the face and/or chest before age 30
- breast density
- weight, if you’re overweight or obese
- level of physical activity
- any use of postmenopausal combined hormone replacement therapy (HRT)
- alcohol consumption, if you regularly drink more than 3 alcoholic beverages per week
- the amount of processed food and trans fats you eat
- your smoking history
- whether or not you had a full-term pregnancy or breastfed
Breastcancer.org stands by its recommendation that all women have mammograms annually starting at age 40. We also believe that monthly breast self-exam and annual physical exams by a doctor are essential parts of an overall breast cancer screening strategy. If you’re at high risk for breast cancer, you should talk to your doctor about starting annual mammograms at a younger age and consider other screening tools (such as MRI or ultrasound) to maximize the opportunity for early detection.
For more information on mammograms, including where to get one and the benefits and risks, visit the Breastcancer.org Mammograms page.