There's a lot of confusion about screening mammography guidelines and that uncertainty is negatively impacting the number of women who get potentially life-saving mammograms.
The U.S. Preventive Services Task Force (USPSTF) started the mammography muddle by issuing a controversial recommendation in 2009 that routine screening mammography shouldn't begin until age 50, and should be provided every other year rather than every year. That recommendation flew in the face of previous guidelines and put primary care providers at a loss for the best guidance in detecting breast cancer at the earliest stage possible.
That uncertainty remains nearly a decade later, so I used the opening session of the 2018 Society of Breast Imaging/American College of Radiology (SBI/ACR) Breast Imaging Symposium in Las Vegas to dispel the most common myths about screening mammography.
I reminded symposium participants of their role in early detection and shared the science behind the American College of Radiology's message that women of average risk for breast cancer should be screened annually, beginning at age 40.
Here are the top eight myths regarding screening mammography and breast cancer, along with my personal plea to debunk them—for patients and primary care providers alike.
#1 Myth: Harm Outweighs Benefit
The overriding myth, propagated by the USPSTF, is that the harms of screening before the age of 50 and after the age of 74 may outweigh the benefits. That's nonsense. We know from multiple randomized controlled clinical trials that regular screening saves lives and that 40 percent of the years of life lost occur in women under age 50, so age 40 is a good time to start screening.
In the past 25 years, the death rate from breast cancer has decreased by about 35 percent. That's largely due to the widespread availability of screening mammography. If you take into account the results of more recent studies, which include women who have actually been screened, instead of those just “invited” to be screened, the decrease in death rate approaches 50 percent.
#2 Myth: Breast Cancer Overdiagnosis
Another dangerous myth is that 10-50 percent of breast cancers are overdiagnosed, meaning some tumors may not be lethal if left untreated. There is no documented case of an invasive breast cancer that has regressed without treatment.
The rationale behind the overdiagnosis myth is wrong—plain and simple. It was based on the faulty premise that the incidence of breast cancer has not changed—just more diagnoses than would be expected. We have tumor data registry dating back to 1940 that unequivocally disproves that.
#3 Myth: False-Positive Harm
The USPSTF cites false-positive mammogram results as a “harm” yet the nomenclature and stats dispute this prevailing myth. When a woman is called back from screening for additional tests, it's not really a false-positive examination. Those examinations are interpreted as “incomplete,” not positive. A false-positive is when a test says a woman has cancer and she doesn't.
In truth, when a thousand women are screened, 100 will be called back for additional views and/or an ultrasound. Only 15 of those 1,000 women will undergo biopsy to identify five who have cancer. The rest will be told everything is okay. Look at this way: to find one cancer from screening, we have to do three biopsies. In my book, that's a good ratio.
When I started my practice in 1991, all women with suspicious mammographic abnormalities had to undergo surgery for diagnosis. The diagnosis is now made by needle biopsy, usually performed by a radiologist with imaging guidance. The so-called “harm” has actually decreased, since women who don't have cancer don't have to undergo the risks of surgery and general anesthesia.
#4 Myth: Anxiety Associated With Abnormal Screening
A byproduct of the false-positive myth is the anxiety that a woman experiences when called back for an abnormal screening mammogram. Some, including the USPSTF, say that associated anxiety outweighs the benefits of screening mammography.
I believe the idea that women can't handle such anxiety is utterly sexist. Studies have shown that an overwhelming majority of women would gladly endure a few days of anxiety—the time between the screening mammogram and the problem-solving diagnostic follow-up—to find an early breast cancer. I've never heard anyone talking about men not being able to cope with the stress of false-positive results from prostate screening.
#5 Myth: Imaging Radiation Causes Cancer
I still talk to women who choose not to be screened because of the myth that screening may cause breast cancer. The risk of dying from breast cancer, which is very real, since one in eight women will develop this disease, dwarfs the theoretical risk that the small radiation dose from a mammogram will induce malignancy. The real risk is about the same as taking a round-trip flight to Paris.
#6 Myth: Dense Breast Tissue Diminishes Effectiveness
I'm also concerned that women with dense breast tissue will shrug off mammography, thinking it's ineffective in dense breast tissue. This is not true. Although screening is less sensitive in dense tissue, it still picks up most breast cancers. And now that we have 3-D mammography, we can find even more cancers in women with dense and very dense tissue.
#7 Myth: Screening Not Cost-effective
The myth that screening isn't cost-effective is simply not true. What isn't cost-effective is finding a late-stage breast cancer, one that will be expensive to treat, debilitating for the patient, and most often terminal. You can find five early breast cancers for the same price as treating one late-stage cancer. Even if we don't consider the quality-of-life benefit, the math is stark and compelling.
#8 Myth: Adequacy of Screenings Every Other Year
The final myth that I addressed at the SBI/ACR conference is that it's okay to screen women every other year instead of annually. The American Cancer Society's position paper on mammography screening, which was published in JAMA in October 2015, says mortality increases by 20 percent when screening occurs every other year instead of every year (2015;314(15):1599-1614). That's an important number to remember.
While there's significant irony in the use of the word “myth” in a scientific talk, science is being challenged by unfounded claims nearly every day of late. So, myth-busting skills are an important tool for all physicians to have and use—for the sake of patients everywhere.
BRETT PARKINSON, MD, is Imaging Director for Intermountain Healthcare and Medical Director of the Intermountain Medical Center Breast Care Center in Salt Lake City.