Busting the Myths About Mammography Screening: Intermountain Imaging Expert to Address National Breast Imaging Symposium to Correct Myths

Brett Parkinson, MD, imaging director for Intermountain Healthcare and medical director of the Intermountain Medical Center Breast Care Center, says there are now as many different screening recommendations as there are professional organizations which advise patients on best practices for the early detection of breast cancer. That’s caused too much confusion, he says. 

 Dr. Parkinson will address the opening session of the 2018 Society of Breast Imaging/American College of Radiology’s National Symposium in Las Vegas on Thursday, April 11. Dr. Parkinson will address the issue head on and will debunk common myths surrounding screening mammography with hard science.  

Since Utah ranks among the lowest states for screening rates in the United States, Dr. Parkinson says there is an urgency in getting out the message of the American College of Radiology that women of average risk for breast cancer should be screened annually, beginning at age 40.  

Since the United States Preventive Services Task Force (USPSTF) issued a controversial recommendation in 2009 that screening mammography shouldn’t routinely begin until age 50, and only every other year until age 74, primary care providers have been at a loss as to what to tell their patients concerned about detecting breast cancer at the earliest stage possible.

“Everybody suffers when the science is ignored,” says Dr. Parkinson. “At the conference, I intend to present the science behind our recommendation to begin annual screening at 40, and while I’m at it, explain the solid research behind it to bust the myths about screening.”

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.  “Nonsense,” says Dr. Parkinson. “We know from multiple randomized controlled clinical trials  that regular screening saves lives, and that 40% of the years of life lost occur in women under age 50.”  

Dr. Parkinson points out that the incidence of breast cancer doubles between the ages of 35 and 40, and it increases with every decade of life.

“Age 40 is a good time to start to start screening as approximately 20% of breast cancers occur in many women under 50, most of whom are in their 40’s,” he notes. “Since most major medical organizations no longer recommended self-examination, or even clinical breast examination by a doctor, those cancers will be missed unless a woman is screened.”

In the last 25 years, the death rate from breast cancer has decreased by about 35%.  This is largely due to the widespread availability of screening mammography.

“If you take into account the results of more recent observation studies, which include women who have actually been screened, instead of those just ‘invited’ to be screened, the decrease in death rate approaches 50%,” Dr. Parkinson adds.

Another commonly circulated myth that Dr. Parkinson intends to debunk is that 10-50 percent of breast cancers are over-diagnosed, meaning some tumors may not be lethal if left untreated.  Dr. Parkinson is adamant when he says, “there is no documented case of an invasive breast cancer that has regressed without treatment.”

The science behind the over-diagnosis controversy is wrong, as it was based on the faulty premise that the underlying incidence of breast cancer has not changed, resulting in more diagnoses than would be expected, Dr. Parkinson contends. “We have tumor data registry dating back to 1940 that disproves that.”

Dr. Parkinson is quick to point out that the so-called “harms” of screening are not actually harms, another common myth. One of the harms cited by the USPSTF is the false positive mammogram.  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, he says.

“A false positive is when a test says a woman has cancer and she doesn’t. 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, and five of them will have cancer. The rest will be told everything is okay,” said Dr. Parkinson. “So, to find one cancer from screening, we have to do three biopsies, which isn’t bad.”

When Dr. Parkinson began his 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 “harms” have actually decreased, since women who don’t have cancer do not have to undergo the risks of surgery and general anesthesia, Dr. Parkinson said.

Another concern cited by the USPSTF, and common myth, is that the anxiety that a woman experiences when being called back for an abnormal screening mammogram should override the benefit of screening mammography.

Dr. Parkinson says that studies have shown that an overwhelming majority of the women would gladly endure of a few days of anxiety – the time between the screening mammogram and the problem-solving diagnostic follow-up – to find an early breast cancer.

Dr. Parkinson maintains that the whole idea that women can’t handle such anxiety is sexist.  “You never hear scientists talking about men not be able to cope with equivocal or false positive results of prostate screening,” he is quick to point out.

Dr. Parkinson says he still talks 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 the disease, dwarfs the theoretical risk that the small radiation dose from a mammogram will induce malignancy,” he notes. That real risk is about the same as taking a round-trip flight to Paris, he adds.

He is also concerned that some women will not be screened because they have dense breast tissue, thinking that mammography is ineffective in dense breast tissue. “Not true,” he says.  “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.”

Dr. Parkinson says the myth that screening is not 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. You can find five early breast cancers for the same price as treating a late-stage cancer, so you do the math,” he challenges.

The final myth he will debunk is that it is okay to screen women every other year, instead of annually. “Even in its position paper on screening in JAMA in October 2015,  the American Cancer Society noted that the mortality benefit of going to biennial, as opposed to annual screening, is decreased by at least 20 percent, he points out.

Dr. Parkinson notes there is some irony in his use of the word “myth” in a scientific talk.  However, in this day and age when science is being challenged by unfounded claims, myth-busting is a useful skill he intends to use for the sake of his patients.