Why the Screening Mammography Recommendations are Flawed
Why the Screening Mammography Recommendations are Flawed
The recent national news story bashing screening mammography deserves consideration and appropriate responses. American women deserve no less as they make decisions about their breast screenings and overall health care.
The medical professional response is quite detailed and necessarily scientific. However, it clearly exposes the shortcomings and flaws of a rationale suggesting that screening mammography in women 40 to 50 years of age should be questioned or even suspended.
In the past two decades, there have been a number of well designed, randomized and controlled clinical trials that clearly indicate that women in their 40s who were screened with mammography had a 15 percent reduced risk of dying from breast cancer compared to women that were not screened. The mortality reduction increases to 20 percent for women in their 50s.
Some would argue the reduction is even greater, but suffice it to say, there are clearly proven unquestionable benefits to screening mammography. The American Cancer Society recognizes this benefit and recommends yearly screening mammography after age 40, as has been the official recommendation for many years.
Nothing has changed.
On the other hand, the recent story focuses on the scientifically flawed Canadian National Breast Screening Study (CNBSS) which forms the basis for the equally flawed recommendations of the United States Preventive Services Task Force (USPSTF) that women in their 40s not receive the benefits of annual screening mammography. The CNBSS was released more than two decades ago and if nothing else, is severely outdated.
However, close scrutiny of the study indicates several violations of scientific study, rendering it useless to those who seriously consider data that can shape broad policy regarding recommendations for women across America. Obviously any organization or agency can choose to ignore scientific evidence-based studies to formulate their own self-serving recommendations. The informed consumer of healthcare services will see through this shallow posturing and specious argument.
Several things render the CNBSS study — and therefore the USPSTF recommendations — useless.
1. The study was released more than 20 years ago, so the current recommendations are based on poor quality mammography that used second-hand machines, which were not state-of-the-art at the time of the trial.
2. Present day mammography techniques use grids which reduce scatter radiation and improve resolution and image clarity making cancers easier to see on mammograms. Most of the mammograms used in the Canadian trial did not use grids.
3. The CNBSS mammogram technologists were not taught proper positioning techniques for performing mammograms nor did the radiologists have special training in mammogram interpretation. Current technologists are certified in mammographic positioning and current radiology residency training programs devote months of training to interpret mammograms.
4. Women were not properly selected or randomized for the trial. They were physically examined first and women with palpable breast masses (that could be felt) were more often “randomized” to the mammography group. Women without a mass were more often sent to the “control” group. It is no wonder that the mammography group showed more cancers; these women likely had cancer before they were ever enrolled in the trail. Obviously this group would have a higher mortality rate. The USPSTF chose to ignore this scientific data since it would invalidate their recommendation.
5. Current US mammogram centers must be accredited to pass the Mammography Quality Standards Act (MQSA) federal inspection standards to permit payment for their services. It is almost certain that the majority of the centers used for the Canadian trial would fail current MQSA inspection and not be allowed to perform mammograms, let alone form the basis for a far-reaching recommendation suggesting that women in their 40s should consider not getting mammography.
The common sense approach is not scientifically detailed, but perhaps is more understandable by the majority of readers who depend on their medical providers for sound advice.
It is a well-understood axiom that regardless of the issue, it is better to identify a problem when it is small and more manageable than when it gets larger and becomes more difficult to handle. Indeed, if left too long, it may be impossible to fix.
I would offer two every-day examples that everyone can easily understand.
1. The On-Star service currently installed in many GM vehicles will send a periodic email to the customer, equivalent to a screening mammogram. This “screening” email will tell the customer many things about the current condition of the vehicle, much like a screening mammogram tells the woman about the state of her breast health.
For this example, let’s focus on the tire air pressure readings. If the pressure in one tire is low, it will be colored yellow or red indicating an issue that the customer should address. He may choose to ignore the warning and run the risk of ending up with a flat tire or getting in an accident, but more likely he will take action and get it fixed. The customer (or woman) knows that the On-Star screening service (mammogram) they have received is designed to identify a small tire problem (or breast issue) in its earliest stages when it can be more effectively taken care of or cured.
Few of us would ignore a warning that our tire is going flat because we don’t want to deal with a catastrophe down the road. Similarly, why would we ever choose to avoid screening mammography when it could save our life through earlier detection of a cancer?
2. We are all cognizant of identity theft and most of us have heard of agencies, or even our credit card companies, that “screen” or monitor our credit and the use of our credit cards. Most of us get periodic notifications from them when our credit card balance increases by some specific amount, when our credit report has been accessed by some organization or when there has been unusual activity in our account. Most of us would take these “screenings” seriously since we want to avoid the catastrophe of identity theft. We watch things carefully so we can identify any irregularity very early on and catch any problem early when it can be effectively handled before it’s too late.
None of us would ignore a notification or “screening alert” telling us that there was unknown activity in our credit account. Similarly, why would we ever choose to avoid screening mammography when it could prevent the catastrophe of dying from breast cancer?
It is so obvious and yet it still bears repeating. Mammography is still the best defense we have against breast cancer. We have all been touched by women who have had breast cancer. It is clear that a 42-year-old woman who has a screening mammogram that detects a breast cancer the size of a pea has a whole lot better chance of surviving than a 50-year-old women who is diagnosed with a golf-ball sized cancer at her first mammogram since she waited to be screened because of what she read in the news or because she followed the USPSTF guidelines.
Bottom line: Don’t do what the US task force recommends. Do what the American Cancer Society and knowledgeable medical societies recommend. Begin annual screening mammograms at age 40. This recommendation is scientifically based and has not changed for decades. It will save lives.