cross posted at http://www.arthritis-alternatives.com
A Swedish study published recently maintains that mammograms for women in their 40s save lives. It contradicts numerous studies done over the past 20 years, as well as recommendations from The American College of Physicians in 2007 and from the expert U.S. Preventive Services Task Force in 2009 which concluded that the benefits of mammography screening before age 50 do not outweigh the risks, something that has been widely acknowledged in public health circles since mammography became big business in the late 1980s.
First, the Swedish study. You'd never know it to listen to the TV docs and their cheering section, but the Swedish study has been widely criticized by scientists for its lack of internal consistency. The research group that received mammograms was not similar to the comparison group that did not and also did not weigh risks against benefits. No conclusions of any kind can be drawn from such a hodgepodge.
Next: that cheering section. It's understandable that 24 hour news channels require something to fill air space and that they will glom on to anything that might hold a viewer's attention. It is not so understandable that they would ignore a study published a week or two earlier from Norway and Harvard that not only confirmed the findings of the Task Force but questioned whether mammograms actually benefit woman of any age. In other words, a direct contradiction to the Swedish study that also, remarkably, questioned the screening value of mammograms for anyone and received no media attention at all.
By far the worst of the cheerleaders for the Swedish study has been Dr Richard Besser, formerly director of the Centers for Disease Control and Prevention and now an expert talking head on all things medical for ABC.
On air, his opinion was that mammograms should continue for women in their 40s because of this apparently "well done study" which he had clearly neither read nor had vetted for him. He said that there was no reason to question the findings of the Swedish article and that women should ask "Why not? Why shouldn't I have a mammogram?"
OK, Dr. Besser. Let's talk about why not.
1. Overdiagnosis. Because screening tests are often based on imprecise measurements and are subject to human error, like the mammogram and the PSa test for prostrate cancer, a great many people are misdiagnosed as having a life threatening condition when they don't. Once a diagnosis of breast cancer is made, the next steps are preordained. What follows is enormous anxiety on the part of the patient, discussions with radiologists, oncologists, surgeons and other doctors about how to treat, the order of treatment and the side effects at each step. There is enormous expense involved at each level of discussion.
And consider this: approximately 1300 women over age 50 must be screened for years to avert one death. In the 40s that figure is 1900 screened. That's thousands of mammograms, hundreds of biopsies, and many cancers treated as if they were life-threatening when they are not.
What no one is likely to tell the patient is that some cancers are slow growing, or will not expand, or might clear up by themselves as the woman's immune system comes to the rescue. These cancers need to be just watched; no immediate action necessary.
It has been estimated that 25%-30% of breast cancer found on mammograms is the result of overdiagnosis. Further, an estimated 6% of the time the finding of breast cancer from a mammogram is a false positive. Translated, that means that more than one patient in 20 is told she has breast cancer when she does not.
There is a huge emotional and financial cost associated with overdiagnosis and mis-diagnosis, part of the reasoning of the 2009 U.S. Preventive Services Task Force. The down side hazards of mammograms make them unsuitable for women in their 40s who are at low risk for breast cancer, anyway.
2. Radiation: Every dose of radiation from chest xrays, dental xrays, mammograms and other sources is cumulative. When it comes to radiation, nothing is for free. Radiation damages DNA and has been a known to cause serious disease since the scientist who discovered it, Madame Curie, died of aplastic anemia, a rare and quickly fatal blood disorder.
Changes to the DNA resulting from xrays may later cause cancer. That is a major reason for the deep concern and criticism among many scientists regarding mammograms. It's a reason to avoid unnecessary xray exposure (and to reject routine dental xrays.)
One study showed a much higher incidence of invasive breast cancer in women who had been subject to routine mammograms than those who had not. The suspicion among some scientists is that the mammograms themselves are responsible.
What the experts have said: