Mammography Guidelines: You Can’t Dress It Up

I don’t like to keep kicking the proverbial can down the road, but a column in yesterday’s Wall Street Journal about the statistics in the recent mammogram guideline recommendations from the U S Preventive Services Task Force is worthy of comment.


 


Aside from “getting it right” in my opinion, Carl Bialik’s (“The Numbers Guy”) discussion highlights the imperfection of the statistics that the Task Force relied on in making a recommendation to the public that we should abandon a long standing (and, in my opinion, effective) public health recommendation that women at average risk of breast cancer get a screening mammogram every year beginning at age 40.


 


The reality is that the fall out from the Task Force recommendations is just beginning, with one state government cutting mammograms for women in their 40’s and insurers concerned that their contracts with companies to provide health insurance benefits for employees will require them to do the same.


 


Mr. Bialik points out that one of the key statistics was not as perfect as one might think.  In fact, the statistic is so imperfect in this case as to make it meaningless. 


 


As Mr. Bialik reported, the “number needed to screen to save one life”—which the task force said was 1904 for women in their 40’s and 1339 for women in their 50’s—could have in fact been much lower or much larger both for 40-49 year old women and the 50-59 year old age group (see my initial blog on the Task Force report for further discussionon the confidence intervals for these numbers).


 


If you look at the number and understand statistics, you realize that the Task Force concluded there was a real difference in the impact of screening mammography in saving lives from breast cancer between the 40 and 50 year old age groups. That led the Task Force to conclude there was sufficient benefit in the older women but not in the younger women.


 


From a science standpoint, as pointed out in the column, that simply isn’t true.  There was so much overlap in the statistic between the two groups as to make any reliable difference in benefit impossible to detect with any degree of certainty.


 


Then there was the issue of the computer model and the role of value judgments comparing years-of-life-lost to how many “extra” mammograms would be required to save those years of life (as though the computer models all agreed on the same numbers, which they don’t).


 


Would I be intemperate to suggest that if given a choice, women would rather have the extra mammogram than die? 


 


Putting an extra mammogram up against losing your life–and coming to the conclusion that women would prefer to avoid that extra mammogram as opposed to saving their life–is an incredibly naïve conclusion in my opinion.  And that’s assuming the computer model is perfect in its conclusions, which is probably not the case.


 


A comment in the article from a Task Force member also has me concerned: 


“Diana Petitti, a professor in biomedical informatics at Arizona State University and vice chairwoman of the panel, said the task force looked at a range of evidence in making its recommendation. ‘This is purposely a qualitative assessment and not an assessment based on some magic number,’ she said in an email.” 


The Task Force, on its website says it is the “gold standard” in determining what medical screening interventions are effective and which are not.   


I have sat through a number of presentations from the Task Force—including one from its current chairman—where they have emphasized the impartiality of the task force, and the fact that they use a strict “evidence based” standard to make their recommendations.  No evidence or insufficient evidence means no recommendation for or against a particular screening test. 


In this current situation, their vice-chair is now saying that they made “qualitative assessments.”  My interpretation of that statement is that they applied their own values to the interpretation of the evidence, which is what I wrote when their report first came out. They have ignored the valid scientific/data based assessments of others, who have looked at the same data and came to different conclusions about the value of screening mammograms in women ages 40-49.


 That is not what I thought the Task Force was supposed to do.   


I went to the Task Force website today, and here is what I found for their current recommendation language: 


“The decision to start regular, biennial screening mammography before the age of 50 years should be an individual one and take patient context into account, including the patient’s values regarding specific benefits and harms. Grade: C recommendation. 


“On December 4, 2009, the USPSTF unanimously voted to update the language of their recommendation regarding women under 50 years of age to clarify their original and continued intent.” (emphasis mine) 


Follow the embedded link for “C recommendation” and this is what you will find:


 Definition:                                                               Suggestions for practice: 







The USPSTF recommends against routinely providing the service. There may be considerations that support providing the service in an individual patient. There is at least moderate certainty that the net benefit is small.


Offer or provide this service only if other considerations support the offering or providing the service in an individual patient.


 Tap dance all you want, the bottom line is that the task force still recommends against routine screening mammography. 


What’s worse in my opinion is that there is no evidence based research to show that following the Task Force recommendation will in fact save lives from breast cancer for women in their 40’s.  None, nada, nothing. 


This is beginning to look like an effort to put “lipstick on the pig”.   


What happened to evidence based recommendations?   


Clearly their “suggestions for practice” has no evidence base whatsoever for women at average risk of breast cancer.  No study has ever been done which confirms that physicians and other health care professionals can accurately predict which women in their 40’s are at greater risk of getting breast cancer and should therefore be advised to get a screening mammogram.  That’s important when you consider the fact that most women who get breast cancer in fact have no specific risk factors for the disease, and that there is a not inconsequential incidence of breast cancer in this age group. 


All of this discussion would be nothing more than interesting chatter and disagreement among scientists if it did not have practical implications. 


Already, we are hearing that insurance companies are concerned they may have to change their policies based on contracts that require them to follow the Task Force recommendations.  And the state of California has taken advantage of the dispute to restrict screening mammograms to disadvantaged women under 50 because of the state’s budget crisis.  The guideline is the reason they have made this decision. 


So what is the solution? 


A respected, evidence-based organization comes out with a guideline that is formed in no small part by opinion rather than solid evidence.  They fail to provide compelling evidence that would support the need for them to change their prior recommendations, which in fact were fairly consistent with other organizations.  They try to “dress up” their recommendation, but when you look behind the screen you see that in fact they still haven’t changed their recommendation, which is against routine mammography for women in their 40’s.  State governments and perhaps insurance companies start to restrict their coverage, in accordance with insurance contracts and other political considerations. 


Maybe it is time for some further action.  Maybe it is time for the Task Force to at least admit that the evidence is inconclusive one way or the other.  Although many of us don’t agree with that, at least it would move us in the right direction. 


The organizations that have supported the USPSTF because those organizations believe  the Task Force relied on solid evidence may not be so comfortable when they actually look at the evidence, or consider the comments from the Task Force.  And I suspect they may be a bit concerned that the task force now admits they made a judgment call, and not one based only on what the science was clearly telling them. 


And let’s also note that supporters of the Task Force—invoking the “evidence standards” of the Task Force—suggested that those who disagreed with the Task Force did so only because of their uninformed or otherwise conflicted reasoning, as though organizations like the American Cancer Society don’t consider the evidence before coming out with their own recommendations or comments. 


It appears that the Task Force feels that decreasing the number of mammograms is a better deal than saving lives.  All one has to do is listen to the outcry from other scientists, physicians, and the public to figure out that there are a couple of folks out there who don’t agree with them. 


It’s time they set the record straight, even if it means changing their recommendation. 


Too many lives may hang in the balance.


 


 


 

9 thoughts on “Mammography Guidelines: You Can’t Dress It Up

  1. With all due respect Dr. Len, you are only telling part of the story. There are many respected scientists who do not believe that pre-menopausal women benefit from mammography, and in fact there is evidence of bona fide harm. Please see:

    http://jnci.oxfordjournals.org/cgi/content/short/95/20/1508

    In general, mammography benefits some women. There is evidence that it harms many others, and the harms are not trivial. How many women would like to lose a breast and undergo radiation and chemotherapy unnecessarily? These interventions have their own (small) risk of death. Some scientists believe that this is why screening mammography has never been shown to decrease all-cause mortality – screened women face the risk of death from unnecessary cancer treatment. According to Ismael Jatoi, Professor of Surgery, National Cancer Institute:

    “…overdiagnosis leads to over treatment, and this may increase a woman’s overall risk of death (all-cause mortality). Indeed, once a woman is overdiagnosed with breast cancer, she might be subjected to cancer-specific treatments (surgery, systemic therapy, radiotherapy), all of which are associated with a very small risk of death. In a woman with a potentially lethal breast cancer, these treatments are justified because their benefits clearly outweigh the risks of breast cancer progression. However, a woman with a harmless breast tumor is exposed to the inherent risks of treatment without any potential benefit. The randomized trials have shown that mammography screening reduces breast cancer-specific mortality, without a reduction in all-cause mortality. This inconsistency might now be partly explained by a small excess in all-cause mortality among women overdiagnosed with breast cancer. Thus, the full impact of publicly organized mammography screening programs should be assessed with breast cancer-specific mortality to assess the benefits of screening and all- cause mortality to assess the harmful effects of overdiagnosis.”

    Why can’t the ACS come clean on this issue? There are 2 sides to this story, and both need to be told. Women have been misled and as a result they cannot give informed consent to screening mammography. This has to change, and the sooner the better.

  2. kittykitty7555, your argument might have some meaning if we had any clue at all what constitutes a harmless breast tumor vs. a harmful one. At this point, the only way we have to tell the difference between the two is to do nothing and see what happens – is that the new “gold standard” of screening? I’m sure there are women diagnosed with breast cancer that probably never would have caused any problems. But there are also women (particularly women under 40) who find lumps and are told that they’re too young for cancer, “it’s probably just a cyst, don’t worry about it,” and by the time they do convince someone they need a mammogram, they’re stage III or IV. Until we have a reliable way of determining whether a breast tumor is harmful or not, early detection and treatment are the way to go. Are we overtreating? We simply have no way of knowing, and until we do, better to over-treat than under-treat and allow more women to die.

  3. I agree with Elizabeth. I know full well that my tumor was not cancercous on a mammo, but in effect it proved to be cancer and I have had metasis from the original site elsewhere. Where would I be today, if it weren’t for mammo’s and a doctor sending one for second opinions. When in doubt, get a second opinion and if necessary a third.

  4. The emphasis on mammography is a lot of feel-good PR that had taken attention away from the lack of cure. The focus on “awareness” has lead to a focus on mammograms, and the task force is the first time anyone’s done a critical evaluation of whether all that focus on screening has paid off. The numbers say that it has not.

    We need better, not more screening. We need more investigation of the causes of this disease – for example, why have BC rates gone up 400% in women under 45?

    Mammograms have their place, but they are not the end-all, and they are not prevention. They have also muddied the statistical waters by throwing DCIS and low grade tumors into the “cure” rates.

    Endocrine therapy and herceptin have done a huge amount to dent the death rates. Mammograms are not. Why are they such a sacred cow? Because the ACS has sold us all a bill of goods.

  5. The USPSTF would seem as unlikely a target for attack as Santa’s elves. For a quarter-century, this squeaky-clean, underappreciated group of doctors and nurses who are specialists in preventive medicine has toiled away in obscurity in the selfless service of public health.

    Appointed by the Agency for Healthcare Research and Quality, the task force panel is independent and does not take costs into consideration and it evaluates only the risks and benefits of preventive medicine strategies. The task force must be reeling over the vicious reaction to its latest recommendations regarding screening mammography.

    The guidelines are based on an exhaustive analysis of recent studies from Sweden, the United Kingdom, and the U.S. Breast Cancer Surveillance Consortium involving a total of more than 830,000 women, and a specially commissioned study funded by the National Cancer Institute in which six separate teams studied the risks and benefits of 20 screening strategies through mathematically modeling.

    The panel recommended against routine screening mammograms for women 40-to-49 years old, and screening every two years for women 50 to 74. These not-exactly-radical recommendations are almost identical to the World Health Organization guidelines, which recommend screening every one-to-two years between ages 50 and 69.

    Because mammography is less effective at distinguishing cancers from normal breast tissue in premenopausal women, mammograms miss cancers in some younger women and raise a false alarm in others. This can cause real harm; one woman may ignore a cancerous lump because her mammogram was normal; another may undergo an unnecessary surgical procedure because her mammogram was suspicious.

    http://www.thehastingscenter.org/Bioethicsforum/Post.aspx?id=4194

  6. Dr thank you for your input on this. Why do so many agencies and people choose to ignore the studies regarding THC (the active component of marijuana) and its ability to kill cancer through ingestion, injection, and topical use (not inhalation). The proof is out there and wealths of complete indepth medical studies. We could be curing cancer! If you want to research more on this topic and view the studys start at MarijuanaCuresCancer.net there is a huge wealth of information on this site

  7. I’m copying this note right from our blog. My mom’s life was undoubtedly saved by a mammogram when she was 48 years old: When I was diagnosed at 48 years old, I thought it was all a big mistake. I’d had a false finding during my first mammo when I was 40, and decided I wasn’t going to have them anymore. When we changed insurance companies some years later, I had to pick a new primary care physician who insisted I get a mammogram. A week later, the doctor called and left three messages to call her back. When I reached her, she told me the results showed a mass and I needed to contact a surgeon. I explained emphatically how my left breast had shown a mass during my first mammo and it was just asymmetrical tissue, etc, and so this was just the same big mistake. She let me go on, and when I finished she very calmly said “It’s your right breast dear.” So it began.
    – Jean Soulios, founder of Jeans Cream, 2-time survivor breast cancer

  8. It seems to me that the ACS all read from the same playbook. It is amazing to me that you ignore all the previos research. This is not a new issue it goes back to a Canadian study that after seven years showed 36 percent more deaths from screened women than amongst unscreened women called the “breast mortality paradox” this fell to 14 percent after 10 years. Also the research of Dr. Goetzche. with the Cochrane Collaboration. It is interesting how you avoid the issue of “ionizing radiation”, and how you downplay this known cause of cancer. No mention of a-t gene, interesting. Dr.John Gofman a leader in the field stated that there is no safe level of radiation.Yet if you check out the ACS position you find it full of outright lies about the hazards. You also ignore talking about over diagnosis, another issue that you downplay. Instead of fund raising maybe the ACS you should start spending some its money on some meaning full research.

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