Ramblings on healthcare, medical education, and life with a spinal cord injury
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Screening Mammography

Far be it from me to attempt to solve a complex matter like the current debate on screening mammography.  I’m a first-year medical student and haven’t had extensive experience treating patients dealing with cancer. But the climate of the current debate is troubling for a number of reasons, not the least of which being the knee-jerk reactions many people are having that fail to take into consideration a lot of the science behind it all.  I’ve been talking about this with a lot of people lately and figured I’d share some of my thoughts on the matter.

First, a brief disclaimer.  Of course, none of what’s said in here should be construed as any kind of guidance or medical advice.  I’m a student, I don’t know much of anything at this point, and this is a complex matter that women should discuss with their physicians before making any decisions with regard to their personal health.  What’s contained herein is merely my opinion on the current debate.

There is some criticism of the US Preventative Services Task Force (USPSTF) in that it does not contain an oncologist among the panel.  The argument would be that it did not need to – although it surely would have helped for PR reasons. Actually, the report could have used some serious professional PR consultation, but that’s a whole separate story.  The study, and I would HIGHLY encourage you to read over the full study in detail so you’re familiar with what’s being talked about in the news, was done as a public health study using purely epidemiological analysis. Most mass guidelines are written as a result of epidemiological data in this manner.  In fact, I don’t know how one would go about writing large-scale guidelines like this without basing it on epidemiology, and as such, MPHs and epidemiologists are best suited to analyze the data. They’re based on statistics, reports, other studies and previously collected data. One does not need to intimately know how to treat a challenging case of aggressive metastatic infiltrating ductal carcinoma or the technology behind mammography to analyze data showing its efficacy or lack thereof.  That’s for the public health policy wonks.

Unfortunately, this fact has recently been latched onto by people who wish to politicize this whole thing.  On Thursday I saw Rep. Debbie Wasserman-Schultz on television distorting the facts and making quite an egregious politicization of this report.  Here’s the whole interview:

She’s far from the only one to attempt to politicize the report, and that’s one of the most troubling things to come from it.  Some thoughts on the interview.  Robert Bazell states:

this is not a study, that’s one of the things about it that’s a misnomer. People say this is science.  This is an obscure federal agency called the US Preventative, uh, Health Task Force that’s setup to analyze other studies.  And it looks at some of what things that are science.  It is science to say that 6.1 lives are saved per 1,000 women in their forties and 5.4 per 1,000 fifty and above.  That’s science.  But to decide which is more valuable, that’s a value judgment, that’s politics, that’s not science.

I feel that calling the USPSTF “obscure” just because the average citizen is unaware of what they do is a bit disingenuous.  The agency has been around for twenty-five years, and their mission is:

to evaluate the benefits of individual services based on age, gender, and risk factors for disease; make recommendations about which preventive services should be incorporated routinely into primary medical care and for which populations; and identify a research agenda for clinical preventive care.

Bazall says that what they do is not science.  That’s not exactly true.  Analyzing data that arise from other studies is science.  The USPSTF report also didn’t say “6.1 lives are saved per 1,000 women in their forties and 5.4 per 1,000 fifty and above.”  It states that the number of women to be screened is “1904 (CI, 929 to 6378) to prevent 1 breast cancer death in women aged 39 to 49 years,” 1339 women between 50 and 59 to achieve the same benefit, and 377 women between 60 and 69.  These are the numbers at the core of the controversy surrounding the USPSTF recommended guidelines.

When it comes to screening for Down Syndrome in expectant mothers, there is a scientific reason it has historically not been indicated until women are thirty-five or older (although the American College of Obstetrics and Gynecology has recently recommended that screening be offered to all women, regardless of age): thirty-five is the age at which the risk of having a child born with Down Syndrome becomes greater than the risk of complications from the actual testing procedures.  I’ve been unable to find any studies that look specifically at complications due to biopsies and other procedures that are used in diagnosing and treating breast cancer, or the myriad risks from overdiagnosis, although I’m sure some have to have been done.  I would really like to compare results of studies like these to the tests looking at screening mammography.  As best I can tell, there have been some smaller studies done on the complications of overscreening and overdiagnosis, but we need a detailed, thorough study on the various risks and complications in order to know for sure.

It would seem logical to me that the determination of when women should be screened, like with Down Syndrome screening, should correlate to a point at which the risk of complications from not having the test becomes greater than the risk of complications due to having the test.  To be sure, the death of a woman due to a breast tumor that could have easily been diagnosed with a simple mammogram is a tragedy.  But is it worth preventing that death by screening 1,904 women if two women in that group who wind up negative for breast cancer die due to complications from the unnecessary procedures they receive?  Now, I completely made up that second number.  My point is that with all this talk of complications due to unnecessary testing, I would really love if it somebody has some real facts they can point me to.  Until we have numbers to compare, the difference between 1:1904 and 1:1339 is a value judgment. Or a cost judgment. And although insurance actuaries place numerical values on life all the time, it’s hard to quantify that kind of thing at this level.  When people speak of “cost” when it comes to unnecessary testing, it isn’t just financial cost.  It’s a far more complex issue than that.  The USPSTF acknowledges that further research on overdiagnosis is needed:

In general, more studies of overdiagnosis, including comparisons of lifetime breast cancer incidence among similar screened and unscreened women, would be helpful. Studies on overdiagnosis might also include long-term follow-up of women with probable missed cases of DCIS on the basis of microcalcifications that were missed in an earlier mammogram

Chris Matthews continues on to say that it’s “common sense” that all women should examine their own breasts, commenting on the portion of the USPSTF’s report that recommends against teaching breast self examination (BSE).  Thankfully, Bazell corrects him that the report does not say women shouldn’t regularly examine their own breasts and note any changes – it says that the way BSE has been formally taught is not recommended as it does not provide any improvement in mortality.

For the teaching of BSE, there is moderate certainty that the harms outweigh the benefits.

Adequate evidence suggests that teaching BSE does not reduce breast cancer mortality.

Two large trials of teaching BSE outside the United States (7) demonstrated no mortality benefit in the intervention groups.

In two randomized, controlled trials with 5 to 10 years of follow-up, both conducted outside the United States, breast cancer mortality rates were similar in women instructed in BSE and in noninstructed controls

One study indicated that anxiety was not a concern with BSE. The 2 available trials (20, 21) indicated that more additional imaging procedures and biopsies were done for women who performed BSE than for control participants.

The USPSTF now recommends against teaching BSE (D recommendation), replacing the previous statement of insufficient evidence.

This is in line with recommendations from the American Cancer Society, the Canadian Task Force on Preventive Health Care and the World Health Organization.

Then comes Rep. Wasserman Schultz.  I have a big problem with how she presents the report, because she misrepresents the facts by acting as though it is intentionally trying to kill women.  First and foremost, before even getting into the details, this is what the USPSTF has actually stated in their report:

The USPSTF recommends against routine screening mammography in women aged 40 to 49 years. 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. This is a C recommendation.

It doesn’t say that women of this age should not receive mammography.  It says that the old recommendation that women of this age automatically receive a mammogram every year shouldn’t apply to every woman without consideration to her unique details.  This should always be the case.  Women should be fully aware of all of the risks and complexities involved in screening and should make the decision in concert with their physician after all of these factors have been taken into account.  For those women with greater risk, they will need to test even more judiciously.  On to Rep. Debbie Wasserman Schultz.

This task force, Chris, is telling women 40-49 “no mammogram in that ten year period.  Oh, by the way, don’t do breast self exam either” and telling doctors in the same set of recommendations that clinical breast exams are inappropriate also.  They’re leaving women forty to forty-nine with nothing…  Their recommendations actually say, after they released them, that women should not do breast self exam… Now, it’s one thing to say that we shouldn’t, you know, systematically teach breast self exam, they are recommending against breast self exam.  You have most women who are forty to forty-nine catch their breast cancer themselves through a breast self exam.

Well, Rep. Wasserman Shultz, the recommendations do not “actually say” that.  As quoted above directly from the report, the USPSTF does not recommend against women examining their own breasts – they do recommend against the structured teaching of breast self exam.  Big difference.  The report says nothing about women examining themselves, other than that they receive subsequently more “additional imaging procedures and biopsies.”  And as you’ve already read, the USPSTF does not tell women “no mammogram in that ten year period.”  It frustrates me when people so egregiously misrepresent the facts, and this reeks of a disgusting level of politicking.  I don’t know whether she just hasn’t read and thought about the actual report and just went on national television to respond to the hyperbole with more of the same, or she has read it and thinks she can just gloss over the facts in the hopes that other people won’t read it.  But neither one is something a person in her position in government should be doing. If she can’t even be bothered to read and get a small report right, should her constituents really trust her to get a two-thousand page healthcare reform proposal right?

One of the large studies referenced observed 120,000 women and found “no difference” between the BSE and the control groups with respect to catching cancers and the stage at which they were caught.  The other large study tracked over 267,000 women and again found no difference in the discovery or severity of lesions between women formally trained in BSE and those without formal education.  An article published in the Journal of Family Practice that looked at several other studies found, in fact, that:

Breast self-examination has little or no impact on breast cancer mortality and cannot be recommended for cancer screening (strength of recommendation [SOR]: A, based on a systematic review of high-quality randomized, controlled trials [RCTs]).

It also states the same conclusion of the USPSTF that there was no reduction in mortality found in women who perform BSE.  The article goes on to suggest that clinical breast exams by a physician are better, although using proper and deliberate technique is critical.  Interestingly, it cites a very large Canadian study that suggests that when done properly, “clinical breast examinations may be as effective as a mammography screening program.”

So in summary, studies done on nearly 400,000 women have failed to show any benefit to formal BSE training, as compared to women being aware of their bodies and being aware of any changes that occur.  Additionally, the USPSTF report states:

For BSE, sensitivity ranges from 12% to 41%, lower than that of CBE and mammography, and is age-dependent

Sensitivity is a measure of the ability of a test to assess the absence of disease.  It is calculated as the number of people who have a condition and test positive for it divided by the total number of people who have that disease (which is equal to the number of people who have it and test positive for it plus the number of false negatives, or those who have it but test negative for it).  A test that is highly sensitive is one with very few false negatives.  In other words, a negative test result means that someone is actually negative.  So highly sensitive tests are used to rule out a disease because they have a low false negative rate.  Tests with a low sensitivity have a lot of false negatives.  A sensitivity range of 12-41% means that of those women who do actually have breast cancer and do a BSE, 59-88% will falsely test negative via BSE.  This doesn’t say anything about false positives, but it does say that BSE is not very good at detecting tumors.

Clearly, time and money invested in BSE could be far better spent put toward research that can help drive more effective treatment without any impact on mortality.  Yes, women should absolutely be aware of the shape and nature of their breasts.  But just because “common sense” says that women find breast cancer by BSE and as such we should invest in teaching structured BSE doesn’t make it true.  Often times, evidence-based medicine will challenge those “common sense” beliefs by presenting numerical data that contradict them.  And as surprising as that may be, numerical data are grounded in science and data.  ”Common sense” is not always so.

Furthermore, her statement that the USPSTF said “clinical breast exams are inappropriate also” is just plain wrong.  What the USPSTF actually said was:

The USPSTF concludes that the current evidence is insufficient to assess the additional benefits and harms of clinical breast examination beyond screening mammography in women 40 years or older. (I statement)

This is neither a statement for or against CBE.  What it actually says is that there is insufficient evidence to say whether CBE provides any benefits or harm beyond mammography. This is FAR from what Rep. Wasserman Schultz has said.

I’m not sure where she gets her statement that “most women..catch their breast cancer themselves through a breast self exam.”  A study published in the journal “Cancer” specifically looked at women, age 40-49, who were diagnosed with breast cancer.  It found that while most, 58.1% did catch their own breast cancer, less than half of the women who discovered their own breast cancer, 20.6%, discovered it through a breast self exam. The majority of women who discovered their own cancer, 37.5%, did so incidentally.  It also means that 79.4% of breast cancers in the study group were discovered by a means other than BSE.  Again, that doesn’t mean women should not be aware of and pay attention to any changes in their breast tissue.  It does, however, mean that Rep. Wasserman Schultz is stating as fact things that do not seem based in actual evidence.

Rep. Wasserman Shultz continues:

And on top of that, what they’re saying is, well now if you’re forty to forty-nine, you should just talk to your doctor about your risk.  About 75% of women who have breast cancer didn’t have any risk, weren’t in a higher risk category.  I was in a higher risk category, didn’t even know it, until I found my lump myself and went to the doctor.  So these recommendations are really patronizing because they’re presuming that women can’t handle more information and make a rational decision with their healthcare provider.  It’s really outrageous.

I tried to find evidence either supporting or refuting the “75%” comment, and couldn’t find anything.  What I did find was one statement on an alternative medicine site that said “70-80%” of women with breast cancer have no known factors, and something on WebMD that said “75% of all women with breast cancer have no known risk factors.”  But this does not present any supporting evidence or references, and is far from scientific. Additionally, the Sprecher Institute for Comparative Cancer Research at Cornell University further suggests that this number may be less than reliable:

Studies estimate that between 20 and 60 percent of all breast cancer cases could be prevented if major risk factors for this disease were removed from the population. The range of this estimate is wide and reflects the difficulty of this theoretical question. The very notion of eliminating risk factors for breast cancer is difficult to imagine and these values have been incorrectly interpreted to indicate the percentage of cases which are not explained by major risk factors. In addition, a number of the major risk factors, such as timing of childbirth, are very personal and depend on a woman’s age and social circumstances and are thus far less than easy to change.

This suggests that the 75% number may not have any basis in fact.  Cancer risk is very difficult to quantify.  The notion that it can be boiled down to a simple statement regarding women who develop cancer with “no risk” is far from accurate.

She continues to share her own story, and many in the press have been sharing their own anecdotes as to why this report is wrong. And I certainly don’t want to detract from her experience dealing with breast cancer.  I admire her for her battle, and for being so public in her experiences. Unfortunately, anecdotes are just that. They’re stories about one or two people who deviate significantly from the norm. They’re emotional, and they tug at people’s heartstrings. They’re also not science. We’re taught never to use the words “always” or “never” when discussing medicine and science. There are ALWAYS exceptions (yes, I just used both words in two consecutive sentences). And while we hear about the one woman who had a screening mammogram at age 42 and had a tumor discovered that may have killed her, we don’t hear about the woman who didn’t have a mammogram and had a growth that would have turned out positive on a mammogram, that later completely regressed on its own that she never knew about. Our understanding of cancer has changed dramatically over time, and now we do know that sometimes benign lesions actually do disappear on their own. We also don’t hear about the women who’ve had countless unnecessary invasive tests done which all turned out to be benign, because they’re happy to be alive and healthy, and they move on with their lives and don’t talk about it. It also would make for very boring news.  We also don’t hear about how many women had unnecessary tests and then suffered numerous complications as a result of it.

Rep. Wasserman Schultz’s concluding statement is, “so these recommendations are really patronizing because they’re presuming that women can’t handle more information and make a rational decision with their healthcare provider.”  Unfortunately, this is also untrue.  In actuality, the USPSTF report ultimately concludes that the decision should be left to a case-by-case basis, with patients discussing options with their doctors.  That women are capable of making this difficult decision on their own, weighing the merits of screening with the risks, is the central focus of this very report.  To me, it is the Representative who is making the patronizing statements.  It also concludes that these guidelines are specifically only for women who are in the asymptomatic, non-risk group. They do not apply to women with a history of cancer in their families, women who have tested positive for various genetic cancer markers, nor to women who’ve felt any changes in their breast tissue.

One of the technicalities that’s being lost in the debate is the difference between screening and diagnostic tests. And for good reason: it’s a complicated subject! We’ve come up against the issue numerous times in medical school, and medical students can even have a difficult time at first differentiating when a procedure is used for screening, and when it is being used for diagnosis. The same procedure can be considered either, depending on the situation. If a women is completely asymptomatic and has no other suggestive factors, a mammogram is considered a screening test. She doesn’t have any indications of having breast cancer, so the test is used just to screen for any possible indications. However if a woman has noted changes in her breast tissue or has other indications that something might be wrong, that same mammogram is diagnostic. The USPSTF’s report is only suggesting a change in screening mammography, not diagnostic.

It’s worth nothing that back in 1994, the American Journal of Public Health called for a similar change in guidelines.

But in making decisions on mammography screening for millions of women, we need to continue to rely on evidence from research, and the uncertainty of the available evidence for women aged 40 through 49 calls for a change in guidelines that excludes these women from programs for mass, routine screening with mammography.

The recommendations proposed by the USPSTF are not new, and the same recommendations continue to be made by various organizations even as time goes on.  It seems worthy to me that we give them serious consideration, rather than just dismissing them.

Additionally, most of the EU uses guidelines in line with the USPSTF’s recent recommendations. People argue, “who is the USPSTF to say that 2,000 screenings to save one life is not recommended?” Well, who were they to say the guideline was recommended last time? Who are they to say it’s not worth it to do 10,000 procedures to save one life in the 30-39 group? Unfortunately, it’s a value judgment. Science often has to arbitrarily draw a line in the sand somewhere, and 1:2000 may be where the line should be drawn now. I don’t know.

This is a complicated subject, and people have strong opinions on either side. Neither side is “right” or “wrong” and ultimately the decision of whether or not screening is worth the risks really should be left up to the educated patients in concert with their physician(s).  I urge women to research both sides of the topic at length and to speak with their physicians to ultimately come to an appropriate decision with respect to their own health.  We’ve entered a new age where patients are becoming more educated about their health, and ultimately this is an incredible thing.  The fervor surrounding this topic is making more people aware that there are risks inherent in many screening procedures, and I hope that this will be an impetus to educate people as to both sides of this complex decision.

A surgical oncologist that specializes in breast cancer and who writes for one of my favorite blogs recently discussed the issue at length. I would highly recommend reading it. http://www.sciencebasedmedicine.org/?p=1926

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