Category Archives: Mammography

ACOG’s New Mammogram Recommendations – Not What You Think

The American College of Obstetrics and Gynecology has issued new breast cancer screening guidelines recommending that mammography be offered annually to women beginning at age 40. This is a change from their prior recommendations for mammogram screening every 1-2 years in women ages 40-49, and annually thereafter.

The media is playing the announcement as a face off between ACOG and the United States Preventive Services Task Force (USPSTF), which initially recommended against routine annual mammograms in women in their 40’s, but later softened that statement by saying that the decision to start mammograms in the 40’s should be an individualized one.

But is it really ACOG vs USPSTF? 

Here’s the statement from ACOG’s press release–

Based on the incidence of breast cancer, the sojourn time for breast cancer growth, and the potential for reduction in breast cancer mortality, the College recommends that women aged 40 years and older be offered screening mammography annually.

Here’s that statement in context in from the ACOG practice bulletin (requires paid subscription)-

Based on the incidence of breast cancer, the sojourn time for breast cancer growth, and the potential for reduction in breast cancer mortality, the College recommends that women aged 40 years and older be offered screening mammography annually.

However, as with any screening test, women should be educated on the predictive value of the test and the potential for false-positive results and false-negative results. Women should be informed of the potential for additional imaging or biopsies that may be recommended based on screening results. The physician should work with the patient to determine the best screening strategy based on individual risk and values. In some women, biennial screening may be a more appropriate or acceptable strategy. Some average-risk women may prefer biennial screening, which maintains most of the benefits of screening while minimizing both the frequency of screening and the potential for additional testing, whereas other women prefer annual screening because it maximizes cancer detection.

Hmm…..That’s not really so different from the USPSTF guidelines, which state –

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.

There is a difference, however. By starting with a statement to offer mammography annually, ACOG seems to be trying take the USPSTF recommendations for individualized screening and put some teeth into them. They are also, I think, aligning themselves with the majority of women, who favor annual screening, regardless of its potential harms. (More on this tomorrow…)

As a clinician, what I think ACOG is saying is that I should be sure I offer an annual mammogram, even if the patient and I end up making an individual decision about having screening that goes another way. It’s a strategy that assures that every woman has the opportunity to have an annual mammogram if that is what she wants, ideally after she has engaged in a discussion that takes into accounts the benefits as well as harms of screening in the context of her own risks, beliefs and concerns.

I think that’s right.

Unfortunately, ACOG’s press release says nothing about individualizing screening decisions

It’s incredible, really.

Just like the USPSTF, ACOG has written a press release and summary statement that does not exactly match it’s recommendations or place them in context. Worse still, they have placed their full recommendations behind a paid subscription firewall, assuring that few folks other than gynecologists will have access to them. This deprives the public (and many reporters and bloggers) of the opportunity to read what is an extremely well-written summary of the current state of knowledge about breast cancer screening.

ACOG has also missed a real opportunity to better inform women about the magnitude of breast cancer risk (much lower than most women think), and the limitations of mammography (much greater than most women think).

Finally, and most importantly, by leaving out any context of individualized risk assessment, benefits and harms of screening, and shared decision making, ACOG has left the simplistic misperception that anything other than an annual mammogram is bad medicine.

And that’s just not fair.

To me, or to my patients.

And, as any women who has tried to fit into a one-size fits all pair of pantyhose will tell you, it’s a set up for failed expectations and anger on all sides.

Not to mention a really bad run.

Preventing Breast Cancer Deaths – How Much Credit Does Mammography Get?

Much less, it appears, than we’ve been giving it.

So say researchers who measured breast cancer mortality before and after the introduction of routine mammography screening in Norway. They compared breast cancer death rates between two groups of women in their 50’s – those who were offered routine mammograms and those who were not – between 1996 and 2005.

Their thinking goes something like this – If mammography prevents breast cancer mortality, then women who were offered mammograms should have fewer breast cancer deaths now compared with historical rates before mammogram screening was offered. And they did – about 7 less deaths per 100,000 person-years (the so-called screening effect in that chart up  there).

But here’s the rub – women who did not have screening mammography also had less deaths than their historical counterparts – about 5 less per 100,000 person-years. (The so-called time effect)

This means that the mortality reduction credited to mammograms is about 2 per 100,000 person years, or about a 10% reduction in breast cancer deaths. The lion’s share of mortality reduction appears to be due to advances in breast cancer treatment and possibly medical care in general, something researchers have long suspected but have been unable to prove.

What do the Critics Say?

Experts at the American Cancer Society have criticized some aspects of this study. They point out that while mammography had little impact on mortality in early stage breast cancer, the impact on stage 2 disease mortality was significant. They also criticize the very short follow up period of the study – an average of 2.2 years. Finally, they cite the lack of control of subject behavior (or “contamination” as women may have accessed mammograms outside the national program), and the fact that Norway’s mammogram screening program coincided with a national program of multidisciplinary breast cancer treatment that is not in place in the United States, making mammography potentially more important here.  The ACS continues to recommend annual mammgraphy in average risk women starting at age 40.

The accompanying editorial in the New England Journal of Medicine takes a a different tack, and suggests that the decision to preform screening mammography is, in fact, “a close call”, but stops short of actually making the call.  (I encourage you to read the editorial – it summarizes well the results, strengths and limitations of the Norwegian study.)

My Take

I’m not sure that we should use the results of this population-based data to refute the results of randomized trials, which have shown mammography to reduce mortality by about 25% in women ages 50-59.  In evidence-based medicine, the randomized trials tend to win out.

Still, the data presented make a compelling argument that on a national scale, mammograms may have had limited impact compared with advances in and coordination of breast cancer treatment.

I’ve raised the question before as to whether mortality should be the only bar against which we measure mammography. I wonder if women who get diagnosed with breast cancer on screening mammography have more very early stage disease, more options for localized therapy instead of mastectomy, or less use of chemotherapy than women who do not have mammgorams routinely? I’ve yet to see much discussion on this issue among the decision makers on mammography, but suspect it’s an important consideration for women.

What I’m Doing in My Practice

I’m continuing to recommend screening mammography in women ages 50 and above, and in high risk women at an appropriate age depending on family history. This study is raising important questions for that group, and is sure to generate a few phone calls and fuel some discussions during office hours, but I’m not changing my recommendations just yet in this age group.

For average risk women under age 50, I’ve recently begun to have individualized discussions about the screening mammography, and learning that it’s not an easy discussion to have. To that end, I initiated a project with my colleagues here at Cornell and at Memorial Sloan Kettering Cancer Center to begin to develop tools to assist women and their clinicians in having informed discussions about mammography. We just got a small pilot grant – wish us luck!
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More Questions About Questions About Mammography

A well-done analysis in the BMJ this week calls into question previous research that has been used to tout mammography as an effective tool for lowering breast cancer mortality in Denmark.  That previous study compared breast cancer death rates in Copenhagen, where women were offered screening mammography in 1991, to areas in Denmark where mammograms were not offered until 17 years later, and concluded that the introduction of mammogram screening resulted in a 25 % reduction in breast cancer mortality in screened areas.

The new study adds an additional county where screening was offered (with a little implication that perhaps the previous researchers should have included this other area, but I’ll stay out of the academic finger pointing) and then reanalyzes the data.

The researchers found that breast cancer deaths declined nationwide during the time period studied, in all areas, regardless if that area was one offering the screening program. Much of this decline occurred in women ages 40-49, who were too young to have been offered screening. This suggests that it is breast cancer treatment rather than screening that should take the credit for most of the mortality declines in Denmark over the time period studied.

The researchers then go on to make this statement-

We believe it is time to question whether screening has delivered the promised effect on breast cancer mortality.

-practically guaranteeing that I’d have to read their paper and comment on it. So I am.

My take

I’m not convinced that this paper makes the point that mammograms are ineffective. The authors themselves argue that the effect size of mammography, estimated at about 15-16% in randomized trials, is too small to be measured in epidimiologic studies. I  agree. It is just impossible to control all the confounding factors inherent in an entire population of individuals to tease out the effect of a single intervention over time, particularly when breast cancer treatment was evolving so rapidly over the time period being studied.

I have to admit that I have a hard time believing that, for 17 years, women living outside of Copenhagen never entered that fair city to have a mammogram on their own dollar once they found out that their city-dwelling friends were being offered the test and they weren’t. (The paper used to support the claim doesn’t make the case in my opinion.) I know that Europeans have not bought the whole mammogram thing hook, line and sinker the way we here in the States have, but I don’t think it is as black and white as the Danes would like us to believe. (If you are a Danish woman reading this, feel free to enlighten us…) But that’s just an aside.

Bottom Line

This is an important paper in that it effectively refutes previous conclusions about the Danish mammogram screening program. Unfortunately, I don’t think this study stands on any stronger ground in arguing that mammograms are ineffective. Nothing in this paper rescinds the results of the randomized trials, which the authors themselves state find a mortality reduction of about 15-16% for mammography. In my opinion, their results primarily show us that population based data is nearly impossible to use to make any valid conclusions about mammogram screening – either for or against it.
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Hat tip to Gary Schwitzer for pointing me to this study

Jack Black Gets a Mammogram

A very funny, if utterly simplistic message from the Men for Women Now Facebook campaign, which uses male celebs to urge women to get mammograms and pap smears.

Despite the controversy over the new mammogram guidelines, it is acknowledged that the test remains under-utilized among women who should have the screening, particularly minorities and women in medically under-served areas. In addition, most cervical cancers occur in women who fail to get Pap smears. So the goal of getting these women to screening is a noble and important one.

Unfortunately, the nuances of cancer screening decisions get lost with these kind of mass marketing campaign. Not to mention the blurred demographic targeted when these guys are used to deliver the message.
Still, I gotta’ say I love Jack Black, who in my opinion is one of the most talented human beings on the planet.

The New Mammogram Guidelines – What You Need to Know

Unless you’ve been living on another planet, you know that in mid-November, the US Preventive Services Task Force released new recommendations on screening mammography, in which they recommended against routine mammogram screening in women under age 50, and recommended that mammograms now be every two years in women ages 50-74.

What you may not have heard is that the Task Force has acknowledged that the mammogram guidelines were poorly worded, and have revised their original statement to clarify their intentions, mostly by removing those two little words “recommends against”.

Here’s how the guidelines now read (changes in red)
  • The USPSTF recommends biennial screening mammography for women aged 50 to 74 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.
  • The USPSTF concludes that the current evidence is insufficient to assess the additional benefits and harms of screening mammography in women 75 years or older.
  • The USPSTF concludes that the current evidence is insufficient to assess the additional benefits and harms of either digital mammography or magnetic resonance imaging (MRI) instead of film mammography as screening modalities for breast cancer.

They’ve also included this statement right in with the guidelines –

“So, what does this mean if you are a woman in your 40s? You should talk to your doctor and make an informed decision about whether mammography is right for you based on your family history, general health, and personal values.”

What the USPSTF meant to say

What the Task Force is saying is simply this – On a population basis, the net gain from adding 10 years of mammography in all women is small in relation to the risks of over-diagnosis, over treatment, unnecessary biopsies and anxiety. But you, as a patient, in consult with your physician and assessing your own personal risks of breast cancer, may decide you want to get a mammogram anyway.

What they meant to do was to take mammography out of the realm of the knee-jerk, automatic and into the realm of informed decision making. They meant to inform women that mammography’s 15% or so reduction in mortality comes at a price – a price that is physical, emotional and financial, in the form of false positive results, unnecessary biopsies and the anxiety and dollar cost that accompanies them. They also meant to dispel popular overblown notions about what mammograms actually do by clarifying both their benefits and their risks, so that women are making the most informed decision they can about whether or not to have this potentially lifesaving test.

Unfortunately, they blew their 15 minutes. Which leaves it to the rest of us to clean up the mess. So, let’s see if I can add my two sense to the party.

What you need to know about the USPSTF

First off, let’s dispel the conspiracy theories. The US Preventive Services Task Force is an independent panel charged with making health care recommendations based on current scientific evidence. They do not make health care policy or decide insurance coverage.

The task force members should have anticipated that the timing of their recommendations coincident with health care reform would lead to misunderstanding about their role. Their cluelessness in this regard alone should be proof that they have no ties with the stakeholders in health care reform, who clearly would have managed the spin upfront.

Which is not to say that the task force’s recommendations won’t be used to guide policy decisions, which is why everyone is taking this all so seriously.

What you need to know about mammograms

The lay public has an almost magical thinking about what mammograms actually do. This is not surprising given the intensity with which we have been advising them to have mammograms over the years. So it is not unexpected that women have been taken aback by the hard reality about mammograms that they are now being asked to accept. That said, here’s what you need to know –

1. Mammograms don’t prevent cancer. They diagnose it. It’s a simple but important distinction that gets clouded by the magical thinking surrounding this screening test. The value of mammography lies in its potential to diagnose cancers at an earlier stage, allowing life-saving treatment to begin earlier.

2.Because they use radiation, mammograms can actually cause cancers. Though a single mammogram has a low risk in this regard, the radiation exposure from annual mammograms over many years adds up. The task force estimated that on a population basis, annual mammograms from age 40-50 would induce 8 breast cancers for every 100,000 women.

3. Mammograms are not a perfect test. In general, they miss about 10% of cancers, more if you have dense breasts, which are more common in women under age 50. In addition, mammograms have a high false positive rate, meaning that if you have an abnormal mammogram, the odds are high that your biopsy will be benign, and technically unnecessary.

The task force estimated that the cumulative risk for a false-positive mammogram with 10 years of annual screening was about 50%. The younger you are, the higher the chance your abnormal mammogram will be a false alarm. The higher your risk of breast cancer going into screening, the lower your risk of a false positive result.

4. Mammograms may be better at diagnosing slower-growing cancers than more aggressive tumors. Think about it. If a tumor is growing slowly, testing once a year will find it sooner rather than later. If it’s a fast growing, aggressive tumor that spreads out of the breast at a smaller size, a test that is done only once a year may not pick it up before it has spread beyond the breast. So we may be finding and over-treating tumors that may never cause much problem, while missing the bad players. (I myself have a harder time accepting this as an argument for cutting back on screening in women under age 50 than for women over age 70.)

In this regard, one of the most problematic diagnoses made by mammography is that of DCIS, or ductal carcinoma in situ, a non-invasive neoplastic growth that looks like breast cancer by has not invaded beyond the duct wall, and may never become invasive. Mammograms are really good at finding DCIS, since its hallmark is calcifications, which tend to show up pretty well even in dense breasts. So we end up treating and even performing a lot of mastectomies because of DCIS, without knowing if we are impacting mortality.

Finally, if mammograms were as good as everyone thinks they are, then we should expect over the years to find less and less advanced breast cancers, since we should be picking them up earlier and treating them. Unfortunately, this has not yet been proven.<

5. Mammograms are a better screening tool in older versus younger women. In women ages 40-49, 1900 mammograms must be performed to prevent a single death in this age group, compared with 1339 women age 50-60, and 377 women age 60-69. This is because breast cancer risk increases with age (meaning a positive result is more likely to be a true positive) and because older women have less dense breasts, so that there are less false negative mammograms.

Measuring mammogram success by years of life saved instead of mortality alone, mammograms starting at age 40 look better as a screening tool, but still perform better in women over age 50.

6. The benefit of annual vs. biennial mammograms is negligible. Meaning you can go every other year without sacrificing much in the way of benefit (about 1-2% absolute risk reduction benefit), and save additional radiation exposure.

7. Despite their imperfections, Mammograms save lives. To the tune of about a 15-20% reduction in women ages 40-49, the group most affected by the new recommendations. This is an important fact that, in my opinion, keeps getting lost in the discussion about the guidelines.

Which brings me to the elephant in the room.

The Elephant in the Room

Breast cancer causes about 4,500 deaths annually in women ages 40-49, and is one of the leading causes of death in women in this age group. (This data does not include cancer deaths occurring after age 49 in women diagnosed in these years.) In the 10 year interval between 40 and 49, then, about 45,000 lives are lost to breast cancer. That’s no small number, and it’s why breast cancer advocates are up in arms at the recommendations.

Which brings me to the real crux of the question – how many of these breast cancer deaths is mammogram preventing in women ages 40-49? Put another way, if you forgo mammograms in that age group, what are your odds of dying as a result of that choice?<

A age 40, what are your odds of dying in the next 10 years from breast cancer?]

This was not an easy number to find. SEER data on cancer mortality groups ages from 35-44, 45-55 and so on, so it’s taken me a long time to find the data. But I finally found it.

At age 40, your chance of developing breast cancer in the next 10 years is 1.44% or about 1 in 69. Your chance of dying from breast cancer in that interval is about 1 in 480. (This compares to a risk of about 1 in 280 for a woman at age 50, 1 in 146 for a woman at age 60, and 1 in 108 at age 70, and so on.) Here’s how that risk looks visually, in the thousand dot graph below, with the red dots representing breast cancer deaths among 1,000 women.

So if mammograms prevent 15% of breast cancer deaths, then if you are 40, and have mammograms for the next 10 years, your chance of dying from breast cancer is reduced from 1 in 480 t0 about 1 in 564.

USA today estimates that annual mammograms reduce the 10 year mortality risk for women ages 40-49 from 1 in 300 to 1 in 357, as compared to women age 50-59 whose risk is reduced from 1 in 112 to 1 in 144.

That’s not a big individual reduction as far as cancer screening goes, especially when one compares it to, say, colon cancer screening, which reduces deaths from colon cancer by as much as 60%.

Looking at the numbers from a population rather than individual standpoint, assuming a US population of about 21 million women age 40-49, routine mammograms in this age group prevents about 680 deaths per year. Is that really worth having 21 million women get an annual test that over 10 years will result in 50% of them having an unnecessary breast biopsy? It certainly does not stand up to the standards we’ve set for screening tests in the past.

But breast cancer advocates will argue that every one of those 680 lives represents someone’s friend, spouse, parent or relative. How can we say those lives aren’t worth saving? But with that kind of argument, we’d be mammogramming 20 year olds. If mammograms were free and perfect, that would be a good argument. But they are neither.

I think when a screening test has such a high potential for false positives and invasive biopsies over time, it makes sense to allow individuals to make their own decisions about that screening. I also believe that breast cancer, because it is a leading cause of death in women age 40-50, deserves to be addressed as a risk, even if it is to decide in an individual to forgo screening.

What if You are High Risk?

The data the task force used to make their recommendations encompassed all women having screening, including both low and high risk women. But what if you are at increased risk?

You can calculate your individual risk for breast cancer by using one of several risk assessment tools – the most commonly used one being the Gail Model. The Gail model can give you your individual risk of being diagnosed with breast cancer in the next 5 years. You can then us this number to discuss with your doctor whether or not you want to start mammograms before age 50. I don’t know that the model can be used to predict mortality reduction from mammography in high risk women, but would say that if your risk for breast cancer approaches that of a 50 year old woman, you should start routine screening mammograms.

An important high risk group not addressed by the guidelines are African American women, who in general are diagnosed at more advanced stages of breast cancer and have higher breast cancer mortality rates than Caucasian women. Given that much of the data being used to support the USPSTF guidelines come from Scandinavian countries, one must question their application to non-white populations, including Hispanic and Asian women. Fortunately, the Gail model does include ethnicity in its risk calculation.

Bottom Line

Mammograms in women under age 50 are less efficient than in women over age 50, and come at a higher cost in terms of over-diagnosis and potential over-treatment. The USPSTF made a decision that the cost differential was enough to recommend against knee-jerk, routine mammograms in all women under age 50, and instead recommend that women discuss the decision with their doctor before deciding to start screening.

The American Cancer Society, the American College of Obstetricians and Gynecologists and the American College of Radiology continue to recommend routine mammogram screening every 1-2 years starting at age 40.

What do I recommend?

I’ve addressed this issue before, and have not changed my practice, which at this point is to offer mammograms starting at age 40 in all my patients. However, I am now framing it as an option rather than an undebatable recommendation for my low risk patients, which means we spending more time discussing the issue before I place the order.

So far, when presented with the data, every one of my low-risk patients age 40-50 has decided to have their mammograms. However, more than a few made that decision only after confirming that their insurer would continue to pay for the test. I’ve queried a few as to how much they would pay to have that mammogram if their insurer declined to pay – about $200 seems to be the break point above which those few low risk patients would decline the test based on cost alone. Most women are either willing to pay or fight for payment whatever the cost. (This is by no means a scientific sample, but I think captures the gestalt in my practice, which happens to include a fair number of high risk women.) In the absence of any other screening, most women seemed willing to accept the high rate of biopsy in return for a mortality reduction, however small.

I also frequently order screening sonograms in high risk women with dense breasts, and MRI in women with a first degree relative with premenopausal breast cancer or other risk factors for whom this testing has been recommended.

I am comfortable spacing mammogram screening to every other year, especially since that’s about the frequency many of my patients end up getting them anyway. The task force recommendations have certainly made me more comfortable reassuring the patient who calls a few weeks before her annual mammo is due and can’t be fit into the radiologist schedule for several months.

I have to admit I have some concerns about my risks if and when a patient declines routine mammograms. Will I get sued if I don’t urge her to get a routine mammogram and she ends up with an advanced stage breast cancer at some point in the future? Should I have her sign something to protect myself? What is the minimum I need to document to cover my tail? I’m also wondering how long it will be before the first lawsuit against a doc who follows the taskforce guidelines is filed. Will they try to sue the taskforce members themselves? (I wouldn’t put it past some of the lawyers.)

A Call for a Decision Tool

The Australian Screening Mammogram Decision Trial has a wonderful web-based tool to assist women age 40 in making a decision about mammography. I’d like to see the USPSTF develop a similar tool for American women incorporating the latest data they used. It’s the least they can do to help American women and their physicians begin to incorporate their recommendations into practice.

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Recommended reading
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Photo credit Wikipedia
Note – I clarified morality statistics from a previous version of this post, and apologize if they appeared misleading. They were technically correct, but I think this is clearer. Looking at deaths in this age group overall, cancers as a group account for about 30% of deaths, and breast cancer a third of these, or 10% of deaths overall. Heart disease as a group accounts for about 20% of deaths, with heart attacks about 5% of deaths overall.

What is the Role for Breast Sonogram?

The WSJ has an article this week discussing MRI and breast sonogram as adjuncts to mammogram, and the debate going on in the medical community as to how these modalities should be used. The article does a nice job framing the debate that is occurring among physicians regarding when to use these modalities.

Medical practitioners are divided about the proper role of ultrasound in breast-cancer screening. Wendie Berg, a radiologist at a clinic in Lutherville, Md., who was the lead author of the study published in JAMA, says she recommends ultrasound screening to some women who don’t have evidence of very high risk that would justify an MRI. “It is a judgment call. The denser the breast, the more difficult the mammogram is to read, the more likely I am to recommend an ultrasound,” she says.

But Constance Lehman, a University of Washington professor of radiology who led a study published last year in the New England Journal on MRI screening, says she never advises ultrasound for patients. “We find it ineffective as a screening tool,” she says. “It’s not even in the same ballpark” as an MRI.

I’ve been actively debating the songram issue with an internal medicine colleague. She’s anti-sono, I tend to favor the screening method, but with caveats. She and I decided the issue is pervasive enough to discuss publicly, and are setting up a debate forum this fall with a panel of respected breast specialists and radiologists to see if we can come to some resolution on the matter.

Will let y’all know how that turns out.

Does a Brief Cessation of Hormone Therapy Lead to a Better Mammogram?

Since we know hormone replacement therapy (HRT) increases breast density, it seems logical that a short break from hormones prior to a mammogram might improve mammographic sensitivity. In fact, some doctors would recommend that women on HRT stop their hormones for as long as several weeks prior to a scheduled routine mammogram.

However, a recent study in Maturitas suggests that stopping HRT for as long as a month before having a mammogram makes no difference in mammographic breast density.

Researchers in the UK enrolled HRT users who were willing to have a mammogram, then stop their hormones for 4 weeks and repeat the mammogram. The mammograms were read by two experienced radiologists and scored for breast density using two different visual methods and two different computer methods.

All told, 44 women completed the study. The researchers found that stopping HRT for 4 weeks made no difference in mammographic density measured either visually or by the computer. In addition, there was no significant effect on breast tenderness during mammography.

The study’s findings stand in contrast to other studies that suggested stopping hormones might be helpful prior to mammography. But these studies were either confined to women with abnormal mammograms or compared groups of women to each other (case controls).

What makes this study especially compelling was that it used women as their own controls, included women who had used HRT for longer than one year, and was in the setting of routine mammograms. In addition, the researchers used several different techniques for measuring breast density, and found agreement among them in their results.

Weaknesses of the study are that it was relatively small, and that duration of HRT use varied within the population studied.

If supported by other studies, these findings are not so good news for women on hormone replacement hoping to mitigate some of the adverse breast effects of their hormones, at least as it relates to mammographic sensitivity and specificity. However, it is good news in that women should not be asked to suffer without their hormones without a proven benefit.

What is Mammographic Breast Density?

Mammographic density is a measure of permeability of x-ray, and an indirect measure of the density of breast tissue. Increased breast density is an independent risk factor for breast cancer, but is more likely a marker for underlying biologic differences in breast composition rather than a pathologic process in itself.

HRT can increase breast density, though not in all users. Intermittent progestin HRT regimens cause less of an increase in breast density than continuous regimens, and new low dose regimens may not increase breast density at all.

I tell my patients that reading a mammogram of a dense breast can be like looking through fog. If there’s an abnormality there, it may be harder to see. By contrast, a mammogram of a fatty breast is like a clear blue sky. Dense breasts are also harder to examine, and I am less confident in my ability to detect small masses in a woman with dense breast tissue on exam.

There’s a lot of active discussion these days as to how to improve breast cancer screening in women with dense breasts. Use of digital mammography, sonogram and MRI may improve detection of breast cancer in women with dense breasts, but the latter two come at a price of increase in false positives and biopsies.

What Should You Do?

Here comes the usual answer – Talk to your doctor. When data in the literature conflict, and there is not a clear recommendation as to which is the best way to go, then it’s really up to you to bat it around with your doctor before making any change in your hormone regimen before a routine mammogram. There is certainly no serious downside to stopping HRT for a short time, and if you’re willing to do so in order to have a better mammogram, then I say go for it.

To be honest, though, I do not routinely advise my patients to stop their hormones before having a routine mammogram. Stopping HRT for as little as a few days for some women can mean re-emergence of bothersome symptoms, including vaginal bleeding.

My experience is that a woman willing to stop her hormones for 4 weeks because she was worried about mammographic density would be a woman who would probably not ever take HRT in the first place. Most of my patients these days who choose to use HRT are truly miserable without it, and living the kind of high functioning lives that would be adversely impacted by a month off HRT. Without proven benefit, I see no reason to ask these women to stop hormones before a routine mammogram.

However, this reasoning on my part is very likely influenced by the fact that I don’t hesitate to order breast sonogram for women with dense breasts on mammography, especially if the radiologist hedges their reading by stating that the breast density “may lower the sensitivity of mammography in this patient.”

But that’s another controversial topic for another day, so stay tuned.
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– Weaver K et al. Does a short cessation of HRT decrease mammographic density? Maturitas. 2008 Apr 20;59(4):315-22.
–Mammogram information from the NCI.
–Improving Breast Cancer Screening– Info from the NCI

Screening Mammograms After Age 70

There are no universal recommendations for routine mammograms in women over age 70. That’s because we don’t have robust mortality data from mammogram use in this population. And so, older women are advised to make their own individual decisions about mammogram along with their doctor, based on other medical issues, life expectancy and health beliefs.

But do women have the information they really need to be deciding this question?

That’s what researchers at the University of Sydney asked when they did a study to determine what would happen if they gave women over age 70 Decision Aids (simple, visual aids) to inform their decision about having screening mammograms.

Here is an example of a decision aid. It visually represents the risk in 1,000 women over age 70 of being diagnosed with breast cancer over the next 10 years (brown boxes) if you do (right group) or don’t (left group) have a mammogram, as well as the chance you’ll have an unnecessary biopsy as a result of a false positive mammogram (dark purple boxes on the right).

The researchers found that while the women using Decision Aids made more informed decisions about having mammograms, the information did not impact the rate of mammogram use in the study population. There was an impact in that undecided women tended to get off the fence and make a choice, and women felt less anxiety and insecurity about the choice they made.

So, for most women, what Decision Aids do is make them feel better about their choices. Which says to me that most patients (and I suspect, doctors) make pre-determined decisions about mammography based on factors unrelated to the statistics of outcome, but use those statistics to support their beliefs, whichever way they decide.

Sort of like politics.

But unlike politics, those designing the decision aids are not trying to move votes, they’re trying to help you find the choce that’s right for you. If you’re undecided, or ucomfortable with your choice, a decision aid may be just the right thing for you.

Now if someone would just come up with a decision aid for the 2008 elections…
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The researchers are conducting a similar but web-based trial for younger women (over age 40). If you want to participate, or see what a decision aid is, click on the link below.

http://www.mammogram.med.usyd.edu.au/

It’s really interesting, I encourage you to do it. See if it changes your choice about mammogram or not. Or just makes you feel better about your choice.

Mammograms – The Brits vs the Yanks

It appears that my recent post about the Lancet study has stirred things up a bit over at Dr Crippin’s blog. The trans-Atlantic discussion in the comments section is quite an interesting read, and I encourage you to head one over there for it. From what I read, we Americans have slightly different recommendations for mammogram screening than do our counterparts in the UK.

Mammograms in America

We recommend routine mammograms every 1-2 years in women age 40 and over. (Read the NCI justifications for this recommendation here) Although this screening is not universally free, it is covered by all insurances (some annually, some every 2 years). For women without insurance, there is a free national screening program, and many local screening programs exist as well. Women can self–refer, but must identify a physician to receive the mammogram report.

Mammograms in Britian

In the UK, breast cancer screening appears to be free to all for women through the NHS Screening Programme, but is not routinely offered until after age 50, and then every 3 years:

The NHS Breast Screening Programme provides free breast screening every three years for all women in the UK aged 50 and over. Around one-and-a-half million women are screened in the UK each year. Women aged between 50 and 70 are now routinely invited.

Because the programme is a rolling one which invites women from GP practices in turn, not every woman will receive an invitation as soon as she is 50. But she will receive her first invitation before her 53rd birthday. Once women reach the upper age limit for routine invitations for breast screening, they are encouraged to make their own appointment.

Higher risk women can be identified by their physicians and referred to more intensive screening programs in the UK. The women in these programs either have BRCA mutations or a 20% or higher chance of being a BRCA carrier. The intensive screening programs offer individualized risk assessment and screening, including mammography, sonograms and MRI.

It appears from the NICE guidelines (see below) that only women who raise concerns about their family history to their GP get referrals to high risk centers:

1.3.1.2 Healthcare professionals should respond to women who present with concerns but should not, in most instances, actively seek to identify women with a family history of breast cancer.

Some thoughts

Both the UK and American program recommendations are evidence-based, but appear to be relying on either different evidence, or making different conclusions based on the same evidence. Perhaps concerns about liability and very strong breast cancer awareness and concerns among American women are driving our guidelines a bit more than those in the UK.

The increase in mammogram use in the US and the UK has been associated with a decline in mortality from breast cancer in both countries. Advances in treatment, however, may be as much responsible for the decline in mortality, since in the US, the rate of new advance breast cancers has not changed, despite a marked increase in diagnosis of early stage and in-situ cancers.

One could argue that the increase in mammograms has done nothing more than diagnose early indolent cancers that would never have killed anyone. It’s a salient argument, but until we have some way of distinguishing who is going to get the aggressive vs indolent tumors, it doesn’t change screening. However, advances in proteomics and DNA testing are rapidly being made, and currently are driving treatment decisions so that women with more agressive tumors get more agressive treatments.

Someday, we’ll have a better screening than mammogram. It may be MRI, it may be a serum test. It may even be a genetic test to identify the women at risk, so that those at no risk can avoid mammograms altogether. Wouldn’t that be great?

Category: Second Opinions

Mammograms in Women Under 50 – The Lancet Study Reviewed

That graph up there shows the main outcomes of the AGE Trial, a large study of mammography screening in England that asked the question “Does offering mammograms to women in their 40’s save lives?” The dotted red line represents the mortality from breast cancer in women offered mammograms annually between ages 40 and 48 through the National Health Service (or NHS). The solid line represents the control group of women who were not offered mammogram screening by the NHS until after age 50.

The investigators are interpreting that graph to mean that mammograms in women under age 50 are not worth doing.

Let’s talk, shall we?

The study, which was published Dec 9 in the Lancet, randomized 160,921 women on a 1:2 basis to either annual mamograms from age 40-48 or to a control group of “usual care”, which in the NHS is an invitation to a first mammogram between ages 50-52. Deaths were identified through the NHS central registry for a mean follow up of 10.7 years.

There was a 17% reduction in breast cancer mortality in the early screen group. (That’s the graph up there)

As it turns out, only 69% of the women invited to screen actually came for the initial screening, and overall, only 81% of them ever got a mammogram during the study. The women who never showed up for the mammograms had a higher rate of breast cancer deaths than those who got the screening. When adjusting for these two factors, the investigators found that women who actually showed up for the early mammograms had a 24% reduction in mortality from breast cancer compared with the control group.

Sounds pretty clear, doesn’t it?

Well, unfortunately, it’s not. You see, neither the numbers I quoted nor the difference up there in the graph between the red and black lines is statistically significant.

Why not? Very possibly because the study wasn’t big enough to detect the difference in breast cancer mortality with enough certainty to call it real . You see, the NHS ran out of money and personnel partway throught the study, so the sample size was smaller than initially planned. Secondly, mortality in the control group was much lower than initially estimated, making it even harder to find a statistically significant difference with the smaller sample size. Here’s what the investigators said about this:

The power of the trial to show a reduction was diminished both by the smaller than planned sample size and by the lower than anticipated mortality from breast cancer in the control group (2·35 per 1000 vs 3·3 per 1000), resulting in a revised power of 60% to detect a 20% mortality reduction, and the CI does not exclude a reduction of 34% or an increase of 4%.

Most studies are powered at 80%, meaning that, going into the study, there is an 80% possibility that the study has enough subjects to be able to detect a difference with 95% certainty between the groups. (or something like that – statisticians, feel free to correct me.). If the study is too small, then the odds are stacked from the get-go against finding anything to hang your hat on in terms of results. And that’s what happened here.

Finally, the mammograms performed in this study were below standard. Although the first screens were standard two view mammos, subsequent screens in the under 50 group were single view only. This was done in an attempt to diminish radiation dose, but likely resulted in lower detection rates in the screened group, since single view mammograms are less sensitive and specific than two view mammos. (Current standards in both UK and US are two view mammograms.)

The end result is that the Lancet study failed to show a benefit to mammograms before age 50. What a shame – to do all that work, and have your final study size to small to detect a difference between your two groups with any confidence.

Perhaps to ease our disappointment with their study, the investigators did make a very nice graph of the clinical trials of mammograms in women under 40 to date:

For the lay crowd, what this graph means is that the risk of dying from breast cancer in women getting mammograms before 50 is smaller relative to those who wait till after 50. (The black boxes up there) But the 95% confidence intervals (the thin lines) of almost all of these studies crosses one, meaning that the protective effect of mamograms is still not statistically significant overall. However, I would say there is a clear trend to protection against dying in the early mammogram group, wouldn’t you? (All the black boxes except one fall below 1)

What about other outcomes?

Dying or living are not the only two possible outcomes that might be affected by earlier diagnosis of breast cancer. We all know that cancers picked up earlier are more likely to be amenable to breast-conserving surgery and less likely to require chemotherapy. I don’t know about you, but if I am going to get breast cancer, I would rather have it diagnosed at a stage where I can keep my breast and avoid chemo. Also, chemo can be associated with secondary cancers years later, something a 10 year study would not pick up.

Bottom line – this study adds little to our understanding of the role of today’s mammograms in women under age 50 as practiced in the United States. For my patients, I will continue to recommend mammograms every 1-2 years beginning at age 40, and annually at age 50 and above. I advise women with dense breasts to have digital mamograms and ultrasound in addition to mammography, especially if there is a family history of breast cancer.

Hopefully, the data from this latest Lancet study will not be used by the NHS to continue to deny this same screening to women in the UK. ________________________________________________

United States Preventive Services Taskforce recommendations for mammograms

NCI statement on mammograms in women under age 50

Info on Digital Mammography from the NCI

University Of Pennsylvania’s Med Page Today critique of the Lancet Study (excellent read)

Thanks to Rachel for pointing the Lancet article out to me.

Category: Second Opinions