Breast Cancer Screening Guidelines Report
Nov. 16, 2009 – A recent report from the U.S. Preventive Services Task Force takes a new look at screening guidelines for breast cancer. The report contradicts some longstanding recommendations about breast self-exams and the frequency of mammography. In this episode of Cancer Connection, Siteman Cancer Center radiologist Barbara Monsees, MD, explains the conclusions described in the report and discusses what she hopes women will take away from this new analysis.
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TRANSCRIPT OF AUDIO FILE
On this edition of Cancer Connection, we’ll discuss new recommendations about breast cancer screening and what a woman needs to know.
Host: Thanks for downloading this podcast from the Siteman Cancer Center at Barnes-Jewish Hospital and Washington University School of Medicine in St Louis. I’m Jason Merrill. The U.S. Preventive Services Task Force is an independent expert panel on primary care and prevention that reviews evidence of effectiveness and develops recommendations for clinical preventive services. Today – Nov. 16 – they issued new recommendations for breast screening that are published in the latest issue of the Annals of Internal Medicine. They are biannual screening for women 50 to 74; for women between 40 and 49 years old, routine screening is not recommended, however, women should discuss whether they should be screened with their health care provider; and thirdly, they say there’s no good evidence for average women that self-examination is effective.
Obviously, these recommendations do come with some controversy, and to talk with us about what these recommendations mean is Barbara Monsees, MD. She is chief of breast imaging at Washington University School of Medicine and the Siteman Cancer Center. Dr. Monsees, thank you for joining us.
Monsees: Thank you, my pleasure.
Host: Your thoughts on the recommendations?
Monsees: These are recommendations from the U.S. Preventive Services Task Force. There were several articles published today in the Annals of Internal Medicine and an accompanying editorial all coming out, being released today. And the general purpose of the U.S. Preventive Services Task Force is a very good one. The idea is to appoint an unbiased panel and to take an unbiased look at all of the evidence that’s available and make a recommendation based on science. That’s what medicine is about these days – evidence-based recommendations.
So this task force was specifically looking at the benefits and harms of breast cancer screening, including mammography, digital mammography, magnetic resonance imaging, breast self-examination and clinical breast exam, all of those things. In the process, what they attempt to do is balance the pros against the cons, the benefits against the harms of doing screening, and the benefit is measured by the efficacy in reducing the death rate from breast cancer. That’s the objective: Can we save lives? The harms that they looked at included things such as discomfort from mammography, anxiety from recall, ultrasound, needle biopsies, etc., generated by the screening.
What’s getting so much attention today is the recommendation for mammography screening and, in particular, for screening women between 40 and 50. Despite controversy in the past, and there’s been a lot of it, there’s now universal agreement that screening mammography saves lives. That is not the question. The question is: How many lives? So there is disagreement in the estimates of how many lives are actually saved by a screening mammography program. This is incredibly important because in weighing the benefits and the harms, the big benefit here is the number of deaths that can be averted. The task force used an estimate of about 15 percent reduction in breast cancer deaths. They derived their estimate only from randomized controlled trials. Now these trials are very important. They were important in validating that mammography indeed saves lives, but for a variety of reasons, they underestimate the benefit of screening. The task force excluded other types of data that shows a much greater benefit from mammography.
For example, when mammography screening was introduced in Sweden, the death rate from breast cancer was reduced by about 40 percent. And if they actually looked at women who came for screening, not just all the women who were invited for screening, the death rate went down 50 percent to 60 percent, so a big incremental drop in breast cancer death rates. In the United States, the breast cancer death rate has decreased by 30 percent since 1990. Screening mammography was widely utilized after that period of time, so it took a while for the death rate to come down. Before that time, before 1990, the breast cancer death rate had been unchanged for the preceding 50 years. These recent improvements in the death rate are felt to be primarily due to screening, although there has been some benefit from newer treatments, new chemotherapeutic regimens, for example.
So the task force, in its balance of the benefits and harms of mammography, I believe they underestimated the benefit of screening with mammography. In addition, I believe the task force was overly concerned with the harms of screening. In fact, surveys have shown that the public understands that screening methods such as mammography are not perfect tests, and the public is willing to accept minor inconveniences in the form of a little bit of anxiety, compression of the breast, maybe some biopsies that don’t turn out to be cancer in order to maximize the opportunity of finding a cancer early by screening.
The task force is recommending against routine screening mammography in women 40 to 49, suggesting that a decision be made on an individual basis for women of that age group based on the patient’s preferences, benefits and harms. However, the fact is that most women in that age group don’t have risk factors that would suggest they get screened. So most cancers that are found in women in their 40s, those women are not going to have risk factors, and they may not be screened if we go to that regimen.
The task force also commissioned computer modeling methods to simulate screening beginning and ending at different ages, and they looked at screening yearly and every other year. In the end, they decided to recommend that women begin screening at age 50 and be screened every two years until age 74. I believe that screening should be done yearly. The task force said that there was insufficient data to make a recommendation for women age 75 or older. That’s because only two of the randomized controlled trials included women over the age of 69. However, I’d like to point out that women who are 75 and who are healthy have a long life to live, and while there’s no proof that mammography saves lives at that age, there’s no reason to believe that it wouldn’t. It just hasn’t been tested.
The task force couldn’t find enough information to make any recommendation on digital mammography or magnetic resonance imaging of the breast because there were no randomized controlled trials of those modalities. It’s also recommending against breast self-examination, and it says that it has insufficient data to make a recommendation on clinical breast exam, exam by a patient’s doctors.
The American Cancer Society uses all the available evidence in making its screening recommendations. They include trends in mortality and other publications, not just published randomized controlled trials. I endorse the recommendations of the American Cancer Society, which recommends yearly mammography screening beginning at age 40 and continuing as long as a woman is in good health. It’s a good idea that women should speak to their physicians if they have a strong family history of breast or ovarian cancer because such women may also benefit from supplemental screening with magnetic resonance.
Medicare and third-party payers often use the task force’s recommendations in deciding on payment for medical services. I worry that if insurers cut screening benefits, this will result in fewer women being screened regularly and an increase in the breast cancer death rate.
Host: Now these recommendations – where a woman gets a mammogram biannually, for example, or if you’re between 40 and 49, it’s not necessary – it wouldn’t be hard to find any woman out there who said, “Geez, I had my mammogram annually, my life was saved.” There are going to be a lot of people confused by this decision. What do you say to women who are confused and really don’t know what to do?
Monsees: What I’m saying is rely on the American Cancer Society to give you the best information regarding how to deal with screening recommendations. I think they take all of the evidence into consideration, and they make recommendations for individual women. The task force looked at what’s best for society as a whole based on mathematical modeling and based on some old data – very unfortunately, old data – and they didn’t address, really, individuals. If the best advice they can give is that a woman should speak to her doctor but they can’t tell that doctor what risk factors are important enough for a woman to be screened, that’s not helpful information. It is confusing. And so I again suggest look to the American Cancer Society. Rely on them because I think that they really give good information.
Host: Now it should also be pointed out these recommendations are for women of average risk. What are the task force’s recommendations for people at high risk for breast cancer, and what are the risk factors that make someone a high-risk candidate for breast cancer?
Monsees: The task force did weigh in here on average-risk women, so women who have a known genetic mutation that is likely to put them at high risk for breast cancer or women who have a strong family history that suggests that they have a genetic predisposition in their family, those women are high risk. This would not apply to them, and they should speak to their physicians. Those are the women that not only should they get screening probably on a yearly basis, but they may begin early because those families tend to have cancer earlier in their families, earlier than 40, and they may benefit from supplemental screening with magnetic resonance imaging. So that’s one big group. It’s a very small part of the general population. Nevertheless, it’s a very important one. So women with a family history – first-degree relative with breast cancer or a relative with ovarian cancer – should speak to their doctor about their risk.
There’s a whole host of other women who are at higher risk, women who’ve had benign breast biopsies that show that they have a slightly higher risk than the general population but not as high as the women with this genetic predisposition. Those women also are at higher risk and certainly ought to consider screening yearly. They may begin early, but again, that has to be individualized according to the physician’s recommendations. And one should go and ask a physician who’s going to know about this kind of thing, not necessarily a physician who’s a general practitioner, who may or may not. So I think the conversation has to be had between the woman and her physician. “How much do you know about this? Do I need to go to somebody who’s an expert, or can you handle this for me?” And I think from there the woman gets her advice.
Host: Now, you did touch on it in the opening, where you were discussing the risks vs. benefit and that’s how the task force came to this decision. To the average person, they’re really confused by a risk vs. benefit because the benefit would be you get your breast cancer screened early, it can save your life. They can get confused about the risk. How does a risk vs. benefit work?
Monsees: Well, you have to figure out how you’re going to measure the benefit, and you have to figure out how you’re going to measure the risk. The task force carefully delineated where they got their information. In this case, estimates of the benefit can come from a variety of sources. One is randomized controlled trial data that was done decades ago. There’s one recent trial that was included in the task force information, but it wasn’t very well-done. It showed the same benefit that the trials that were done 30 and 40 years ago and intermediate-time trials also showed. So they chose to limit the data that they looked at to those randomized controlled trials.
There’s other ways that one can come up with estimates, for example, looking at trends in cancer mortality. So in the United States, I told you the death rate since 1990 for breast cancer has come down by 30 percent. That’s very helpful information and incredibly important to include in these types of deliberations. There are other types of published information that are not randomized controlled trials. The one in Sweden that I talked about and others like it are publications on, again, trends in mortality before and after the introduction of screening.
When looking at the harms, the task force made a laundry list of all the possible down sides. We all know what they are, and some of them are worse than others. I would say that the compression from mammography is fairly minor. To have to undergo a benign breast biopsy to find out if you have a cancer or not causes anxiety. It’s a procedure, and yes that is also considered a harm. Those are the kinds of things that they looked at in weighing the benefits and the harms.
Host: The other part of this that we haven’t touched on yet is a decision about breast self-exam. I believe the wording was that it didn’t show any clinical benefit. How many women have you heard in your life who said, “I was in the shower doing my monthly self-exam, and I felt a lump. I was concerned and went to my doctor, and I’m here today.” How does that decision weigh in on all of this?
Monsees: There have been two randomized controlled trials of women for breast self-exam. Neither of them showed that it saves lives from breast cancer. So that’s where they got their data from. On the other hand, mammography is not a perfect test; and therefore, if a woman has a mammogram and it’s negative and she feels a lump in her breast, what should she do? Should she wait until the next year and wait until the radiologist tells her there’s something? Or should she bring it to the attention of her doctor? In an individual case, I think the woman would benefit from bringing that to the attention of her doctor.
Now, there’s a difference between just finding a lump and practicing breast self-exam. And their test was practicing self-exam. However, I would argue that if a woman is going to develop breast cancer, she’d rather know sooner than later. So since it doesn’t cost anything to society as a whole – although it does result in some biopsies that are benign and thus there are some financial costs and there are some harms from it – it’s probably not a bad idea to do, although there’s no proof that it does benefit people in terms of saving lives. So I would recommend that women should know their bodies, and if they feel something, they should bring it to the attention of their physician.
Host: So overall, the message is follow the American Cancer Society guidelines, correct?
Monsees: Yes. That’s my message. And I hope that women are not confused by this because what I don’t want to happen is for this confusion to undermine women’s confidence in screening. It’s a wonderful tool. It’s not a perfect tool. It’s not going to find all cancers, but it is of benefit to them. And if one wants to do everything that one can to try and decrease the death rate from breast cancer, that has to include mammography.
Host: Dr. Monsees, thank you for joining us.
Monsees: Thank you.
Host: To find out your own risk of breast cancer, visit our Your Disease Risk site at www.yourdiseaserisk.wustl.edu. For more information about breast cancer, visit the Siteman Cancer Center online at www.siteman.wustl.edu or call 800-600-3606. Thanks for downloading. Until next time, I’m Jason Merrill.