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Suzanne Fletcher, M.D.
Harvard Medical School
"Breast Cancer Screening: Prevention is More Complicated Than We Thought"
March 17, 2004

What I think we all know what a terrible disease breast cancer is. I am going to focus though not on breast cancer disease and what we should do about it once a woman knows she has it but rather on what I’ve learned when we’re trying to find it in women at risk, because we are women, but who do yet have the disease.

I want to make sure we are all on the same wavelength here about screening and the whole idea of screening is to identify a health problem before it causes trouble and remove or treat it. T his maintains health and prevents disease not only for the individuals, but for the whole population and we must do this for everyone at risk. Now applying this to breast cancer the whole idea that we’ve had since the beginning of screening is the earlier we find the cancer the better. We need to screen all women who are at risk for disease and basically that is all women beyond a certain age group.
Now, how do you begin to study this? When I was first asked to join a task force thirty years ago now in Canada to look at what is the evidence for screening, not only breast cancer at that time but a whole series of other conditions, we came up with three criteria. We said, well the condition has to be important. We said we must know that the package of screening plus treatment actually prevents bad outcomes in this case preventing breast cancer mortality. Finally, we have to know that we have a pretty good screening test.

How does this translate for breast cancer? Well, there is no question about the seriousness of the disease. As most people in this room know, it is the most common non-skin cancer in women and there is an estimated forty thousand who will die of this disease this year. We have more evidence about the effectiveness of, and I am going to concentrate on mammography because it is our best screening tool at the present time. We have more evidence about mammography screening than for any other cancer and indeed for screening for any other condition.
A half million women have been involved in eight randomized trials and these trials have been followed now for at least fifteen years. We know that women 50 to 69 have had decreased mortality somewhere between 20 and 35% in these trials and for younger women, it is slightly less. It took a little longer to show. There are some questions, as I will mention. We know we have a good test in mammography.

So what’s the complication? Well first, I should indicate that there are some controversies; medical scientists always have controversies. One question is does mammography work in women under age 50. I am not going to spend time on that question. By and large, the longer these women have been followed, the more it looks like there is an effect. Just how big the effect is we are not sure. And furthermore there is a large trial going on in England right now that is going to help settle this question once and for all. But meanwhile, most major groups in the Unites States recommend screening starting at age 40.

And the second question is, “does mammography work at all?” For some people who are not in the medical field here may have seen a news reports about a new analysis done by two investigators in Denmark going over all the old trials. They decided these trials were not good enough and they basically threw them out. Other independent groups have reexamined these trials in light of those criticisms and almost all of the groups have said, and I agree with these groups, these gentlemen are wrong. So I am going to put those aside.

What are the complications? The first one I would like to talk about is the social context of breast cancer. I think it is enormously important and I think it underlies much of our approach to breast cancer screening. And what is the social context of breast cancer? Well we see it every time we go into a drug store or magazine shop. There is a sexual connotation of the breasts. It is an extremely important part of the feeling feminine in our culture. This is not new.
I strongly suggest that you read this book, A History of the Breast by Marilyn Yalom who is from Stanford. A fascinating book. What she pointed out is if you go back to 28, 000 B.C. these figurines show an importance of breasts and of, by the way, pregnancy for fertility and for nurturing. If you fast-forward to the end of the twentieth century, Yalom points out something very new in human history is happening. The breast is becoming a symbol of death.

Now what is this doing with our society? Well one very good thing is that women are mobilized. Women activists are the reason for an enormous increase in funding for breast cancer research. We always hear about the AIDS group but here is AIDS and here is breast cancer research. This is 1997, totally out of date. We are now at about 800 million dollars.
Another thing that has happened with this social background is so much fear is out there about breast cancer. Several years ago colleagues and I did surveys in a couple of communities in North Carolina and you can see the women, a quarter of the women were worried about breast cancer, a half of them feared finding it, and three quarters thought that looking for it made women worry. Another survey in New England found that younger women enormously overestimated the chance of dying of breast cancer. That is twenty-fold, that is 2000 times what it really is. And they also overestimated their risk of getting breast cancer.

And finally, sadly, the other thing that has happened because of this special social context for breast cancer is that it has become the number one reason for malpractice claims in this country and the number two for the financial settlements. And obviously the mammographers have been the most hit by this. But physicians who are not used to getting sued for such things, like family physicians, family internists, they are getting caught up this maelstrom as well. So these are the social realities that effect all of our decisions about breast cancer and about breast cancer screening that should be aware of. We rarely talk about them.

I am going to move to the next complication. That is how to describe the risk of breast cancer. Most women if you pick up any magazine that has an article about breast cancer, and by the way there are an awful lot of women magazines that do, these are the kinds of numbers that women will read. That in this year, it is estimated that 216,000 women will be diagnosed with breast cancer and 40,000 of them will die. These are horrific numbers.

The other number that they read off is that over a lifetime, one in eight will get breast cancer; that means several women in this room will be diagnosed with breast cancer. Now, people who work with these numbers and the American Cancer Society actually has decided this is not the way to talk about risk. Knowing what it is for the whole nation doesn’t help a woman, an individual woman, have any idea what her risk is. And knowing what her lifetime risk is, the trouble is women often translate that into a risk in the next year or two.

So, how should we define risk and describe risk to patients? I think this is the information that we need to convey. I don’t think this is necessarily the way to convey it but what this slide shows is that among women at various ages, what’s their risk over the next ten years. Let’s take the line, the first line. At age 40, if 1,000 women turn age 40 today, how many of them will have breast cancer sometime over the next ten years by the time they turn 50? It turns out 15, 15 out of 1,000. That is not I out of 8. 2 of them will die of breast cancer and 21 of them will die of something. About as close to immortality you can get is being a woman age 40 in the United States.

At age 50, a woman is at greater risk. At age 60, she is at greater yet and 70 and finally it levels off. And at 80 she is at greater risk of developing breast cancer, she is also at a greater risk of dying of breast cancer. And most of all, she is at greater risk of dying. In fact as you can see, once a woman hits 80, fewer than half of those women are going to see 90. This is the kind of information we have to somehow get across to our patients. I am not sure that all these numbers is the way to do it.

I want to tell you one little episode. When I was at North Carolina and it became known that I was interested in breast cancer screening, several students at Carolina would come to my practice and many of them would have absolutely no risk factors that I could discern. But they were very worried about getting breast cancer. I would tell them, “We couldn’t even put on it on this kind of graph. You know a 20 year olds risk of breast cancer in the next year is somewhere around1 in 100,000.” I could sort of tell, “What does that mean?” So I went and looked up a few more numbers and the next time I had such a patient I said, “Look, a 70 year-old man has 5 times your chance of getting breast cancer in the next year. And they said, “ I have never heard of a man getting breast cancer.” I said, “Exactly. Now go out, stop worrying about breast cancer at this age, and buckle your seatbelt.”

So we have a lot of work to do. This is not just for breast cancer; this is for any cancer or any thing. I mean Americans are overwhelmed by discussions of risk nowadays. We must figure out a way to individualize it and make it meaningful for them.

I just want to very quickly acknowledge that there are factors that increase risk. We just talked about increasing age. Genetic mutation. What I am saying is not applicable to those few women who have deleterious genes that put them at very high risk for breast cancer. That is another discussion for another day. Luckily there are few such women; it is not common. Increased breast density on mammography and atypical hyperplasia on biopsy also increase the risk. Much more moderate increases are seen if your mother or sister has had breast cancer, if there is increased bone density, if there is older age at first birth, if menopause is late and menarche is early and so forth. If there’s anything combining that is common to all these it is probably that it increases exposure to estrogen. We don’t know exactly how all that is working but an increased exposure to estrogen is not good.

And here are some things that decrease the risk of breast cancer and frankly all of those decrease exposure to estrogen. Now I want to make sure that the women in the room know that if they want to look up your own risk of breast cancer, you can do so by going to and this is an NCI site and it is a breast cancer risk assessment tool. It asks you your age, your family history, and what not. And out comes your risk over the next five years compared to the risk of an average woman your age. So I wanted to spend some time on breast cancer risk because I think it is absolutely crucial and we haven’t spent enough time. We need a lot of work in figuring out how to communicate this to women.

The next thing I wanted to talk about is unintended consequences of screening. We’ve been a bit slow in figuring these out but we are making progress in medical science. I want to talk about just two of them because I think they relate not only to breast cancer screening but to cancer screening in general.

The first is abnormal screening mammograms. Most women don’t know that nationally when she goes to get a mammogram, about one in ten will be read out as abnormal. And what I mean by abnormal is that the mammographer thinks something else should be done: another view, a repeat view, a biopsy, an ultrasound. Something else needs to be done. It is not come back at your usual time.

And nationally, this is a national figure, in a very good group in northern California it was read out about 6% of the time. As you can see almost all of these 11 are actually false positive readings. What do I mean by that? It means that the woman did not have cancer. You follow her forward, you do all these tests, and a year later there is no cancer. A few did have cancer. That’s why we are doing screening and it produces follow-up procedures. Now this is looking at it if from the perspective of the mammogram. What if we look at it from the perspective of a woman because we are not asking the woman to get just one mammogram, we are asking her to come back year after year after year?

A group of us looked at this in Boston and what we found is that the chances of an abnormal mammogram reading, a false positive reading, goes up year after year until after ten mammograms about half the women will have experienced a false positive mammogram. We also found that you could predict who was going to get this. That younger women, women who were on estrogen, women who had a lot of biopsies, had family history of breast cancer, had no comparison of previous mammograms, had a long time between screens, and who had a radiologist who tended to call abnormal mammograms; she had a very high risk of getting a false positive. On the other hand, a low risk woman was sort of the reverse of all of these. She was older, not on estrogen, did not have a family history of biopsies, and went to a radiologist with a lower tendency to call positive mammograms.

And why do we care? Why do we care about false positive mammograms? Well there is a financial reason. It adds about a third to the cost of a screening program. There are, for far as I’m concerned, far more important personal reasons. This causes women anxiety. There have now been at least eighteen studies done of women who have had false positive mammograms; seventeen showed that they were more anxious than women who had normal mammograms. Not only that, the anxiety persisted long after they knew that it was a false positive. Even more concerning perhaps, as a colleague of mine showed, is that the health care utilization in the year after a false positive mammogram goes a woman goes back to the doctor more for non-breast related complaints. In fact we found that she was going back for mental health visits more as well as others.

The bottom line is that patients do not react well to being told your screening test was not quite normal. This is true not only for breast cancer, this has been looked at in prostate cancer, in cervical cancer, in things that are not cancer: in hypertension, in mitral valve prolapse. We have to figure out how to help with this because we do not want to have such large percentages of the population feeling vulnerable. We didn’t go into prevention to create a sense of vulnerability; we went into prevention to create more health and vigor.

Now some colleagues and I thought well what can we do about this? Maybe we can educate the woman. So what we did is we came up with a pamphlet, came up with a video and while the woman was waiting to make sure the mammogram films were okay, we shared this with her. That was in one half the group and a random half we did not share and of that with her. Then three weeks after the mammogram, we called them up. And by the way, we also did this with normal people.

This is a scale of anxiety. What we found is that normal women scored rather low and actually went even lower after three months. We did this three weeks, three months. Women we gave the education to really didn’t very much compare to the women we didn’t give the education to. I would say this is an example of a negative study. While we were doing this study, there was a natural experiment going. Some of these women had the mammograms read by the mammographer while they were there. The others had the mammograms read by the mammographer in what’s called “batch” at another time.

The women who had their mammograms read while they were there had a lower anxiety than the ones who did not. When we asked them it became clear that many of these women who had the mammograms read right away were not even aware that they had an abnormality because it was checked right away and said, “Oh came you come back”; they had not even gotten dressed yet. So it looked like that that is a good beginning.

I think the major beginning is whether we can get down that number of recalls, whether mammographers can get fewer called abnormal in the first place. That is very tough in our malpractice environment but in some places like England and the continent, they have a much lower recall rate and yet they seem very good at preventing breast cancer mortalities. So that is something we need to work on and it is going to be tough.

The other issue that I wanted to talk about along these lines is over diagnosis, ductal carcinoma in situ. And again for women for women who are not in this field, I want to make sure you understand what ductal carcinoma in situ is because many surveys have shown that women do not know what it is. It is a pre-malignant lesion in the breast. It has a terrible name: it is called carcinoma. But it is not carcinoma; it is not invasive but it does give you a much higher risk of developing breast cancer. Now this is a disease basically, or a condition that hardly existed before women started getting mammography a great deal in our country.

If you look in the left-hand side here, back in 1983, less than 5 per 100,000 women were diagnosed with ductal carcinoma in situ. And then this very rapid rise until 2000 and it just shows that more and more women are getting mammography and more and more women are getting diagnosed with DCIS. At this point about 60,000 women are diagnosed with it per year and it accounts for about 20% of all “cancer.” In mammography, women who have had mammography, it is about 30% and in younger women it is even higher.

Now, what do you do with DCIS? We know that some of these women are going to have recurrences and in this slide, women who just got a lumpectomy, about a quarter of them had a recurrence within 8 years and 13% had invasive recurrences. So, that is something you don’t want to mess around with; this is very important. The problem is that many of these women will never have any more problems with breast cancer or with DCIS in the future and we don’t know how to separate those two. This is a modern quandary. Technology can find lesions that look but don’t act like cancer in large numbers of women or people and we don’t know which of these lesions will progress to act like cancer but we have to do something.

What do we do? This is not just in breast cancer; this is in cervical cancer, this is in lung cancer, this is in colon cancer and in fact, it has been worked out best in colon cancer. Our whole idea of finding cancer early is getting turned on its head a little bit because it is clear that we no longer have a situation where you are either normal or you have cancer. What it is is you are normal and then there are a few cells that get genetic changes and so you are somewhat abnormal and then somewhat more abnormal and finally it becomes cancer. Where on this continuum? Because many people do not keep proceeding along. They get a little abnormal and they stop, others get a little more abnormal and stop. So where do you intervene on that big continuum? That is a really important problem that we have to figure out in all cancer; hopefully genetics will help this.

So, the final complication. What do we tell the patients? How do we help women? More and more of the expert groups that make recommendations about breast cancer screening are saying involve the woman. This should be informed decision making. And by the way, women agree. The surveys that have been done, about 45% of them say, “ I want to make this decision by myself.” Another 45% say. “ I want some help with my clinician.” And finally some say, “ I want the clinician to make the decision.” Very interesting. But they all say they want information from their clinicians.
So what do we do? Most groups now say okay, you must consider family history for breast and ovarian cancer at any age to find as very few women at high risk for a deleterious mutation in a gene. But for women starting at age 40, you should discuss breast cancer risks and benefits and hazards of screening. You should take into account the woman’s individual, personal values. You should record the screening decision and I think you should also, very clearly indicate that most groups that have looked at this suggest she be screened. If she says, “you decide doctor” then you should decide but I think most would say, “Look, the weight of the evidence is here.”

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