Screening Controversy
Posted 10/22/2009
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Yesterday's reports about the disappointing results of screening and early detection, especially for breast and prostate cancers, have been confusing and distressing for many people. Part of the problem, I think, is that we all have been lulled into thinking that "finding it early" always translates to cure. This has never been true although, certainly, many small cancers have been successfully treated and never return. One of our senior breast cancer oncologists has often said something like: "Most breast cancers, if treated appropriately, will be fine--no matter which treatment we choose. There are a few, however, that will be lethal no matter what we do." The problem has been trying to identify which are the potentially lethal ones.
Recent advances in genetic mapping of tumors and targeted therapies have begun to move us in this direction. We know, for example, that her2positive breast cancers respond to Herceptin. The introduction of the Oncotype DX test has helped many women and their doctors make a more informed decision about the value of adjuvant chemotherapy. We do have a long way still to go.
My own take on the recent discussion is that screening is still important even though we are reminded that it is not a panacea. In my own life, my first breast cancer never showed on a mammogram (even though I could feel it), but my second breast cancer was identified during an annual mammogram. I am glad I had that yearly test.
Here is more information about screening:
Excerpted from:
Analysis Questions Breast and Prostate Cancer Screening
ABC News contacted a wide array of clinical experts who were asked to put the research discussed in this MedPage Today report into clinical context. Here are the responses.
Freya Schnabel, MD Director of Breast Surgery, Medical Director of Women at Risk, NYU
It is always important for us to be thoughtful and challenge assumptions and update approaches in medicine, as in other areas. However, I think the message in the Times article is confusing, and somewhat off the point. And this article may discourage women and men from screening for breast and prostate cancer, and by extension, other diseases.
We have improved the survival from breast cancer in the modern era of screening. The recently released ACS statistics confirm this. Early detection is a big part of this effect. Clearly, there are always outliers -- cancers that are detected when small in size, but the patients have a poor outcome because the disease is biologically aggressive. These outliers should not be used to argue that early detection is worthless. Early detection gives better prognosis, and, specifically in breast cancer, early detection affords women the opportunity for less difficult treatment (unlike prostate cancer, where impotence and incontinence can result from treatment of early stage disease). Also, in the modern era, false positive results from screening exams are frequently resolved with minimally invasive needle biopsies, not invasive surgery.
I agree that our approach to early stage breast cancer could use some refinement. Specifically, we need to look carefully at the issue of overtreatment, particularly as many of our treatments are costly and carry the potential for significant side effects. The oncology community can continue to work towards understanding which women do not need chemotherapy, biologic therapy, and the like, because the benefits do not outweigh the risks (including costs). We need to continue to refine the surgical and other approaches to local treatment for early stage disease as well. And we need to be especially careful about recommending advanced screening such as MRI to patients whose risk of disease does not justify the disadvantages of that screening method. I hope that with the integration of new science, including genomic profiling of tumors, we will be able to refine our treatments -- "right-size" them based on a more clear understanding of the tumor biology.
I hope we do not see a return to the situation before screening, when most women came to breast cancer diagnoses with palpable, extensive disease. Patients with early stage disease are more likely to continue their busy, productive lives during treatment and for all the years beyond -- and our entire society benefits.
Susan Love, MD Dr. Susan Love Research
This is a great story and one that many of us having been saying for years. Breast self-exam was shown not to work and analysis on mammography show that 25% of cancers will go away by themselves if you do nothing! What did not seem to come out clearly in the Times piece is the fact that it is not that imaging is not good enough but the biology of cancer. Over the past decade it has become very clear that cancer is not just the problem with one cell going bad and gradually multiplying and then spreading. It is a combination of a mutated cell in a local environment that is egging it on. There is cross talk and influences of the local cells around the tumor (i.e. the stroma that are as important at the cells themselves).
Secondly not all cancers are the same, there are at least five or six different cancers that probably have different risk factors and different etiologies and they all do not behave the same. Screening is best at finding the "good" cancers and not the bad ones. It is as if you had a robber who took five minutes to get in and out of a building, a security guard that could get around the building in an hour would probably miss him while finding the robbers who takes an hour and a half.
This recent paper points out the fact that we need to go beyond screening for cancers that are already there, to finding the cause and prevention of breast cancer once and for all! Not all cancers are alike. We have focused on the risk factors, chemoprevention, and screening for the "good" cancers" that are hormonally sensitive and generally postmenopausal and have not done as much for the more aggressive premenopausal cancers. The Love/Avon Army of Women is an effort to recruit one million women willing to participate in research to find the cause and prevention of this disease once and for all!
Clifford Hudis, MD Chief, Breast Cancer Medicine Service, Memorial Sloan-Kettering Cancer Center
It has always been the case that screening for any disease finds more cases than not screening and that the survival impact of the screening is less, numerically, than the detection rate. The fact is that nobody can say which cancers are bad - potentially lethal - and which ones can be ignored. But overall, deaths are reduced in a screened population.
<>You are used to this dilemma in other settings: Do we screen 95 year-old men for prostate cancer? No. Do they have it? Almost 100%. Is it lethal at that point? No. Would the same disease in a younger person potentially shorten their lifespan? Yes.
So all what is added here is something that screening experts already know well: The real goal of an ideal screening program is to find the "bad" cancers and ignore the "good" ones. But we have to add that we don't yet have that ability and no or reduced screening would result in inferior survival for society as a whole.
Daniel Hayes, MD Clinical Director, Breast Oncology Program, University of Michigan
It's a story that keeps percolating, and most of us in academics agree: Screening (at least for breast, cervical, probably colon; maybe but probably not prostate and not lung) probably does save lives, but it is not a panacea. It highlights the difference between an understanding of biology and science versus public perception that everything is black or white: or put another way, public health (do we improve the health of the general public by doing more good than harm) vs. individual patient care (this either works or doesn't work for me).
Interesting, the best note of caution in which it is stated that this story will lead to headlines like "Screening doesn't work" was, indeed, buried back in the later pages of the story-exactly as predicted. It needs to be handled carefully. There is no question that screening mammography reduces mortality when applied to patients likely to get the disease and die from it, but it isn't perfect and it probably only reduces mortality by 20-50% (see Berry, NEJM, 2005). There is no question screening mammography is has been over-hyped, both in terms of applying it to women who are very unlikely to die of breast cancer (women in their early 40s) and it's relative contribution to reduction in mortality. The hype over other methods of screening, such as use of MRIs, is even worse. But we don't want to throw the baby out with the bathwater-it should be emphasized that, on a public health basis, thoughtful screening recommendations should be followed. …
I thought Otis Brawley's comments were very courageous and thoughtful. This is a sea-change for ACS, which has always promoted screening, with or without supporting data. Otis has induced a new culture into ACS, and he will take heat for it-so he needs to be quoted accurately and his intent (to induce evidence-based medicine into ACS guidelines) needs to be understood, without seriously diluting the beneficial effects that screening does have.
Fran Visco President, National Breast Cancer Coalition
The National Breast Cancer Coalition has said for over a decade that mammography has serious limitations, has not been shown to reduce mortality in women under 50 and should be a personal decision, not a public health message. There have been other very well designed studies and analyses over the years that led us to this position, including studies by the Cochrane Collaboration and Don Berry's group. The American Cancer Society largely helped create the public's unwarranted obsession with screening, they will have to work very hard to help fix the current situation which, again, they caused. It is long overdue that we recognize that we should not be pushing for more mammography, should accept that breast self examinations do not save lives and can result in harm and, rather than try to expand screening into younger and younger ages, we should focus on figuring out which breast cancers will be harmful and how to deal with those.
October is all about pink and early detection. Breast cancer is anything but "pink and pretty" and it's time women understood the reality about screening. The National Breast Cancer Coalition has said for over a decade that mammography has serious limitations, has not been shown to reduce mortality in women under 50 and should be a personal decision, not a public health message. There have been other very well designed studies and analyses over the years that led us to this position, including studies by the Cochrane Collaboration and Don Berry's group. The American Cancer Society largely helped create >the public's unwarranted obsession with screening, they will have to work very hard to help fix the current situation which, again, they caused. It is long overdue that we recognize that we should not be pushing for more mammography, should accept that breast self examinations do not save lives and can result in harm and, rather than try to expand screening into younger and younger ages, we should focus on figuring out which breast cancers will be harmful and how to deal with those.
October is all about pink and early detection. Breast cancer is anything but "pink and pretty" and it's time women understood the reality about screening. It will be close to impossible to move the public away from the "Early Detection Saves Lives" mantra that ACS ingrained in many of us. There is a huge infrastructure built up around mammography screening, hundreds of organizations have been formed around that issue and hundreds of millions, if not billions, of dollars feed this area of breast cancer year after year. Breast cancer awareness campaigns and the >millions of dollars behind them mostly focus on screening. The truth about these issues threatens the groups behind the messages and the very real economic benefit that comes from screening healthy populations. This is the perfect case study for never releasing public health messages unless there is an extremely high level of evidence behind them and true consensus.
Larry Norton, MD Deputy Physician-in-Chief for Breast Cancer Programs, Head, Solid Tumor Division, Memorial Sloan- Kettering Cancer Center
The study on which the article is based, and which may have influenced the ACS statement, found that the ratio of early to advanced breast cancers at diagnosis has changed since screening (more early cancers), but that the decline in advanced cancers found--while real--is not as large as one would expect if most of those early cancers detected< would have become advanced cancers if left untreated. This shouldn't be turned into a "screening is bad" message, even if it is a "screening isn't perfect" message.
Moreover, if the true incidence rates have risen over the past decade and a half (which is certainly possible given changes in obesity rates among other factors), then the decline in advanced cancers may be much more impressive than it might seem from a first view of these data. These are points that need to be discussed among experts. The simple fact is that if a woman wants to reduce her chances of dying of breast cancer, she should choose mammography.
Christine Laronga, MD, FACS Chief of the Don and Erika Wallace Comprehensive Breast Program, H. Lee Moffitt Cancer Center & Research Institute
The American Cancer Society has always led the way with respect to its message of prevention and early detection of cancer. So this news comes as a shock. Thanks to their efforts and others, the compliance with screening mammography guidelines has increased over the last 2 decades. However it still isn't 100%, explaining why there isn't as large a decline in women presenting with advanced disease. As a result of this increased screening the incidence of breast cancer has increased accordingly, largely from detection of Ductal Carcinoma In Situ, a noninvasive type of breast cancer, and small invasive cancers.
The question of the natural history of these identities if left untreated is largely unknown. Perhaps they would not progress and spread to other sites or perhaps they will regress. However there has been no evidenced-based large clinical trial randomizing these women to standard treatment versus observation alone. Why? Because the majority of women diagnosed with cancer don't opt for observation alone and physicians / researchers aren't at the point yet where they can differentiate between those that will regress from those that will progress and spread.
We are in the molecular assay era where we can investigate many genes within a person's tumor to personalize / tailor treatment accordingly. The horizon looks promising for having a gene chip on everyone's tumor to know what works, what doesn't; who needs treatment, who doesn't. But we aren't there yet. For now, every physician would prefer to tell a woman that her cancer was caught early (stage 0 or 1), then answer her question of whether or not her cancer would have been detected at an earlier stage if she had her mammogram last year on schedule with current screening guidelines.
Emanuela Taioli, MD, PhD Chair, Department of Epidemiology and Biostatistics, SUNY
Downstate Medical Center
First of all, it is important to spread the message to the public that screenings are still the best tool for cancer early detection. It would be a disastrous public health message to let people believe that cancer screenings are useless. Having said that, both prostate and breast cancer share a common factor, i.e. hormones (both estrogens and androgens) are strong promoters, therefore a cancer that have been silent for years could suddenly become clinically relevant if the person's hormone balance undergoes a suddent change, for example during menopause.
Therefore breast and prostate cancers, being hormone dependent cancers, are a changing dinamic reality during a person lifetime. This factor is one of the contributing elements to the fact that many small cancers detected by screening would probably never become aggressive, deadly cancers, or would become so much later in life, when hormone balance changes.
This introduces overtreatment or un-necessary treatment. What is important to note, however, is that now there are very many biomarkers available that can distinguish between sub-categories of cancers, identifying those that are more aggressive from those that are less so. The widespread use of clinical biomarkers of cancer aggressiveness together with regular screening procedures may be one of the ways to optimize the results of conventional screening practices, by allowing the identification of those sub-categories of cancer that are very likely to become clinically evident and deadly over a person's lifetime.
Ben Park, MD, PhD Associate Professor of Oncology, Associate Director, Medical Oncology Fellowship Training Program, Johns Hopkins Medical
There a few things about this article that merit discussion. First, similar to what was said in the article, I worry that this will be construed incorrectly and send the wrong message. In particular, women who are receiving screening mammography may read this and think that they should no longer continue with their screening.
Clearly screening mammography can save lives, and although the reduction may not be enormous, even 5% to 10% of women who would otherwise die from breast cancer translates into thousands of lives that are saved each year in this country alone. One cannot ignore that absolute number.
Second, I agree that often times screening for cancer is overstated as we have long known that PSA screening for prostate cancer has been challenging. Yet very little attention has been given to successful screening interventions such as the ones mentioned for colorectal and cervical cancer screening. The issue with cancers such as breast and prostate, I feel, is that they are a much more heterogeneous group than other types of cancers.
While the notion of cancers going away is indeed "hard to swallow", the idea that some cancers will have a much more indolent course and may not require active or aggressive therapy is not new and has clearly been demonstrated in some adult cancers.
Thus, the real challenge for screening in my view, is to adopt what we are trying to do with treating cancers at an individual level; so called "personalized medicine". Who needs to be screened for these types of cancers, who is at risk, and what are the predictive biomarkers that will allow us to identify those individuals who will benefit from such screening and those who will not are the next big questions to be answered. We have embraced this concept for the treatment of cancers, and are only now moving towards this concept for cancer screening and prevention. Thus it may be in the future that we will not recommend that all women receive screening mammography, but only those with identifiable risks.
Anne Wallace, MD Director of Breast Care Unit, University of California
I fully agree with this message. The message of screening has been important so as to detect earlier those cancers that biologically may behave differently if found smaller. But there are still cancers that no matter when we find them have biologic aggressiveness. The small aggressive tumor can sometimes have much more potential to spread than a much larger less aggressive tumor. In addition, women with breast cancer are mislead into thinking they need more and more advanced imaging to "prevent" them from ever getting or dying of breast cancer. That has led to more wide spread unnecessary imaging and biopsing of things that we don't even know are biologically significant. I applaud the ACS for this message.
Tomasz Beer, MD Assistant Professor in Medicine, Oregon Health & Sciences University
I applaud Dr. Brawley for his honest and forthright approach to these very tough issues. It is important that we recognize that the principle of early detection and treatment is sound. The challenges we face today reflect the limitations of our screening tests, which can both detect insignificant cancers and miss potentially lethal ones. We must develop more robust tests and that ability to better understand the lethal potential of small tumors.
Patricia Ganz Director of cancer prevention and control research, Jonsson Comprehensive Cancer Center, UCLA
I think the American Cancer Society is definitely on target. I think what we really need to understand when we see pre-cancers and very early cancers in screening is which have a lethal trajectory and which do not. Once we do a screening and see something, it puts us on a path to treatment because most people cannot live with knowing they< have something like that inside of them.
The way to avoid this is to not screen so early and not screen so many people. It's tough for the American Cancer Society to have a simple message on screening because pap smears and colonoscopies do work. However, the evidence is not there for mammograms and prostate cancer screening.
I don't mean to be provocative, but maybe we shouldn't start screening women until they're post-menopausal. Most of the non-serious pre-cancers and very early, small cancers would probably disappear as hormone levels drop. It is a difficult situation for me because I see many young women with breast cancers that were found on their first mammograms and they say that screening saved their lives. But I think there are too many women with pre-cancers and very early cancers that are being overtreated.
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