American College of Physicians: Internal Medicine — Doctors for Adults ®

Monday, March 24, 2014

Can we unmuddle mammography?

A new study of mammography, showing lack of survival benefit, has once again muddied these waters and muddled the relevant messaging. The study, generating considerable controversy, as has much prior research on the topic, looked at breast cancer mortality over a 25-year period in nearly 90,000 Canadian women assigned to mammography or usual medical care without mammography during the initial 5 years of the study period. There was no appreciable difference between groups.

Perhaps you see a major problem already. To study the effects of mammography, or any cancer screening, on mortality over time requires time. Time goes by at its customary pace no matter the research goals. So, if it takes 25 years to get the desired data, the intervention needed to take place 25 years ago. And so, inescapably, this study is entirely blind to any advances in mammography technique, technology, or interpretation over the last 20 years at least. In medicine, 2 decades is just about forever.

Perhaps the value of mammography is perennially muddled, if just a bit less so than prostate cancer screening, for the most obvious of reasons. The truth is in the middle, between slam-dunk and fuhggeddaboudit. With the apparent exception of titillating (if not salacious) novels, we don’t tend to like shades of gray. But that’s where mammography falls. It’s pretty close to a toss-up.

There is a long history of research on the topic, and conclusions have been anything but consistent. Some studies suggest clear potential benefit for women who would not otherwise be screened. But, of course, women who would not be screened are apt to differ in a variety of ways from those who would, including, perhaps, their access to, and the quality of, primary medical care. Unbundling such influences is nearly impossible.

But, if, instead, you attempt to study women who would be screened anyway, how do you randomize them to a control group? What woman, inclined to get mammograms, would go without for 20 years for the sake of a clinical trial? Not very many I know.

Enrollment in a trial itself can exert an influence. Regardless of assignment to mammogram or control, there may be more attention to breast health and a greater likelihood of finding breast cancer early among all women participating in a study. This effect obscures any real world, and potentially important differences between intervention and control arms.

We are, as well, dependent on an imperfect technology. Even if finding breast cancer early through imaging is decisively beneficial, studies will produce variable results based on flawed imaging, variable performance of the same technology in different women, and variation in the quality of interpretation of mammograms. That much more so when today’s data are the product of mammography done 20 to 25 years ago. There have been improvements in scans, scanners, and the training of radiologists during that span.

And complicating things further, mammography is a source of radiation, and may be doing some direct harm as well as good.

The false positive error rate of mammography is notoriously high, and unavoidably so if we want to avoid false negatives. False positives occur when we think we’ve found cancer that isn’t there. It can be avoided by raising the bar, but then there is a risk of missing cancers that are there. We tend to favor the former error over the latter, and in the absence of perfect tests, are forced to choose.

We may have failed to translate good evidence into practice. Pre-menopausal mammography would likely be more useful if performed more than once a year. Breast cancer tends to be more aggressive and progress faster in younger women. Post-menopausal mammography might be just as useful done every other year. A 1-size-fits-all approach may attenuate benefit and raise the rates of harm to both groups.

And then, perhaps most important: not all the trouble we find through screening deserves the attention it gets. Some tiny breast cancers, like the majority of prostate cancers, are destined to do nothing if just left alone. These are cases where cure is very likely to be worse than disease, but we are not good yet at differentiating. Doing so requires analysis at the level of histopathology (i.e., tissue and cell analysis), and molecular genetics. This can be done, but it’s not routine and our abilities in this space remain limited.

One very important issue routinely ignored when parsing the benefits of any cancer screening modality, mammography included, is that screening does not prevent cancer. The goal of screening is to find cancer early, which is generally much better than finding it late. But it’s not nearly as good as not getting it in the first place. The evidence is strong that optimal lifestyle practices can slash risk for all major chronic diseases, cancer included. Related evidence shows that lifestyle as medicine can modify gene expression in a manner projected to protect against cancer development and progression. DNA is not destiny. Dinner may be! There is interesting literature on the relevant timing as well. It may be the best way to improve breast cancer in women is to focus on healthy living in childhood. That we could dramatically lower rates of cancer overall by living well across the life span is all but undisputed.

There are many reasons why decisive evidence that mammography confers net survival benefit at the population level, or that it lacks benefit and should be abandoned, is elusive. The result is something of a muddle for epidemiology. Until technology, interpretation, application and histopathological confirmation all rise to consistently high standards, we can’t unmuddle mammography for populations.

But by combining what we know about the test with what you and your doctor know about you, a basis for a good decision should be at hand. Inquire about the technology, making sure it is state of the art. Ask about the training of the radiologist reading the film. Ask as well about plans for immediate next steps if the mammogram is abnormal. Good breast care centers follow up right away with additional testing to differentiate false from true positives. Ask whether screening has been personalized, taking into account your age, breast density, family history and risk profile.

Evidence-based recommendations about mammography for the population at large where one size must fit all are, for now, ineluctably muddled. By personalizing the decision, as good clinical medicine always should, we can, I believe, unmuddle things for you.

David L. Katz, MD, FACP, MPH, FACPM, is an internationally renowned authority on nutrition, weight management, and the prevention of chronic disease, and an internationally recognized leader in integrative medicine and patient-centered care. He is a board certified specialist in both Internal Medicine, and Preventive Medicine/Public Health, and Associate Professor (adjunct) in Public Health Practice at the Yale University School of Medicine. He is the Director and founder (1998) of Yale University's Prevention Research Center; Director and founder of the Integrative Medicine Center at Griffin Hospital (2000) in Derby, Conn.; founder and president of the non-profit Turn the Tide Foundation; and formerly the Director of Medical Studies in Public Health at the Yale School of Medicine for eight years. This post originally appeared on his blog at The Huffington Post.

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Members of the American College of Physicians contribute posts from their own sites to ACP Internistand ACP Hospitalist. Contributors include:

Albert Fuchs, MD
Albert Fuchs, MD, FACP, graduated from the University of California, Los Angeles School of Medicine, where he also did his internal medicine training. Certified by the American Board of Internal Medicine, Dr. Fuchs spent three years as a full-time faculty member at UCLA School of Medicine before opening his private practice in Beverly Hills in 2000.

And Thus, It Begins
Amanda Xi, ACP Medical Student Member, is a first-year medical student at the OUWB School of Medicine, charter class of 2015, in Rochester, Mich., from which she which chronicles her journey through medical training from day 1 of medical school.

Ira S. Nash, MD, FACP, is the senior vice president and executive director of the North Shore-LIJ Medical Group, and a professor of Cardiology and Population Health at Hofstra North Shore-LIJ School of Medicine. He is Board Certified in Internal Medicine and Cardiovascular Diseases and was in the private practice of cardiology before joining the full-time faculty of Massachusetts General Hospital.

Zackary Berger
Zackary Berger, MD, ACP Member, is a primary care doctor and general internist in the Division of General Internal Medicine at Johns Hopkins. His research interests include doctor-patient communication, bioethics, and systematic reviews.

Controversies in Hospital Infection Prevention
Run by three ACP Fellows, this blog ponders vexing issues in infection prevention and control, inside and outside the hospital. Daniel J Diekema, MD, FACP, practices infectious diseases, clinical microbiology, and hospital epidemiology in Iowa City, Iowa, splitting time between seeing patients with infectious diseases, diagnosing infections in the microbiology laboratory, and trying to prevent infections in the hospital. Michael B. Edmond, MD, FACP, is a hospital epidemiologist in Iowa City, IA, with a focus on understanding why infections occur in the hospital and ways to prevent these infections, and sees patients in the inpatient and outpatient settings. Eli N. Perencevich, MD, ACP Member, is an infectious disease physician and epidemiologist in Iowa City, Iowa, who studies methods to halt the spread of resistant bacteria in our hospitals (including novel ways to get everyone to wash their hands).

db's Medical Rants
Robert M. Centor, MD, FACP, contributes short essays contemplating medicine and the health care system.

Suneel Dhand, MD, ACP Member
Suneel Dhand, MD, ACP Member, is a practicing physician in Massachusetts. He has published numerous articles in clinical medicine, covering a wide range of specialty areas including; pulmonology, cardiology, endocrinology, hematology, and infectious disease. He has also authored chapters in the prestigious "5-Minute Clinical Consult" medical textbook. His other clinical interests include quality improvement, hospital safety, hospital utilization, and the use of technology in health care.

Juliet K. Mavromatis, MD, FACP, provides a conversation about health topics for patients and health professionals.

Dr. Mintz' Blog
Matthew Mintz, MD, FACP, has practiced internal medicine for more than a decade and is an Associate Professor of Medicine at an academic medical center on the East Coast. His time is split between teaching medical students and residents, and caring for patients.

Everything Health
Toni Brayer, MD, FACP, blogs about the rapid changes in science, medicine, health and healing in the 21st century.

Vineet Arora, MD, FACP, is Associate Program Director for the Internal Medicine Residency and Assistant Dean of Scholarship & Discovery at the Pritzker School of Medicine for the University of Chicago. Her education and research focus is on resident duty hours, patient handoffs, medical professionalism, and quality of hospital care. She is also an academic hospitalist.

Glass Hospital
John H. Schumann, MD, FACP, provides transparency on the workings of medical practice and the complexities of hospital care, illuminates the emotional and cognitive aspects of caregiving and decision-making from the perspective of an active primary care physician, and offers behind-the-scenes portraits of hospital sanctums and the people who inhabit them.

Gut Check
Ryan Madanick, MD, ACP Member, is a gastroenterologist at the University of North Carolina School of Medicine, and the Program Director for the GI & Hepatology Fellowship Program. He specializes in diseases of the esophagus, with a strong interest in the diagnosis and treatment of patients who have difficult-to-manage esophageal problems such as refractory GERD, heartburn, and chest pain.

I'm dok
Mike Aref, MD, PhD, FACP, is an academic hospitalist with an interest in basic and clinical science and education, with interests in noninvasive monitoring and diagnostic testing using novel bedside imaging modalities, diagnostic reasoning, medical informatics, new medical education modalities, pre-code/code management, palliative care, patient-physician communication, quality improvement, and quantitative biomedical imaging.

Informatics Professor
William Hersh, MD, FACP, Professor and Chair, Department of Medical Informatics & Clinical Epidemiology, Oregon Health & Science University, posts his thoughts on various topics related to biomedical and health informatics.

David Katz, MD
David L. Katz, MD, MPH, FACP, is an internationally renowned authority on nutrition, weight management, and the prevention of chronic disease, and an internationally recognized leader in integrative medicine and patient-centered care.

Just Oncology
Richard Just, MD, ACP Member, has 36 years in clinical practice of hematology and medical oncology. His blog is a joint publication with Gregg Masters, MPH.

Kevin Pho, MD, ACP Member, offers one of the Web's definitive sites for influential health commentary.

MD Whistleblower
Michael Kirsch, MD, FACP, addresses the joys and challenges of medical practice, including controversies in the doctor-patient relationship, medical ethics and measuring medical quality. When he's not writing, he's performing colonoscopies.

Medical Lessons
Elaine Schattner, MD, FACP, shares her ideas on education, ethics in medicine, health care news and culture. Her views on medicine are informed by her past experiences in caring for patients, as a researcher in cancer immunology, and as a patient who's had breast cancer.

Mired in MedEd
Alexander M. Djuricich, MD, FACP, is the Associate Dean for Continuing Medical Education (CME), and a Program Director in Medicine-Pediatrics at the Indiana University School of Medicine in Indianapolis, where he blogs about medical education.

More Musings
Rob Lamberts, MD, ACP Member, a med-peds and general practice internist, returns with "volume 2" of his personal musings about medicine, life, armadillos and Sasquatch at More Musings (of a Distractible Kind).

David M. Sack, MD, FACP, practices general gastroenterology at a small community hospital in Connecticut. His blog is a series of musings on medicine, medical care, the health care system and medical ethics, in no particular order.

Reflections of a Grady Doctor
Kimberly Manning, MD, FACP, reflects on the personal side of being a doctor in a community hospital in Atlanta.

The Blog of Paul Sufka
Paul Sufka, MD, ACP Member, is a board certified rheumatologist in St. Paul, Minn. He was a chief resident in internal medicine with the University of Minnesota and then completed his fellowship training in rheumatology in June 2011 at the University of Minnesota Department of Rheumatology. His interests include the use of technology in medicine.

Technology in (Medical) Education
Neil Mehta, MBBS, MS, FACP, is interested in use of technology in education, social media and networking, practice management and evidence-based medicine tools, personal information and knowledge management.

Peter A. Lipson, MD
Peter A. Lipson, MD, ACP Member, is a practicing internist and teaching physician in Southeast Michigan. The blog, which has been around in various forms since 2007, offers musings on the intersection of science, medicine, and culture.

Why is American Health Care So Expensive?
Janice Boughton, MD, FACP, practiced internal medicine for 20 years before adopting a career in hospital and primary care medicine as a locum tenens physician. She lives in Idaho when not traveling.

World's Best Site
Daniel Ginsberg, MD, FACP, is an internal medicine physician who has avidly applied computers to medicine since 1986, when he first wrote medically oriented computer programs. He is in practice in Tacoma, Washington.

Other blogs of note:

American Journal of Medicine
Also known as the Green Journal, the American Journal of Medicine publishes original clinical articles of interest to physicians in internal medicine and its subspecialities, both in academia and community-based practice.

Clinical Correlations
A collaborative medical blog started by Neil Shapiro, MD, ACP Member, associate program director at New York University Medical Center's internal medicine residency program. Faculty, residents and students contribute case studies, mystery quizzes, news, commentary and more.

Interact MD
Michael Benjamin, MD, ACP member, doesn't accept industry money so he can create an independent, clinician-reviewed space on the Internet for physicians to report and comment on the medical news of the day.

PLoS Blog
The Public Library of Science's open access materials include a blog.

White Coat Rants
One of the most popular anonymous blogs written by an emergency room physician.

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