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

Tuesday, January 26, 2016

DNA is not destiny? Well, duh

A high profile paper just published in the highly prestigious journal Nature suggests that overwhelmingly, cancer results from “extrinsic factors,” namely behaviors and exposures, rather than the “intrinsic” transgressions of our chromosomes. The media response is a proclamation that no, cancer is not just about “bad luck.” So august a platform for so salient a proposition seems to demand a highly erudite response, and I've got just the one: duh.

Didn't we know this already?

Yes, it's true, that almost exactly a year ago, a paper was published in the only journal that competes with Nature for prestige, Science, attributing cancer risk to the frequency of stem cell divisions, and propagating a spate of media coverage about the randomness of cancer. But the fallacy in that reporting is a long-established fact of epidemiology: Cancer rates vary substantially with lifestyle and environments. While variation in stem cell divisions might say something about the aggregation of mutations in any given tissue, we have long had cause to know it does not meaningfully account for differential cancer risk among people, or populations.

The novelty of the new paper is not the emphasis on environmental and behavioral explanations for many cases of cancer. One might call that yesterday's news, but in reality, it was yesterday's news long before yesterday; it was yesterday's news in 1982. Sir Richard Doll and Richard Peto published a famous paper in the Journal of the National Cancer Institute in 1981 characterizing the substantial preventability of cancer. A recent reassessment of their estimates concluded they appear to be valid after 35 years of scrutiny. And, of course, when McGinnis and Foege told us in 1993 that premature deaths in the United States were overwhelmingly preventable, again by modifying behaviors and exposures, cancer deaths were certainly in that mix.

The novelty in the new paper in Nature was to apply what we have long known about the salience of “extrinsic” causes of cancer directly to the proposition about “intrinsic” causes in the prior Science paper. What the current group concluded is that more frequent stem cell divisions does, indeed, create more opportunity for carcinogenic mutations- but that external factors provoke those mutations. Nature, in other words, has come down on the side of nurture.

In this epigenetic age, there is an expression that captures this interplay: Genes load the gun, but lifestyle pulls the trigger.

Even more bluntly: DNA is not destiny. There are exceptions, of course. If you are dealt two copies of the sickle cell anemia gene, you develop sickle cell anemia inevitably. The same is true with just one copy of the gene for Huntington's disease. Such exceptions are rare enough, however, to reaffirm rather than refute the basic proposition: generally, DNA is not destiny.

To a large, and largely neglected degree, dinner is. Or could be.

Of course, the alliteration is nice, but it's not really just “dinner.” It's breakfast, too. It's our overall dietary pattern. And it's not just diet either. It's our lifestyle.

Lifestyle, in turn, is accountable to and dependent on social and environmental factors. Even causes have causes. The choices we make are ultimately subordinate to the choices we have. Some whole cultures serve up choices that foster health. Some do rather the contrary.

Still, we might constructively collate these insights. Whether by virtue of behaviors chosen and practiced by individual bodies, or by exposures, environments, and policies referable to the body politic, the underlying causes of cancer, as for other major chronic diseases, are overwhelmingly preventable. The new paper posits the arrestingly high figure of up to 90% so. Whether it is that, or the more modest 60% that has long been touted by those in the know, it is a luminous and tantalizing proposition just the same.

Even as we concede that the daily choices we make as individuals are to varying degrees subordinate to the choices we have by virtue of our culture, we might acknowledge one choice we could make any time. We could choose to stop rediscovering what we already know.

We have long known that lifestyle practices, whether born of personal choice, or public action, could eliminate the majority of cancers, and an even higher majority of other chronic diseases. We have long known how to prevent some 80% of premature deaths.

But as long as we remain interested in rediscovering what we know rather than putting it to good use, knowledge isn't power. And while DNA isn't destiny, at present, neither is dinner, at least not the favorable destiny it might be. Rather, our destiny seems much consigned to our collective, cultural dysfunction.

We are ill-served by headlines that made cancer random a year ago and overwhelmingly preventable this year. Both studies in both prestigious journals contributed something to our basic understanding, but neither changed our options or the prevailing view from altitude. We don't know how to prevent every case of cancer, certainly, but cancer, along with every other major chronic disease, occurs far less often in populations that eat well, don't smoke, and stay active. The numerous centenarians in the Blue Zones are obviously not just not dying of heart attacks at age 70 or 80. Living to 100 means they are also not dying of anything else then either, cancer included.

A new year dawns, and with it, the alluring promise of new knowledge. We may hope that some of that knowledge will pertain to advances in the prevention and effective treatment of cancers, particularly those that defy our best efforts, and those that do seem truly random. But perhaps one of its greatest prospects for us all resides with the opportunity to renounce the need to rediscover next year what we knew and failed to apply last.

May this, then, be the year the wishful proposition about knowledge and power comes true. May it be the year we come together to lay hold of the master levers of medical destiny that have long been in our hands, and heave together. May this be the year we stop rediscovering what we already know, and actually, finally, do something with it.

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.

Labels: , , , , ,


Post a Comment

Subscribe to Post Comments [Atom]

<< Home

This is a printer-friendly version of this page

Print this page  |  Close the preview




Contact ACP Internist

Send comments to ACP Internist staff at

Blog log

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.

Powered by Blogger

RSS feed