Tuesday, January 17, 2012
Reviewing the IOM report on breast cancer and the environment
Earlier this month the Institutes of Medicine (IOM) issued a big report on breast cancer and the environment. The thick analysis, commissioned and sponsored by the Susan G. Komen for the Cure, was authored by an expert panel. Their task, to assess all available information on what causes breast cancer, and make recommendations accordingly, was essentially impossible. Some immediately critiqued the work and, perhaps implicitly, the funding, for its failure to yield sharp or clearly-actionable insights into breast cancer causes.
The document starts, blandly, with some straightforward stuff. The recommendations for lifestyle changes seem paternalistic when not obvious. Where the report gets interesting, and offers value, is in considering a few specific environmental toxins that might be causative in the current breast cancer epidemic. While proving that any one (or several) of the chemicals listed below causes breast cancer will be difficult, developing a clear, working list of likely compounds that merit research attention is an important step.
Some background
Each year, over 230,000 women in the U.S. develop a breast tumor. The problem, in terms of preventing breast cancer, is that most established risk factors, like being older, later age at menopause, being young at the time of first menstruation and some genetic traits, aren't amenable to intervention.
For this project, the IOM committee interpreted the term "environment" broadly. It considered all possible causes of breast cancer that aren't directly inherited through DNA, including factors that might influence a genetic disposition. They looked at a wide range of exposures: "how a woman grows and develops during her lifetime; what she eats and drinks; the physical, chemical, and microbial agents she encounters; how much physical activity she engages in; medical treatments and interventions she undergoes; and social and cultural practices ..."
What they found, with my comments interspersed and conclusions:
The most convincing evidence linked breast cancer to hormone therapy with estrogen and progesterins, ionizing radiation (as might occur in medical procedures like CT scans; the amount of radiation in mammography is too low for concern, the committee emphasizes), excess weight (i.e. being fat, or more-than-fat) in postmenopausal women, and alcohol (addressed here, previously).
Where they found no clear link: smoking (surprise! the evidence is limited, they say), personal use of hair dyes, non-ionizing radiation (like that emitted by microwaves and other electrical devices).
On the up side: Physical activity appears to lessen a woman's breast cancer risk.
Quite a few factors fell into a gray zone, for which "the evidence is less persuasive but suggests a possible association with increased risk." These are: exposure to secondhand smoke (this might be a cause, but smoking isn't? seems unlikely), nighttime shift work (steroids/stress effect? Or just too much junk food).
Finally, they name some chemicals: benzene, ethylene oxide, or 1,3-butadiene (these may be present in some workplaces; one might be exposed from breathing auto exhaust, pumping gas, or inhaling tobacco smoke, they indicate) and bipsphenol A (BPA), one of the "biologically plausible hazards in the environment." As they indicate, animal data provide clear evidence for a mechanism by which BPA, which is widely-used in plastic containers and food packaging, might cause breast cancer. "But studies to assess the risk in humans are lacking or inadequate."
The IOM committee study authors consider the difficulties in testing environmental hazards. Of course, as they point out, it wouldn't be ethical to deliberately expose women to potentially harmful substances in a clinical trial. For this reason, they advocate more research in animals and in vitro systems. But those kinds of experiments are limited, in their words: "they can provide indications that a chemical or other agent may cause harm, but these models are approximations of human experience."
So we're stuck with a lot of inconclusive data, and an obvious moral imperative not to systematically test the effects of possible environmental toxins on women who might develop breast cancer. There's a table posted, with strategies to reduce risk, but it recommends for the most part obvious things, and an annoyingly-toned paragraph:
These actions include avoiding unnecessary medical radiation throughout life, avoiding use of postmenopausal hormone therapy that combines estrogen and progestin, avoiding smoking, limiting alcohol consumption, increasing physical activity, and, particularly for postmenopausal breast cancer, minimizing weight gain. Some of these actions may have additional health benefits beyond their potential contribution to reducing breast cancer risk. In many cases, women can be aided by the actions of others, including their families and health care providers.
(Why don't they just say: "be a good girl, get rest, and stay slim?")
The segment on the future and needed research emphasizes the need for research on early-life exposure to chemicals, pre-menopausal obesity, and other factors that may influence development of breast cancer later on in a woman's life. This makes sense to me.
The most troubling findings have to do with the chemicals. Carcinogens like benzene are hard to put a finger on, when it comes to causing cancer in a population where cars are abundant and oil leaks often, and occasionally abundantly, into large gulfs of water. The BPA issue is a genuine concern, with little clear data in humans. Until those data are evident (which, if it takes decades to show the effects on youngsters exposed who develop breast cancer in, say, their 40s), will not be for a while. You have to wonder if doctors should recommend more drastic steps to avoid routine exposure to and ingestion of potentially toxic chemicals.
If you'd like to read about this report and some of the concerns about chemicals that might cause breast cancer, I recommend this post by Julia Brody, of the Silent Spring Institute.
This post originally appeared at Medical Lessons, written by Elaine Schattner, ACP Member, a nonpracticing hematologist and oncologist who teaches at Weill Cornell Medical College, where she is a Clinical Associate Professor of Medicine. She 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.
Labels: breast cancer, Elaine Schattner, environment, guest post, Medical Lessons, research
posted by Elaine Schattner, MD at
11:00 AM
Contact ACP Internist
Send comments to ACP Internist staff at acpinternist@acponline.org.
Previous Posts
- Doctors' choices at the end of life, for themselve...
- QD: News Every Day--Residents aren't learning how ...
- Filling the void (... the young docs, vol. 2)
- Are you at risk for an adverse medication reaction...
- QD: News Every Day--15 top causes of death detaile...
- Sports concussion fumbled by team physicians
- Plan B needs a plan D, for 'data'
- QD: News Every Day--Resveratrol researcher alleged...
- Another crack at medical cranks
- Four Ts to transforming medical education: Trust, ...
Blog log
Members of the American College of Physicians contribute posts from their own sites to ACP Internist and 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.
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.
DrDialogue
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.
FutureDocs
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
ACP Member Mike Aref, MD, PhD, ACP Member, 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.
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.
KevinMD
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, ACP Member, 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.
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).
Prescriptions
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.
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.
White Coat Underground
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.
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.
db's Medical Rants
Robert M. Centor, MD, FACP, contributes short essays contemplating medicine and the health care system.
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.
0 Comments:
Post a Comment
Subscribe to Post Comments [Atom]
<< Home