Risk, Randomness and Cancer
The risk of developing many kinds of cancer may rely on random luck.
Cristian Tomasetti, PhD, and Bert Vogelstein, MD, cancer scientists at Johns Hopkins University School of Medicine, report in a Science magazine article that many cancers are caused by random mutations that happen when healthy stem cells divide. Cancers are known to result from life styles, inherited proclivities, and environmental exposures, as well as causes that can't be identified. A New York Times story by Denise Grady reports that the authors found chance was a bigger factor than they'd expected. "It was about double what I would have thought," Dr. Tomasetti, a biostatistician and professor told the Times. Basically, the risk of cancer is highly correlated with the number of stem cell divisions over time.
A Johns Hopkins press release explains that Tomasetti and Vogelstein charted the number of stem cell divisions likely to occur in 31 tissue types during an average life span, and compared these rates with the lifetime risk of cancer in the same tissues among adult Americans. Adult stem cells are a specialized population of cells in each organ or tissue that divide or self-renew indefinitely to generate replacement parts as other cells wear out.
The researchers report, for example, that the large intestines have more stem cells than small intestines, and those cells divide 73 times a year, compared with cells in the small intestines that divide 24 times a year. The lifetime risk of cancer in the large intestine is 4.8 percent, which is 24 times higher than the risk of a small intestine cancer. Their calculations show that about two thirds of the variation in cancer risk was explained by the number of stem cell divisions, and about one third is explained by heredity and environment.
They compare cancer with a car accident. The longer the trip, the higher the risk of accident. They say the mechanical condition of the car is a metaphor for inherited genetic factors and road conditions are like environmental factors. We may not know which of these three conditions contributed most to a particular wreck, but well maintained roads and vehicles can reduce overall risks. Knowledge that some factors are beyond our control may reduce stigma and comfort some cancer patients who blame themselves for their illness. Findings also suggest more cancers will appear simply because aging increases the number of stem cell divisions, the authors say in the release, so research on early detection, treatment and the biology of the disease is more important than ever.
Breast and prostate cancers were not included in the study because researchers lacked data on breast and prostate stem cell division rates. Lung cancer cases were divided between smokers and non-smokers, leading some readers to note that smoking also contributes to many other cancers. The American Lung Association reports that smoking causes nearly 90 percent of all lung cancer cases.
In a lengthy blog post on the article, oncologist David Gorski, MD, cites research suggesting one third to one half of all cancers are "potentially preventable," meaning they come from environmental factors that could be altered, such as smoking, alcohol use and weight control. He has some quibbles with the article, and wishes the discussion of it had been more nuanced. Bob O'Hara and GirrlScientist writing in The Guardian complain that too many news stories about the research confuse the variation in cancer risk with absolute risk of cancer, thereby blurring what constitutes bad luck.
Sometimes luck is randomly good. In the press release, Dr. Vogelstein observes cancer free longevity in people exposed to tobacco smoke and other carcinogens, often attributed to good genes, is likely to be good luck.
React to this piece on the Complexity Matters blog.
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PlexusCalls
Friday, January 9, 2015 1:00PM Eastern
Strategies for Adaptive Leadership and Innovation
Guests: Daniel Pesut and Charlie Garland
You've heard discussions about technical and adaptive leadership. Charlie Garland has explored some of the tools and thinking strategies that aid development of adaptive leadership skills.
Charlie Garland is an innovation expert who provides services as consultant, executive coach, trainer and author. He has developed a series of tools and models that show how our natural thought processes, psychology and experiential learning can evolve into the creation of new value. His clients have ranged from Fortune 100 corporations to early stage entrepreneurs across industries that include finance, IT, manufacturing, publishing fashion, law and entertainment. He earned a BS degree in industrial engineering from the Worcester Polytechnic Institute, and an MBA from the Amos Tuck School at Dartmouth College. He launched The Innovation Outlet in 2011.
Daniel Pesut, PhD, is professor of Nursing Population Health and Systems Cooperative Unit and Director of the Katharine J. Densford International Center for Nursing Leadership and holds the Katherine R. and C. Walton Lillehei Chair in Nursing Leadership at the University of Minnesota School of Nursing. Throughout his 38 year career as a nurse he has held positions in both academic and public sectors serving in a variety of roles that include staff nurse, clinical nurse specialist, director of nursing services, academic department chair, and associate dean. He values and supports creativity and innovation and is dedicated to the development of next generation nursing leaders through his coaching and consulting practice. He served as a Trustee of the Plexus Institute from 2005-2010 and was the Chair of the Plexus Institute Board of Trustees from 2011-2012.
Healthcare PlexusCalls
Wednesday, January 21, 2015 1:00PM Eastern
Embracing Complexity: Managing Treatment-Related Symptoms During and After Cancer Treatments
Guests: Noah Zanville, Sarah Shockley and Christine Cote
Cancer remains a leading cause of death for individuals in the U.S., but has increasingly become a disease patients can survive, thanks to a growing arsenal of effective treatments. For patients today, this arsenal includes cutting-edge surgery, hormone therapy, chemotherapy, radiation therapy, biologics and immune-modulating drugs. Together, this collection of treatments is helping more and more patients to fight, and win, their battle against cancer. Unfortunately, many of these treatments can also lead to side-effects that can disrupt patient's transition back to wellness and, in some cases, threaten their ability to finish their cancer treatment. This tension between treatments that heal and treatments that harm is a major theme in oncology, and is made worse by the fact that in many cases, there are no treatments for these side-effects. Social factors like an aging population, increasing pressure to stay in the workforce and spiraling healthcare costs further underscore the need to help patients, their families, and their providers to manage treatment-related symptoms during and after cancer treatment.
Noah, Sarah and Christine will join the call for a roundtable conversation about the challenges of cancer treatment and what "embracing a complexity perspective" might look like in the everyday care of cancer patients. Please bring your voice and your own experience to this important conversation. Read the guests complete bios.
See all upcoming PlexusCalls on the Plexus Calendar. Subscribe to the PlexusCalls or Healthcare PlexusCalls podcasts. Or, visit the Community section of plexusinstitute.org for the audio archive.
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