Another Look at Luck and Cancer: Risk Accumulation & Prevention

by Graham Colditz

The debate regarding luck, prevention, and cancer risk is in the media again today (see Science, NPR, Forbes, and many others).

The authors of this new paper -- a follow-up of their original published two years ago and which caused such stir -- make a clear effort too classify cancer risk as due to H - hereditary (our parents - who we cannot change), E - environmental exposures (modifiable risk factors, such as cigarette smoking, weight gain in adult years, and lack of physical activity) and R - rate of DNA damage accumulated as cells divide.  By taking this approach, however, we continue to focus on the underlying rate of division and DNA damage, not the factors that modify this rate and certainly are known to modify cancer risk.

Doll and Armitage showed in 1954 that 5 to 6 mutations were needed to generate cancer in lung, colon, and numerous other organ sites. Yes, the multistage model proposed in 1954 was largely correct based only on assessment of age and cancer mortality in the UK. Of course, back then, treatment did not change outcomes to any great extent.

Today, we have more evidence that the rate of DNA damage varies by age.  For example, breast cancer shows this clearly in animal models and through incidence in women. The stages of a woman's life are associated with different rates of cell division - faster from the time a woman has her first menstrual period to the time she has her first baby, then more slowly after each baby, to even slower after menopause (unless a women uses hormone therapy that consists of estrogen-plus-progestins).

We wrote on this some time ago, (see below) as have many others.

While risk accumulates through cell divisions, we know that avoiding smoking and other major risk factors dramatically reduces the risk of specific cancers.

As the cancer burden continues to increase globally, using what we know from decades of cancer research lets us as a society reap benefits now.  Our return on investment on what we already know is waiting to be collected.  We just need the foresight and political will to do it.

Room for Improvement: Most Breast Cancer Risk Sites Fall Short in Readability

by Katy Henke

Breast cancer is one of the most well known cancers as well as the leading cause of cancer death in women worldwide (1). In an effort to educate and prevent future breast cancer cases and deaths, online health assessment tools have been created to help women understand their risk for developing breast cancer as well as learn how to reduce or manage their risk. These tools allow individuals to input their own health history and family health history into a calculator that then estimates the risk for developing breast cancer.

A recent publication by faculty members at Washington University School of Medicine highlights that many online tools may not be understandable for all users. In the study, 42 online assessment tools were analyzed using specific suitability and readability criteria, and only 21 percent of websites received a superior rating. In rating the tools, the study looked at website content, writing style, context, layout, subheadings and model behavior. Additionally, all websites were rated based on their readability. Overall, the sites had an average of a 12th grade reading level. The recommended reading level for patient-directed health information is 5th or 6th grade (2).

With these findings, the authors recommended future online assessment tools take into account the broader audience who may be utilizing the online health tools. Over a third of the United States population has limited health literacy (3). And these numbers can vary greatly by income, education, and race/ethnicity. Taking steps to improve the readability and usability of online breast health assessment sites would mean that a broader audience would have the possibility of benefitting from their important messages.

What can be done to improve these assessment tools? The study concluded each tool should feature an overview of the assessment tool and explain its purpose to users, what the user’s cancer risk is, and what the user can do to reduce it. Each online assessment tool should also be written at a 5th grade reading level. This would allow the majority of United States population to understand the content. Additionally, vocabulary should include common words, shorter sentences, and words with fewer syllables. The authors also suggested illustrations and graphics that are friendly and inviting when portraying relevant health information.

To help improve risk communication and reduce the health literacy barrier, breast cancer assessment tools can be reformatted in a more user friendly way. Ideally this will help individuals understand their own breast cancer risk as well as ways to reduce and prevent breast cancer.

For a list of assessment tools rated as “superior,” see table below.

From Table 1; Cortez et al, 2015

References

1. Center for Disease Control and Prevention. Breast Cancer Statistics. 2015 Aug 20. http://www.cdc.gov/cancer/breast/statistics/index.htm 
2. Friedman D.B., & Hoffman Goetz L. 2006 Jun. A systematic review of readability and comprehension instruments used for print and web-based cancer information. Health Education and Behavior. 33(3): 352-373. DOI: 10.1177/1090198105277329. http://heb.sagepub.com/content/33/3/352.long. 
3. The Health Literacy of America’s Adults: Results from the 2003 National Assessment of Adult Literacy. 2006 Sep. U.S. Department of Education. National Center for Education Statistics, Washington, D.C. https://nces.ed.gov/pubs2006/2006483.pdf.

Prevention of Colon Cancer: time for action is now

Recent updated evidence from the United States National Health And Nutrition Survey (NHANES) show that the majority of US adults have more than one modifiable risk factor for colon cancer that needs attention (see article). While screening is advocated for prevention of colon cancer and supported by evidence from randomized controlled trials (1), we have shown that even after screening, those with poor risk profiles remain at elevated risk of colon cancer (2). In particular, and analyzing data from the Nurses’ Health Study, Wei and colleagues show that lack of physical activity, red meat consumption and high alcohol intake and lack of regular aspirin use, leave women who have been screened for colon cancer at substantially elevated risk of cancer in subsequent years.

What do we know about the US population and primary prevention of colon cancer?

Analyzing the NHANES data, Joshu and colleagues tracked colon cancer risk factors form 1999 to 2008 (3). Obesity, physical inactivity, red meat consumption, and alcohol intake, together account for more than 70% of colon cancer (4). Over this decade of repeated surveys the adult US population remained largely unchanged in their poor risk profile for colon cancer. 4 out of 5 US adults had one or more risk factors that could be modified. This was true for men and women, for White, Black, and Hispanic populations, and for each age group from 20 to 69. Almost 20% of adults have 3 or more modifiable risk factors. Thus they could take action now to lower their risk of colon cancer.

Why lower your risk?

Lifestyle changes significantly lower risk of colon cancer. 

It is time to act on what we know and reduce the population burden of colon cancer - a leading cause of cancer mortality. In fact, treatment of colon cancer accounted or 11% of all US cancer care expenditures in 2010. That is some 14 billion dollars spent on treating a cancer that is highly preventable. 

We can all take action now that will reduce the number of cases diagnosed over the coming years and the suffering that goes with this disease; save unnecessary expenditures; and improve quality of life. 

For help identifying risk factors you can work on today, visit our award winning web site your disease risk .

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Web resources
Your Disease Risk

Literature cited

1.         W. S. Atkin, R. Edwards, I. Kralj-Hans, K. Wooldrage, A. R. Hart, J. M. Northover, D. M. Parkin, J. Wardle, S. W. Duffy, J. Cuzick, Once-only flexible sigmoidoscopy screening in prevention of colorectal cancer: a multicentre randomised controlled trial. Lancet 375, 1624 (2010); published online EpubMay 8 (S0140-6736(10)60551-X [pii]10.1016/S0140-6736(10)60551-X).

2.         E. K. Wei, G. A. Colditz, E. L. Giovannucci, C. S. Fuchs, B. A. Rosner, Cumulative Risk of Colon Cancer up to Age 70 Years by Risk Factor Status Using Data From the Nurses' Health Study. Am J Epidemiol,  (2009); published online EpubSep 1 (kwp210 [pii]10.1093/aje/kwp210).

3.         C. E. Joshu, G. Parmigiani, G. A. Colditz, E. A. Platz, Opportunities for the primary prevention of colorectal cancer in the United States. Cancer prevention research 5, 138 (2012); published online EpubJan (10.1158/1940-6207.CAPR-11-0322).

4.         E. A. Platz, W. C. Willett, G. A. Colditz, E. B. Rimm, D. Spiegelman, E. Giovannucci, Proportion of colon cancer risk that might be preventable in a cohort of middle-aged US men. Cancer Causes  and Control 11, 579 (2000).