Monday, August 20, 2012

Preventing colon cancer: Screening works – mortality down 30% nationwide from 1992 through 2009.


The evidence on screening as an effective strategy to reduce colorectal cancer mortality has its roots in studies of fecal occult blood testing (FOBT) that showed a reduction in colorectal cancer mortality1-3. These three independent trials were conducted in the US, England and Scandinavia. Completing the clinical trials of fecal occult blood testing case-control sampling frames were also used to analyze prospective data from the Kaiser Permanente Health Plan 4,5, showing significant reductions in colorectal cancer mortality. In 1997, the combined efforts of gastroenterologists and others led to the seminal paper recommending colorectal cancer screening 6 and ACS also adopted a guideline recommending screening for colorectal cancer 7. Congress subsequently approved screening for colorectal cancer to be covered by Medicare, providing coverage for Americans over age 65. Many other activities at the local and national level to promote colon screening have led to increase in screening and reduction in colorectal cancer mortality.

In the figure below, we see that there is a steady decline in mortality from colorectal cancer form 1992 through 2009. 


The goals of the American Cancer Society included a target of 55% of the population being screened and up to date for CRC screening by 2015 8. We have already met this national goal. Data from CDC indicate that in 2010 we already have met this goal, in fact the national average was 64.5% of adults 50 to 75 years of age were up to date 9. Variability is substantial – in Massachusetts screening increased to 75% of the population.

Does screening reduce colon cancer? – yes.
Randomized trial evidence now builds on the evidence available in 1997 and confirms the value of screening to reduce mortality. In 2010, Atkin and colleagues published a randomized trial of once-only flexible sigmoidoscopy conducted in the United Kingdom 10. Both incidence and mortality from colorectal cancer were reduced among those randomized screening compared to the control arm. Most recently, data from the PLCO randomized trial also show a reduction in incidence and mortality 11.

Despite national access to screening through Medicare, rates of screening vary substantially between states. Massachusetts has the highest uptake of screening as of 2010. Rates of screening by 2010 varied from 54 to 59% in the bottom quartile of States to 70 to 75% in New England, Maryland and Washington State 9. Likewise the drop in colorectal cancer mortality varies substantially over the past 20 years.  New England states and New York have had the highest drop in colorectal cancer mortality – rates declining by 30 to 37% from 1994 to 2007 12.

Promoting population health through reduction in colorectal cancer mortality requires successfully moving from knowledge through translation to implementation in widespread practice. Preventive action usually lags behind the science. Colorectal cancer is the second ranked leading cause of cancer mortality. Yet screening within the US has substantial variation in the rate of uptake and the associated decline in mortality. However, the overall national average of 64% exceeds the ACS challenge goals of 55% up to date by 2010 8.

National changes in access through Medicare coverage and in professional awareness through publication of prevention guidelines recommending screening alone do not speed translation to practice 13. Components of implementation, for example within health systems 14, show how changes can be made to speed implementation of new guidelines such as screening for colorectal cancer. But much of the colorectal prevention and screening effort promoted over the past 15 years extends beyond individual provider systems and insurance providers.

To be effective public health programs must engage providers but also build community support for the preventive efforts. This requires education and awareness beyond the clinical care setting. Massachusetts led many education and outreach efforts that spread across New England from a partnership of academics, the ACS, and the Massachusetts Medical Society. Alas, to this day CDC still only funds about half of all states to promote colorectal cancer screening 15.

One might contrast the substantial decline in mortality across New England, New York, New Jersey, and Maryland (all greater than 30% decline in mortality) with states such as Mississippi, Wyoming and Alabama where in the same time period mortality has declined by less than 10% 12

Why do we have such variation in the implementation of a program that can almost halve mortality from colorectal cancer? The Richmond model of health policy and prevention offers a unifying approach to this and many cancer prevention issues 16,17. In the model, Richmond sets forth the interplay of three interrelated forces: the scientific knowledge base; political will to allocate resources towards a prevention program; and a social strategy to implement the prevention activity and reduce the burden of illness. This model developed in part through the design of Healthy People, 1979 18, offers a structure to evaluate the strategies that have been employed to promote screening over more than 15 years. A social strategy includes a multilevel approach promoting health through healthcare providers, through regulatory changes, and through individual and community changes. A multilevel set of issues must be addressed to implement a comprehensive social strategy.  Particularly in Massachusetts where a broad coalition came together to promote awareness and work to implement screening such an approach appears to have paid off. 

Our priority going forward is to understand how other states can emulate the success in prevention achieved in New England. Where do you think our priorities for prevention should be now?


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Web resources


Literature cited

  
2.      Hardcastle JD, Chamberlain JO, Robinson MH, et al. Randomised controlled trial of faecal-occult-blood screening for colorectal cancer. Lancet. Nov 30 1996;348(9040):1472-1477.
3.      Kronborg O, Fenger C, Olsen J, Jorgensen OD, Sondergaard O. Randomised study of screening for colorectal cancer with faecal-occult-blood test. Lancet. Nov 30 1996;348(9040):1467-1471.
4.      Selby JV, Friedman GD, Quesenberry CP, Jr., Weiss NS. A case-control study of screening sigmoidoscopy and mortality from colorectal cancer. N Engl J Med. Mar 5 1992;326(10):653-657.
5.      Selby JV, Friedman GD, Quesenberry CP, Jr., Weiss NS. Effect of fecal occult blood testing on mortality from colorectal cancer. A case-control study. Annals of Internal Medicine. Jan 1 1993;118(1):1-6.
6.      Winawer SJ, Fletcher RH, Miller L, et al. Colorectal cancer screening: clinical guidelines and rationale. Gastroenterology. Feb 1997;112(2):594-642.
7.      Byers T, Levin B, Rothenberger D, Dodd GD, Smith RA. American Cancer Society guidelines for screening and surveillance for early detection of colorectal polyps and cancer: update 1997. American Cancer Society Detection and Treatment Advisory Group on Colorectal Cancer. CA Cancer J Clin. May-Jun 1997;47(3):154-160.
8.      Byers T, Mouchawar J, Marks J, et al. The American Cancer Society challenge goals. How far can cancer rates decline in the U.S. by the year 2015? Cancer. 1999;86:715-727.
9.      Joseph DA, King JB, Miller JW, Richardson LC. Prevalence of colorectal cancer screening among adults - behavioral risk factor surveillance system, United States, 2010. Morbidity and mortality weekly report. Surveillance summaries. Jun 15 2012;61(2):51-56.
10.    Atkin WS, Edwards R, Kralj-Hans I, et al. Once-only flexible sigmoidoscopy screening in prevention of colorectal cancer: a multicentre randomised controlled trial. Lancet. May 8 2010;375(9726):1624-1633.
11.    Schoen RE, Pinsky PF, Weissfeld JL, et al. Colorectal-cancer incidence and mortality with screening flexible sigmoidoscopy. N Engl J Med. Jun 21 2012;366(25):2345-2357.
12.    Naishadham D, Lansdorp-Vogelaar I, Siegel R, Cokkinides V, Jemal A. State disparities in colorectal cancer mortality patterns in the United States. Cancer epidemiology, biomarkers & prevention : a publication of the American Association for Cancer Research, cosponsored by the American Society of Preventive Oncology. Jul 2011;20(7):1296-1302.
13.    Bero L, Grillr R, Grimshaw J, Harvey E, Oxman AD, Thompson M. Closing the gap between research and practice: an overview of systematic reviews of interventions to promote the implementation of research findings. BMJ. 1998;317:465-468.
14.    Yano EM, Green LW, Glanz K, et al. Implementation and spread of interventions into the multilevel context of routine practice and policy: implications for the cancer care continuum. Journal of the National Cancer Institute. Monographs. May 2012;2012(44):86-99.
15.    Joseph DA, DeGroff AS, Hayes NS, Wong FL, Plescia M. The Colorectal Cancer Control Program: partnering to increase population level screening. Gastrointest Endosc. Mar 2011;73(3):429-434.
16.    Richmond J, Kotelchuck M. Coordination and development of strategies and policy for public health promotion in the United States. In: Holland W, Detel R, Know G, eds. Oxford Textbook of Public Health. Vol 1. Oxford: Oxford University Press; 1991.
17.    Atwood K, Colditz GA, Kawachi I. From public health science to prevention policy: placing science in its social and political contexts. Am J Public Health. Oct 1997;87(10):1603-1606.
18.    U. S. Department of Health E, and Welfare,. Healhty People. The Suregeon General's report on health promotion and disease prevention, 1979. Washington, DC: Office of the Assistant Secretary for Health and Surgeon General;1979.


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