Look to Poland! Conversion from opportunistic screening to a randomized, national screening program for colorectal cancer

Any new treatment modality or healthcare provision should pass through a stage of high quality randomized trials before being implemented, and colorectal cancer (CRC) screening is no exception [1]. However, this basic rule has not always been followed. Historically, several countries implemented fecal occult blood testing (FOBT), flexible sigmoidoscopy, and colonoscopy screening before the results from randomized trials were available [2]. The scientific community must take some responsibility for this situation, but the mere thought of randomizing health services (leaving one group behind as controls) has not been well accepted by politicians who basically want to provide what they believe to be good health services to the whole population. Beliefs have overruled proof. Comparative effectiveness research (CER) within the framework of screening programs has been suggested as a method to compensate for always lagging behind the demand for results from randomized trials [3]. CER implies comparing one treatment, one strategy, or one intervention against another, for example, comparing different screening modalities against each other or against a standard. This standard may be “care as usual,” which in terms of CRC screening services still means “no screening” for many. Thus, CER may include traditional randomized trial design.

There are many unanswered questions in screening, including those relating to screening utility, screening strategies, screening methods, and surveillance. The effects of screening as we see it today may have been overrated, and overdiagnosis and overtreatment have been shown to be issues for both mammography and CRC screening [4]. In addition, studies investigating the possible role of easily overlooked proximal serrated polyps in CRC incidence [5] [6] have shown that results from flexible sigmoidoscopy screening (considered a “half-way colonoscopy”) should not be used to assume that total colonoscopy will show an effect that is “twice as good.” In addition, time trends in CRC epidemiology and improved treatment of symptomatic CRC may reduce the validity of randomized screening trials that were initiated 15 or more years ago. Acceptance of the need for more and better research on screening has led to a shift in attitude so that randomization within screening programs is now an acceptable method of investigation.

The randomized implementation of screening was first demonstrated in the Finnish FOBT program initiated in 2004 [7], and CER within the framework of pilot screening programs has also been adopted in other countries [2]. Randomized implementation according to the Finnish model implies randomization to immediate or delayed screening after a defined period of time. This delay may be governed by the time and resources required to build up a high quality service (e. g. colonoscopy and histopathology services) with adequate capacity to serve the entire target population. This concept of randomized, delayed intervention has recently also been used in the testing of a novel Ebola virus disease vaccine [8]. This design defines the control group by the delay period before a staggered intervention. In the Ebola study, the delay was 21 days. The Finnish CRC screening program was initially planned for a 6-year invitation delay for the control group, but the delay was later extended to an additional 5 years to adjust power estimates for updates on background CRC incidence and a lower attendance than expected [9].

• References

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• 5 Rex DK, Ahnen DJ, Baron JA et al. Serrated lesions of the colorectum: review and recommendations from an expert panel. Am J Gastroenterol 2012; 107: 1315-1329
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• 10 Kaminski MF, Kraszewska E, Rupinski M et al. Design of the Polish Colonoscopy Screening Program: a randomized health services study. Endoscopy 2015; 47: 1144-1150