P-226 - The influence of change in methodology on the responding rate in the colorectal cancer screening program

Date 04 July 2015
Event WorldGI 2015
Session Posters
Topics Aetiology, Epidemiology, Screening and Prevention
Colon and Rectal Cancer
Basic Scientific Principles
Presenter R. Gmajnic
Citation Annals of Oncology (2015) 26 (suppl_4): 1-100. 10.1093/annonc/mdv233
Authors R. Gmajnic1, S. Samardzic2, S. Pribic1, D. Samardzic1
  • 1Faculty of Medicine Osijek, Osijek/HR
  • 2Institute of Public Health for the Osijek-Baranja County, Osijek/HR



Colorectal cancer (CRC) is the third most prevalent human cancer worldwide. In Croatia there has been an increase in CRC incidence from 34.5/100,000 (1990) to 64/100,000 (2005), as well as an increase in mortality from 21.9/100,000 (1990) to 40.6/100,000 (2006). In Osijek-Baranja County, The National Program of Prevention and Early Detection of Colorectal Cancer started in November 2007.


The screening method for early detection of colorectal cancer was the guaiac Faecal Occult Blood Test (gFOBT). The target population was the asymptomatic population at average risk, aged 50–74. The target population numbered 105,075 people, comprising 31.2% of the county's population. Although the Programme stated an invitation cycle of two years, we concluded the first screening cycle in February 2013 – 6 years after starting the invitation process. The reasons for this prolongation were problems in implementation, as well as an inadequate estimation of health sector funds; for instance, an inadequate number of colonoscopies and personnel in colonoscopy units.

In the first cycle invitation letters have been sent by mail. In an envelope, there are three gFOBT with instructions for their use, a questionnaire about risk factors and an educational brochure. The respondents were given detailed instructions on how to diet before sampling. The tests were processed without rehydration. People testing positive are invited for colonoscopy in the Clinical Hospital Centre Osijek by mail. In the second cycle there was a change in methodology which now includes sending a written informed consent form and, after receiving a signed informed consent form, sending gFOBTs.


In the first cycle FOBT was sent to 105,075 individuals. 8,609 (4.635 men and 3.974 women) had an incorrect address, performed a colonoscopy or FOBT in the year before the Program started, died or have declared themselves unwilling to undergo testing. The responding rate (of those who received the invitation) was 20.3% (14.9% of men and 19.3% of women). The goal of the Program was to achieve a responding rate higher than 60%.

The second invitation cycle started in fall of 2013. By the end of 2014 67.4% (65751 of 97487) of the target population was invited. We received 21.5% of signed informed consent forms (21.0% male and 22.0% female). 72.3% of people who signed the informed consent form (68.4% male and 75.4% female) sent a collected gFOBT, accounting for15.6% of all people invited for testing (14.3% male and 16.6% female).


In the second cycle of screening implementation in the Osijek-Baranja County there has been a significant reduction in the responding rate due to the introduction of a written informed consent form in the procedure. Compared to the first cycle, the responding rate has dropped by 4.7%. Although the expected goal for the responding rate has been lowered from 60% to 45%, we are still far from what is expected. The question that should be asked is whether the change in methodology is more important than the responding rate?