001). Results on the knowledge statements about the screening modality are displayed in Table 3. Screenees: Two out of three statements on colonoscopy were answered correctly by a large majority of colonoscopy screenees: “colonoscopy can lead to bleeding and/or perforation” (91%) and “if polyps are detected during colonoscopy, they can be directly removed in most cases” (98%). Two out of six statements on CT colonography were answered correctly

by a large majority of CT colonography screenees: “during CT colonography CO2 will be insufflated in the bowel” (95%) and “if polyps and/or colorectal cancer are detected on CT colonography, a follow-up examination (colonoscopy) is needed” (97%). Non-screenees: The percentage of correct responses of colonoscopy non-screenees on three statements on colonoscopy, ranged from 73% IWR-1 molecular weight DAPT chemical structure to 80%. The following statement was answered most often correctly: “if polyps are detected during colonoscopy, they can be directly removed in most cases”. The percentage of correct responses for the statements

on CT colonography and follow-up colonoscopy among CT colonography non-screenees ranged between 51% and 90%. Low scores were observed for the following statements: “during CT colonography the large bowel is visualized using an endoscope” (51%) and “in 100 participants, CT colonography will detect polyps or colorectal cancer in approximately 14 subjects” (58%). Screenees versus non-screenees: The largest difference in correct answers between colonoscopy screenees and non-screenees was found for the following statement: “if polyps are detected learn more during colonoscopy, they can be directly removed in most cases” (98% versus 80%; p < 0.001). All statements presented to CT colonography invitees were more often answered correctly by screenees. The largest differences in correct responses were observed for the following statements: “during CT colonography the large bowel is visualized using an endoscope” (84%

of screenees versus 51% of non-screenees; p < 0.001), “if polyps are detected on CT colonography, they can be removed directly” (89% versus 62%; p < 0.001) and “during CT colonography CO2 will be insufflated in the bowel” (95% versus 73%; p < 0.001). The results on the attitude of screenees and non-screenees are shown in Fig. 2. Cronbach’s alphas of the attitude scales of colonoscopy and CT colonography were 0.83 and 0.82, respectively, indicating high internal consistency. Overall, 89% of colonoscopy and 91% of CT colonography screenees had an attitude score of 17 or more and were classified as having a positive attitude toward screening. In contrast, 48% of responding colonoscopy and CT colonography non-screenees had a positive attitude toward screening.