Psychological effects of colorectal cancer screening: Participants vs individuals not invited

AIM: To investigate the possible long-term psychological harm of participating in colorectal cancer (CRC) screening in Norway. METHODS: In a prospective, randomized trial, 14294 participants (aged 50-74 years) were invited to either flexible sigmoidoscopy (FS) screening, or a faecal immunochemical test (FIT) (1:1). In total, 4422 screening participants (32%) completed the questionnaire, which consisted of the Hospital Anxiety and Depression Scale and the SF-12, a generic health-related quality of life (HRQOL) measurement, when invited to screening and one year after the invitation. A control group of 7650 individuals was invited to complete the questionnaire only, at baseline and one year after, and 1911 (25%) completed the questionnaires. RESULTS: Receiving a positive or negative screening result and participating in the two different screening modalities did not cause clinically relevant mean changes in anxiety, depression or HRQOL after one year. FS screening, but not FIT, was associated with an increased probability of being an anxiety case (score ≥ 8) at the one-year follow-up (5.6% of FS participants transitioned from being not anxious to anxious, while 3.0% experienced the reverse). This increase was moderately significantly different from the changes in the control group (in which the corresponding numbers were 4.8% and 4.5%, respectively), P = 0.06. CONCLUSION: Most individuals do not experience psychological effects of CRC screening participation after one year, while FS participation is associated with increased anxiety for a smaller group.