Subjective and objective risk of colorectal cancer (UK)

The aim of this study was to see whether individuals who perceive their risk for developing colorectal cancer (CRC) as lower than average are found to be at lower risk as determined by findings at flexible sigmoidoscopy (FS) screening.

Participants (n = 10,551) were men and women aged 55-64 years from a subset of participants in the UK FS Trial. Self-report questionnaires assessed perceived comparative risk of developing bowel cancer prior to participants being invited to attend FS screening. Objective risk was judged from polyp status during the FS test.

A very modest relationship was found between risk judgments and actual risk with 77% of 'optimists' having negative findings compared to 71% of 'pessimists'. More pessimists (14%) had an adenoma compared to optimists (11%). Compared to pessimists the odds of optimists actually being at lower risk of CRC equaled 0.70 (0.57, 0.86).

The results suggest that people may have a limited ability to assess their risk of developing CRC. Health professionals should not assume that individuals have an accurate perception of their risk for cancer. Increasing people's ability to accurately perceive their risk may encourage more appropriate cancer preventive behavior.