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Published: 08 February 2023

Study finds misconceptions and avoidance are factors in decisions not to take part in bowel screening

By Dr Nick Clarke, Dublin City University School of Psychology

Bowel cancer is one of the most treatable cancers, especially if detected early. However, only around 4 in 10 people who are eligible for bowel screening take up the offer from the National Bowel Screening Programme. Why?

In 2015 I partnered with the Tallaght bowel screening programme (a population-based screening programme which ran prior to the introduction of the National BowelScreen programme) to survey people in Dublin who had been invited to take part in bowel screening over 2 screening rounds (2-yearly periods). We surveyed people who had decided not to take the home test kit, along with a sample of people who had taken the home test.

Following two reminders, our questionnaires were completed by 1,988 people who took part in screening and 311 people who did not.

Our research found that people who did not take the home test kit were more likely to react defensively to their bowel screening invitation. We found that this defensiveness was a factor in their decision not to take part.

We measured defensive reactions using a scale called the ‘defensive information processing scale’. It included reactions that are called ‘avoidance’, ‘blunting’, ‘suppression’ and ‘counter-arguing’, as follows:

  • avoidance = reducing their awareness of risk through avoiding the issue
  • blunting = actively disengaging from the information by avoidance and denial
  • suppression = acknowledging other peoples’ risk but avoiding their own risk because they believe that something about them makes them different from the majority
  • counter-argumentation = arguing against the evidence 

What makes people defensive when considering screening?

  • Misconceptions: Peoples’ defensiveness was in some instances driven by misconceptions they held, such as having a healthy lifestyle or having regular bowel movements. Because of these factors they said they believed they did not need to be screened. 
  • Waiting for a better test: Some people believed they could put off doing the screening test until there was a ‘better’ test - even though the current BowelScreen test works well and is the best home bowel screening kit available. 
  • Prioritising other health concerns: Others said that it was best to delay screening while they sorted out their other health concerns.
  • Cancer is fatal: Another common reason for a defensive reaction to an offer of bowel screening was the belief that cancer is always fatal.  

Our study found that all of these factors can result in people making a decision not to take the home-based screening test used by BowelScreen.

Bowel cancer screening should be something that everyone routinely does when they reach middle age. The measures used in this study could be used to help identify people who may need extra support to take part in colorectal cancer screening programmes worldwide, and so increase uptake of this potentially life-saving test.

Even well-designed health communication campaigns and proactive screening programmes may be hindered by peoples’ defensive beliefs.

Our results suggest that screening programmes need strategies to decrease procrastination and address misconceptions about bowel cancer and screening.

The study, ‘The role of Defensive Information Processing in population-based colorectal cancer screening uptake’ by Nicholas Clarke, Louise Hayes, Amy McQueen, Pamela Gallagher, Patricia M. Kearney, Deirdre McNamara, Colm A. O’Morain, Christian von Wagner, Therese Mooney, and Linda Sharp is published in CANCER; the American Cancer Society Journal: February 6, 2023 (DOI: 10.1002/cncr.34603).