Test sensitivity and bowel prep tied to patient preferences in colon cancer screening

By Rob Goodier

NEW YORK (Reuters Health) - Less need for bowel preparation is unlikely to boost uptake of screening CT colonography if it means a lower sensitivity, a new online survey from the UK shows.

"Our findings suggest that future screening invitees consider anticipated preparation burden to be about as important as the sensitivity for adenomas which different preparations allow," said lead author Alex Ghanouni, a doctoral student at University College London.

"When physicians are discussing screening test options with their patients, both issues and the possible trade-offs should be discussed so that people's preferences can be taken into account," he told Reuters Health by email.

The researchers, whose findings were published online April 3 in BMJ Open, sent an web-based survey to 607 colorectal screening candidates, asking them to choose between different scenarios.

The options included tradeoffs between degrees of sensitivity and specificity for detecting polyps versus three different amounts of laxatives that they would have to take beforehand to prepare: either full, reduced or none at all.

The sensitivity of each option in the survey was based on realistic estimates; for a non-laxative preparation, for instance, it was set at 86% and for a full-laxative preparation, 92%. But the researchers caution that those figures derive from a limited literature.

The team found that both bowel prep and sensitivity were significantly linked to patients' test preference -- though in opposite directions -- and were similarly predictive.

"It is good to see that patients value sensitivity of the exam heavily in their preferences," said Dr. Tim Byers, the associate director for Cancer Prevention and Control at the University of Colorado Cancer Center in Aurora, who was not involved in the research.

"This is an example of a type of research we need more often -- assessing patient preferences when there are options involving tradeoffs," Dr. Byers says.

Given that patients place importance on both bowel prep and sensitivity, Ghanouni and his colleagues conclude that "a more sensitive form of reduced-laxative or non-laxative preparation might improve uptake substantially."

"The best case scenario for screening invitees, policy makers and physicians would be a preparation that did not involve a tradeoff between accuracy and burden," Ghanouni added. "Future research could clarify whether, A. Such a preparation exists, or B. Whether this tradeoff could be eliminated in (the) future, either through refinements to preparation or CTC technique."

SOURCE: http://bit.ly/1gQmoFi

BMJ Open 2014.

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