How do cancer screening guidelines trade off benefits versus harms and burdens of screening? A systematic survey

OBJECTIVES: Cancer screening guidelines differ in their recommendations for or against screening. To be able to provide explicit recommendations, guidelines need to specify thresholds for the magnitude of benefits of screening, given its harms and burdens. We evaluated how current cancer screening guidelines address the relative importance of benefits versus harms and burdens of screening. DATA SOURCE: We searched the Guidelines International Network, International Guideline Library, ECRI Institute and Medline. Two pairs of reviewers independently performed guideline selection and data abstraction. ELIGIBILITY CRITERIA: We included all cancer screening guidelines published in English between January 2014 and April 2019. RESULTS: Of 68 eligible guidelines, 25 included a statement regarding the trade-off between screening benefits versus harms and burdens (14 guidelines), or a statement of direction of the net effect (defined as benefits minus harms or burdens) (13 guidelines). None of these 25 guidelines defined how large a screening benefit should be to recommend screening, given its harms and burdens. 11 guidelines performed an economic evaluation of screening. Of these, six identified a key benefit outcome; two specified a cost-effectiveness threshold for recommending a screening option. Eight guidelines commented on people's values and preferences regarding the trade-off between benefits versus harms and burdens. CONCLUSIONS: Current cancer screening guidelines fail to specify the values and preferences underlying their recommendations. No guidelines provide a threshold at which they believe the benefits of screening outweigh its harms and burdens. PROSPERO REGISTRATION NUMBER: CRD42019138590.