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

Article type
Authors
Zeng L1, Helsingen LM2, Nampo FK3, Wang Y4, Siemieniuk RA5, Yao L4, Bretthauer M4, Guyatt GH4
1West China Second University Hospital, Sichuan University; Department of Health Research Methods, Evidence and Impact, McMaster University
2Clinical Effectiveness Research Group, Institute of Health and Society, University of Oslo and Department of Transplantation Medicine, Oslo University Hospital
3Latin-American Institute of Life and Nature Sciences; Evidence-Based Public Health Research Group, Federal University of Latin-American Integration
4Department of Health Research Methods, Evidence and Impact, McMaster University
5Department of Health Research Methods, Evidence and Impact, McMaster University
Abstract
Background:
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 it’s harms and burdens. Cancer screening guidelines have a potential advantage over guidelines in other areas of medicine because they often have one or two key benefit outcomes: reduction in cancer mortality or cancer incidence. Therefore, the central question guideline panels face may be framed as: Given the harms and burden of screening, what magnitude of its key benefits (effect on cancer incidence and/or mortality) would people require to undergo screening? In other words; what is the threshold above which people would undergo screening and below which they would not? By establishing such a threshold, a panel makes transparent, through a quantitative tradeoff between benefits and harms or burdens, their assessment of the values and preferences of the target population.
Objectives:
We evaluated how current cancer screening guidelines address the relative importance of benefits versus harms and burdens of screening.
Methods:
We searched the Guidelines International Network, International Guideline Library, ECRI Institute, and Medline. Two pairs of reviewers independently performed guideline selection and data abstraction. We included all cancer screening guidelines published in English between January 2014 and April 2019. We established specific criteria to evaluate whether and how cancer screening guidelines defined a threshold for a key benefit outcome in the tradeoff between benefits versus harms and burdens, and in cost-effectiveness evaluation. We also evaluated whether the guidelines qualitatively commented on the tradeoff between benefits versus harms and burdens (e.g. a statement of benefits over harms and burdens, or a statement of the magnitude of net effect) or commented on the target population’s values and preferences regarding the tradeoff between benefits versus harms and burdens.
Results:
Of 68 eligible guidelines, 25 included a statement regarding the tradeoff 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.
Patient or healthcare consumer involvement: Not involved