healthy debate: excluding experts doesn't make sense
6 minute read
shushiela appavoo: there always have been disparate opinions on breast-cancer screening, but does the current controversy stem from the scientific evidence around screening or is it about the methods employed by the task force itself?
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this story was originally published on healthy debate.
ontario is lowering the age for regular, publicly funded breast-cancer screenings to 40 from 50, mirroring a similar recommendation from the u.s. preventive services task force last may.
now, the attention turns toward the canadian task force on preventive health care. will it follow the u.s. recommendations, as it has in the past?
the ongoing discourse surrounding mammographic screening has stirred speculation about the upcoming revision of canadian guidelines that were last updated in 2018. the process has been expedited with substantial funding of $500,000, with the revision expected this fall.
there always have been disparate opinions on breast-cancer screening, but does the current controversy stem from the scientific evidence around screening or is it about the methods employed by the task force itself?
the task force operates as an independent arm’s length body under public health agency of canada (phac) and deliberately excludes content experts from voting on evidence review and guideline panels. it is comprised of 15 members who predominantly have been family physicians along with some specialists and other health-care professionals, including nurses, a dietician, an occupational therapist and a chiropractor.
when i have asked patients and primary care physicians, most assume that the canadian task force guidelines are led by content expert specialist clinicians, scientists and patients. however, this is not its methodology. experts are not involved, save for minimal written input without dialogue for most of the existing guidelines. as the task force itself states, “clinical and content experts do not provide input into or vote on task force recommendations.”
the sole reason the task force provides to exclude content experts from genuine involvement in guideline development is to avoid conflicts of interest. however, this assumes that content experts are seeking personal gain from the guideline outcomes. in the canadian health-care context, this is not a valid argument. screening activities are usually very poorly reimbursed, if at all. blood tests, such as psa and hcv screening, do not directly benefit specialists. some expert recommendations, such a self-administered hpv screening rather than pap tests, actually would decrease specialist involvement and income from screening. it is important to recognize that biases can be mitigated through well-established methods; more significantly, the nuanced understanding and expertise of content specialists cannot be disregarded or outweighed by concerns about bias.
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task force members themselves are not exempt from bias and predetermined conclusions. for example, a few days following the publication of the draft u.s. task force revision of its guideline, guylène thériault, the co-chair of the canadian task force and chair of the current breast screening guideline panel, said “she does not see any reason to change [canada’s] guidelines” and that “looking at the [u.s.] guidelines, we don’t see that there was anything new.”
while the longstanding contention about screening mammography may overshadow discussions about the task force, it prompts questions about development processes behind other guidelines. the fact that content experts are not pleased to be excluded is clear from excerpts from response letters and position statements from leading specialists and specialty societies, excerpted below. all refer to existing guidelines that have yet to be updated and thus currently influence canadian health-care policy.
- wei-yi song (past-president, canadian psychiatric association), issued 2019: “guidelines developed by non-specialists and that are based solely on clinical trial data may oversimplify treatment and ignore clinical scenarios that require comprehensive judgment in addition to data, and may be harmful to patients.”
- obgyn k. joan murphy (clinical lead of ontario cervical screening program) on task force recommendation against hpv screening, issued 2013: “we believe that the evidence strongly supports primary hpv screening is a significant step toward both increasing the efficacy of screening and decreasing its harms.”
- iain murray, gastroenterologist, on behalf of the board of directors, ontario association of on colorectal screening issued 2016: “the task force suggests that colonoscopy does harm… as the incidence of colon cancer (1:19) far outweighs risk associated with colonoscopy, we are concerned that there could be more harm done when cancers are missed by inferior tests.”
- pediatrician john c leblanc on developmental delay screening guideline issued 2016: “we believe that grade criteria for a strong recommendation have not been met … these facts, outlined in the statement itself, justify a ‘weak’, not a ‘strong’ recommendation.”
- hepatologist eric yoshida (chair of canadian liver foundation medical advisory committee) on hcv screening issued 2017: “this can only perpetuate canada’s low hcv diagnosis rates leading to the late diagnosis of liver cancer, decompensated cirrhosis and extra-hepatic illnesses.”
- canadian ophthalmological society president yvonne buys on impaired vision screening issued 2018: “given that the authors acknowledged there was no evidence of harm associated with screening adults for impaired vision and the evidence overall for this analysis was ‘low-quality,’ we believe a recommendation of against screening seems to be extreme. denying this opportunity to diagnose a vision related health care issue is misguided.”
- medical oncologist garth nicholas on lung cancer screening issued 2016: “the recommendation that patients should be screened annually for two years only is problematic. such a short interval of screening is practical in the context of a clinical trial with a limited time horizon, but not in routine practice.”
- chris de gara, bariatric surgeon (past president, canadian association of general surgeons, former director of bariatric surgery revision clinic, alberta health services) on adult obesity screening issued 2015 (overturned with new bariatric specialist guidelines published in cmaj in 2020). “to not present a balanced picture of the care available to the obese patient is a disservice and to misrepresent the evidence for bariatric surgery in patients with severe obesity is unfortunate.”
- canadian society of breast imaging position statement on breast screening guidelines issued 2018: “task force guidelines overly utilize data that is more than 30 years old. the guidelines ignore new research that incorporates the use of newer technologies, and which show a 40-60 per cent reduction in breast cancer mortality.”
- canadian association of radiologists position statement on breast screening issued 2018: “task force recommendation against using tomosynthesis on average risk women, cited in the guidelines as a “strong recommendation, no evidence” ignores the very large body of evidence on tomosynthesis which has been summarized in 2015 by the canadian agency for drugs and technologies in health (cadth)”
- canadian urological association position statement on prostate cancer screening issued 2014: “importantly, the members of the task force did not include any clinician or scientist with a background in prostate cancer. “
- b.c. reproductive mental health program and perinatal services bc statement on pregnancy and postpartum depression screening issued 2022: “we disagree with the task force conclusion that the evidence in support of instrument -based screening for perinatal depression is very uncertain. our position aligns with the conclusions of the us preventive services task force and american college of obstetricians and gynecologists (acog) that there is evidence in favour of screening for depression in the perinatal period.”
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within the existing guidelines, there are common themes of exclusion of highly qualified experts who are leaders in their fields. specialists almost universally disagree with the guideline content in their own fields and point to an excessive emphasis on harms, inexpert understanding and handling of evidence.
the canadian task force should be dismantled and rebuilt. the reconstructed version of the task force should fully include content experts as leaders and voting members, working side by side with population health experts and patient partners. it should use updated methodology, such as that proposed by internationally recognized methodologists.
transparency and accountability must be integral to the new structure. mandatory evaluation of population outcomes resulting from guideline recommendations is essential, ensuring a systematic assessment of the guidelines’ impacts. timely rectification of any errors found in the guidelines is imperative to maintain accuracy and effectiveness.
ultimately, the restructured canadian task force on preventive health care should emerge as a progressive expert body that canadians can trust implicitly. its primary goal should be to provide reliable health guidance, promoting high-quality care and responsible allocation of resources.
by addressing the shortcomings of the current system, we can cultivate a task force that serves as a beacon of forward-thinking and reliable information and promotes the well-being of the nation.
shushiela appavoo is a general radiologist in edmonton. she has an interest in breast imaging and chairs the canadian society of breast imaging patient engagement group.
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