BACKGROUND: Unlike reduced mortality rates, improved survival rates and increased early detection do not prove that cancer screening tests save lives. Nevertheless, these 2 statistics are often used to promote screening. OBJECTIVE: To learn whether primary care physicians understand which statistics provide evidence about whether screening saves lives. DESIGN: Parallel-group, randomized trial (randomization controlled for order effect only), conducted by Internet survey. (ClinicalTrials.gov registration number: NCT00981019) SETTING:National sample of U.S. primary care physicians from a research panel maintained by Harris Interactive (79% cooperation rate). PARTICIPANTS: 297 physicians who practiced both inpatient and outpatient medicine were surveyed in 2010, and 115 physicians who practiced exclusively outpatient medicine were surveyed in 2011. INTERVENTION: Physicians received scenarios about the effect of 2 hypothetical screening tests: The effect was described as improved 5-year survival and increased early detection in one scenario and as decreased cancer mortality and increased incidence in the other. MEASUREMENTS: Physicians' recommendation of screening and perception of its benefit in the scenarios and general knowledge of screening statistics. RESULTS: Primary care physicians were more enthusiastic about the screening test supported by irrelevant evidence (5-year survival increased from 68% to 99%) than about the test supported by relevant evidence (cancer mortality reduced from 2 to 1.6 in 1000 persons). When presented with irrelevant evidence, 69% of physicians recommended the test, compared with 23% when presented with relevant evidence (P < 0.001). When asked general knowledge questions about screening statistics, many physicians did not distinguish between irrelevant and relevant screening evidence; 76% versus 81%, respectively, stated that each of these statistics proves that screening saves lives (P = 0.39). About one half (47%) of the physicians incorrectly said that finding more cases of cancer in screened as opposed to unscreened populations "proves that screening saves lives." LIMITATION: Physicians' recommendations for screening were based on hypothetical scenarios, not actual practice. CONCLUSION: Most primary care physicians mistakenly interpreted improved survival and increased detection with screening as evidence that screening saves lives. Few correctly recognized that only reduced mortality in a randomized trial constitutes evidence of the benefit of screening. PRIMARY FUNDING SOURCE: Harding Center for Risk Literacy, Max Planck Institute for Human Development.
RCT Entities:
BACKGROUND: Unlike reduced mortality rates, improved survival rates and increased early detection do not prove that cancer screening tests save lives. Nevertheless, these 2 statistics are often used to promote screening. OBJECTIVE: To learn whether primary care physicians understand which statistics provide evidence about whether screening saves lives. DESIGN: Parallel-group, randomized trial (randomization controlled for order effect only), conducted by Internet survey. (ClinicalTrials.gov registration number: NCT00981019) SETTING: National sample of U.S. primary care physicians from a research panel maintained by Harris Interactive (79% cooperation rate). PARTICIPANTS: 297 physicians who practiced both inpatient and outpatient medicine were surveyed in 2010, and 115 physicians who practiced exclusively outpatient medicine were surveyed in 2011. INTERVENTION: Physicians received scenarios about the effect of 2 hypothetical screening tests: The effect was described as improved 5-year survival and increased early detection in one scenario and as decreased cancer mortality and increased incidence in the other. MEASUREMENTS: Physicians' recommendation of screening and perception of its benefit in the scenarios and general knowledge of screening statistics. RESULTS: Primary care physicians were more enthusiastic about the screening test supported by irrelevant evidence (5-year survival increased from 68% to 99%) than about the test supported by relevant evidence (cancer mortality reduced from 2 to 1.6 in 1000 persons). When presented with irrelevant evidence, 69% of physicians recommended the test, compared with 23% when presented with relevant evidence (P < 0.001). When asked general knowledge questions about screening statistics, many physicians did not distinguish between irrelevant and relevant screening evidence; 76% versus 81%, respectively, stated that each of these statistics proves that screening saves lives (P = 0.39). About one half (47%) of the physicians incorrectly said that finding more cases of cancer in screened as opposed to unscreened populations "proves that screening saves lives." LIMITATION: Physicians' recommendations for screening were based on hypothetical scenarios, not actual practice. CONCLUSION: Most primary care physicians mistakenly interpreted improved survival and increased detection with screening as evidence that screening saves lives. Few correctly recognized that only reduced mortality in a randomized trial constitutes evidence of the benefit of screening. PRIMARY FUNDING SOURCE: Harding Center for Risk Literacy, Max Planck Institute for Human Development.
Authors: Christine M Gunn; Barbara G Bokhour; Victoria A Parker; Tracy A Battaglia; Patricia A Parker; Angela Fagerlin; Worta McCaskill-Stevens; Hanna Bandos; Sarah B Blakeslee; Christine Holmberg Journal: Med Decis Making Date: 2019-02-25 Impact factor: 2.583
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