AUTHOR=Scharf Tamara , Janggen Marc-Andrea , Martin Yonas , Jakob Julian , Tal Kali , Biller-Andorno Nikola , Bulliard Jean-Luc , Selby Kevin , Auer Reto , Rohrbasser Adrian 
  
TITLE=Optimizing colorectal cancer screening through quality circles of primary care physicians: a cluster randomized controlled trial
  
JOURNAL=International Journal of Public Health
  
VOLUME=Volume 71 - 2026
  
YEAR=2026
  
URL=https://www.ssph-journal.org/journals/international-journal-of-public-health/articles/10.3389/ijph.2026.1608462
  
DOI=10.3389/ijph.2026.1608462
  
ISSN=1661-8564
  
ABSTRACT=ObjectivesColorectal cancer (CRC) screening rates are low in Switzerland. This study tested whether a PCP intervention—training sessions and performance feedback within quality circles (QC) increased CRC screening rates.MethodsA pragmatic randomized controlled trial was conducted in Switzerland (2018–2021) with PCP in QC. The intervention included three training sessions, shared decision-making materials, and performance feedback based on 40 consecutive patients per PCP. The primary outcome was the difference in CRC screening rates between the intervention and control group after 12 months.ResultsOf 120 invited QC, nine participated (5 intervention, 4 control). A total of 63 PCPs (32 intervention, 31 control) collected data on 2,112 patients (1,130 intervention, 982 control; mean age 61.5, 53% women). Analysis clustered by PCP and QC showed screening rate was 58% in the intervention group vs. 42% in controls (OR1.98; 95% CI:1.14–3.42). Screening rates in the intervention group increased from 55% to 57.9% (absolute increase: 2.9%; 95% CI:1.1%–6.9%; OR1.29; 95% CI:1.08–1.55, p < 0.01).ConclusionTraining sessions and performance feedback in QC increased screening rates, but few QCs chose to participate.Clinical Trial RegistrationClinicalTrials.gov, identifier NCT03510858.