Do clinical trials change practice? A longitudinal, international assessment of colorectal cancer prescribing practices.

Introduction: Over half of the 1.5 million individuals globally who are diagnosed with colorectal cancer (CRC) present with stage II-III disease. Understanding clinician attitudes towards treatment for this group is paramount to contextualise real-world outcomes and plan future trials. The aim of this study was to assess clinician awareness of trials assessing the optimal duration of CRC adjuvant therapy, their attitudes towards shorter treatment and their self-reported practice.

Methods: A survey was developed using OnlineSurveys® and distributed to clinicians in April 2019, with a follow-up survey disseminated to a subset of respondents in August 2020. Microsoft Excel® and Stata® were used for analysis.

Results: 265 clinicians replied to the first survey, with the majority aware of findings from the International Duration Evaluation of Adjuvant Therapy collaboration and contributory trials. Practice change was greatest for patients under 70 with low-risk stage III CRC, with most uncertainty around using 3-months of doublet chemotherapy for high-risk stage II disease. In August 2020, clinicians (n = 106) were more likely to use 3-months of FOLFOX for low-risk stage III disease and 3-months of CAPOX for stage II disease compared to April 2019. There was no indication that the COVID-19 pandemic had enduring changes on treatment decisions beyond those made in response to trial evidence.

Discussion: Clinicians use a risk-stratified approach to treat CRC the adjuvant setting. Lower utilisation of doublet chemotherapy for older and stage II patients has affected the extent of trial implementation. Active dialogue regarding how trial results apply to these groups may improve consensus.