Cancer trial impact: understanding implementation of the Short Course Oncology Treatment (SCOT) trial findings in colorectal cancer at a national level

Aims: The Short Course Oncology Treatment (SCOT) trial indicated that 3 months of adjuvant doublet chemotherapy was non-inferior to 6 months of treatment for patients with colorectal cancer, with considerably less toxicity. The SCOT trial results were disseminated in June 2017. The aim of this study was to understand if SCOT trial findings were implemented in Scotland. 

Materials and methods: A retrospective analysis was carried out on a dataset derived from a source population of 5.4 million people. Eligible patients were those with stage II or III colorectal cancer who received adjuvant chemotherapy. Logistic regression was applied to understand the extent of practice change to a 3-month adjuvant chemotherapy duration after the SCOT trial results were disseminated. Interrupted time series analysis was used to visualise differences in prescribing trends before and after June 2017 for the overall cohort, and by SCOT trial eligibility. 

Results: In total, 2310 patients were included in the study; 1957 and 353 treated pre- and post-June 2017, respectively. The median treatment duration decreased from 21 weeks (interquartile range 14–24) prior to June 2017 to 12 weeks (interquartile range 12–21 weeks) after June 2017 (P < 0.001). The proportion of patients receiving over 3 months of adjuvant treatment decreased from 75% to 42% (P < 0.001). This change was most noticeable for patients who met the SCOT trial eligibility criteria, and specifically for those with low-risk stage III disease and those treated with capecitabine and oxaliplatin (CAPOX). Although practice change occurred in all locations, there were differences between regions that could be explained by pre-SCOT trial prescribing trends. 

Discussion: A significant change in chemotherapy prescribing occurred after dissemination of the SCOT trial results. National, real-world data can be used to capture the extent of implementation of clinical trial results. In this case, implementation was aligned with clinical trial subgroup findings. This type of analysis could be conducted to evaluate the impact of other clinical trials.