Changes in Prescribing Patterns in Stage III Colon Cancer

For patients with resected stage III colon cancer, 6 months of adjuvant fluoropyrimidine-based chemotherapy has been the standard of care. The IDEA collaboration aimed to evaluate whether 3 months of adjuvant chemotherapy was noninferior to 6 months. Despite failing to meet its primary endpoint, the subgroup analyses demonstrated noninferiority based on regimen and treatment duration when a risk-stratified approach was used.

To evaluate the impact of the results of the IDEA collaboration, we evaluated adjuvant chemotherapy prescribing practice patterns, including planned adjuvant treatment regimen and duration from January 1, 2016, to January 31, 2021. The time period was selected to evaluate chemotherapy prescribing patterns prior to the abstract presentation of the IDEA collaboration in June 2017 and after full manuscript publication in March 2018.

A total of 399 patients with stage III colon cancer who received adjuvant chemotherapy were included in the analysis. A significant increasing trend for use of 3 months of adjuvant chemotherapy was observed after presentation of the IDEA abstract (P<.001). A significant change in CAPOX (capecitabine/oxaliplatin) prescribing was also observed, increasing from 14% of patients prior to presentation of the IDEA abstract to 48% after presentation (P<.001). Comparing 3 months of CAPOX with 6 months of FOLFOX (fluorouracil/leucovorin/oxaliplatin), 3 months of CAPOX use also steadily increased over time (adjusted odds ratio [aOR], 1.28; 95% CI, 1.20-1.37; P<.001). Among subgroups of interest, no differences in adoption of CAPOX were observed. The adoption of 3 months of CAPOX was similar in patients with low-risk cancer (aOR, 1.27; 95% CI, 1.17-1.37) and those with high-risk cancer (aOR, 1.31; 95% CI, 1.16-1.47).

Despite the IDEA collaboration failing to demonstrate noninferiority of 3 months' duration of adjuvant therapy compared with 6 months, the findings have influenced practice prescribing patterns, favoring CAPOX and a shorter duration of planned adjuvant treatment.