The Early Impact of the IDEA Collaboration Results: How the Results Changed Prescribing Practice

Traditionally, adjuvant treatment for colon cancer has been 6 months of combination chemotherapy. Six phase III trials tested the hypothesis that 3 months is noninferior in efficacy to 6 months and reduces long-term side effects for patients. The results were pooled in the International Duration Evaluation of Adjuvant therapy (IDEA) collaboration. Although this did not meet the noninferiority endpoint, a preplanned subgroup analysis by chemotherapy regimen did demonstrate noninferiority for capecitabine and oxaliplatin. Additionally, risk stratification by T and N stage was defined.

In an effort to understand the real-life impact of these results, 4 months after the IDEA results, an online survey was distributed to clinicians to ask their approach to the adjuvant treatment of patients with stage III colon cancer.

The survey was completed by 458 clinicians from 12 countries. Assuming that 6 months of treatment was the pretrial standard of care, 89.5% of clinicians reported they had changed practice to prescribe 3 months of treatment for some patients. For patients with low-risk stage III disease, there was a preference for 3 months, and for patients with high-risk stage III disease, most clinicians still prescribed 6 months at that time. Overall, capecitabine and oxaliplatin regimen was the most popular. There were important differences in responses depending on the location of respondent and T and N stage of disease.

This survey shows that the IDEA collaboration has been practice changing but reveals important differences in the way results are interpreted by individual clinicians.