Duration of Adjuvant Chemotherapy in Colon Cancer: Current Standards and New Updates

Abstract

Adjuvant therapy for 6 months is the standard of care for stage III colon cancer. The use of oxaliplatin-based therapy over fluoropyrimidine alone increases toxicity, including dose-dependent peripheral neuropathy. Evaluation of a shorter duration of adjuvant therapy was therefore warranted, aiming to reduce toxicity while maintaining clinical efficacy. The International Duration Evaluation of Adjuvant chemotherapy (IDEA) collaboration was a pivotal prospective pooled analysis of 6 randomized phase III trials across 12 countries. IDEA evaluated the non-inferiority of 3 versus 6 months of adjuvant oxaliplatin-based chemotherapy. The 3-year disease-free survival was very similar between the 3-month and 6-month study arms. Despite this, non-inferiority was not confirmed. However, important differences were observed between FOLFOX and CAPOX regimens, and risk groups within stage III disease, which allow for greater individualization of adjuvant therapy. The IDEA results suggest 3 months of therapy is reasonable in most patients with stage III disease, especially those with low-risk disease. Importantly, 3 months of therapy is associated with a dramatic reduction in peripheral neuropathy. A thorough discussion of the risks and benefits with patients regarding the duration of therapy is required. In this review, we discuss the IDEA findings and the optimal duration of adjuvant chemotherapy in stage III colon cancer.