Three Versus 6 Months of Adjuvant Oxaliplatin-Fluoropyrimidine Chemotherapy for Colorectal Cancer: Final Results of SCOT-An International, Randomized, Phase III, Noninferiority Trial.

Adjuvant chemotherapy for colorectal cancer (CRC) with oxaliplatin and fluoropyrimidine was traditionally given for 6 months but is associated with cumulative peripheral neuropathy. The SCOT study (ISRCTN59757862) was an international, randomized, phase III, noninferiority trial investigating treatment reduction from 6 to 3 months. It originally reported noninferior disease-free survival with reduced toxicity and improved quality of life for 3 months of treatment in 6,088 patients. Here, we report overall survival (OS) with 38 months of additional follow-up. Patients with high-risk stage II and stage III CRC were assigned (1:1) to receive 3 or 6 months of either capecitabine and oxaliplatin (CAPOX) or infusional fluorouracil, leucovorin, and oxaliplatin (FOLFOX; bolus and infused fluorouracil with oxaliplatin) that were selected before random assignment. With a median of 113 months follow-up and 1,255 OS events, 5-year OS for 3 versus 6 months of treatment was 82.4% in both groups (hazard ratio, 0.96; 95% CI, 0.8 to 1.07), proving noninferiority of 3 months of treatment. Noninferiority of 3 months of treatment for OS was also shown in 1,087 patients with rectal cancer. The duration effect is regimen-dependent with noninferiority shown for CAPOX but not for FOLFOX. In summary, SCOT has shown noninferiority for OS with 3 months of adjuvant chemotherapy treatment, which should be recommended for most patients.