Three Versus Six Months of Adjuvant Oxaliplatin-Containing Chemotherapy for Patients With Stage III Colorectal Cancer: A Contemporary Real-World Analysis.

Purpose: Based on the International Duration Evaluation of Adjuvant Chemotherapy analysis, 3 months of adjuvant chemotherapy with capecitabine and oxaliplatin (CAPOX) is an option for stage III colorectal cancer (colorectal cancer [CRC]), with cost and toxicity benefits. We examined the patterns of uptake of CAPOX versus fluorouracil, leucovorin, and oxaliplatin (FOLFOX) and chemotherapy duration in a contemporary real-world cohort of patients in Canada.

Methods: The provincial pharmacy database was used to identify patients with resected stage III CRC receiving adjuvant chemotherapy between January 2021 and December 2022. Demographic, tumor, and treatment information was collected and compared.

Results: Of 452 patients, 234 (52%) and 218 (48%) were planned to receive 3 and 6 months of chemotherapy, respectively. Within the 3-month group, 226 (97%) received CAPOX. Within the 6-month group, there was a 51%-49% split between CAPOX and FOLFOX. Age >70 years (P = .039), well/moderately differentiated (P = .005), and low-risk disease (P < .0001) were significantly associated with 3 months. Performance status, ileostomy, or preexisting neuropathy did not affect treatment choice. Of patients planned for 6 months, 29% had low-risk disease, with 52% of these receiving CAPOX. Patients receiving 6 months were more likely to report neuropathy (68 v 36%, P < .0001) and to stop oxaliplatin early (54 v 31%, P < .0001). The most likely reason for early adjuvant discontinuation was neuropathy in the 6-month group and gastrointestinal toxicity in the 3-month group (P < .0001). Irrespective of duration, mean time from consult to starting chemotherapy was longer for FOLFOX versus CAPOX (24 v 19 days, P = .007).

Conclusion: In this contemporary cohort, 6 months chemotherapy is still being offered to patients with low-risk disease and is associated with more neuropathy. Exploration of patient preferences and resource costs may improve adoption of reduced duration adjuvant CAPOX in stage III CRC.