FOLFOX or CAPOX in Stage II to III Colon Cancer: Efficacy Results of the Italian Three or Six Colon Adjuvant Trial

TOSCA Investigators, Alberto Sobrero, Sara Lonardi, Gerardo Rosati, Maria Di Bartolomeo, Monica Ronzoni, Nicoletta Pella, Mario Scartozzi, Maria Banzi, Maria Giulia Zampino, Felice Pasini, Paolo Marchetti, Maurizio Cantore, Alberto Zaniboni, Lorenza Rimassa, Libero Ciuffreda, Daris Ferrari, Vittorina Zagonel, Evaristo Maiello, Sandro BarniEliana Rulli, Roberto Labianca

Research output: Contribution to journalArticlepeer-review


Purpose Given the cumulative neurotoxicity associated with oxaliplatin, a shorter duration of adjuvant therapy, if equally efficacious, would be advantageous for patients and health-care systems. Methods The Three or Six Colon Adjuvant trial is an open-label, phase III, multicenter, noninferiority trial randomizing patients with high-risk stage II or stage III colon cancer to receive 3 months or 6 months of FOLFOX (fluorouracil, leucovorin, and oxaliplatin) or CAPOX (capecitabine plus oxaliplatin). Primary end-point is relapse-free survival. Results 3,759 patients were accrued from 130 Italian sites, 64% receiving FOLFOX and 36% CAPOX. Two-thirds were stage III. The median time of follow up was 62 months and 772 relapses or deaths have been observed. The hazard ratio (HR) of the 3 months versus 6 months for relapse/death was 1.14 (95% CI, 0.99 to 1.32; P [for noninferiority] = .514) and the CI crossed the noninferiority limit of 1.20. However, the absolute difference in 3-year RFS was 1.9% (95% CI, -0.7% to 4.4%). Counter-intuitively, while the RFS curves were similar for stage III (HR, 1.07; 95% CI, 0.91 to 1.26) and for CAPOX treated patients (HR, 0.98; 95% CI, 0.77 to 1.26), they were not for stage II and for FOLFOX treated patients, with HR of 1.41 (95% CI, 1.05 to 1.89) and 1.23 (95% CI, 1.03 to 1.46), respectively, favoring the 6 months of treatment. Conclusion The Three or Six Colon Adjuvant trial failed to formally show noninferiority of 3 versus 6 months of treatment to the predefined margin of 20% relative increase. The results depended on the adjuvant regimen and risk. For CAPOX, 3 months were as good as 6 months; for FOLFOX, 6 months added extra benefit. Counter-intuitively, the low-risk patients benefitted more than the high-risk population from the 6-month duration. The choice of regimen and duration should depend on patient characteristics and be balanced against the extra toxicity of longer therapy.
Original languageEnglish
Pages (from-to)1478-1485
Number of pages8
JournalJournal of Clinical Oncology
Issue number15
Publication statusPublished - May 20 2018


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