Phase III trial comparing 3-6months of adjuvant FOLFOX4/XELOX in stage II-III colon cancer: Safety and compliance in the TOSCA trial

S. Lonardi, A. Sobrero, G. Rosati, M. Di Bartolomeo, M. Ronzoni, G. Aprile, M. Scartozzi, M. Banzi, M. G. Zampino, F. Pasini, P. Marchetti, M. Cantore, A. Zaniboni, L. Rimassa, L. Ciuffreda, D. Ferrari, S. Barni, V. Zagonel, E. Maiello, E. RulliRoberto Labianca, TOSCA (Three or Six Colon Adjuvant) Investigators

Research output: Contribution to journalArticlepeer-review


Background: Six months of oxaliplatin-based adjuvant chemotherapy is standard of care for radically resected stage III colon cancer and an accepted option for high-risk stage II. A shorter duration of therapy, if equally efficacious, would be advantageous for patients and Health-Care Systems. Patients and methods: TOSCA ['Randomized trial investigating the role of FOLFOX-4 or XELOX (3 versus 6 months) regimen duration and bevacizumab as adjuvant therapy for patients with stage II/III colon cancer] is an open-label, phase III, multicenter, noninferiority trial randomizing patients with high-risk stage II or stage III radically resected colon cancer to receive 3 months (arm 3 m) versus 6 months (arm 6 m) of FOLFOX4/XELOX. Primary end-point was relapse-free survival. We present here safety and compliance data. Results: From June 2007 to March 2013, 3759 patients were accrued from 130 Italian sites, 64% receiving FOLFOX4 and 36% XELOX in either arm. Treatment completion rate without any modification was 35% versus 12% and with delays or dose reduction 52% versus 44% in arm 3 and 6 m. Treatment was permanently discontinued in 8% (arm 3 m) and 33% (arm 6 m). In arm 6 m, 50% of patients discontinuing treatment did so after completing 80% of planned program. Grade 3+ toxicities were higher in arm 6 m than that in 3 m. Grade 2+ neuropathy was 31.2% versus 8.8% (P < 0.0001) while grade 3+ was 8.4 versus 1.3 (P < 0.0001), in arm 3 and 6 m. Seven deaths within 30 days from last treatment administration in arm 6 m and three deaths in arm 3 m were observed (0.3% versus 0.1%, P = 0.34). Conclusions: TOSCA is the first trial comparing 3 versus 6 months of adjuvant chemotherapy completing accrual within the international initiative of treatment duration evaluation (International Duration Evaluation of Adjuvant, IDEA). High compliance to treatment in control arm will allow a correct assessment of potential differences between the two treatment durations.

Original languageEnglish
Pages (from-to)2074-2081
Number of pages8
JournalAnnals of Oncology
Issue number11
Publication statusPublished - Nov 1 2016


  • Adjuvant chemotherapy
  • Colon cancer
  • Duration

ASJC Scopus subject areas

  • Hematology
  • Oncology

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