High-risk early breast cancer: 15-year results show dose-dense chemo beneficial in MIG-1 trial

  • Br J Cancer

  • curated by Miriam Davis, PhD
  • Univadis Clinical Summaries
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Takeaway

  • The 15-year results of the phase 3 Italian Mammella InterGruppo (MIG)-1 trial show that most survival outcomes remained numerically but not statistically superior with dose-dense (DD) adjuvant chemotherapy (every-2-week cycles) vs every-3-week cycles for high-risk early breast cancer.

Why this matters

  • Findings reveal long-term benefit of DD chemotherapy, primarily based on numerical superiority.

Study design

  • Italian phase 3 randomized controlled trial (RCT), 1214 patients with high-risk early breast cancer.
  • High risk was defined by lymph node-positive or lymph node-negative disease with ≥1 of 5 other factors, including tumor size >2 cm.
  • Patients given 5-fluoruracil, epirubicin, and cyclophosphamide (FEC) every 2 weeks (FEC14, the DD group) or FEC every 3 weeks (FEC21, the regular frequency group) for 6 total cycles.
  • Funding: Italian Ministry of Health; other.

Key results

  • Median follow-up, 15.8 years.
  • DD vs the regular frequency group had numerically but not statistically superior:
    • OS:
      • 71% vs 68%.
      • HR, 0.89 (P=.25). 
    • Event-free survival:
      • 47% vs 43%.
      • HR, 0.87 (P=.18).
  • DD subgroup with hormone-receptor-negative tumors vs regular-frequency group had: 
    • Numerically superior OS:
      • 70% vs 65%.
      • HR, 0.73 (95% CI, 0.51-1.06).
    • Statistically superior event-free survival:
      • 58% vs 43%.
      • HR, 0.70 (95% CI, 0.51-0.96). 

Limitations

  • Underpowered because planned accrual not reached.