High-risk BCa: postmastectomy HF-RT equal to conventional RT

  • Lancet Oncol

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

  • A randomized controlled trial (RCT) shows that hypofractionated radiotherapy (HF-RT) is noninferior to conventional fractionated postmastectomy radiotherapy (RT) for 5-year locoregional recurrence with similar toxicities for high-risk women with breast cancer (BCa).

Why this matters

  • HF-RT is more convenient and less costly for the patient and enables providers to treat more patients.

Study design

  • Phase 3 RCT of Chinese women (n=820), aged 18-75 years, with high-risk BCa (prior mastectomy; ≥4 positive nodes; primary tumor stage T3-T4 disease).
  • Patients were randomly assigned to either conventional chest wall and nodal irradiation (dose: 50 Gy in 25 fractions over 5 weeks; the conventional group) or to 43.5 Gy in 15 fractions over 3 weeks (HF-RT group).
  • Primary outcome was 5-year locoregional recurrence.
  • 5% margin for noninferiority.
  • Funding: Cancer Foundation of China; others.

Key results

  • Median follow-up, 58.5 (interquartile range [IQR], 39.2-81.8) months.
  • Hypofractionated group was noninferior in 5-year cumulative incidence of locoregional recurrence (8.3% [90% CI, 5.8%-10.7%] vs 8.1% [90% CI, 5.4%-10.6%] for the conventional group; absolute difference, 0.2%; HR, 1.10; P<.0001>
  • No difference in toxicities except for fewer cases of grade 3 acute skin toxicity in the hypofractionated group (3% vs 8%; P<.0001>

Limitations

  • Open-label design.
  • Study limited to women who had not undergone reconstruction.