HER2+ breast cancer: hypofractionated radiotherapy plus trastuzumab carries no excess cardiotoxicity

  • Sayan M & al.
  • Front Oncol
  • 1 Jan 2019

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

  • Hypofractionated radiotherapy (Hypo-RT) given concurrently with trastuzumab is not associated with excess cardiotoxicity compared with conventionally fractionated radiotherapy (Conv-RT)+trastuzumab in patients with human epidermal growth factor receptor 2 (HER2)-positive breast cancer (BCa).

Why this matters

  • Preclinical data suggest that trastuzumab has a radiosensitizing effect.

Study design

  • Retrospective cohort comparing trastuzumab recipients treated with Hypo-RT (n=41) vs those treated with Conv-RT (n=100).
  • Cardiotoxicity was assessed as a significant decline in left ventricular ejection fraction (LVEF) of ≥10% below lower limit of normal or ≥16% from baseline.
  • Funding: Breast Cancer Research Foundation.

Key results

  • Median follow-up was 32 (range, 13-90) months.
  • Mean heart dose was 101 cGy in the Hypo-RT group and 163 cGy in Conv-RT group (P=.897).
  • Baseline median LVEF: 62% (range, 50%-81%) in Hypo-RT group vs 64% (range, 51%-76%) in the Conv-RT group (P=.893).
  • Final median LVEF: 60% (range, 50%-75%) in each group (P=.998).
  • Significant LVEF decline: 7% in Hypo-RT group vs 5% in Conv-RT group (P=.203).
  • No difference in mean heart dose in patients who developed significant LVEF decline vs patients who did not develop significant LVEF decline in the Hypo-RT (P=.427) and in Conv-RT groups (P=.354).
  • Neither group developed congestive heart failure.

Limitation

  • Retrospective, observational, single-center design.
  • Small number of patients in the Hypo-RT group.