Early breast cancer: real-world IORT efficacy is lower than in trials

  • Valente SA & al.
  • Ann Surg Oncol
  • 12 Jan 2021

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

  • The 5-year real-world ipsilateral recurrence rate with intraoperative radiation therapy (IORT) was 6.6% in the observational TARGIT-R study of patients with early breast cancer.

Why this matters

  • IORT is an experimental procedure consisting of the delivery of a single dose of radiation in the operating room to the lumpectomy cavity.
  • The real-world findings are worse than the 2.1% reported for the randomized controlled TARGIT-A trial.
  • More research is needed before IORT can be considered a viable treatment option.

Study design

  • TARGIT-R is a retrospective cohort study of 667 patients in North America given IORT.
  • Primary outcome was ipsilateral breast tumor recurrence (IBTR).
  • Funding: None.

Key results

  • Median follow-up was 5.1 years.
  • IBTR rates:
    • All patients: 6.6%.
    • With primary IORT: 8%.
    • With unintended boost cohort: 1.7%.
    • With delayed IORT: 0%.
    • With intended boost IORT: 0%.
    • With primary IORT with adherence to endocrine therapy: 3.9%.
  • Those with nonadherence to endocrine therapy and receiving IORT had a 5-year IBTR risk >3.5 times higher (HR, 3.67; 95% CI, 1.66-8.11) than those with endocrine therapy adherence and IORT.

Limitations

  • Retrospective, observational study.