Endorectal Brachytherapy Boost After External Beam Radiation Therapy in Elderly or Medically Inoperable Patients With Rectal Cancer: Primary Outcomes of the Phase 1 HERBERT Study

Eva C. Rijkmans*, Annemieke Cats, Remi A. Nout, Desiree H. J. G. van den Bongard, Martijn Ketelaars, Jeroen Buijsen, Tom Rozema, Jan-Huib Franssen, Laura A. Velema, Baukelien van Triest, Corrie A. M. Marijnen

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

Purpose: To evaluate the toxicity and efficacy of the combination of external beam radiation therapy (EBRT) followed by high-dose-rate endorectal brachytherapy (HDREBT) boost in elderly and medically inoperable patients with rectal cancer.

Methods and Materials: A phase 1 dose-escalation study was performed. Treatment consisted of EBRT (13 x 3 Gy) followed by 3 weekly brachytherapy applications 6 weeks later. The HDREBT dose started at 5 Gy per fraction, increasing with 1 Gy per fraction if dose-limiting toxicity (DLT, defined as grade >= 3 proctitis

Results: Thirty-eight patients with a median age of 83 years were included in the study. Thirty-two were evaluable for DLT and late toxicity and 33 for response evaluation. Maximum delivered dose was 8 Gy per fraction, resulting in a recommended dose of 7 Gy per fraction. Response occurred in 29 of 33 patients (87.9%), with 60.6% complete response (CR). The L-PFS and OS rates were 42% and 63%, respectively, at 2 years. Patients with CR showed a significantly improved L-PFS (60% at 2 years, P=.006) and a trend in improved OS (80% at 2 years, P=.11). Severe late toxicity occurred in 10 of 32 patients.

Conclusion: We found that HDREBT after EBRT results in a high overall response rate, with improved L-PFS for patients with a CR. The high observed rate of severe late toxicity requires further evaluation of the risks and benefits of an HDREBT boost. (C) 2017 Elsevier Inc. All rights reserved.

Original languageEnglish
Pages (from-to)908-917
Number of pages10
JournalInternational Journal of Radiation Oncology Biology Physics
Volume98
Issue number4
DOIs
Publication statusPublished - 15 Jul 2017

Keywords

  • COMPLETE CLINICAL-RESPONSE
  • CONTACT RADIOTHERAPY
  • NEOADJUVANT CHEMORADIATION
  • ORGAN PRESERVATION
  • INTEGRATED-BOOST
  • ADENOCARCINOMA
  • EXPERIENCE
  • CHEMORADIOTHERAPY
  • ENDOCAVITARY
  • TOMOTHERAPY

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