Pulsed-Reduced Dose Rate (PRDR) Radiotherapy for Recurrent Primary Central Nervous System Malignancies: Dosimetric and Clinical Results

Tugce Kutuk, Ranjini Tolakanahalli, Nicole C. McAllister, Matthew D. Hall, Martin C. Tom, Muni Rubens, Haley Appel, Alonso N. Gutierrez, Yazmin Odia, Alexander Mohler, Manmeet S. Ahluwalia, Minesh P. Mehta, Rupesh Kotecha

Research output: Contribution to journalArticlepeer-review

Abstract

Purpose: The objective was to describe PRDR outcomes and report EQD2 OAR toxicity thresholds. Methods: Eighteen patients with recurrent primary CNS tumors treated with PRDR at a single institution between April 2017 and September 2021 were evaluated. The radiotherapy details, cumulative OAR doses, progression-free survival (PFS), overall survival (OS), and toxicities were collected. Results: The median PRDR dose was 45 Gy (range: 36–59.4 Gy); the median cumulative EQD2 prescription dose was 102.7 Gy (range: 93.8–120.4 Gy). The median cumulative EQD2 D0.03cc for the brain was 111.4 Gy (range: 82.4–175.2 Gy). Symptomatic radiation necrosis occurred in three patients, for which the median EQD2 brain D0.03cc was 115.9 Gy (110.4–156.7 Gy). The median PFS and OS after PRDR were 6.3 months (95%CI: 0.9–11.6 months) and 8.6 months (95%CI: 4.9–12.3 months), respectively. The systematic review identified five peer-reviewed studies with a median cumulative EQD2 prescription dose of 110.3 Gy. At a median follow-up of 8.7 months, the median PFS and OS were 5.7 months (95%CI: 2.1–15.4 months) and 6.7 months (95%CI: 3.2–14.2 months), respectively. Conclusion: PRDR re-irradiation is a relatively safe and feasible treatment for recurrent primary CNS tumors. Despite high cumulative dose to OARs, the risk of high-grade, treatment-related toxicity within the first year of follow-up remains acceptable.

Original languageEnglish (US)
Article number2946
JournalCancers
Volume14
Issue number12
DOIs
StatePublished - Jun 1 2022
Externally publishedYes

Keywords

  • CNS malignancies
  • glioma
  • PRDR
  • pulsed reduced dose rate radiotherapy
  • re-irradiation
  • recurrence

ASJC Scopus subject areas

  • Oncology
  • Cancer Research

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