A safety study of ultra-high dose rate FLASH radiotherapy in the treatment of superficial skin tumors: study protocol of a phase I trial (ChiCTR2400080935)

Abstract

Objective: Ultra-high dose rate FLASH radiotherapy (FLASH-RT) is emerging as a novel technique to improve the normal tissue tolerance by delivering ultra-high dose rate radiation several orders of magnitude higher than convention radiotherapy. It has been shown in preclinical studies to cause less injury to surrounding normal tissues during radiation treatment, while still maintaining local tumor control. The purpose of this protocol is to evaluate the safety of fractionated FLASH-RT in skin cancer.

Method: Patients with superficial skin tumors will be enrolled. The eligible patients will undergo electron FLASH-RT (24-40 Gy/3-5 fractions) to the tumor volume. The primary outcome is to evaluate the safety of FLASH-RT by collecting the acute (< 90 days) skin toxicity adverse events of radiation according to Common Terminology Criteria for Adverse Events (CTCAE) version 5.0. Secondary objectives include late (> 90 days) skin toxicity after FLASH-RT according to CTCAE version 5.0 and treatment response.

Discussion: If the results show that delivering FLASH-RT is safe and feasible for skin tumors, further investigation will be conduct to evaluate efficacy of FLASH-RT in a phase II trial.

Trial Registration number: ChiCTR2400080935. https://www.chictr.org.cn/showproj.html?proj=220336

Keywords

Radiation-associated adverse events / Safety / Superficial skin cancer / ultra-high dose rate FLASH radiotherapy

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2025 The Author(s). Precision Radiation Oncology published by John Wiley & Sons Australia, Ltd on behalf of Shandong Cancer Hospital & Institute.