An ultra-fast proton therapy treatment could offer pain-relieving benefits to patients with bone metastases without increasing their risks of adverse events associated with conventional radiation therapy.
The ultra-high dose rate (UHDR) radiotherapy, or FLASH therapy, was tested in humans for the first time recently, and although the sample size was small—comprised of just 10 patients with bone metastases in the extremities—experts involved in the clinical research suggested that their findings are in line with that of conventional palliative radiotherapy [1].
“The unique biologic effects of ultra-high-dose-rate radiotherapy delivered at more than 40 Gy/sec, now known as FLASH therapy, were first reported more than 50 years ago,” corresponding author John Breneman, MD, of the University of Cincinnati College of Medicine and co-authors explained. “Interest in this modality began re-emerging recently, concurrent with the advent of commercial radiotherapy equipment capable of delivering these ultra-high dose rates in a clinical setting.”
At the 2022 American Society for Radiation Oncology annual meeting, Emily Daugherty, MD, of the University of Cincinnati Cancer Center, presented the findings. During her presentation, she shared that not only was FLASH therapy an effective pain-relieving treatment option, but that it also could be implemented into everyday practice without interfering with clinical workflows.
For the study, patients received 8 Gy of radiation in a single fraction, delivered at ≥40 Gy per second to their metastatic sites using a FLASH-enabled proton therapy system. The patients’ average treatment time on the table was 18.9 minutes total, 15.8 minutes per site. Patients followed up for an average of 4.8 months.
Site pain relief was reported by 67% of patients, and pain in 50% of the sites was reported to have resolved completely. Adverse events were in line with that of conventional radiotherapy and pertained mostly to skin changes (hyperpigmentation and pruritus).
The authors concluded that their findings indicate FLASH is a feasible option for patients with metastases and could change the way patients are treated in the future. They recommended that future work explore the efficacy of FLASH in other parts of the body—thorax, pelvis, head and neck—to better understand whether the lack of adverse events reported in this study are transferable to areas more susceptible to the toxic effects of radiation.
The study abstract can be found in JAMA Oncology.
In addition to her background in journalism, Hannah also has patient-facing experience in clinical settings, having spent more than 12 years working as a registered rad tech. She joined Innovate Healthcare in 2021 and has since put her unique expertise to use in her editorial role with Health Imaging.