Abstract
Background: FLASH radiotherapy (RT) is a novel method for delivering ionizing
radiation, which has been shown in preclinical studies to have a normal tissue
sparing effect and to maintain anticancer efficacy as compared to conventional
RT. Treatment of head and neck tumors with conventional RT is commonly
associated with severe toxicity, hence the normal tissue sparing effect of FLASH
RT potentially makes it especially advantageous for treating oral tumors. In this
work, the objective was to study the adverse effects of dogs with spontaneous
oral tumors treated with FLASH RT.
Methods: Privately-owned dogs with macroscopic malignant tumors of the oral
cavity were treated with a single fraction of ≥30Gy electron FLASH RT and
subsequently followed for 12 months. A modified conventional linear accelerator
was used to deliver the FLASH RT.
Results: Eleven dogs were enrolled in this prospective study. High grade adverse
effects were common, especially if bone was included in the treatment field. Four
out of six dogs, who had bone in their treatment field and lived at least 5 months
after RT, developed osteoradionecrosis at 3-12 months post treatment. The
treatment was overall effective with 8/11 complete clinical responses and 3/11
partial responses.
Conclusion: This study shows that single-fraction high dose FLASH RT was
generally effective in this mixed group of malignant oral tumors, but the risk of
osteoradionecrosis is a serious clinical concern. It is possible that the risk of
osteonecrosis can be mitigated through fractionation and improved dose
conformity, which needs to be addressed before moving forward with clinical
trials in human cancer patients.
radiation, which has been shown in preclinical studies to have a normal tissue
sparing effect and to maintain anticancer efficacy as compared to conventional
RT. Treatment of head and neck tumors with conventional RT is commonly
associated with severe toxicity, hence the normal tissue sparing effect of FLASH
RT potentially makes it especially advantageous for treating oral tumors. In this
work, the objective was to study the adverse effects of dogs with spontaneous
oral tumors treated with FLASH RT.
Methods: Privately-owned dogs with macroscopic malignant tumors of the oral
cavity were treated with a single fraction of ≥30Gy electron FLASH RT and
subsequently followed for 12 months. A modified conventional linear accelerator
was used to deliver the FLASH RT.
Results: Eleven dogs were enrolled in this prospective study. High grade adverse
effects were common, especially if bone was included in the treatment field. Four
out of six dogs, who had bone in their treatment field and lived at least 5 months
after RT, developed osteoradionecrosis at 3-12 months post treatment. The
treatment was overall effective with 8/11 complete clinical responses and 3/11
partial responses.
Conclusion: This study shows that single-fraction high dose FLASH RT was
generally effective in this mixed group of malignant oral tumors, but the risk of
osteoradionecrosis is a serious clinical concern. It is possible that the risk of
osteonecrosis can be mitigated through fractionation and improved dose
conformity, which needs to be addressed before moving forward with clinical
trials in human cancer patients.
| Original language | English |
|---|---|
| Article number | 1256760 |
| Pages (from-to) | 1-10 |
| Journal | Frontiers in Oncology |
| Volume | 13 |
| DOIs | |
| Publication status | Published - 2023 Sept 11 |
Subject classification (UKÄ)
- Cancer and Oncology
- Radiology and Medical Imaging
