Related Experiment Video
Updated: Aug 21, 2026
Proton Therapy Delivery and Its Clinical Application in Select Solid Tumor Malignancies
Published on: February 6, 2019
Local control and outcomes associated with proton spine hypofractionated radiation therapy
Christopher B Jackson1, Daniel S Higginson1, Haibo Lin2
1Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York, USA.
Purpose:
Little is known about the long-term outcomes of patients with spinal metastases treated with proton hypofractionated radiotherapy (pHFRT), particularly in the setting of re-irradiation (re-RT).
Methods:
This is a retrospective cohort study of patients treated between 2015-2023 utilizing pHFRT (≤10 fractions). All patients received follow-up magnetic resonance imaging at least 1 month after treatment. Outcomes of interest included local failure (LF), defined radiographically, as well as long-term adverse events.
Results:
A total of 52 patients treated to 58 lesions met inclusion criteria. Median follow-up after RT was 14 months (IQR 8-25). The most common dose-fractionation scheme was 40 Gy in 5 fractions (n=47, 81%). There were 10 cases of first-time RT utilizing protons (17%), whereas 25 courses (43%) were second-time re-RT, 19 courses (33%) were third-time re-RT and 4 courses (6.9%) were fourth-time re-RT. Median cumulative equivalent dose in 2-Gy fractions (EQD2) was 115 Gy (IQR 91-153). The 1-year LF rate was 10% (95% confidence interval (CI) 4-20%), and the 2-year LF rate was 22% (95% CI 12-35%). There were 5 grade (G) 3 adverse events, including radiation myelitis (1), esophageal fistula (1), esophageal stricture (1), wound dehiscence (1), and bowel necrosis (1). All G3 adverse events occurred in patients who received 3-4 overlapping courses of RT. There were no G4-5 adverse events.
Conclusion:
PHFRT is associated with excellent local control in this large cohort of heavily re-irradiated patients (81% re-RT). G3 adverse events were limited to patients who received 3-4 overlapping courses of RT.
