ESTRO 2024 - Abstract Book

S2070

Clinical - Paediatric

ESTRO 2024

treatment course, utilizing advanced imaging modalities for accurate tumor targeting and sparing nearby normal tissues. The shorter treatment duration and potential for outpatient care make SRT an attractive alternative, reducing healthcare costs. Moreover, several clinical studies have reported superior local control rates and effective pain palliation with SRT, while maintaining an acceptable toxicity profile. The aim of our study was to assess local control disease and rate of chronic toxicities in a cohort of patients undergoing SRT for spinal bone metastases (SBM).

Material/Methods:

Data from patients with SBM treated with SRT who referred to our institution from January 2021 to December 2022 were collected; only patients for whom radiological follow-up was available were included. Local control of the treated field was evaluated at baseline and during radiological follow ‐ up. Statistical analysis was performed to identify predictors of disease control. Descriptive analysis was performed; Kaplan Meier analysis was carried out to estimate local control. Toxicities were assessed throughout the follow-up and scored according to CTCAE v5.0 scale.

Results:

Among 226 patients treated with SRT for SBM, radiological follow-up was available in 109 patients. Cervical, dorsal and lumbosacral tracts were involved in 3, 74 and 32 cases, respectively (3%, 68%, 29%). Overall, 29 treatments were delivered in VMAT and 80 with robotic-arm linac (27% and 73%, respectively). Most represented primary tumors were prostate (n=40) and colorectal (n=20) carcinoma. The majority of treatment schedules adopted were 24 Gy in 2 fractions (n=49) and 27-30 Gy in 3 fractions (n=60); median BED was 53 (51.3-60). Median follow-up was 10 months (2-27). The 12 and 18-months local control rates were 99% and 96% (fig.1). Late toxicity occurred in 2 patients (2%). One patient developed G3 neuropathic pain 8 months after S1-S2 radiotherapy: dose constraints to caudal tract and sacral roots were respected at plan review. Following radiological review, one case of vertebral fracture was identified 3 months after SBRT.

Conclusion:

SRT in spinal metastasis showed beneficial and durable local control, consistent with the available literature and manageable toxicity. A follow up of at least 6 months is necessary to better assess local failure rate and incidence of late toxicity.