ESTRO 2022 - Abstract Book

S210

Abstract book

ESTRO 2022

proportional hazards model with backward elimination. The model consistency was checked by 500 bootstrap replications. Our prognostic score was calculated by evaluating the most statistically significant factors. Patients were grouped and compared according to our proposed score, SIR, and BS-BM. Results Total 85 patients were included, and 67 (79%) of them had positive growth in the size of brain metastasis. The median follow-up duration was 20 months (interquartile range [IQR] 10-34 months). Overall survival for the whole cohort was 17 months (95% confidence intervals [CI], 12–22 months). We developed the prognostic model based on the most important predictors of OS: percentage change in lesion size per day between the diagnostic and stereotactic MRI (hazard ratios [HR] of ≥ 1% vs <1%, 2.33; 95% confidence interval [CI], 1.22–4.44), extracranial oligometastatic diseases ( ≤ 5 involvements) (HR, 0.27; 95% CI, 0.14–0.53), and the presence of neurological symptoms (HR, 2.91; 95% CI, 1.31–6.42). For our model, patients with scores 0, 1, 2, and 3 had a median OS of 3.7 (95% CI 0.8–not reached [NR]), 2.0 (95% CI 1.2–NR), 1.0 (95% CI 0.6–1.8), and 0.2 (95% CI 0.1–NR) years, respectively. Pairwise comparisons using Log-Rank tests showed statistically different survival except between score 0 and 1. The optimism-corrected c-index for the proposed model, SIR, and BS-BM were 0.681 (95% CI, 0.594–0.773), 0.560 (95% CI, 0.450–0.662), and 0.559 (95% CI, 0.461–0.657), respectively.

Conclusion Our model is useful to identify patients with brain metastasis treated with SRS with different OS. Its prognostic ability appeared slightly better than SIR and BS-BM in our cohort. However, further studies to validate our findings are needed.

PD-0250 Therapeutic use of Linac-based SRS in malignant spasticity: early results from a prospective trial

L. Nicosia 1 , R. Avesani 2 , E. Rossato 2 , F. Ferrari 2 , F. Cuccia 1 , V. Figlia 1 , N. Giaj-Levra 1 , R. Mazzola 1 , F. Ricchetti 1 , M. Rigo 1 , G. Attinà 1 , C. Vitale 1 , F. Marchioretto 3 , M. Zamperini 4 , A. De Simone 1 , R. Ruggeri 1 , F. Alongi 1 1 IRCCS Sacro Cuore Don Calabria Hospital, Cancer Care Center, Advanced Radiation Oncology Department, Negrar, Italy; 2 IRCSS Sacro Cuore Don Calabria Hospital, Department of Rehabilitation, Negrar, Italy; 3 IRCCS Sacro Cuore Don Calabria Hospital, Neurological Unit, Negrar, Italy; 4 Intensive Care and Pain Therapy, IRCCS Ospedale Sacro Cuore Don Calabria, Department of Anesthesia, Negrar, Italy Purpose or Objective spasticity is a clinical event characterized by increased muscle contraction, sometimes painful, secondary to central nervous system damage. It leads to a high rate of nursing procedures, hospital admissions, and costs and quality of life impairment with problems in sleeping, breathing, and speaking. Standard treatment for systemic spasticity is represented by oral or intrathecal baclofen. In the case of focal spasticity, available treatment options are intramuscular botulinum toxin, alcoholic or surgical neurolysis or even selective neurotomies or rhizotomies. However, these surgical procedures are characterized by prolonged surgical sessions and may have infective, anesthetic and surgical complications. They