ESTRO 2023 - Abstract Book

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ESTRO 2023

1. Karnofsky Performance Score (<80% vs. ≥ 80%, HR=0.47, p=0.001) 2. ACE-27 comorbidity score (0-1 vs. 2-3, HR=0.49, p<0.001) 3. Primary tumor type (breast carcinoma: HR=0.35, p=0.007; prostate carcinoma: HR=0.46, p=0.012; lung carcinomas were chosen as the reference variable) These factors were considered for the scoring tool. Because the hazard ratios of the significant factors were close to each other, the presence of any positive prognostic factor was assigned 1 point, resulting in 4 prognostic groups with 0 to 3 points accordingly (A: 3 points, B: 2 points, C=1 point, D=0 points). Survival rates at 12 and 24 months were 92% and 69% in group A, 64% and 48% in group B, 31% and 18% in group C, and 16% and 6% in group D, respectively; median survival rates were 44.4 months (95% CI 23.1-65.6 months), 23.5 months (95% CI 17.6-29.4 months), 5.2 months (95% CI 3.9-6.6 months), and 2.6 months (95% CI 1.4-3.8 months) in the respective groups. Conclusion For the first time, this study could demonstrate that in addition to general condition and tumor histology, comorbidities play a central role in survival prognostication of elderly patients after palliative RT of SBM. Therefore, the proposed new tool may support radiation oncologists when assigning RT to elderly patients with SBM. External validation of the scoring tool is ongoing. E. Pastorello 1 , L. Nicosia 1 , N. Giaj-Levra 2 , R. Mazzola 1 , F. Cuccia 2 , V. Figlia 2 , P. Ravelli 2 , F. Ricchetti 2 , M. Rigo 2 , R. Ruggieri 2 , F. Alongi 2,3 1 IRCCS Sacro Cuore Don Calabria Hospital, Radiation Oncology, Negrar di valpolicella (VR), Italy; 2 IRCCS Sacro Cuore Don Calabria Hospital, Radiation Oncology, Negrar di Valpolicella (VR), Italy; 3 University of Brescia, Radiation Oncology, Brescia, Italy Purpose or Objective Spinal metastases develop in almost one third of cancer patients and because of their association with pain and sometimes neurological symptoms, they can bring to a reduction of quality of life. Stereotactic body radiation therapy (SBRT) is a well established technique for treating oligometastatic patients. Even if radiotherapy has a consolidate antalgic role in bone metastases using palliative doses, few data are available on its use with ablative doses in spinal metastases. The aim of our study is to evaluate efficacy, toxicity and pattern of progression in spinal oligometastatic patients treated with SBRT. Materials and Methods We treated a series of spinal oligometastatic patients in our departement between May 2018 and December 2021. Clinical target volume was defined according to Cox criteria for spinal metastases. The primary objective was local control (LC). Secondary objectives were toxicity, distant progression free survival (DPFS), overall survival (OS) and pattern of relapse (sequential oligometastatic disease (SOMD) versus polimetastatic disease (PMD)). The following covariates were evaluated: primary tumor hystology, biologically effective dose (BED), dose boost to the macroscopic disease, and number of metastases. Results Ninety-two spinal oligometastases in 66 patients were treated. Primary hystology was: prostate (39), breast (18), lung (3), others (6). Median dose was 21 Gy (12-30) delivered in 1 to 5 fractions. Dose boost to the macroscopic lesion up to 24-27 Gy was administered with simultaneous integrated boost techniques in 35 metastases (38%). One-, and 2-year LC was 93.7% and 91.6%. At the univariate analysis, breast and prostate cancer metastases had a trend toward improved LC compared to other histologies (p=0.052). Moreover, dose boost to macroscopic lesion resulted in a significantly improved 2-year LC (100% versus 86.4%; p= 0.04). At the last follow-up 6 (6.5%) metastases locally relapsed. Two patients were surgically treated with laminectomy due to local progression, and vertebroplasty after a traumatic fracture with no evidence of local relapse. 6-months and 1-year DPFS were 63%, and 34.4%, respectively. Median sequential oligometastatic disease (SOMD) time was 15 months (10-36), and the 1- and 2- year SOMD were 58.5%, and 37.8%. Polymetastatic disease (PMD) occurred after median 16.5 months (8.6-37.6), and the 1- and 2-year PMD were 55.9%, and 44.6%. At the univariate analysis, the number of spinal oligometastases correlated with PMD occurrence. In particular, patients with 1, 2-3, and 4-5 oligometastases had a median time to PMD of 37.6, 23.8, and 5.3 months, respectively (p=0.00). One- and 2-year OS were 92.8% and 85.7%. No grade ≥ 3 toxicity occurred. Conclusion Spinal SBRT is an effective tool in oligometastatic patients. Dose boost could be safely administered to improve significantly LC. Among oligometastatic patients, those with more than 3 lesions at baseline are more likely to develop rapidly PMD. PO-1601 Stereotactic body radiotherapy (SBRT) with or without dose boost in spinal oligometastatic patients

PO-1602 Hypofractionated dose-intensified palliative RT: 25 Gy in 5 fractions for enhanced symptom control

J. Paragas 1 , V. Di Lalla 1 , M. David 1 , S. Skamene 1 , L. Alvarado 1

1 McGill University Health Centre, Division of Radiation Oncology, Montreal, Canada

Purpose or Objective