ESTRO 2022 - Abstract Book

S1227

Abstract book

ESTRO 2022

Median overall survival was 107 days (95% CI 90-124). Median survival according to PS group 0-3 was 383 days (148-612), 153 (110-196), 62 (37-87) and 50 (17-83), respectively. Overall survival rates at 6 months and 1 year were 33.5% (SD +/-3) and 19.1% (SD +/-2), respectively. In Cox regression analysis, age (hazard ratio (HR) 1.02, 95% CI 1.00-1.03) and PS (HR 2.1; 1.77-2.52) were significant predictors of survival. Additional adjustment for histopathological status and PDL1 receptor status did not change the association. Conclusion Median overall survival after WBRT was more than 3 months but was markedly lower in PS 2 and 3. Age and PS was significant predictors of survival, with no significant impact of histopathology or PDL1 receptor status.

PO-1447 Stereotactic radiation therapy for non-spine bone oligometastases: predictive factors of outcome

S. BORGHESI 1 , C. Gasperi 2 , F. Terziani 1 , A. Rampini 1 , P. Paola 3 , R. De Majo 1 , S. Bertocci 1 , C. Iermano 4 , P.G. Gennari 1 , P.L. Losardo 1 , E. Tucci 1 1 Azienda USL Toscana Sud Est, San Donato and S. Maria alla Gruccia Hospital, Radiotherapy Department, Arezzo - Valdarno, Italy; 2 Azienda USL Toscana Sud Est, San Donato Hospital, Health Department Staff Medical Physics, Arezzo, Italy; 3 Azienda USL Toscana Sud Est, San Donato and S. Maria alla Gruccia Hospital, Radiotherapy Department , Arezzo - Valdarno, Italy; 4 Azienda USL Toscana Sud Est, San Donato and S. Maria alla Gruccia Hospital , Radiotherapy Department , Arezzo - Valdarno, Italy Purpose or Objective to examine the toxicity and outcomes of Stereotactic Body Radiation Therapy (SBRT) for non-spine bone metastases. Materials and Methods Between 2015 and 2018, 40 patients and 46 oligometastatic non-spine bony metastases were treated with SBRT at the Radiotherapy Unit of Arezzo-Valdarno, and retrospectively reviewed. CT/PET was fused on simulation CT and used to outline the target volume in order to reduce inter-observer variation. Local control (LC), overall survival (OS), and progression- free survival (PFS) were evaluated and predictive factors for LC were examined. Acute and late toxicity were reported and graded as per standardized Common Toxicity Criteria for Adverse Events 4.0 criteria. Results The median age of patients treated was 72 years (range 49-85). The most common histology was prostate cancer (50%), followed by breast (25%), bladder (10%), lung (5%), kidney (5%), and rectal cancer (5%). Most of the non-spine bony metastases laid within the pelvis (80%). Pain was present before SBRT in 50% of cases and assessed according to the Numerical Rating Scale (NRS). Median SBRT dose used was 30 Gy (range 25-36) in 3-5 fractions. Early pain relief was observed in all symptomatic patients. After a median follow up of 27 months (range 5-60), 1-year LC, OS and PFS rates were 90%, 95% and 72%, respectively. Local progression occurred in 9 patients with a median time to local failure of 22.5 months. Three patients developed acute toxicity (grade 1 fatigue in 1 case and grade 1 acute pain flare in 2); no late toxicities were observed. Predictive factor of better LC was smaller PTV (p = 0.03). Conclusion SBRT is a feasible treatment for non-spine bony metastases and yields high rates of long-term LC with low acute toxicity and no long term side effects. S. BORGHESI 1 , C. Gasperi 2 , F. Terziani 1 , A.S. Curion 2 , A. Rampini 3 , P. Pernici 1 , S. Bertocci 4 , P.G. Gennari 1 , C. Iermano 5 , R. De Majo 5 , P.L. Losardo 3 , E. Tucci 1 1 Azienda USL Toscana Sud Est, San Donato and S. Maria alla Gruccia Hospital, Radiotherapy Department, Arezzo - Valdarno, Italy; 2 Azienda USL Toscana Sud Est, San Donato Hospital, Health Department Staff Medical Physics, Arezzo, Italy; 3 Azienda USL Toscana Sud Est, San Donato and S. Maria alla Gruccia Hospital, Radiotherapy Department, Arezzo - Valdarno, Italy; 4 Azienda USL Toscana Sud Est, San Donato and S. Maria alla Gruccia Hospital , Radiotherapy Department, Arezzo - Valdarno, Italy; 5 Azienda USL Toscana Sud Est, San Donato and S. Maria alla Gruccia Hospital, Radiotherapy Department , Arezzo - Valdarno, Italy Purpose or Objective To explore the role of FDG positron emission tomography/computed tomography (FDG PET/CT) in Volumetric- Modulated Arc Therapy (VMAT) Stereotactic Ablative Radiotherapy (SABR) of oligometastases. Materials and Methods Seventy consecutive patients with oligometastases underwent FDG PET/CT scanning for staging and radiation treatment planning. CT-based gross tumor volumes (GTVCT) was first delineated using clinical information and CT imaging data, and after by a gradient autosegmented PET/CT-based GTVs (GTVPETCT). The mean GTV, proximal and distal margins were compared. For lung oligometastases, 4D CT was used and ITV derived for comparison with GTVPET CT. The differences in the volume, position, matching index (MI) and degree of inclusion (DI) of the GTVPET CT and PO-1448 VMAT Stereotactic Ablative Radiotherapy for oligometastatic patients: role of FDG PET/CT