ESTRO 2021 Abstract Book

S1686

ESTRO 2021

PO-1983 Radiosurgery (SRS) in spinal metastatic (SM). Result of a hospital center. R. Rubiato Aragón 1 , M.S. Talaya Alarcon 1 , D. Hernandez Gonzalez 2 , M.T. Murillo Gonzalez 3 1 h.U. La Princesa, Radiation Oncology, Madrid, Spain; 2 h.U. La Princesa, Medical Physics, Madrid, Spain; 3 h.U. La Princesa, Radiation Oncology, Madrid , Spain Purpose or Objective INTRODUCTION:5-40% of cancer patients will develop vertebral metastases . Stereotactic body radiosurgery (SBRS) has emerged as a new treatment option in the multidisciplinary treatment option in the multidisciplinary management of vertebral metastases. SBRS provides high dose per radiation fraction over a target volume and high biological equivalent dose (BED) , with high precision and high dose gradient, with lower dose in OAR . OBJECTIVE: to evaluate local progression-free survival (PFS), overall survival (OS), disease-free survival (DFS) and distant progression-free survival (PFS). Materials and Methods PATIENTS AND METHODS: between 2011-2017, 27 patients (p) with SM were treated with SRS. Clinical characteristics: male (15p), female (12p); median age: 62y (50-74); primary tumor: breast (7p), lung (7p), prostate (5p) 16 patients had exclusive vertebral involvement: 14 p had progressive systemic disease. Location: Lumbar: 14p, Dorsal 10p; Cervical 1p and Sacral 1p. In all cases a single fraction was administered. Radiotherapy: Treatment volume according to the Consensus Guidelines of the International Spine Radiosurgery Consortium. Mean dose: 15.18 Gy (8.18); Most patients had received treatment on a Novalis BED accelerator mean: 91 Gy10 (53-151). Evaluation of response by RECIST and MRI criteria and toxicity by CTCAE v4. Statistics: Kaplan-Meier. Results RESULTS: after a mean follow-up of 13 months (1-42), 10 of 27p (37%) have died. 14p (50%) had clinical improvement or stability of symptoms. Local RECIST response (22p) was: progressive disease (7p, 32%), partial response (8p, 36%) and stable disease (7p, 32%). OS, PFS and PFS at 1 and 3 years were 78%, 50% ,71% and 72%, 46% 19%, respectively. No post-treatment fractures or acute Gardo II-IV toxicity were observed. Conclusion CONCLUSIONS: Radiosurgery for the treatment of vertebral metastases offers symptomatic relief and acceptable disease control with low toxicity for the treatment of vertebral metastases. Possible objectives of the study would be to evaluate the reduction of reirradiation and to evaluate treating previously irradiated lesions with some safety. PO-1984 Early toxicity with stereotactic body radiation thrapy for prostate cancer J. Saavedra Bejarano 1 , M. Rubio Jiménez 1 , G. Campos Rivera 1 , M. Órtiz Seidel 2 , H. Miras del Río 2 , A. Illescas Vacas 1 1 Hospital Universitary Virgen Macarena, Oncology Radiotherapy, Seville, Spain; 2 Hospital Universitary Virgen Macarena, Medical Physical, Seville, Spain Purpose or Objective The safety and efficacy of postoperative hypofractionated radiation therapy (HRT) on prostate carcinoma (PC) has been evaluated by multiple series with favorable results. In addition, radiobiological analyzes indicate that PC α/β ratio is low which supports the choice of HRT. However, we do not have results from randomized trials comparing HRT with conventionally fractionated RT (CFR). We examined the impact of HRT for prostate cancer on toxicity after radical prostatectomy (RP). This communication shows our data prospective about acute genitourinary (GU) and gastrointestinal (GI) toxicity after This retrospective and observational study included 81 patients who underwent HRT at the dose of 60 Gy in 24 or 25 fractions and 62,1 Gy in 27 fractions between March 2019 and January 2021. IMRT and VMAT were used as radiotherapy techniques. The following variables were recorded: age, past medical history, previous treatment with anticoagulant or antiplatelet drugs, Performance Status (PS), ACE-27 score, clinical and pathological Gleason score, clinical and patological Tumor Stage, Risk group following clinical and pathological NCCN, PSA levels initial and pre-radiotherapy, surgical margin, hormonotherapy, radiation area, RT doses as well as different toxicity types depending on genitourinary or gastrointestinal adjuvant or salvage HRT. Materials and Methods