ESTRO 2023 - Abstract Book

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ESTRO 2023

predictive factor for worst PFS (HR 1.81), including regional-PFS (HR 1.71) and distance-PFS (HR 3.01). For local control, the lesion diameter and volume were the only variables marginally significant (HR 1.03, for both). In multivariate analysis, volume and EPD continued significant predictive factors for regional-PFS and distance-PFS. Age was also statistically significant for regional-PFS. PFS was significantly influenced by age and EPD. Conclusion SBRT is an effective and safe option for local treatment of lung metastasis, with a local control rate similar to described in the literature. Age, volume of pulmonary metastasis and presence of extrapulmonary disease were important prognostic factors.

PO-1610 SBRT as a radical local treatment in oligometastatic disease

E. Gonzalez Del Portillo 1 , A. Castaño Cantos 2 , R. Rosel Aller 3 , M. Rodríguez Roldán 4 , I. Garrido Botella 5 , M. Teja Ubach 4 , M. González Cantero 4 , B. Debén Méndez 4 , V. Duque Santana 4 , I. Rodríguez Rodríguez 4 , L.A. Glaría Enríquez 4 , A. Escribano Uzcudun 4 , B. Belinchón Olmeda 4 , Á. Manso de Lema 4 , R. Matute Martín 4 , L. Miralles Olivar 4 , R.M. Morera López 4 1 HOSPITAL UNIVERSITARIO LA PAZ, RADIATION ONOLOGY , MADRID, Spain; 2 Hospital Universitairo La Paz, Radiation Oncology, Madrid, Spain; 3 Hospital Universitario La Paz, Radiationn Oncology, Madrid, Spain; 4 Hospital Universitario La Paz, Radiation Oncology, Madrid, Spain; 5 Hospital Universitario La Paz, Radiation Oncology , Madrid, Spain Purpose or Objective Oligometastatic patients benefit from radical local treatment, including SBRT (stereotactic body radiation therapy). The selection criteria for these patients are not well established in the literature, but it is generally accepted that a patient with up to 5 metastases is an oligometastatic patient. The latest publications classify these lesions according to whether they are genuine vs. induced, de novo vs. repeat, synchronous vs. metachronous, oligorecurrence vs. oligopersistence vs. oligoprogression, with the aim of better classifying these lesions and patients in order to offer the best therapeutic strategy. The aim of this work is to analyze the diagnostic criteria for the oligometastatic disease and the results of SBRT in our centre. These results will be the first step in determining which types and subtypes of patients and lesions benefit most from this therapeutic strategy. Materials and Methods Patients who received SBRT treatment from January to December 2020 were included. The primary tumour could be any location. The location of the lesion treated with SBRT was extracerebral. Fractionation schedules ranged from 1 to 8 fractions depending on location and patient characteristics. Results Seventy-seven patients and 103 lesions were treated by SBRT. The most frequent primary tumor and histology were prostate cancer (40.26%) and adenocarcinoma (70.13%), respectively. The 80.52% of patients were classified as oligometastatic (<5 lesions), and 87.01% corresponded to 'genuine oligometastatic disease'. In this group, the majority were 'de-novo oligometastatic disease'(79.22%). These patients were metachronous in 66.23%. Oligorecurrence occurred in 44.16%, oligoprogression in 33.77% and oligopersistence in 14.29% of patients at diagnosis of the metastasis to be treated. Table 1 describes the schedules used. The most frequent were 30 Gy in 3 fractions (36.89%) and 60 Gy in 3-5 fractions. The most frequent locations were bone (38.24%), lung (25.49%) and ganglion (20.59%). The evaluation at 6 and 12 months showed a complete or partial response in 56.57% and 50%, respectively (Table 2). Only 7 patients developed grade 1 acute toxicity and only one patient developed grade 1 chronic toxicity. 18.18% were exited during the first year of evolution.