ESTRO 2021 Abstract Book

S724

ESTRO 2021

location or pretreatment pain intensity score).

PD-0886 30-Day Mortality after Palliative Radiation Therapy for Painful Bone Metastases M. Vázquez Varela 1 , A.A. Geng 1 , J. Garre 1 , E. Recalde 1 , M. Altabas 1 , A. Giraldo 1 , V.M. Reyes 2 , X. Maldonado 1 , B. Navalpotro 1 , M. Ramos 1 , R. Vergés 1 , S. Benavente 1 , S. Micó 1 , R. Granado 1 , J. Giralt 1 1 Vall d'Hebron University Hospital, Radiation Oncology, Barcelona, Spain; 2 Vall d'Hebron University Hospital, , Radiation Oncology, Barcelona, Spain Purpose or Objective Palliative radiotherapy (PRT) for bone metastases is useful for symptom control and can improve the quality of life of advanced cancer patients. However, optimal pain control after PRT to bone metastases is usually obtained after 3-4 weeks after the PRT. Thus, when survival is too short, these patients may not benefit. 30- day mortality (30-DM) is a parameter of avoidance of harm that is especially useful to evaluate the futility of a certain treatment in cancer patients. Our purpose is to know the 30-day mortality after PRT to painful bone metastases and to identify potential prognosis factors related to it. Materials and Methods We conducted a retrospective study including patients treated with PRT to painful bone metastases during 2018 and 2019. Patients under 18 years old, spinal cord compression or post-operative radiotherapy were excluded. We stablished two groups according to their state at 30-days after the start of the PRT (dead or alive), as Lower Survival Group (LS-group) and Better survival group (BS-group). Chi-square test and Fisher exact test were used for the descriptive analysis. A logistic regression model was carried out considering the following covariates: age, sex, ECOG PS, primary tumor, presence of visceral disease, treatment location, fractionation regimen and reirradiation Results 708 patients were treated with PRT, of whom 330 patients were treated for painful bone metastases. The most frequent primary tumor was lung cancer, (24.8%) and the predominant location of the treatment was the spine (37.9%). Single doses were the most used regimen (57.2%) and the vast majority completed the scheduled treatment (97.9%). The LS-group had a major prevalence of male sex (77.2% vs 37.4%; p= 0.003), Eastern Cooperative Oncology Group (ECOG) Performance Status (PS) 2-3 (77.2% vs 56%; p< 0.0001) and visceral metastases (68.4% vs. 52%; p= 0.028). The use of single doses in the LS-group was significantly higher than in the BS-group (71.9% vs. 54.1%; p= 0.029), but the completion of the treatment was lower (91.2% vs. 99.3%; p= 0.002). The 30-DM was 17.3%. The following parameters had significant impact on 30-DM: Male sex (OR 2.65; 95% CI: 1.36 - 5.15; p= 0.004), ECOG PS 2-3 (OR 2.67: 95% CI 2.91 - 11.03; p< 0.0001), gastrointestinal and lung cancer (OR 8.89; 95% CI 2.38 - 33.2; p= 0.001, and OR 8.91; 95% CI 2.55 - 31.15 p= 0.001, respectively), and presence of visceral metastases (OR 1.99; 95% CI 1.08 - 3.66; p= 0.025).