ESTRO 2020 Abstract Book

S202 ESTRO 2020

arm were offered SBRT(1x 18Gy, 3x 10Gy or 5x 7Gy), which they could accept or refuse. In case of refusal, they underwent cRT. Patients randomized to the control arm were not informed about the trial and received treatment as usual(cRT, 1x 8Gy or 10x 3Gy). Primary endpoint was best pain response within 3 months after radiotherapy, following the international consensus by Chow et al. and assessed by the Brief Pain Inventory(BPI) questionnaire. Secondary outcomes were quality of life(QoL) and physical functioning in the first 3 months following radiotherapy as assessed by the QLQ-C15-PAL questionnaire. Questionnaires were filled out before start of radiotherapy and 2, 4, 6 and 8 weeks and 3 months after radiotherapy. Chi square test was applied to compare pain response rates between arms(Intention to Treat(ITT) and Per Protocol(PP)) and mixed model analysis was applied to compare QoL outcomes. Results Between April 2015 and march 2019, 110 patients were included. In the ITT analysis, 45 patients in each arm were available for analysis(fig 1). In the intervention arm 12 patients(27%) refused the offer to undergo SBRT, and seven patients(16%) were unable to undergo SBRT. Main reason for refusal was the extra waiting time for SBRT due to an extra MRI before treatment. In the cRT arm, 51% received 1x 8Gy and 33% received 10x 3Gy. In the ITT analysis, 36 of the 45 patients(80%) in the control arm and 37 of the 45 patients(82%) in the intervention arm reported a pain response within three months(p=0.87). In the PP analysis, 24 of the 26 patients(92%) in the intervention arm and 36 of the 45 patients(80%) in the control arm reported a pain response(p=0.39). There was no difference in pain scores over time between the arms(fig 2), nor were there differences in QoL and physical functioning.

Conclusion In this randomized controlled trial within the PRESENT cohort, no difference was found between cRT and SBRT in terms of pain response after radiotherapy for painful bone metastases. One in four patients preferred to undergo cRT over SBRT, mainly due to time consuming and complicated logistics of SBRT. OC-0373 SBRT versus TAE/TACE in Hepatocellular Carcinoma: results from a Phase III trial (NCT02323360) T. Comito 1 , M. Loi 1 , C. Franzese 1 , E. Clerici 1 , V. Pedicini 2 , D. Poretti 2 , L. Solbiati 2 , L. Rimassa 3 , M. Scorsetti 1 1 Humanitas Research Hospital, Radiotherapy and Radiosurgery, Rozzano Milan, Italy ; 2 Humanitas Research Hospital, Interventional Radiology, Rozzano Milan, Italy ; 3 Humanitas Research Hospital, Medical Oncology, Rozzano Milan, Italy Purpose or Objective Hepatocellular carcinoma (HCC) is the most common primary liver tumor and the third cause of cancer death in the world. In unresectable HCC patients with intermediate-stage disease, transcatheter arterial embolization (TAE) +/- co-administration of arterial chemotherapy (TACE) has shown partial responses in 15– 55% of cases, and significantly delays tumor progression and vascular invasion. However while repeated courses of TAE/TACE can be administered in case of incomplete response, alternative treatment options may be considered to maximize local control. Stereotactic body radiotherapy (SBRT), delivering very high doses in a limited number of fractions in a highly conformal manner, is an emerging treatment option for radical treatment of inoperable HCC and may be proposed in case of local relapse following one or more TAE/TACE courses. Material and Methods This is a multicentre, prospective, randomised controlled, unblinded, parallel-group superiority trial of SBRT versus standard TAE/TACE for the curative treatment of intermediate stage of HCC after incomplete reponse following one TAE/TACE cycle (NCT02323360). Primary endpoint was Local Control (LC). Secondary endpoints were Progression Free-Survival (PFS), Overall Survival (OS) and incidence of acute and late complications. In order to detect an HR=0.18 (which translates in 45% difference at the analysis time) with a power of 80% at 5% 2 sided of the log-rank test , 18 events (approximately 50 patients, 25