ESTRO 2021 Abstract Book

S302

ESTRO 2021

Materials and Methods Clinical data from three monocentric phase I-II trials and one monocentric phase II trial were pooled for this analysis. A total dose of 14-20 Gy in 3.5-5 Gy/fraction was delivered twice a day with 3D-conformal RT. Pain and quality of life were recorded according to the Visual Analog Scale (VAS) and the CLAS scales, respectively. Symptomatic response was evaluated 20 days after RT and every two months thereafter. Results One hundred and eighty patients were included in this analysis. Fifty-two patients (28.8%) had advanced primary or metastatic H&N tumors, 54 patients (30.0%) locally advanced or metastatic thorax cancers, 25 patients (13.9%) locally advanced pelvic cancers, and 49 patients (27.2%) complicated bone metastases. The most frequent baseline symptom was pain (63.9%). The overall palliative response rate (complete plus partial) was 88.9% with a median palliative duration of 4 months. The response rate for pain was 86.8% (CI 0.95: 79.8%-91.7%). Pre- and post-treatment mean VAS were 5.3 and 2.5, respectively (p < .00001). Overall, most patients (92.2%) were able to rank the different aspects of QoL as well-being (CLAS1), fatigue (CLAS2), and ability to perform daily activities (CLAS3). An improvement of CLAS1, CLAS2, and CLAS3 values was recorded in 80 (48.2%), 70 (42.2%), and 77 (46.4%) patients, respectively. Only 4/180 patients (2.2%) presented G ≥ 3 acute toxicity: 3 patients treated at 20 Gy had mucosal toxicity (n=2) or esophagitis (n=1), while 1 patient treated at 16 Gy had lung toxicity. Only 1 patient (0.5%) with a H&N lesion (dose: 20 Gy) experienced G 3 late skin toxicity (marked atrophy and telangiectasia). No other patients experienced G > 2 late toxicity. The treatment was well tolerated also when administered between systemic therapy courses. Conclusion Hypo-fractionated accelerated RT delivered twice a day in two consecutive days is effective in the symptomatic treatment of advanced and metastatic solid cancer. Currently, seven multicenter non-inferiority randomized phase III trials comparing the SHARON regimen to a standard one (30 Gy in 10 daily fractions) are ongoing in different palliative settings. OC-0407 Quality of Life after Palliative Radiotherapy for Bone Metastases: Analysis of the PRESENT- cohort M. Bartels 1 , J. van der Velden 1 , B. Pielkenrood 1 , S. Gerlich 1 , M. Bras 1 , J. Verlaan 2 , E. Monninkhof 3 , M. Peters 1 , Y. van der Linden 4 , H. Verkooijen 1 1 UMCU, Radiation Oncology, Utrecht, The Netherlands; 2 UMCU, Orthopedic Surgery, Utrecht, The Netherlands; 3 UMCU, Julius Center, Utrecht, The Netherlands; 4 Leiden University Medical Center, Radiation Oncology, Leiden, The Netherlands Purpose or Objective Symptomatic bone metastases are a frequent and serious problem for patients with advanced cancer, as painful lesions negatively impact overall quality of life (QoL). Improving or maintaining the different domains of QoL in patients with a limited life expectancy is a priority form patient, patients' carers, and research perspectives. The aim of this study is to evaluate the course of Quality of Life (QoL) in patients with painful bone metastases treated with palliative radiotherapy and to analyze whether the course of QoL differs between patients who do and do not experience pain relief after treatment. Materials and Methods This study is nested within the prospective PRESENT cohort on bone metastases. All patients treated with conventional radiotherapy for painful symptomatic bone metastases originating from solid tumors were selected. Patient reported outcomes were collected before start of radiotherapy, and at 4, 8, 12 weeks, 3 and 6 months thereafter. Response was defined as a 2-point decrease in pain score without increase in analgesic use according to the international consensus. Linear mixed models were used to assess QoL by comparing differences in domain scores of the EORTC QLQ-C15-PAL and EORTC QLQ-BM22 QoL questionnaires between responding and non-responding patients. We adjusted for baseline QoL and potential confounding factors. Results Responding patients (n=275, 58%) showed significantly better overall QoL scores over time compared to non- responders (n=197, 42%). Responders performed better on functional and symptom scales. A significantly higher percentage of patients with a response to radiotherapy improved at any time during follow-up i n all QLQ-BM22 domains and in half of the QLQ-C15-PAL domains. Fig 1 - Mean scores of BM22 domains, comparing responders (red) and non-responders (blue). Higher scores in psychosocial and functional scores indicate better functioning, higher scores on pain scales reflect worse symptomology.