ESTRO 2024 - Abstract Book

S1857

Clinical - Mixed sites, palliation

ESTRO 2024

Radiology, Bologna, Italy. 4 IRCCS Azienda Ospedaliero-Universitaria di Bologna, Radiation Oncology, Bologna, Italy. 5 Alma Mater Studiorum - Bologna University, Department of Medical and Surgical Sciences (DIMEC), Bologna, Italy. 6 University of Turku and Turku University Hospital, Department of Oncology and Palliative Center, Turku, Finland. 7 Isala Hospital, Department of Radiotherapy, Zwolle, Netherlands. 8 University of Turku and Turku University Hospital, Department of Radiology, Turku, Finland

Purpose/Objective:

The current standard local treatment of painful bone metastases is external beam radiotherapy (EBRT). EBRT may take up to four weeks to induce adequate pain relief, and (partial) pain response is achieved in around 60-70% of the patients. Magnetic Resonance-guided High Intensity Focused Ultrasound (MR-HIFU) has been shown to induce fast pain relief (within days), and hence may improve pain palliation in the non-spinal patient subpopulation. However, MR-HIFU is rather complex due to need for sedation or general anesthesia, longer duration of the procedure, and technical constraints of the treatment. These factors have implications for implementation of MR HIFU in the first-line management of patients with painful bone metastases. The FURTHER-trial is a three-armed international multicenter randomized controlled trial, funded by the European Commission, which compares the effectiveness of standard treatment (EBRT) to MR-HIFU (with and without EBRT). In the context of the FURTHER trial, we studied which proportion of patients referred for radiotherapy for (painful) non-spinal bone metastases would be eligible to undergo MR-HIFU as an alternative to EBRT for pain relief, and assessed reasons of ineligibility.

Material/Methods:

Four radiotherapy departments in Finland, Italy, and the Netherlands participated. All adult patients referred to one of the participating centers for EBRT of ≥1 non -spinal bone metastases of solid tumors were screened for eligibility for MR-HIFU treatment. All patients were assessed for eligibility for MR-HIFU by a local team consisting of radiation oncologists, radiologists and clinical researchers. For each ineligible patient, the main reason(s) of ineligibility was/were recorded, and categorized as patient-related factors or lesion-related factors. For a random subsample of 30 ineligible patients, a detailed analysis was performed to identify all different reasons of ineligibility.

Results:

Overall, 639 patients with 741 non-spinal bone metastases were included in this study. Of those, 153 lesions (21%) in 113 patients were ineligible because of patient-related factors, including curative treatment intent for oligo metastatic disease (n=76, 10%), poor performance status (n=56, 8%), and contra-indication for MRI (n=10, 1%). Of the remaining 588 bone metastases in 526 patients, 531 lesions (470 patients) were ineligible for MR-HIFU because of lesion- related factors, including ‘target lesion too large / too extensive (n=212, 29%), ‘(risk of) a pathological fracture’ (n=114, 15%), and ‘no moderate/severe pain’ (n=80, 11%). In 57 of 741 lesions (8%), MR -HIFU could serve as a stand-alone alternative treatment to EBRT for pain palliation. Eligibility rates varied from 4% to 30% between centers, which was mainly attributable to differences in patient-related factors. Within the random subsample of 30 patients, 27 patients had more than one reason for ineligibility. For all patients, one or more lesion-related factors would make them ineligible for MR-HIFU treatment, and in 14 (47%) patients, one or more patient-related factors would make them ineligible for MR-HIFU.