MR guided HIFU palliation of painful metastases to bone
Bones are the third most common site of metastasis, and pain from these metastases is the most common cause of cancer-related pain. External beam radiotherapy (EBRT) is the standard of care, with > 40% of patients experiencing at least a 50% reduction in pain at 1 month. However, approximately one-third of patients do not have pain relief after radiation, and retreatment with EBRT is limited by toxicity to normal tissue. MRgHIFU has recently completed a phase 3 trial assessing the effectiveness and safety of this method for palliation of pain in patients with bone metastases.
Images from the pre-treatment PET-CT and MR demonstrate a metabolically active, enhancing expansile mass in the right ischial tuberosity. The patient was unable to sit on his right buttock because of 8 out of 10 pain from this lesion. The MR-HIFU images demonstrate thermal dose, in blue, deposited on the posterior aspect of the right ischial tuberosity. Post-treatment PET-CT and MR images demonstrate diminished metabolic activity and enhancement in a distribution that matches the region of the thermal deposition from the HIFU treatment. More importantly, this patient was able to sit normally within one week, with a pain score of between 0 – 1 out of 10 at 12 weeks.
