Randomized phase III study comparing re-irradiation stereotactic body radiotherapy and conventional radiotherapy for painful spinal metastases: Japan Clinical Oncology Group study JCOG2211 (RESCORE study).

Bone metastases are often associated with pain and can occur in various types of cancer, significantly affecting patients' quality of life. Despite the high response rates to initial conventional radiotherapy in patients with painful spinal metastases, recurrence and inadequate response still occur. Thus, the development of a highly effective strategy for pain recurrence is crucial to improving the quality of life in patients with advanced metastatic cancer. This randomized phase III trial aims to confirm the superiority of re-irradiation with stereotactic body radiotherapy (24 Gy in 2 fractions) over conventional radiotherapy (8 Gy in a single fraction) in achieving a complete pain response at 12 weeks in patients with previously irradiated painful spinal metastases. A total of 158 patients from 33 hospitals will be enrolled in Japan over 3.5 years. This trial has been registered in the Japan Registry of Clinical Trials as jRCTs1030240172 (https://jrct.niph.go.jp/latest-detail/jRCT1030240172).