Radiation Therapy for High-Risk Asymptomatic Bone Metastases: A Pragmatic Multicenter Randomized Phase 3 Clinical Trial (PREEMPT)

This phase III trial compares the effect of adding radiation therapy to usual care on the occurrence of bone-related complications in cancer patients with high-risk bone metastases that are not causing symptoms (asymptomatic). High-risk bone metastases are defined by their location (including hip, shoulder, long bones, and certain levels of the spine), or size (2 cm or larger). These bone metastases appear to be at higher risk of complications such as fracture, spinal cord compression, and/or pain warranting surgery or radiation treatment. Radiation therapy uses high energy x-rays to kill cancer cells and shrink tumors. The total dose of radiation can be delivered in a single day or divided in smaller doses for up to 5 days of total treatment. Usual care for asymptomatic bone metastases may include drugs that prevent bone loss, in addition to the treatment for the primary cancer or observation (which means no treatment until symptoms appear). Evidence has shown that preventative radiation therapy may be effective in lowering the number of bone metastases-related complications, however, it is not known if this approach is superior to usual care. Adding radiation therapy to usual care may be more effective in preventing bone-related complications than usual care alone in cancer patients with asymptomatic high-risk bone metastases.