Prophylactic Radiotherapy to Prevent Bone Complications in Patients With Metastatic Solid Cancers

This is a prospective, randomized, single-center clinical trial evaluating whether early prophylactic radiotherapy to high-risk asymptomatic or minimally symptomatic bone metastases reduces the 1-year rate of skeletal-related events (SREs) in patients with metastatic solid cancers. Patients will be randomized in a 1:1 ratio to receive either standard of care systemic therapy or observation, or prophylactic radiotherapy in addition to standard of care. The primary endpoint is the 1-year rate of SREs. Secondary endpoints include adverse events, quality of life, economic burden, pain-free survival, and overall survival.

Inclusion Criteria: * Age ≥18 years * Histologically confirmed solid malignancy * Metastatic disease confirmed by imaging (CT, MRI, or PET-CT) * Presence of up to five high-risk bone metastases * High-risk bone metastases defined according to protocol criteria * Asymptomatic or minimally symptomatic bone metastases (not requiring opioid analgesics) * ECOG performance status 0-2 * Ability to provide written informed consent Exclusion Criteria: * Prior radiotherapy to the index bone metastases preventing safe treatment planning * Symptomatic bone metastases requiring immediate palliative radiotherapy * Evidence of spinal cord compression * Bone metastases causing significant pain requiring opioid analgesics * Oligometastatic disease suitable for radical treatment * Leptomeningeal disease * ECOG performance status ≥3 * Life expectancy less than 3 months * Any condition that, in the investigator's opinion, would interfere with study participation or assessment