To investigate, whether multi-fraction stereotactic body radiation therapy (SBRT) within 3 treatment fractions is non-inferior to the current standard of care of 5 fraction SBRT regarding pain response at 3 months after radiotherapy.

Inclusion Criteria:

• Personally signed and dated written informed consent,
• Histological diagnosis of malignancy,
• Histologically or radiologically diagnosed bone metastasis,
• Age ≥ 18 years
• Pain or under pain control medication

Exclusion Criteria:

• Pregnant or lactating women,
• Women of childbearing potential or sexually active males not willing to use effective contraception while on treatment and 3 months after the end of treatment,
• Inability to follow the procedures of the study, e.g., due to language problems, psychological disorders, dementia, etc.,
• Prior radiotherapy to the intended treatment site,
• Lesions > 5cm in maximum diameter,
• Prior treatment with radioactive isotopes within 30 days of randomisation,
• Spinal column, hands, feet, or head as intended treatment site,- Fracture at the intended treatment site,
• Surgery required or previous surgery at the intended treatment site
• Instability of the intended treatment site.