BOREALIS is a multicentre, prospective, observational cohort study designed to investigate the effectiveness, feasibility, safety and impact on pain and quality of life of curative-intent cryoablation for the treatment of bone metastases in patients with oligometastatic or bone oligo-progressive disease.

Inclusion Criteria:

• Bone metastases in patients with oligometastatic disease (<5 bone/visceral metastases) or bone oligo-progressive disease (visceral or osseous multi-metastatic disease stable under systemic treatment except 1-3 progressing bone metastases) from solid tumours;
• Number of target lesions ≤ 3
• Size of target lesion(s) < 5 cm (largest diameter);
• Referral to local ablative treatment by multidisciplinary tumour board (MDTB);
• Treatment by percutaneous cryoablation with curative intent (i.e., complete tumour destruction) assessed as technically feasible by the IR in charge;
• Procedure performed with a cryoablation system from Boston Scientific.

Exclusion Criteria:

• < 18 years old;

• Incapacity or refusal to give informed consent;

• Ongoing pregnancy;

• Health status not compatible with the minimum meaningful follow-up period (i.e., 12 months):

  • Karnofsky Performance Scale < 60%, or
  • Bone metastases originating from rapidly evolving tumour histologies not allowing reasonable life expectancy of at least 12 months, or
  • Life expectancy < 12 months

• Infection of treatment site or systemic infection;

• Uncorrectable coagulopathy;

• Haematological disease (including multiple myeloma and plasmacytoma);

• Concomitant radiation therapy or radiation therapy within 12 weeks before the planned cryoablation procedure.

Patients with bone metastases from oligometastatic or bone oligo-progressing disease from solid tumours treated with curative-intent cryoablation may participate in BOREALIS. Patients from vulnerable populations (e.g., minors, pregnant women, incapacitated or unconscious individuals) shall not be included in the study.