Fracture Risk in Men with Metastatic Prostate Cancer Treated With Radium-223.

Radium-223 is a bone-seeking, alpha-emitting radionuclide used in metastatic castration-resistant prostate cancer (mCRPC). Radium-223 increases the risk of fracture when used in combination with abiraterone and prednisolone. The risk of fracture in men receiving radium-223 monotherapy is unclear.

This was a prospective, multicenter phase II study of radium-223 in 36 men with mCRPC and a reference cohort (n = 36) matched for fracture risk and not treated with radium-223. Bone fractures were assessed using whole-body magnetic resonance imaging. The primary outcome was risk of new fractures.

Thirty-six patients were treated with up to six 4-week cycles of radium-223. With a median follow-up of 16.3 months, 74 new fractures were identified in 20 patients. Freedom from fracture was 56% (95% confidence interval, 35.3-71.6) at 12 months. On multivariate analysis, prior corticosteroid use was associated with risk of fracture. In the reference cohort (n = 36), 16 new fractures were identified in 12 patients over a median follow-up of 24 months. Across both cohorts, 67% of all fractures occurred at uninvolved bone.

Men with mCRPC, and particularly those treated with radium-223, are at risk of fracture. They should receive a bone health agent to reduce the risk of fragility fractures.

Clinical genitourinary cancer. 2021 Apr 04 [Epub ahead of print]

Adham Hijab, Sebastian Curcean, Nina Tunariu, Holly Tovey, Roberto Alonzi, John Staffurth, Matthew Blackledge, Anwar Padhani, Alison Tree, Helen Stidwill, Jessica Finch, Peter Chatfield, Sophie Perry, Dow Mu Koh, Emma Hall, Chris Parker

The Royal Marsden NHS Foundation Trust, London, UK., The Royal Marsden NHS Foundation Trust, London, UK; The Institute of Cancer Research, London, UK., The Institute of Cancer Research, London, UK., Mount Vernon Cancer Centre, Northwood, UK., Velindre Cancer Centre, Cardiff, UK., Paul Strickland Scanner Centre, Mount Vernon Cancer Centre, Northwood, UK., The Royal Marsden NHS Foundation Trust, London, UK; The Institute of Cancer Research, London, UK. Electronic address: .