Androgen deprivation therapy (ADT) in men with prostate cancer is associated with a small but significant increase in fracture risk, a UK study has shown.

Using the Hospital Episodes Statistics database for 2004-2008, the authors identified 8,902 men with prostate cancer who had been admitted to hospital with a fracture. Of these, 3,372 (37.8%) had been treated with ADT and 5,530 (62.2%) had not. There were 228,852 admissions in the background population.

In men aged over 50 with prostate cancer the risk of a fracture resulting in hospitalisation increased from 1.12 per 100 person-years in those who had not been treated with ADT to 1.41 per 100 person-years in those who had.

Compared with the background population, with a risk of 0.58 per 100 person-years, this represents a 2.4-fold relative increase in risk but an absolute risk increase of only 0.83 fracture-related admissions per 100 person-years.

Cohort studies in the United States have shown an increased risk of osteoporotic fracture in men with prostate cancer treated with ADT. However, this study of hospital admissions for fractures in men with prostate cancer is the first of its kind in the UK.

While this increased risk is of statistical significance, the absolute increase is small overall.

The NICE guidance on osteoporosis and fragility fracture1 recognises ADT as a risk factor, and advises individualised risk assessment of fracture risk (using FRAX or Qfracture) for all men commencing ADT for prostate cancer.

I feel it would appear sensible for most men, particularly those aged over 75, to receive calcium and vitamin D supplementation while being treated with long-term ADT. Individualised risk assessment will also allow targeted treatment with bisphosphonates to be given to those men at highest risk.

However, the study authors conclude that all men with prostate cancer should undergo risk assessment ‘rather than singling out men on ADT, as all men with prostate cancer have an increased risk of fracture, with men on ADT at slightly higher risk.’

Dr Jonathan Rees