It has long been known that men with prostate cancer are at increased risk of fracture due to both the disease itself (pathological fractures) and also as a result of iatrogenic osteoporosis from androgen deprivation therapy (ADT). However, there is little existing data quantifying the fracture risk.

This retrospective cohort study from Denmark, published in the British Journal of Urology, has found that patients with prostate cancer are at a two-fold increased risk of fracture and a four-fold risk of hip fracture. The study looked at more than 15,000 men aged more than 50 years presenting with a fracture and around 47,000 age-matched men as a control group. A previous diagnosis of prostate cancer had been recorded in 1.3% of controls and 2.5% of fracture cases, with an increased fracture risk becoming apparent early after diagnosis of prostate cancer (median interval of three years).

The increased risk of fracture was most marked in hip fracture, with an odds ratio of 3.7 (3.1 - 4.4). This excess risk was most pronounced in men aged 50-65 years, for whom the odds ratio was 9.2 (4.8 - 17.5).

Statistical analysis revealed that there were 106 hip fractures in Denmark per year that were attributable to prostate cancer or its treatment (3.1% of all hip fractures in that population).

Additionally, the study found that treatment with ADT further increased the risk of fracture, with an odds ratio of 1.7.

This study illustrates that patients with prostate cancer, particularly those receiving ADT, should be considered to be at a significantly increased risk of fractures, many of which are potentially preventable. These men should be educated about measures to protect bone density (ie regular weight-bearing exercise, a balanced diet with at least 1g calcium per day and avoidance of smoking and alcohol excess), and ideally should receive calcium / vitamin D supplementation if on ADT. If any other risk factors for osteoporosis are present, prescription of a bisphosphonate such as alendronic acid should be considered at the onset of ADT.

Abrahamsen B, Nielsen MF, Eskildsen P et al. Fracture risk in Danish men with prostate cancer: a nationwide register study. BJU Int 2007;100:749-54