Incidence of fractures causing hospitalisation in prostate cancer patients: results from the population-based PCBaSe Sweden

Abstract

Background: Prostate cancer patients have an increased risk of fractures as a consequence of skeletal metastases and osteoporosis induced by endocrine treatment. Data on incidence of fractures and risks in subgroups of men with prostate cancer are sparse. Our aim with this study is to report the risk of fractures among men with prostate cancer in a nationwide population-based study.

Patients and methods: We identified 76,600 Swedish men diagnosed with prostate cancer 1997-2006 in the Prostate Cancer Data Base (PCBaSe) Sweden and compared the occurrence of fractures requiring hospitalisation with the Swedish male population.

Results: Only men treated with gonadotropin releasing-hormone (GnRH) agonists or orchiectomy had increased incidence and increased relative risk of fractures requiring hospitalisation. Men treated with GnRH agonists had 9.8 and 6.3/1000 person-years higher incidence of any fracture and hip fracture requiring hospitalisation than the general population. The corresponding increases in incidence for men treated with orchiectomy were 16 and 12/1000 person-years, respectively. Men treated with orchiectomy, GnRH agonists, and antiandrogen monotherapy, had SIR for hip fracture of 2.0 (95% Confidence Interval 1.8-2.2), 1.6 (95% CI 1.5-1.8) and 0.9 (95% CI 0.7-1.1), respectively. Men treated with a curative intent (radical prostatectomy or radiotherapy) or managed with surveillance had no increased risk of fractures. Older men had the highest incidence of fractures while younger men had the highest relative risk.

Conclusion: Prostate cancer patients treated with GnRH agonists or orchiectomy have significantly increased risk of fractures requiring hospitalisation while patients treated with antiandrogen monotherapy had no increase in such fractures. In absolute terms the excess risk in men treated with GnRH agonists corresponded to almost 10 extra fractures leading to hospitalisation per 1000 patient-years. Effects on bone density should be considered for men on long-term endocrine treatment. Unwarranted use of orchiectomy and GnRH agonists should be avoided.