[Prevalence of osteoporotic fractures in patients treated by androgen blockade for prostate cancer].

Introduction: Endocrine therapy is the standard first-line treatment for metastatic prostate cancer. The use of this treatment modality for a number of years in a large population has demonstrated some of its iatrogenic complications, especially bone complications. Hypogonadism induced by chemical castration can be responsible for osteoporosis that may be complicated by fractures.

Objective: Evaluation of the prevalence of fractures in nonmetastatic sites.

Patients And Method: Retrospective study of 49 patients treated for more than 5 years by endocrine therapy with determination of the fracture rate, mechanisms and fracture sites.

Results: Eight patients developed fractures after antiandrogen treatment. Three patients with a traumatic or metastatic fracture were excluded. Five patients (10.2%) were considered to present osteoporotic fractures on the basis of their site (vertebra and neck of femur) or their mechanism (minor trauma). The mean duration of treatment in these patients was 8.1 years. The prevalence of osteoporotic fractures in the general population is estimated to be 2.2 per 1,000 men between the ages of 65 and 80 years and 6.4 per 1,000 men after the age of 80 years.

Conclusion: The prevalence of osteoporosis induced by endocrine therapy is increasing due to longer patient survival and early introduction of treatment. No prophylactic treatment is currently proposed when starting endocrine therapy.