Bone mineral density, pathological fractures and bisphosphonate therapy in prostate cancer patients on androgen deprivation therapy.

OBJECTIVES: The aim of the study is to evaluate the changes of bone mineral density (BMD), incidence of pathological fractures and to asses the effect of bisphosphonate therapy in prostate cancer patients (PCa) on androgen deprivation therapy (ADT) with the use of LHRH. METHODS: In this prospective study bone mass density (BMD) was assessed by dual x-ray absorptiometry (DXA) in 97 PCa patients and 89 patients of compared group. DXA was examined at baseline and patients in the study group were subjected to ADT. PCa patients with osteoporosis were treated by calcium, vitamin D, and bisphosphonate and the subsequent DXA was made after 10 months. All other PCa patients (non-osteoporotic) had DXA examined every 12-14 months. RESULTS: Patients of the study group had significantly lower baseline L1-L4 and total hip BMD (p=0.028, p=0.022). BMD was significantly lower in L1-L4 and total hip (p=0.004, p<0.001, resp.) after 10-14 months and in L1-L4, femoral neck, and total hip (p=0.001, p=0.037, p< 0.001, resp.) after 20-26 months of ADT. After the treatment for osteoporosis with bisphosphonate a significant increase of BMD (p=0.04) was found in a total of 23 patients. Overall, the incidence of fractures after 20-26 months of ADT was 8.5 %. CONCLUSIONS: Osteopenia is very common in hormone naive PCa patients. There was a significant loss of BMD after 12 months of ADT which was progressive while the patients were on ADT. Bisphosphonate therapy was effective after 20 months of treatment. The incidence of pathological fractures was 7-fold higher in the study group.