Incidence of bone fracture in Japanese patients receiving long-term hormone therapy for prostate cancer.

e16098 Background: For patients with advanced prostate cancer, long-term treatment of androgen deprivation has been conventionally performed. Among the adverse events such as hormonal therapy, bone fracture due to osteoporosis or metastatsis is one of indispensable events. We assessed the frequency of bone fractures in Japanese patients received hormonal therapy. Methods: Between 2000 and 2010, 1,108 Japanese patients were treated with hormonal therapy including GnRH agonist plus anti-androgens or GnRH agonist alone at Yokohama City University Hospital. Of those patients, 48 patients (4.3%) had bone fractures during their treatment. In this retrospective study, we examined the association of bone fracture with the long-term hormonal therapy by investigating the duration of hormonal therapy, fracture sites, and the occurrence of fracture in castration resistant prostate cancer (CRPC) patients. Results: The median age of the patients with fracture was 77 (60-85) years; the median duration from the start of hormonal therapy to fracture was 29.4 (5.4-110.4) months. Eight patients with CRPC had pathological fractures at bone metastases. With respect of fracture sites, 22 patients (46%) had spinal fractures and 10 patients (21%) had fracture of lower legs. Of 8 CRPC patients, 7 patients had spinal fracture after long-term hormonal therapy (median: 38.6 months, range: 15.7-99.1 months). Conclusions: Japanese patients with prostate cancer treated with hormonal therapy have lower risk for bone fracture compared with those in western countries and USA, and interestingly, it is recognized that vertebral body is vulnerable to fracture in Japanese, especially in CRPC patients treated for long-term hormonal therapy. Because bone fracture in patients with prostate cancer endanger their prognosis, the bone management how to prevent bone fracture is very important during hormonal therapy. For the purpose of it, more detailed analysis in this retrospective study should be required.