To know the prevalence of osteoporosis in patients with prostate cancer according to the duration of androgen deprivation therapy (ADT).

Dual energy x-ray absorptiometry was used to assess the bone mineral density (BMD) at the lumbar spine, femoral neck, Ward’s triangle, trochanter, and total hip in 390 patients free of bone metastases. Osteoporosis was diagnosed if a T-score of less than 2.5 was detected at any measurement site. A subset of 124 patients were hormone naive at BMD testing, and 112 had undergone ADT for 2 years, 61 for 4 years, 37 for 6 years, 35 for 8 years, and 21 for 10 years or longer.

The osteoporosis rate was 35.4% in hormone-naive patients, 42.9% after 2 years of ADT, 49.2% after 4 years, 59.5% after 6 years, 65.7% after 8 years, and 80.6% after 10 or more years. Conversely, the rate of normal BMD decreased from 19.4% in hormone-naive patients to 17.8% after 2 years of ADT, 16.4% after 4 years, 10.8% after 6 years, 5.7% after 8 years, and 0% after 10 or more years of ADT.

The prevalence of osteoporosis seemed high in hormone-naive patients with prostate cancer, and it increased to more than 80% after 10 years of ADT. Because of the increased risk of bone fractures in those patients, clinicians should be aware of the impact of ADT on BMD to prevent bone mass loss.