High prevalence of vertebral fractures at initiation of androgen deprivation therapy for prostate cancer

PURPOSE: Treatment of Prostate Cancer (PCa) with Androgen Deprivation Therapy (ADT) involves long-term consequences including bone loss and fractures. Our aim was to evaluate the calculated fracture risk and the prevalence of osteoporosis, vertebral fractures (VF) and sarcopenia in men with PCa at initiation of ADT, as ADT will increase fracture risk from that moment onward.

METHODS: In this cross-sectional real-world study in men at ADT initiation, fracture risk factors including comorbidities, medication, and 10-year fracture risk (FRAX®) were assessed. Laboratory tests, dual-energy X-ray absorptiometry, and spinal X-rays were performed. Sarcopenia was defined according to EWGSOP2.

RESULTS: In 115 men at ADT initiation, aged 73.3 (±7.6) years, osteoporosis was diagnosed in 4.3 % and osteopenia in 35.7 %. The mean 10-year fracture risk of major osteoporotic fracture was 4.4 % and of hip fracture 1.7 %, respectively. At least one VF was present in 32.2 % and 33.9 % of men had osteoporosis and/or a VF assessed on spinal X-rays. In 10.4 % at least one new fracture-risk-associated metabolic bone disorder was diagnosed with laboratory testing. Sarcopenia was diagnosed in only one patient.

CONCLUSIONS: Although the prevalence of osteoporosis, sarcopenia and 10-years fracture risk is low, there is a high prevalence of vertebral fractures in a third of the men with PCa at the time of ADT initiation. Besides a BMD measurement and fracture risk calculation using FRAX, a systematic vertebral fracture assessment should be considered in all men with PCa at initiation of ADT to provide a reliable baseline classification of VFs to improve identification of true incident VFs during ADT.