Paul R. Sieber, MD, FACS
The use of androgen deprivation therapy (ADT) in prostate cancer is now a well-established treatment regimen. Whether in the neoadjuvant setting with high-risk prostate cancer, in biochemical recurrence after definitive therapy, or in the setting of metastatic disease, its use can be described as “routine.” Unfortunately, ADT is associated with an increased risk for bone fracture.
The American Urological Association (AUA) guidelines, however, offer just 2 options for the management of bone health:
- Clinicians should offer preventive treatment (eg supplemental calcium, vitamin D) for fractures and skeletal related events to patients with castration-resistant prostate cancer (CRPC).
- Clinicians may choose either denosumab (Prolia) or zoledronic acid when selecting a preventive treatment for skeletal related events for patients with metastatic CRPC and bony metastases.
With that background, urologists need additional information to better understand risk assessment, monitoring, and appropriate treatments for these patients.
As a clinician assesses whether a patient should initiate ADT, there are appropriate minimal steps to take to address bone health. First, obtain a bone health history, including assessing loss in height as an indicator of prior vertebral compression fractures; a personal and family history of fragility fractures, assessing calcium and vitamin D intake; smoking history; ethanol consumption; history of falls, and review of prior BMD assessments. This may not be in the usual routine of a urologist; for example, a fragility fracture is any fracture from a standing height or an asymptomatic vertebral compression fracture.
Figure 1. FRAX Fracture Risk Assessment Tool6
The free online World Health Organization Fracture Risk Assessment Tool (FRAX), which can be used with or without BMD data (FIGURE 16
) is one suggestion. FRAX estimates the 10-year risk of either a major osteoporotic fracture or a hip fracture. FRAX was developed to calculate the 10-year probability of a hip fracture and the 10-year probability of a major osteoporotic fracture (defined as a clinical vertebral, hip, forearm, or proximal humerus fracture), taking into account femoral neck BMD and clinical risk factors (TABLE).6
Table. Clinical Risk Factors Included in the FRAX Fracture Risk Assessment Tool6
Suggested thresholds for pharmacologic intervention include a 20% or greater risk of major osteoporotic fracture risk in 10 years or a 3% or greater risk of hip fracture in 10 years; however, treatment decisions must be made based on the individual’s situation. FRAX is not reliable once patients are receiving antiresorptive therapy.
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