In many patients with prostate cancer, androgen deprivation therapy (ADT) is administered over prolonged periods of time. The benefits of long-term ADT in patients with advanced disease are well established and, more recently, studies have shown that long-term adjuvant ADT used in combination with radiotherapy improves survival in patients with earlier stages of disease. Nevertheless, clinicians should remain aware of the potential long-term side effects of ADT and the strategies that can be used to manage or prevent long-term complications.
One such strategy is intermittent androgen deprivation (IAD), in which patients receive cycles of ADT, the duration of which is usually determined by PSA levels. Accumulating data indicate that this approach improves the tolerability of ADT (particularly sexual dysfunction) and patients' quality of life, without compromising clinical outcomes (progression and survival). Indeed, the latest European Association of Urology guidelines state that IAD should no longer be considered investigational. Nevertheless, some questions remain unanswered, including: who are the most suitable patients for IAD and what are the optimal PSA levels for stopping and restarting treatment?
Osteoporosis (and the resultant increased risk of fractures) is a well-recognized complication of long-term ADT. Bone mineral density should be measured before and during long-term ADT and patients advised to make appropriate lifestyle changes to help preserve bone health. Pharmacological intervention is also an option. Denosumab (an NF-κB ligand inhibitor) significantly reduces ADT-induced bone loss and the risk of fractures in patients with non-metastatic disease. In those whose disease has metastasized, zoledronate and denosumab are licensed to prevent skeletal-related events and a large randomized study has shown that denosumab is more effective than zoledronate in this setting.