Guidance for the assessment and management of prostate cancer treatment-induced bone loss. A consensus position statement from an expert group.

CONTEXT AND OBJECTIVE: Incidence of prostate cancer (PC) is increasing, but androgen deprivation therapy (ADT) and other therapies are substantially improving survival. In this context, careful consideration of skeletal health is required to reduce the risk of treatment-related fragility fractures and their associated morbidity and mortality. This risk is currently not well-managed. ADT causes significant loss of bone mineral density (BMD). In the metastatic setting, systemic treatments (e.g. chemotherapy, abiraterone, enzalutamide) are used alongside ADT and may require concomitant glucocorticoids. Both ADT and glucocorticoids pose significant challenges to skeletal health in a population of patients already likely to have ongoing age-related bone loss and/or comorbid conditions. Current PC guidelines lack specific recommendations for optimising bone health. This guidance presents evidence for assessment and management of bone health in this population, with specific recommendations for clinical practitioners in day-to-day PC management. METHODS: Structured meetings of key opinion leaders were integrated with a systematic literature review. Input and endorsement was sought from patients, nursing representatives and specialist societies. SUMMARY OF GUIDANCE: All men starting or continuing long-term ADT should receive lifestyle advice regarding bone health. Calcium/vitamin D supplementation should be offered if required. Fracture risk should be calculated (using the FRAX® tool), with BMD assessment included where feasible. BMD should always be assessed where fracture risk calculated using FRAX® alone is close to the intervention threshold. Intervention should be provided if indicated by local or national guidelines e.g. UK National Osteoporosis Guideline Group (NOGG) thresholds. Men requiring bone protection therapy should be further assessed (e.g. renal function), with referral to specialist centres if available and offered appropriate treatment to reduce fracture risk. Those near to, but below an intervention threshold, and patients going on to additional systemic therapies (particularly those requiring glucocorticoids), should have FRAX® (including BMD) repeated after 12-18 months. PATIENT SUMMARY: Modern treatments for prostate cancer have led to significant improvements in survival and quality of life. However, some of these treatments may lead to weakening of patient's bones with risk of fracture and it is therefore important to monitor patients' bone health and provide bone protection where needed. This paper provides specific guidance to clinical teams, based on the most recent research evidence, to ensure optimal bone health in their patients.

Bone mineral density loss during adjuvant chemotherapy in pre-menopausal women with early breast cancer: is it dependent on oestrogen deficiency?

Pre-menopausal women given adjuvant chemotherapy for breast cancer experience both premature ovarian failure and loss of bone mineral density (BMD), and this study was designed to see if these observations are causally linked. Chemotherapy was administered to 41 pre-menopausal women with early breast cancer enrolled prospectively in a study of ovarian function and BMD in such women given systemic therapy. After giving written informed consent, all patients underwent baseline and regular on-treatment measurements of BMD by dual-energy X-ray absorptiometry (DXA) scan, bone turnover and ovarian function by analysis of serum hormone levels and self-reported menstrual diaries. Baseline lumbar spine BMD in the 41 women given chemotherapy was higher than the normal population (Z score 0.28 ± 0.14 (mean ± SEM), P = 0.047), and fell significantly over the first 6 months from a mean of 1.05-1.01 g/m(2), P < 0.0001, and similar but smaller changes were demonstrated in hip BMD. This fall was independent of age at diagnosis, type of chemotherapy, development of amenorrhoea or either baseline or on-treatment estradiol concentration. During the 6 months after completion of adjuvant chemotherapy, BMD fell further only in those women with low estradiol or experiencing amenorrhoea during the first 6 months, although all groups showed evidence of increased bone turnover. This study demonstrates loss of both spine and hip BMD in pre-menopausal women during 6 months' adjuvant systemic chemotherapy to be independent of changes in ovarian function. Ovarian function was, however, related to BMD changes after chemotherapy ceased.

Prevention of anastrozole-induced bone loss with monthly oral ibandronate during adjuvant aromatase inhibitor therapy for breast cancer.

PURPOSE: The aromatase inhibitor anastrozole is a highly effective well-tolerated treatment for postmenopausal endocrine-responsive breast cancer. However, its use is associated with accelerated bone loss and an increase in fracture risk. The ARIBON trial is a double-blind, randomized, placebo-controlled study designed to evaluate the impact of bisphosphonate treatment on bone mineral density (BMD) in women taking anastrozole. EXPERIMENTAL DESIGN: BMD was assessed in 131 postmenopausal, surgically treated women with early breast cancer at two U.K. centers. Of these, 50 patients had osteopenia (T score -1.0 to -2.5) at either the hip or lumbar spine. All patients were treated with anastrozole 1 mg once a day and calcium and vitamin D supplementation. In addition, osteopenic patients were randomized to receive either treatment with ibandronate 150 mg orally every month or placebo. RESULTS: After 2 years, osteopenic patients treated with ibandronate gained +2.98% (range -8.9, +19.9) and +0.60% (range -9.0, +6.9) at the lumbar spine and hip, respectively. Patients treated with placebo, however, lost -3.22% (range -16.0, +4.3) at the lumbar spine and -3.90% (range -12.3, +7.2) at the hip. The differences between the two treatment arms were statistically significant at both sites (P < 0.01). At 12 months, urinary n-telopeptide, serum c-telopeptide, and serum bone-specific alkaline phosphatase levels declined in patients receiving ibandronate (30.9%, 26.3%, and 22.8%, respectively) and increased in those taking placebo (40.3%, 34.9%, and 37.0%, respectively). CONCLUSIONS: Monthly oral ibandronate improves bone density and normalizes bone turnover in patients treated with anastrozole.

The role of bisphosphonates in breast and prostate cancers.

Bisphosphonate drugs are a group of pyrophosphate analogues which bind avidly to hydroxyapatite bone mineral surfaces and their major action is to inhibit osteoclast activity and thus bone resorption. In oncology, their role in metastatic bone disease is well established, but there is increasing interest in their potential role in preventing and treating cancer-induced bone loss and their possible anti-tumour effects. Metastatic bone disease is associated with a variety of skeletal complications, including pathologic fractures, bone pain, impaired mobility, spinal cord compression and hypercalcaemia. Intravenous bisphosphonates, particularly zoledronic acid, in conjunction with rehydration, are now established as the treatment of choice for hypercalcaemia. For treatment of bone pain, it has also been shown that bisphosphonates can be an effective supplementary approach to radiotherapy. In breast cancer and myeloma, bisphosphonates have now become part of standard therapy to treat and prevent skeletal-related events (SRE) and, until recently, treatment was largely with intravenous pamidronate or oral clodronate. However, large, randomised, multicentre trials using intravenous administration of the highly potent bisphosphonate zoledronic acid every 3-4 weeks have recently demonstrated a reduction of 20% in the risk of developing an SRE compared with pamidronate for patients with breast cancer. Moreover, these trials have demonstrated, for the first time, that a bisphosphonate significantly reduces the occurrence of skeletal events in hormone-refractory prostate cancer and in non-small cell lung cancer and a range of other solid tumours. Investigations into the potential of the relatively low potency bisphosphonate, clodronate, for the prevention of bone metastases in breast cancer have produced conflicting data. Further large, randomised studies with clodronate and zoledronic acid are planned and until the results are available it is not possible to identify a definite adjuvant role for bisphosphonates. Evidence is accumulating in vitro that bisphosphonates are also able to directly affect tumour cells, in addition to their effects on osteoclasts, with zoledronic acid being particularly potent. Over recent decades there has been a significant improvement in cure rates and survival times in certain cancers and the use of chemotherapy and hormone therapy has expanded greatly, leading to increasing numbers of long-term survivors who have received these treatments. Management of treatment-induced bone loss is therefore assuming a greater importance and bisphosphonates represent an attractive treatment option in such patients. Several placebo-controlled trials using oral clodronate, oral risedronate, intravenous pamidronate and intravenous zoledronic acid have all now demonstrated benefits in reducing the loss in bone mineral density.