Randomized trial of denosumab in patients receiving adjuvant aromatase inhibitors for nonmetastatic breast cancer

Bone Health in Patients with Breast Cancer: Recommendations from an Evidence-Based Canadian Guideline

Bone loss is common in patients with breast cancer. Bone modifying agents (BMAs), such as bisphosphonates and denosumab, have been shown to reverse or stabilize bone loss and may be useful in the primary and metastatic settings. The purpose of this review is to provide clear evidence-based strategies for the management of bone loss and its symptoms in breast cancer. A systematic review of clinical trials and meta-analyses published between 1996 and 2012 was conducted of MEDLINE and EMBASE. Reference lists were hand-searched for additional publications. Recommendations were developed based on the best available evidence. Zoledronate, pamidronate, clodronate, and denosumab are recommended for metastatic breast cancer patients; however, no one agent can be recommended over another. Zoledronate or any oral bisphosphonate and denosumab should be considered in primary breast cancer patients who are postmenopausal on aromatase inhibitor therapy and have a high risk of fracture and/or a low bone mineral density and in premenopausal primary breast cancer patients who become amenorrheic after therapy. No one agent can be recommended over another. BMAs are not currently recommended as adjuvant therapy in primary breast cancer for the purpose of improving survival, although a major Early Breast Cancer Cooperative Trialists’ Group meta-analysis is underway which may impact future practice. Adverse events can be managed with appropriate supportive care.

Denosumab in osteoporosis

INTRODUCTION

Denosumab is a fully human monoclonal antibody against the receptor activator of nuclear factor kappa-B ligand. It is an antiresorptive agent that reduces osteoclastogenesis.

AREAS COVERED

This drug evaluation reviews denosumab for use in osteoporosis. Denosumab has been shown to improve bone mineral density (BMD) and to reduce the incidence of new vertebral, hip and nonvertebral fractures in postmenopausal women. It prevents bone loss and reduces vertebral fracture risk in men with nonmetastatic prostate cancer who are receiving androgen deprivation therapy. It has also been shown to improve BMD in men with osteoporosis unrelated to androgen deprivation therapy. Safety concerns include infections, cancer, skin reactions, cardiovascular disease, hypocalcemia, osteonecrosis of the jaw and atypical femur fractures.

EXPERT OPINION

Although bisphosphonates are typically preferred as initial therapy for osteoporosis, denosumab could be used as initial therapy in select patients at high risk for fracture, including older patients who have difficulty with the dosing requirements of oral bisphosphonates, patients who are intolerant of or unresponsive to other therapies, and in those with impaired renal function. Additional data is needed to address issues regarding treatment duration and discontinuation, as well as to provide more information regarding denosumab's efficacy and safety.

Skeletal manifestations of treatment of breast cancer

Breast cancer and osteoporosis are common diagnoses in women. Breast cancer survival has improved due to earlier detection and improved treatments. As most breast cancers are estrogen receptor positive, treatment is often aimed at altering the hormonal environment. Both pre and postmenopausal women undergoing these therapies are at risk for bone loss. The patient's health care team ought to have an awareness of the potential for breast cancer treatments to accelerate bone loss. Women with early stage breast cancer are treated with curative intent and, therefore, maintaining bone health is important and is part of the survivorship care to ensure an optimal quality of life.

Cancer-associated bone disease

Bone is commonly affected in cancer. Cancer-induced bone disease results from the primary disease, or from therapies against the primary condition, causing bone fragility. Bone-modifying agents, such as bisphosphonates and denosumab, are efficacious in preventing and delaying cancer-related bone disease. With evidence-based care pathways, guidelines assist physicians in clinical decision-making. Of the 57 million deaths in 2008 worldwide, almost two thirds were due to non-communicable diseases, led by cardiovascular diseases and cancers. Bone is a commonly affected organ in cancer, and although the incidence of metastatic bone disease is not well defined, it is estimated that around half of patients who die from cancer in the USA each year have bone involvement. Furthermore, cancer-induced bone disease can result from the primary disease itself, either due to circulating bone resorbing substances or metastatic bone disease, such as commonly occurs with breast, lung and prostate cancer, or from therapies administered to treat the primary condition thus causing bone loss and fractures. Treatment-induced osteoporosis may occur in the setting of glucocorticoid therapy or oestrogen deprivation therapy, chemotherapy-induced ovarian failure and androgen deprivation therapy. Tumour skeletal-related events include pathologic fractures, spinal cord compression, surgery and radiotherapy to bone and may or may not include hypercalcaemia of malignancy while skeletal complication refers to pain and other symptoms. Some evidence demonstrates the efficacy of various interventions including bone-modifying agents, such as bisphosphonates and denosumab, in preventing or delaying cancer-related bone disease. The latter includes treatment of patients with metastatic skeletal lesions in general, adjuvant treatment of breast and prostate cancer in particular, and the prevention of cancer-associated bone disease. This has led to the development of guidelines by several societies and working groups to assist physicians in clinical decision making, providing them with evidence-based care pathways to prevent skeletal-related events and bone loss. The goal of this paper is to put forth an IOF position paper addressing bone diseases and cancer and summarizing the position papers of other organizations.

Denosumab and giant cell tumour of bone-a review and future management considerations

Giant cell tumour of bone (gctb) is one type of giant-cell-rich bone lesion characterized by the presence of numerous multinucleated osteoclast-type giant cells. Giant cells are known to express rankl (receptor activator of nuclear factor κB ligand) and are responsible for the aggressive osteolytic nature of the tumour. No available treatment option is definitively effective in curing this disease, especially in surgically unsalvageable cases. In recent years, several studies of denosumab in patients with advanced or unresectable gctb have shown objective changes in tumour composition, reduced bony destruction, and clinical benefit. Denosumab is a fully human monoclonal antibody that targets and binds with high affinity and specificity to rankl. Several large phase iii studies have shown that denosumab is more effective than bisphosphonates in reducing skeletal morbidity arising from a wide range of tumours and that it can delay bone metastasis. The relevant articles are reviewed here. The controversies related to the future use of denosumab in the treatment of gctb are discussed.

Multifunctional properties of RANKL/RANK in cell differentiation, proliferation and metastasis

It is known that there are close relationships between bone destruction and tumor growth in bone metastasis. RANKL is a central factor in bone metastasis, inducing osteoclastogenesis mediated by its receptor RANK. Recent reports demonstrate that RANKL has important roles in organogenesis stimulating proliferation and differentiation of epithelial and stroma cells. RANKL is induced not only by cytokines and hormones but also by UV-irradiation, inflammation and carcinogens. Expression of RANK and RANKL is found in several human cancer cell lines, and RANK signaling stimulates proliferation, migration and epithelial–mesenchymal transition of cancer cells, which may be involved in metastasis via an autocrine/paracrine mechanism. RANKL regulates the number of Tregs that produce RANKL, which may affect cancer metastasis. In this review we discuss the multifunctional roles of RANKL/RANK in osteoclastogenesis, organogenesis, and the metastasis and tumorigenesis of cancer cells.

Incidence and risk of denosumab-related hypocalcemia in cancer patients: a systematic review and pooled analysis of randomized controlled studies

PURPOSE

The aim of this study is to evaluate the frequency and relative risk of hypocalcemia in cancer patients receiving denosumab.

METHODS

We searched the PubMed (data from 1966 to October 2012), Embase (data from 1980 to October 2012) and Cochrane Library (up to October 2012) electronic databases for relevant randomized controlled trials (RCTs). Abstracts presented at conferences were also searched. Phase II and III trials of denosumab in patients with any type of cancer that reported occurrence of hypocalcemia were eligible. Overall incidence rates, relative risk (RR), and 95% confidence intervals (CI) were calculated employing fixed- or random-effects models depending on the heterogeneity among included trials.

RESULTS

A total of 8990 patients with a variety of solid tumors from seven RCTs were included for the meta-analysis. The overall incidences of all-grade and high-grade hypocalcemia in cancer patients were 5.2% (95% confidence interval [CI]: 2.8-9.3%) and 2.0% (95% CI: 0.7-5.5%), respectively. The use of denosumab was associated with significantly increased risk of developing all-grade (RR 1.932, 95% CI: 1.590-2.347, p < 0.001) and high-grade hypocalcemia (RR 4.027, 95% CI: 2.346-6.912, p < 0.001) in comparison with controls.

CONCLUSIONS

The use of denosumab is associated with a significantly increased risk of developing hypocalcemia (p < 0.001). Physicians should be aware of this adverse effect and should monitor cancer patients receiving denosumab.

Calcium and vitamin D supplementation and loss of bone mineral density in women undergoing breast cancer therapy

An unintended consequence of breast cancer therapies is an increased risk of osteoporosis due to accelerated bone loss. We conducted a systematic review of calcium and/or vitamin D (Ca±D) supplementation trials for maintaining bone mineral density (BMD) in women with breast cancer using the "before-after" data from the Ca±D supplemented comparison group of trials evaluating the effect of drugs such as bisphosphonates on BMD. Whether Ca±D supplements increase BMD in women undergoing breast cancer therapy has never been tested against an unsupplemented control group. However, results from 16 trials indicate that the Ca±D doses tested (500-1500mg calcium; 200-1000IU vitamin D) were inadequate to prevent BMD loss in these women. Cardiovascular disease is the main cause of mortality in women with breast cancer. Because calcium supplements may increase cardiovascular disease risk, future trials should evaluate the safety and efficacy of Ca±D supplementation in women undergoing breast cancer therapy.

Breast cancer survivorship issues

Survivors of breast cancer are confronted with a plethora of cancer treatment-related long-term symptoms, the most common being fatigue, hot flashes, sexual dysfunction, arthralgias, neuropathy, and cognitive dysfunction. Survivors of breast cancer also face cancer treatment-related disease states, such as osteoporosis, cardiac dysfunction, obesity, infertility, and secondary cancers. Evidence-based recommendations for screening, prevention, and early intervention should be implemented to improve quality of life and decrease comorbidities in this population.

Vitamin D supplementation and breast cancer prevention: a systematic review and meta-analysis of randomized clinical trials

In recent years, the scientific evidence linking vitamin D status or supplementation to breast cancer has grown notably. To investigate the role of vitamin D supplementation on breast cancer incidence, we conducted a systematic review and meta-analysis of randomized controlled trials comparing vitamin D with placebo or no treatment. We used OVID to search MEDLINE (R), EMBASE and CENTRAL until April 2012. We screened the reference lists of included studies and used the “Related Article” feature in PubMed to identify additional articles. No language restrictions were applied. Two reviewers independently extracted data on methodological quality, participants, intervention, comparison and outcomes. Risk Ratios and 95% Confident Intervals for breast cancer were pooled using a random-effects model. Heterogeneity was assessed using the I² test. In sensitivity analysis, we assessed the impact of vitamin D dosage and mode of administration on treatment effects. Only two randomized controlled trials fulfilled the pre-set inclusion criteria. The pooled analysis included 5372 postmenopausal women. Overall, Risk Ratios and 95% Confident Intervals were 1.11 and 0.74–1.68. We found no evidence of heterogeneity. Neither vitamin D dosage nor mode of administration significantly affected breast cancer risk. However, treatment efficacy was somewhat greater when vitamin D was administered at the highest dosage and in combination with calcium (Risk Ratio 0.58, 95% Confident Interval 0.23–1.47 and Risk Ratio 0.93, 95% Confident Interval 0.54–1.60, respectively). In conclusions, vitamin D use seems not to be associated with a reduced risk of breast cancer development in postmenopausal women. However, the available evidence is still limited and inadequate to draw firm conclusions. Study protocol code: FARM8L2B5L.

Impact of denosumab on bone mass in cancer patients

Cancer therapy-induced bone loss (CTIBL) is a form of secondary osteoporosis associated with systemic chemotherapy and hormonal ablation therapy. The monitoring and treatment of CTIBL is an important component of comprehensive cancer care, especially for patients with curable disease and long life expectancies. Whereas oral bisphosphonates remain the most commonly used therapeutic option for CTIBL, additional treatment options may be required for patients who do not respond adequately or are intolerant to bisphosphonates, have renal insufficiency, or are receiving treatment with nephrotoxic medications. For these patients, denosumab, a monoclonal antibody targeting the receptor activator of nuclear factor-κB ligand (RANKL), offers an effective and well-tolerated alternative. Several recent randomized trials have examined the use of denosumab as treatment for CTIBL associated with hormone ablation therapy for breast and prostate cancer. Recent data suggest a possible role for RANKL inhibitors in both chemoprevention and the prevention of cancer recurrence through direct effects on breast tissue and breast cancer stem cells. The outcomes of several international Phase III clinical trials currently underway will help clarify the role of denosumab in patients undergoing cancer therapy.

Adjuvant bisphosphonates in breast cancer: has the time come?

SUMMARY Bone metabolism is highly affected by changes in ovarian function, which is a common consequence of the treatment of breast cancer patients. Osteopenia and osteoporosis increase the risk of fractures, which are associated with profound loss in quality of life. Bisphosphonates are used with the objective of preventing bone loss in patients with osteoporosis, but data suggest that agents such as zoledronic acid might play a role in the prevention of metastatic disease and therefore have been evaluated in numerous randomized trials in the adjuvant setting. This review article will discuss and analyze the available data regarding the use of bisphosphonates in the adjuvant setting for breast cancer patients. It will focus on the use of bisphosphonates as anticancer agents, but will also discuss the use of these agents for the prevention of bone loss.

Myeloma bone disease: Pathophysiology and management

Multiple myeloma bone disease is marked by severe dysfunction of both bone formation and resorption and serves as a model for understanding the regulation of osteoblasts (OBL) and osteoclasts (OCL) in cancer. Myeloma bone lesions are purely osteolytic and are associated with severe and debilitating bone pain, pathologic fractures, hypercalcemia, and spinal cord compression, as well as increased mortality. Interactions within the bone marrow microenvironment in myeloma are responsible for the abnormal bone remodeling in myeloma bone disease. Myeloma cells drive bone destruction that increases tumor growth, directly stimulates the OCL formation, and induces cells in the marrow microenvironment to produce factors that drive OCL formation and suppress OBL formation. Factors produced by marrow stromal cells and OCL promote tumor growth through direct action on myeloma cells and by increasing angiogenesis. Current therapies targeting MMBD focus on preventing osteoclastic bone destruction; however regulators of OBL inhibition in MMBD have also been identified, and targeted agents with a potential anabolic effect in MMBD are under investigation. This review will discuss the mechanisms responsible for MMBD and therapeutic approaches currently in use and in development for the management of MMBD.

What Is the Optimal Endocrine Therapy for Postmenopausal Women With Hormone Receptor–Positive Early Breast Cancer?

A 56-year-old postmenopausal woman with a recent diagnosis of breast cancer was referred to discuss adjuvant therapy. Annual screening mammogram demonstrated a suspicious mass in the left breast. Ultrasound-guided core needle biopsy revealed an infiltrating ductal carcinoma that was estrogen receptor (ER) positive and progesterone receptor (PR) negative and lacked amplification of human epidermal growth factor receptor 2 (HER2; ie, HER2 negative). She underwent excision and sentinel node evaluation. Pathology demonstrated a 1.9-cm grade 2 invasive cancer without lymphatic vascular invasion; clean margins were obtained, and both sentinel nodes were free of cancer. The 21-gene recurrence score was 16. She has a body mass index (BMI) of 28.5 but is otherwise healthy; levothyroxine is the only prescription medication she takes. She experienced vaginal spotting 2 years earlier because of an endometrial polyp, which was resected. She exercises regularly and takes a calcium supplement with vitamin D. Bone density study performed 6 months earlier was normal other than mild osteopenia in the femoral neck (T score, −1.3). Radiation therapy is planned

Denosumab in breast cancer treatment

The bone is the most common site to which breast cancer metastasises. Recently, denosumab, a fully human monoclonal antibody that binds to receptor activator of nuclear factor kappa-B ligand (RANKL) has been developed as a new targeted bone therapy. In a large randomized phase III study with a head-to-head comparison of denosumab to zoledronic acid in patients with bone metastases of breast cancer, denosumab significantly delayed the time to first skeletal related event. In the adjuvant setting denosumab significantly increased bone mineral density compared to placebo in a phase III study in patients treated with aromatase inhibitors. Preclinical data suggest an effect of denosumab on tumour growth and even on carcinogenesis. This review describes the current indications for denosumab in the various settings of breast cancer treatment, with special attention for efficacy, short and long term toxicity and other relevant issues for clinical practice. Furthermore possible and necessary future research questions are proposed.

Aromatase inhibitor adjuvant chemotherapy of breast cancer results in cancer therapy induced bone loss

Aromatase Inhibitors are anti-estrogen agents that have proven efficacy for adjuvant therapy of estrogen receptor positive breast cancer primarily in post menopausal women with estrogen receptor positive breast cancer but increase the risk of cancer therapy induced bone loss (CTIBL). Recent studies have shown the potential benefit of bisphosphonate therapy to play a dual role in the management of breast cancer. These studies provide evidence that bisphosphonate therapy in conjunction with aromatase inhibitors (AI), not only decreases the risk of osteoporosis but, in addition, may improve survival from breast cancer.

[Treatment effect of breast cancer and prostate cancer on bone]

Aromatase inhibitors are used in the treatment of breast cancer and androgen deprivation therapy is used in prostate cancer. Both of them induce bone loss and increase fracture incidence. Early detection is important for patients with increased risk of osteoporotic fractures. In this article we review the available treatments and their indication to prevent the onset of osteoporosis and osteoporotic fractures in this patient group.

Responder analysis of the effects of denosumab on bone mineral density in men receiving androgen deprivation therapy for prostate cancer

BACKGROUND

Denosumab, a fully human monoclonal antibody against RANK ligand, increased bone mineral density (BMD) and reduced fracture risk vs placebo in a phase 3 trial in men with prostate cancer on androgen deprivation therapy (ADT). The present analysis of this study evaluated BMD changes after 36 months in responder subgroups and in individual patients for three key skeletal sites (lumbar spine (LS), femoral neck (FN) and total hip (TH)) and the distal radius.

METHODS

Men with nonmetastatic prostate cancer receiving ADT were treated with subcutaneous denosumab 60 mg (n=734) or placebo (n=734) every 6 months for up to 36 months in a phase 3, randomized, double-blind study. Patients were instructed to take supplemental calcium and vitamin D. For this BMD responder analysis, the primary outcome measure was the percentage change in BMD from baseline to month 36 at the LS, FN and TH as measured by dual-energy X-ray absorptiometry. BMD at the distal 1/3 radius at 36 months was measured in a substudy of 309 patients.

RESULTS

At 36 months, significantly more patients in the denosumab arm had increases of >3% BMD from baseline at each site studied compared with placebo (LS, 78 vs 17%; FN, 48 vs 13%; TH, 48 vs 6%; distal 1/3 radius, 40 vs 7% (P<0.0001 for all)). BMD loss at the LS, FN and TH occurred in 1% of denosumab-treated patients vs 42% of placebo patients, and BMD gain at all three sites occurred in 69% of denosumab patients vs 8% of placebo patients. Lower baseline BMD was associated with higher-magnitude BMD responses to denosumab at the LS, FN and TH.

CONCLUSIONS

In men with prostate cancer receiving ADT, significantly higher BMD response rates were observed with denosumab vs placebo. Patients with lower baseline T-scores benefited the most from denosumab treatment.

High- and low-dose OPG-Fc cause osteopetrosis-like changes in infant mice

BACKGROUND

Receptor activator of nuclear factor-κB ligand (RANKL) inhibitors are being considered for use in children with osteogenesis imperfecta (OI). We sought to assess efficacy of two doses of a RANKL inhibitor, osteoprotegerin-immunoglobulin Fc segment complex (OPG-Fc), in a growing animal model of OI, the col1α2-deficient mouse (oim/oim) and its wild-type controls (+/+).

METHODS

Treated mice showed runting and radiographic evidence of osteopetrosis with either high- (20 mg/kg twice weekly) or low-dose (1 mg/kg/week) OPG-Fc. Because of this adverse event, OPG-Fc treatment was halted, and the mice were killed or monitored for recovery with monthly radiographs and assessment of serum osteoclast activity (tartrate-resistant acid phosphatase 5b, TRACP-5b) until 25 wk of age.

RESULTS

Twelve weeks of OPG-Fc treatment resulted in radiographic and histologic osteopetrosis with no evidence of bone modeling and negative tartrate-resistant acid phosphatase staining, root dentin abnormalities, and TRACP-5b activity suppression. Signs of recovery appeared 4-8 wk post-treatment.

CONCLUSION

Both high- and low-dose OPG-Fc treatment resulted in osteopetrotic changes in infant mice, an outcome that was not seen in studies with the RANKL inhibitor RANK-immunoglobulin Fc segment complex (RANK-Fc) or in studies with older animals. Further investigations of RANKL inhibitors are necessary before their consideration for use in children.

Protection of bone in premenopausal women with breast cancer: focus on zoledronic acid

Maintaining bone health is important for patients with breast cancer (BC), the most commonly diagnosed cancer in American women. Indeed, bone loss is common throughout the BC disease continuum. In the metastatic BC setting, patients are likely to develop bone metastases, a painful complication that can lead to potentially debilitating skeletal-related events. Bone health is equally important for patients with early BC. During adjuvant therapy for early BC, the largest challenge to bone health is from accelerated bone mineral density (BMD) loss. Although decreased BMD is well recognized in older, postmenopausal women, it may be underestimated in younger, premenopausal women undergoing endocrine therapy for BC. The rate and extent of cancer therapy-induced bone loss (from chemotherapy or endocrine therapy) are substantially greater than normal decreases in BMD during menopause. Bisphosphonates such as zoledronic acid (ZOL) are antiresorptive agents indicated for the treatment of bone metastases from BC. Clinical trials over the past few years suggest that, although not yet approved for this indication, ZOL can prevent cancer therapy-induced bone loss and improve BMD in premenopausal women receiving adjuvant (endocrine or chemo-) therapy for BC. Furthermore, the benefits of ZOL therapy may go beyond maintaining bone health and include potential anticancer benefits together with favorable tolerability and cost/benefit profiles. This review will focus specifically on the role of ZOL in preserving the bone health of premenopausal women with BC.

Aromatase inhibitors-induced bone loss in early breast cancer

Women with breast cancer have an increased prevalence and incidence of fractures. This increased risk of fracture has become most evident following the use of aromatase inhibitors (AIs) as standard adjuvant therapy. AI-induced bone loss occurs at more than twice the rate of physiologic postmenopausal bone loss. Moreover, peripheral quantitative computed tomography data indicate that effects of AIs on bone strength and on cortical bone have been substantially underestimated by dual-energy X-ray absorptiometry. All AIs have been associated with an increased fracture risk. The incidence of fractures is at least 33-43% higher in AI-treated patients than in tamoxifen-treated patients, and this increase in fracture risk is maintained at least for the duration of AI therapy. Over the last few years, clinical trials have established the effectiveness of bisphosphonates and denosumab to preserve and even increase bone mineral density (BMD) during adjuvant AIs. Most data have been obtained with zoledronic acid administered twice a year, which effectively maintains or increases BMD in women receiving AIs. In addition, zoledronic acid has been shown to delay disease recurrence and maybe prolong survival in women with hormone-responsive tumors, thereby providing an adjuvant antitumor benefit besides preserving BMD. It is likely that a combined fracture risk assessment will more accurately identify women with breast cancer who require bone protective therapy. The FRAX tool probably underestimates the net increase in fracture risk due to AI therapy. Recent guidelines for the prevention of AI-induced bone loss have adequately considered the presence of several established clinical risk factors for fractures, in addition to BMD, when selecting patients to be treated with inhibitors of bone resorption.

The management of osteoporosis in breast cancer survivors

Breast cancer is a common diagnosis and the majority of women treated will be cured. Women with early stage breast cancer may be at increased risk for osteoporosis due to anticancer therapies. Chemotherapy induced amenorrhea and the use of anti-estrogens can promote bone loss; thus, the management of bone health in women with breast cancer is an important component of survivorship care. Osteoporosis is considered a "silent" disease as there are often no discrete warning signs, until a fracture occurs; therefore, clinicians must be cognizant of the underlying risk for osteoporosis and co-morbid conditions and/or medications that accelerate risk of fracture. Breast cancer therapies that effect bone, screening for bone loss and interventions to mitigate the treatment toxicities are reviewed.

Bone health in adult cancer survivorship

Optimizing health outcomes, including prevention of osteoporotic fractures, is essential for promoting the well-being of the growing number of cancer survivors. Medical providers who participate in the care of cancer survivors should be aware that various cancer treatments may cause bone loss, which can increase the risk of subsequent of osteoporosis. Healthy bone remodeling is a balanced and dynamic equation between new bone formation and bone resorption. Aging, natural menopause, and cancer treatments such as surgical oophorectomy, gonadotropin-releasing hormone agonists, chemotherapy-induced ovarian failure, androgen deprivation therapy, and aromatase inhibitors can all promote bone loss. The WHO Fracture Assessment Tool can be used as a clinical aid to assess an individual's osteoporotic fracture risk, with or without bone mineral density measurements obtained from dual-energy x-ray absorptiometry. Preventative strategies include adequate calcium and vitamin D supplementation and modifying risk factors such as alcohol intake, tobacco use, and lack of exercise. Bisphosphonate therapy and rank-ligand monoclonal antibody therapy are the most commonly used agents for management of bone loss resulting from cancer treatment. This review will summarize the mechanisms by which cancer treatments cause bone loss as well provide screening and treatment recommendations for the management of bone loss.

Evaluation of the in vitro and in vivo antiangiogenic effects of denosumab and zoledronic acid

Denosumab (Dmab) and zoledronic acid (ZOL) are antiresorptive agents, with different mechanisms of action, that are indicated for delaying the onset of skeletal-related events in patients with bone metastases from solid tumors. Clinical and preclinical data suggest that ZOL may have also anti-angiogenic activity; however, the effects of Dmab (a fully humanized antibody against the receptor activator of nuclear factor kappa B ligand) on angiogenesis are largely unknown. The objective of this study was to compare the potential anti-angiogenic activity of Dmab with that of ZOL in preclinical models. Dmab (0.31 to 160 μM) had no effect on the viability of human MDA-MB-436 and CG5 breast cancer cells or human umbilical vein endothelial cells (HUVECs) and no effect on tubule formation or invasion of HUVECs. In contrast, ZOL (0.31 to 160 μM) decreased the viability of breast cancer and HUVECs in a time- and concentration-dependent manner and also inhibited HUVEC tubule formation and invasion. In vivo, ZOL (20 μg/mouse for three times a week for three consecutive weeks) inhibited angiogenesis in Matrigel plugs and inhibited the growth and neo-angiogenesis of CG5 xenografts in athymic nude mice. In contrast, Dmab (10 mg/Kg twice a week for 4 consecutive weeks) had no effect on Matrigel vascularization or xenograft growth in this model. These findings support the potential antiangiogenic and anticancer activity of ZOL in vitro and in vivo and further suggest that Dmab does not have antiangiogenic activity. Additional studies are needed to elucidate the potential anticancer activity of Dmab.

Importance of antiresorptive therapies for patients with bone metastases from solid tumors

Patients with bone metastases are at risk of skeletal-related events such as pathologic fractures, spinal cord compression, the need for orthopedic surgery to bone, and palliative radiotherapy for severe bone pain. Antiresorptive therapies have demonstrated efficacy for reducing the risk of skeletal-related events and ameliorating bone pain. Despite the well documented clinical benefits of antiresorptive therapies, patient benefits can be limited or compromised by nonadherence with scheduled therapy. Potential reasons for poor compliance include lack of understanding of how antiresorptive therapies work, neglecting the importance of bone health in maintaining quality of life, and being unaware of the potentially debilitating effects of skeletal-related events caused by bone metastases. Indeed, patients may stop therapy after bone pain subsides or discontinue due to generally mild and usually manageable adverse events, leaving them at an increased risk of developing skeletal-related events. In addition, the cost of antiresorptive therapy can be a concern for many patients with cancer. Medical care for patients with cancer requires a coordinated effort between primary care physicians and oncologists. Patients’ medical care teams can be leveraged to help educate them about the importance of adherence to antiresorptive therapy when cancer has metastasized to bone. Because primary care physicians generally have more contact with their patients than oncologists, they are in a unique position to understand patient perceptions and habits that may lead to noncompliance and to help educate patients about the benefits and risks of various antiresorptive therapies in the advanced cancer setting. Therefore, primary care physicians need to be aware of various mechanistic and clinical considerations regarding antiresorptive treatment options.

Superiority of denosumab to zoledronic acid for prevention of skeletal-related events: a combined analysis of 3 pivotal, randomised, phase 3 trials

BACKGROUND

Patients with bone metastases from advanced cancer often experience skeletal-related events (SRE), which cause substantial pain and morbidity. Denosumab, a fully human monoclonal antibody that inhibits RANK Ligand (RANKL), is a novel bone-targeted agent with a distinct mechanism of action relative to the bisphosphonate zoledronic acid, for prevention of SRE. This pre-planned analysis evaluates the efficacy and safety of denosumab versus zoledronic acid across three pivotal studies.

METHODS

Patient-level data from three identically designed, randomised, double-blind, active-controlled, phase 3 trials of patients with breast cancer, prostate cancer, other solid tumours or multiple myeloma were combined. End-points included time to first SRE, time to first and subsequent (multiple) SRE, adverse events, time to disease progression and overall survival.

FINDINGS

Denosumab was superior to zoledronic acid in delaying time to first on-study SRE by a median 8.21months, reducing the risk of a first SRE by 17% (hazard ratio, 0.83 [95% confidence interval (CI): 0.76-0.90]; P<0.001). Efficacy was demonstrated for first and multiple events and across patient subgroups (prior SRE status; age). Disease progression and overall survival were similar between the treatments. In contrast to zoledronic acid, denosumab did not require monitoring or dose modification/withholding based on renal status, and was not associated with acute-phase reactions. Hypocalcaemia was more common for denosumab. Osteonecrosis of the jaw occurred at a similar rate (P=0.13).

CONCLUSION

Denosumab was superior to zoledronic acid in preventing SRE with favourable safety and convenience in patients with bone metastases from advanced cancer.

Giant-cell tumor of bone, anti-RANKL therapy

Giant-cell tumor of bone (GCTB) is a rare osteolytic tumor of the bone. Although classified as a benign tumor, GCTB is characterized by local aggressiveness and risk of local recurrence. In addition, GTCB can in some cases lead to the development of so-called 'benign' chest metastases. Surgical resection by intralesional curettage with high-speed burring and polymethylmethacrylate cement is the standard treatment for resectable tumors. In cases of metastatic or unresectable disease (when planned surgical procedure is impossible or would result in severe morbidity), medical treatments such as cytotoxic chemotherapy or interferon-α have limited efficacy. Bisphosphonates have been proposed as a therapeutic option to reduce osteoclast activity. In bone, various pathological states may result from an imbalance in the RANK (receptor activator of nuclear factor kappa-B)/RANKL (receptor activator of nuclear factor kappa-B ligand)/OPG (osteoprotegerin) pathway. Involvement of the RANKL pathway in pathogenesis of GCTB was first proposed in 2000. Denosumab is a fully human monoclonal antibody that binds and inhibits RANKL, thereby preventing the activation of the RANK pathway. As it showed the possibility to counteract osteoclast activation in GCTB and prevent the known physiopathological role of RANKL, denosumab has been under evaluation in the clinic as a treatment for GCTB since 2005. Results of a first Phase II trial demonstrate the therapeutic potential of denosumab to inhibit progressive bone destruction and metastatic progression in patients with unsalvageable giant-cell tumor (GCT), and have also provided key insights into the biology of GCT. Denosumab is currently a therapeutic option for patients with unresectable GCTB but its place in the global therapeutic strategy has not yet been defined.

Bone-targeted agents: preventing skeletal complications in prostate cancer

In men, prostate cancer is the most common non-cutaneous malignancy and the second most common cause of cancer death. Skeletal complications occur at various points during the disease course, either due to bone metastases directly, or as an unintended consequence of androgen deprivation therapy (ADT). Bone metastases are associated with pathologic fractures, spinal cord compression, and bone pain and can require narcotics or palliative radiation for pain relief. ADT results in bone loss and fragility fractures. This review describes the biology of bone metastases, skeletal morbidity, and recent advances in bone-targeted therapies to prevent skeletal complications of prostate cancer.

Denosumab, a RANK ligand inhibitor, for the management of bone loss in cancer patients

Bone loss is a common side effect of cancer treatments, especially antihormonal treatments used in the treatment of breast and prostate cancer. Denosumab is a monoclonal antibody given subcutaneously that inhibits osteoclast activity by targeting the RANK ligand. It is effective in settings ranging from preventing skeletal-related complications in cancer patients with metastatic disease to increasing bone mineral density in patients with osteoporosis. In cancer patients with early stage disease, denosumab can attenuate bone loss from antihormonal treatments, and in prostate cancer, may reduce disease progression. Here, we will discuss the important role denosumab may play in the management of bone loss in patients with cancer.

Current perspectives on skeletal health and cancer progression across the disease continuum in breast cancer-the role of bisphosphonates

Pre-clinical and clinical evidence suggest that bisphosphonates inhibit both bone resorption and cancer progression. New and updated analyses from several large, controlled studies in pre- and post-menopausal women with early stage breast cancer (BC) suggest that addition of bisphosphonates improves cancer-related outcomes, particularly in patients with a 'low-estrogen environment'. Further, preliminary clinical data suggest that bisphosphonate therapy may reduce circulating tumour cell numbers (a negative prognostic indicator of disease-free and overall survival) in patients with advanced/metastatic disease. These new findings warrant reconsideration of the therapeutic role of bisphosphonates in BC.

Treatment-induced bone loss and fractures in cancer patients undergoing hormone ablation therapy: efficacy and safety of denosumab

Hormone ablation therapy (HALT) for breast or prostate cancer accelerates the development of osteoporosis in both men and women by causing estrogen deficiency, which increases the risk for fracture by promoting bone resorption mediated by osteoclasts. Denosumab, a fully human monoclonal antibody that inhibits osteoclast formation and function, increases bone mass in patients undergoing hormone ablation therapy. In the HALT study of 1,468 men with prostate cancer on androgen-deprivation therapy, denosumab significantly reduced the risk of new vertebral fractures, increased bone mineral density (BMD), and reduced markers of bone turnover. In a study of 252 women with breast cancer undergoing adjuvant aromatase inhibitor (AI) therapy, denosumab increased BMD at 12 and 24 months, overall and in all patient subgroups. The overall rates of adverse events were similar to placebo. Clinicians should consider fracture risk assessment and therapies such as denosumab to increase bone mass in patients on hormone ablation therapy who are at high risk for fracture.

Mechanisms of multiple myeloma bone disease

Multiple myeloma is the second most common hematological malignancy and the most frequent cancer to involve the skeleton. Multiple myeloma bone disease (MMBD) is characterized by abnormal bone remodeling with dysfunction of both bone resorption and bone formation, and thus can be used as a paradigm for other inflammatory bone diseases, and the regulation of osteoclasts and osteoblasts in malignancy. Studies of MMBD have identified novel regulators that increase osteoclastogenesis and osteoclast function, repress osteoblast differentiation, increase angiogenesis, or permanently alter stromal cells. This review will discuss the current understanding of mechanisms of osteoclast and osteoblast regulation in MMBD, and therapeutic approaches currently in use and under development that target mediators of bone destruction and blockade of bone formation for myeloma patients, including new anabolic therapies.

Skeletal and extraskeletal actions of denosumab

Osteoclasts and osteoblasts define skeletal mass, structure and strength through their respective actions in resorbing and forming bone. This remodeling process is orchestrated by the actions of hormones and growth factors, which regulate a cytokine system comprising the receptor activator of nuclear factor κB ligand (RANKL), its receptor RANK and the soluble decoy receptor osteoprotegerin (OPG). Bone resorption depends on RANKL, which determines osteoclast formation, activity and survival. Importantly, cells of the osteoblastic lineage mainly provide RANKL and therefore, are central in the regulation of osteoclast functions. Catabolic effects of RANKL are inhibited by OPG, a TNF receptor family member that binds RANKL, thereby preventing the activation of its receptor RANK, which is expressed by osteoclast precursors. Because this cytokine network is pivotal for the regulation of bone mass in health and diseases, including osteoporosis, rheumatoid arthritis and malignant bone conditions, it has been successfully used for the generation of a targeted therapy to block osteoclast actions. The clinical approval of denosumab, a fully monoclonal antibody against RANKL, provides a novel option to treat bone diseases with a potent, targeted and reversible inhibitor of bone resorption. Although RANKL is also expressed by endothelial cells, T lymphocytes, synovial fibroblasts and various tumor cells, no meaningful clinical extraskeletal effects have been reported after administration of denosumab. This article summarizes the molecular and cellular basis of the RANKL/RANK/OPG system and presents preclinical and clinical studies on the skeletal actions of denosumab.

The development of denosumab for the treatment of diseases of bone loss and cancer-induced bone destruction

Denosumab is a fully human monoclonal antibody against RANK ligand (RANKL), an essential cytokine for the formation, function, and survival of osteoclasts. The role of excessive RANKL as a contributor to conditions characterized by bone loss or bone destruction has been well studied. With its novel mechanism of action, denosumab offers a significant advance in the treatment of postmenopausal osteoporosis; bone loss associated with hormone ablation therapy in women with breast cancer and men with prostate cancer; and the prevention of skeletal-related events in patients with bone metastases from solid tumors by offering clinical benefit to these patients in need.

Stimulation of host bone marrow stromal cells by sympathetic nerves promotes breast cancer bone metastasis in mice

The activation of sympathetic nerves by psychosocial stress creates a favorable environment in bone for the establishment of cancer cells in a mouse model of breast cancer.

Bone and lung metastases are responsible for the majority of deaths in patients with breast cancer. Following treatment of the primary cancer, emotional and psychosocial factors within this population precipitate time to recurrence and death, however the underlying mechanism(s) remain unclear. Using a mouse model of bone metastasis, we provide experimental evidence that activation of the sympathetic nervous system, which is one of many pathophysiological consequences of severe stress and depression, promotes MDA-231 breast cancer cell colonization of bone via a neurohormonal effect on the host bone marrow stroma. We demonstrate that induction of RANKL expression in bone marrow osteoblasts, following β2AR stimulation, increases the migration of metastatic MDA-231 cells in vitro, independently of SDF1-CXCR4 signaling. We also show that the stimulatory effect of endogenous (chronic stress) or pharmacologic sympathetic activation on breast cancer bone metastasis in vivo can be blocked with the β-blocker propranolol, and by knockdown of RANK expression in MDA-231 cells. These findings indicate that RANKL promotes breast cancer cell metastasis to bone via its pro-migratory effect on breast cancer cells, independently of its effect on bone turnover. The emerging clinical implication, supported by recent epidemiological studies, is that βAR-blockers and drugs interfering with RANKL signaling, such as Denosumab, could increase patient survival if used as adjuvant therapy to inhibit both the early colonization of bone by metastatic breast cancer cells and the initiation of the “vicious cycle” of bone destruction induced by these cells.

Improved detection programs and better drugs to eradicate breast tumors have increased survival in women with breast cancer. However, pain and metastasis to distant organs, including bone, remain significant clinical problems. Understanding why and how metastatic cancer cells colonize specific organs is therefore critical if we are to further improve morbidity and mortality for these patients. Using a mouse model of breast cancer bone metastasis, we present evidence that activation of sympathetic nerves, which is typical in chronic stress or depression, promotes the colonization and establishment of metastatic cancer cells within the bone marrow, leading to an increase in bone osteolytic lesions. We show that this effect is mediated via a β-adrenergic receptor-dependent response of the host bone marrow stroma to catecholamines, that are released upon sympathetic activation, and via the pro-migratory activity of RANKL, a cytokine that is well known to promote bone resorption. Of importance clinically, blocking sympathetic activation with a β-blocker, or blocking RANKL signaling in cancer cells, inhibited the stimulatory effect of sympathetic activation on bone metastasis in this mouse model. Stress-induced sympathetic activation may thus explain, at least in part, the reduced survival rate of breast cancer patients experiencing severe depression. The data also support the use of β-blockers or RANKL blockade as possible adjuvant therapy for women with breast cancer.

Bench to bedside: elucidation of the OPG-RANK-RANKL pathway and the development of denosumab

Bone is a complex tissue that provides mechanical support for muscles and joints, protection for vital organs, a mineral reservoir that is essential for calcium homeostasis, and the environment and niches required for haematopoiesis. The regulation of bone mass in mammals is governed by a complex interplay between bone-forming cells termed osteoblasts and bone-resorbing cells termed osteoclasts, and is guided physiologically by a diverse set of hormones, cytokines and growth factors. The balance between these processes changes over time, causing an elevated risk of fractures with age. Osteoclasts may also be activated in the cancer setting, leading to bone pain, fracture, spinal cord compression and other significant morbidities. This Review chronicles the events that led to an increased understanding of bone resorption, the elucidation of the signalling pathway mediated by osteoprotegerin, receptor activator of NF-κB (RANK) and RANK ligand (RANKL) and its role in osteoclast biology, as well as the evolution of recombinant RANKL antagonists, which culminated in the development of the therapeutic RANKL-targeted antibody denosumab.

Denosumab--a powerful RANKL inhibitor to stop lytic metastases and other bone loss actions by osteoclasts

Denosumab is a perfect example on the targeted anticancer therapy. The inhibition of RANKL activity suppressed the osteoclasts' resorptive function and so prevented skeletal related events. This effect is useful not only against bone metastases, but also in the treatment of other diseases caused by bone loss. In different solid tumors with bone metastasis the quality of life also improved, although the overall survival usually showed no change. On the market the main competitors for denosumab are still the bisphosphonates (questions of costs and reimbursement are not discussed) and some potential new agents e.g. Src kinases (as dasatinib, saracatinib, bosutinib), cathepsin K inhibitors, (e.g. odanacatib), and new selective estrogen receptor modulators (e.g. bazedoxifene, lasofoxifene). Nevertheless, today denosumab is one of the most powerful agents in bone-saving area.

Cost Effectiveness of Fracture Prevention in Postmenopausal Women Who Receive Aromatase Inhibitors for Early Breast Cancer

Purpose

Aromatase inhibitors (AIs) increase the risk of osteoporosis and related fractures in postmenopausal women who receive adjuvant AIs for hormone receptor (HR) –positive early breast cancer (EBC). We compared the cost effectiveness of alternative screening and treatment strategies for fracture prevention.

Methods

We developed a Markov state transition model to simulate clinical practice and outcomes in a hypothetical cohort of women age 60 years with HR-positive EBC starting a 5-year course of AI therapy after primary surgery for breast cancer. Outcomes were quality-adjusted life-years (QALYs), lifetime cost, and incremental cost-effectiveness ratio (ICER). We compared the following strategies: no intervention; one-time bone mineral density (BMD) screening and selective bisphosphonate therapy in women with osteoporosis or osteopenia; annual BMD screening and selective bisphosphonate therapy in women with osteoporosis or osteopenia; and universal bisphosphonate therapy.

Results

ICERs for annual BMD screening followed by oral bisphosphonates for those with osteoporosis, annual BMD screening followed by oral bisphosphonates for those with osteopenia, and universal treatment with oral bisphosphonates were $87,300, $129,300, and $283,600 per QALY gained, respectively. One-time BMD screening followed by oral bisphosphonates for those with osteoporosis or osteopenia was dominated. Our results were sensitive to age at the initiation of AI therapy, type of bisphosphonates, post-treatment residual effect of bisphosphonates, and a potential adjuvant benefit of intravenous bisphosphonates.

Conclusion

In postmenopausal women receiving adjuvant AIs for HR-positive EBC, a policy of baseline and annual BMD screening followed by selective treatment with oral bisphosphonates for those diagnosed with osteoporosis is a cost-effective use of societal resources.

Anti-RANKL therapy for bone tumours: Basic, pre-clinical and clinical evidences

Bone remodelling is related to coordinated phases of bone resorption and bone apposition allowing the maintenance of bone integrity, the phosphocalcic homoeostasis all along the life and consequently the bone adaptation to mechanical constraints or/and to endocrine fluctuations. Unfortunately, bone is a frequent site of tumour development originated from bone cell lineages (primary bone tumours: bone sarcomas) or from nonosseous origins (bone metastases: carcinomas). These tumour cells disrupt the balance between osteoblast and osteoclast activities resulting in a disturbed bone remodelling weakening the bone tissue, in a strongly altered bone microenvironment and consequently facilitating the tumour growth. At the early stage of tumour development, osteoclast differentiation and recruitment of mature osteoclasts are strongly activated resulting in a strong bone matrix degradation and release of numerous growth factors initially stored into this organic/calcified matrix. In turn these soluble factors stimulate the proliferation of tumour cells and exacerbate their migration and their ability to initiate metastases. Because Receptor Activator of NFκB Ligand (RANKL) is absolutely required for in vivo osteoclastogenesis, its role in the bone tumour growth has been immediately pointed out and has consequently allowed the development of new targeted therapies of these malignant diseases. The present review summarises the role of RANKL in the bone tumour microenvironment, the most recent pre-clinical and clinical evidences of its targeting in bone metastases and bone sarcomas. The following sections position RANKL targeted therapy among the other anti-resorptive therapies available and underline the future directions which are currently under investigations.

Role of denosumab in the management of skeletal complications in patients with bone metastases from solid tumors

Skeletal-related events (SREs) including pain, fractures, and hypercalcemia are a major source of morbidity for cancer patients with bone metastases. The receptor activator of NF-κB ligand (RANKL) is a key mediator of osteoclast formation and activity in normal bone physiology as well as cancer-induced bone resorption. The first commercially available drug that specifically targets and inhibits the RANKL pathway is denosumab, a fully human monoclonal antibody that binds and neutralizes RANKL, thereby inhibiting osteoclast function. In this review, we summarize the major studies leading to the US Food and Drug Administration-approval of denosumab for the prevention of SREs in patients with bone metastases from solid tumors. Further, we discuss the role of denosumab in the prevention and treatment of SREs and bone loss in cancer patients. As a monoclonal antibody, denosumab has several advantages over bisphosphonates, including improved efficacy, better tolerability, and the convenience of administration by subcutaneous injection. In addition, as denosumab has no known renal toxicity, it may be the preferred choice over bisphosphonates in patients with baseline renal insufficiency or receiving nephrotoxic therapies. However, other toxicities, including osteonecrosis of the jaw and hypocalcemia, appear to be class effects of agents that potently inhibit osteoclast activity and are associated with both denosumab and bisphosphonate use. The data presented highlight the differences associated with intravenous bisphosphonate and denosumab use as well as confirm the essential role bone-modifying agents play in maintaining the quality of life for patients with bone metastases.

Systemic Therapy for Bone Metastases

Background

Accelerated bone loss in patients with cancer is a frequent problem that may result from invasion of the cancer to bone, paraneoplastic tumor proteins, and/or hormonal therapies utilized for cancer treatment. Patients with osteolytic bone disease from multiple myeloma and bone metastases from solid tumors may develop a vicious cycle of bone destruction involving both osteolytic and osteoblastic effects. Consequently, a variety of skeletal-related events (SREs) may occur, including pathological fractures, hypercalcemia, spinal cord compression, and the need for surgical intervention and radiation therapy.

Methods

This article reviews the results of trials that investigated the safety and efficacy of pharmacologic agents, including bisphosphonates and denosumab, for treatment of bone metastases. This analysis is derived from an assessment of the medical literature.

Results

Beneficial systemic therapies for bone metastases have been developed to decrease SREs. Possible antitumor effects of the bisphosphonates are explored. In addition, the utility of markers of bone turnover in relation to response to therapy and survival, the safety and toxicity of bone-targeted therapies, treatment guidelines, and economic considerations are also discussed.

Conclusions

Effective systemic therapies for metastatic bone disease are available. Ongoing and future research projects in this field are also presented.

Recommendations for antiresorptive therapy in postmenopausal patients with breast cancer: Marburg AIBL Guideline Evaluation Study (MAGES)

Postmenopausal women with hormone-receptor-positive breast cancer usually receive aromatase inhibitor (AI) therapy at some point in their disease management. Accelerated bone loss during AI therapy poses a problem, especially in postmenopausal women who may already have age-related osteopenia or several fracture-related risk factors. Guidelines and algorithms have been developed to identify women at risk for fractures from low bone mineral density and to provide recommendations for antiresorptive treatment. However, the factors used to calculate fracture risk and the thresholds for antiresorptive treatment vary among the current guidelines and algorithms, potentially leading to inconsistent recommendations for or against antiresorptive treatment. The present study analyzed antiresorptive treatment decisions in a population of postmenopausal women with hormone-receptor-positive breast cancer receiving AI therapy using five different guidelines/algorithms (World Health Organization Fracture Risk Assessment tool [FRAX], expert consensus, German Dachverband Osteologie, American Society of Clinical Oncology, and World Health Organization). The consistency of a recommendation for antiresorptive treatment among the five methods was low (4 %). The consistency of a recommendation against antiresorptive treatment among the five methods was higher (57 %), but left approximately 40 % of patients with an inconsistent recommendation. The consequences of overtreatment (unnecessary exposure to adverse events) and undertreatment (increased risk of fractures and possibly decreased disease-free survival) make it imperative that the existing guidelines and algorithms be improved. Moreover, evidence-based outcomes from antiresorptive treatment decisions are required to validate guidelines and algorithms.

Zoledronic acid in the treatment of early-stage breast cancer: is there a final verdict?

Breast cancer, which preferentially metastasizes to bone, is the most common malignancy among women worldwide and is a leading cause of death. Clinical data from large, phase 3 trials (ie, ABCSG-12, ZO-FAST, and AZURE) demonstrate significantly improved disease-free survival with zoledronic acid in some patient populations with early breast cancer. Although the interim results from the AZURE trial did not show a disease-free survival benefit with zoledronic acid in the overall patient population, subset analyses showed that zoledronic acid significantly improved disease-free survival in women with established postmenopausal status at baseline. Similarly, subset analyses of the ABCSG-12 trial showed greater benefits from zoledronic acid in patients over 40 years of age who theoretically would have achieved more complete ovarian suppression. Together, these data support a potential role for zoledronic acid beyond bone health in breast cancer and suggest that the endocrine environment may influence the anticancer potential of zoledronic acid.

Osteoporosis related to disease or therapy in patients with cancer

Osteoporosis is a major public health issue in the general population, particularly in postmenopausal women. Patients with cancer may not only be at risk for primary osteoporosis, but for secondary osteoporosis related to cancer therapies-particularly therapies that impair gonadal function, lead to loss of serum estrogen, and negatively affect bone turnover. Normal bone remodeling is influenced by the receptor activator for nuclear kappa-B ligand pathway, calcium, vitamin D, and other nutrition factors, as well as modifiable and nonmodifiable factors. Identifying which patients with cancer are at risk for bone mineral density loss is important and may include patients with breast or prostate cancer, some survivors of pediatric malignancies, and adults with other tumors. Nurses play a major role in identifying those patients and their risk for low-impact fractures, which can have a significant effect on patient morbidity and mortality. Counseling and teaching are central nursing functions, as well as safely administering therapies, particularly bisphosphonates and denosumab.