The effect of clodronate and antioestrogens on bone loss associated with oestrogen withdrawal in postmenopausal women with breast cancer

Bone-modifying agents for reducing bone loss in women with early and locally advanced breast cancer: a network meta-analysis

BACKGROUND

Bisphosphonates and receptor activator of nuclear factor-kappa B ligand (RANKL)-inhibitors are amongst the bone-modifying agents used as supportive treatment in women with breast cancer who do not have bone metastases. These agents aim to reduce bone loss and the risk of fractures. Bisphosphonates have demonstrated survival benefits, particularly in postmenopausal women.

OBJECTIVES

To assess and compare the effects of different bone-modifying agents as supportive treatment to reduce bone mineral density loss and osteoporotic fractures in women with breast cancer without bone metastases and generate a ranking of treatment options using network meta-analyses (NMAs).

SEARCH METHODS

We identified studies by electronically searching CENTRAL, MEDLINE and Embase until January 2023. We searched various trial registries and screened abstracts of conference proceedings and reference lists of identified trials.

SELECTION CRITERIA

We included randomised controlled trials comparing different bisphosphonates and RANKL-inihibitors with each other or against no further treatment or placebo for women with breast cancer without bone metastases.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data and assessed the risk of bias of included studies and certainty of evidence using GRADE. Outcomes were bone mineral density, quality of life, overall fractures, overall survival and adverse events. We conducted NMAs and generated treatment rankings.

MAIN RESULTS

Forty-seven trials (35,163 participants) fulfilled our inclusion criteria; 34 trials (33,793 participants) could be considered in the NMA (8 different treatment options). Bone mineral density We estimated that the bone mineral density of participants with no treatment/placebo measured as total T-score was -1.34. Evidence from the NMA (9 trials; 1166 participants) suggests that treatment with ibandronate (T-score -0.77; MD 0.57, 95% CI -0.05 to 1.19) may slightly increase bone mineral density (low certainty) and treatment with zoledronic acid (T-score -0.45; MD 0.89, 95% CI 0.62 to 1.16) probably slightly increases bone mineral density compared to no treatment/placebo (moderate certainty). Risedronate (T-score -1.08; MD 0.26, 95% CI -0.32 to 0.84) may result in little to no difference compared to no treatment/placebo (low certainty). We are uncertain whether alendronate (T-score 2.36; MD 3.70, 95% CI -2.01 to 9.41) increases bone mineral density compared to no treatment/placebo (very low certainty). Quality of life No quantitative analyses could be performed for quality of life, as only three studies reported this outcome. All three studies showed only minimal differences between the respective interventions examined. Overall fracture rate We estimated that 70 of 1000 participants with no treatment/placebo had fractures. Evidence from the NMA (16 trials; 19,492 participants) indicates that treatment with clodronate or ibandronate (42 of 1000; RR 0.60, 95% CI 0.39 to 0.92; 40 of 1000; RR 0.57, 95% CI 0.38 to 0.86, respectively) decreases the number of fractures compared to no treatment/placebo (high certainty). Denosumab or zoledronic acid (51 of 1000; RR 0.73, 95% CI 0.52 to 1.01; 55 of 1000; RR 0.79, 95% CI 0.56 to 1.11, respectively) probably slightly decreases the number of fractures; and risedronate (39 of 1000; RR 0.56, 95% CI 0.15 to 2.16) probably decreases the number of fractures compared to no treatment/placebo (moderate certainty). Pamidronate (106 of 1000; RR 1.52, 95% CI 0.75 to 3.06) probably increases the number of fractures compared to no treatment/placebo (moderate certainty). Overall survival We estimated that 920 of 1000 participants with no treatment/placebo survived overall. Evidence from the NMA (17 trials; 30,991 participants) suggests that clodronate (924 of 1000; HR 0.95, 95% CI 0.77 to 1.17), denosumab (927 of 1000; HR 0.91, 95% CI 0.69 to 1.21), ibandronate (915 of 1000; HR 1.06, 95% CI 0.83 to 1.34) and zoledronic acid (925 of 1000; HR 0.93, 95% CI 0.76 to 1.14) may result in little to no difference regarding overall survival compared to no treatment/placebo (low certainty). Additionally, we are uncertain whether pamidronate (905 of 1000; HR 1.20, 95% CI 0.81 to 1.78) decreases overall survival compared to no treatment/placebo (very low certainty). Osteonecrosis of the jaw We estimated that 1 of 1000 participants with no treatment/placebo developed osteonecrosis of the jaw. Evidence from the NMA (12 trials; 23,527 participants) suggests that denosumab (25 of 1000; RR 24.70, 95% CI 9.56 to 63.83), ibandronate (6 of 1000; RR 5.77, 95% CI 2.04 to 16.35) and zoledronic acid (9 of 1000; RR 9.41, 95% CI 3.54 to 24.99) probably increases the occurrence of osteonecrosis of the jaw compared to no treatment/placebo (moderate certainty). Additionally, clodronate (3 of 1000; RR 2.65, 95% CI 0.83 to 8.50) may increase the occurrence of osteonecrosis of the jaw compared to no treatment/placebo (low certainty). Renal impairment We estimated that 14 of 1000 participants with no treatment/placebo developed renal impairment. Evidence from the NMA (12 trials; 22,469 participants) suggests that ibandronate (28 of 1000; RR 1.98, 95% CI 1.01 to 3.88) probably increases the occurrence of renal impairment compared to no treatment/placebo (moderate certainty). Zoledronic acid (21 of 1000; RR 1.49, 95% CI 0.87 to 2.58) probably increases the occurrence of renal impairment while clodronate (12 of 1000; RR 0.88, 95% CI 0.55 to 1.39) and denosumab (11 of 1000; RR 0.80, 95% CI 0.54 to 1.19) probably results in little to no difference regarding the occurrence of renal impairment compared to no treatment/placebo (moderate certainty).

AUTHORS' CONCLUSIONS

When considering bone-modifying agents for managing bone loss in women with early or locally advanced breast cancer, one has to balance between efficacy and safety. Our findings suggest that bisphosphonates (excluding alendronate and pamidronate) or denosumab compared to no treatment or placebo likely results in increased bone mineral density and reduced fracture rates. Our survival analysis that included pre and postmenopausal women showed little to no difference regarding overall survival. These treatments may lead to more adverse events. Therefore, forming an overall judgement of the best ranked bone-modifying agent is challenging. More head-to-head comparisons, especially comparing denosumab with any bisphosphonate, are needed to address gaps and validate the findings of this review.

Antiosteoporosis therapy after discontinuation of menopausal hormone therapy: a systematic review

OBJECTIVE

Menopausal hormone therapy (MHT) has consistently shown a bone protective effect by reducing the risk of vertebral, non-vertebral, and hip fractures in postmenopausal women regardless of baseline fracture risk. However, the optimal sequential treatment after MHT discontinuation has not been determined. This systematic review aimed to obtain the best evidence regarding the effect of antiresorptive or osteoanabolic treatment on bone mineral density (BMD) and/or fracture risk following MHT.

METHODS

A comprehensive search was conducted in the PubMed, Scopus, and Cochrane databases up to October 31, 2023. Randomized-controlled trials (RCTs) and observational studies conducted in postmenopausal women were included.

RESULTS

After the exclusion of duplicates, 717 studies were identified. Two were eligible for qualitative analysis, one RCT and one retrospective cohort study. The RCT showed that alendronate 10 mg/day for 12 months further increased lumbar spine (LS) BMD by 2.3% following MHT and maintained femoral neck (FN) BMD in postmenopausal women (n = 144). It also decreased bone anabolic and resorption markers by 47 and 36%, respectively. In the retrospective study (n = 34), raloxifene 60 mg/day increased both LS and FN BMD at 12 months by 3 and 2.9%, respectively. No fractures were reported.

CONCLUSIONS

Antiresorptive therapy with either a bisphosphonate (i.e., alendronate) or raloxifene could be considered a sequential antiosteoporosis therapy after MHT withdrawal since they have been shown in studies to further increase BMD. However, no safe conclusions can be drawn from the existing literature.

Preventing Bone Loss in Breast Cancer Patients: Designing a Personalized Clinical Pathway in a Large-Volume Research Hospital

BACKGROUND

We assess the impact of bone health clinical management in breast cancer (BC) patients receiving adjuvant endocrine therapy and design a personalized clinical pathway to reduce bone loss in an Italian research hospital.

METHODS

The primary endpoint was to assess (through the process improvement organizational method) the clinical pathway that post-surgical BC patients prescribed with endocrine therapy undergo to prevent bone loss. The secondary endpoint was to design a personalized clinical pathway for a prompt implementation of guidelines, to assess and possibly prescribe antiresorptive therapy.

RESULTS

During the first year of the execution of the new Diagnostic Therapeutic Assistance Pathway, a 60% increase in Dual-Energy X-ray Absorptiometry evaluations within 30 days and a 39.5% increase in antiresorptive therapy prescription within 90 days (since the prescription of endocrine therapy) were shown, thus increasing patients' compliance.

CONCLUSION

Case managers and bone health specialists in this context can improve patients' adherence to therapies and bone health, helping physicians to expand their collaboration.

Bone health care in women with breast cancer

The aim of this article is to analyze and critically appraise the literature regarding optimal bone health care in women with breast cancer and, more specifically, to present (1) the causes of bone loss in breast cancer patients, (2) the appropriate screening for osteoporosis and fracture risk estimation, (3) optimal prevention and therapeutic strategies for osteoporosis and fractures, (4) the role of antiresorptive agents as adjuvant therapy for the prevention of bone metastases and increase of overall survival, and (5) current data on the possible use of menopausal hormone therapy (MHT) in these patients. The objective is to provide a sound pathophysiological background along with evidence-based and practical recommendations for physicians managing such women.

French recommendations on strategies for preventing and treating osteoporosis induced by adjuvant breast cancer therapies

Standard adjuvant therapies for breast cancer such as chemotherapy or aromatase inhibitor and LH-RH agonist hormone therapy are associated with significant survival gains but also induce bone loss by aggravating the estrogen deprivation. The bone loss may be substantial, notably during early treatment, and occurs regardless of the baseline bone mineral density values. The objective of developing these recommendations was to achieve a practical consensus among various scientific societies, based on literature review, about osteoporosis prevention and treatment in these patients. The following scientific societies contributed to the work: Société Française de Rhumatologie (SFR), Groupe de Recherche et d'Information sur les Ostéoporoses (GRIO), Groupe Européen d'Etudes des Métastases Osseuses (GEMO), Association Francophone pour les Soins Oncologiques de Support (AFSOS), Société Française de Sénologie et de Pathologie Mammaire (SFSPM), Société Française de Radiothérapie Oncologique (SFRO). Drug prescription and reimbursement modalities in France were taken into account. These recommendations apply to postmenopausal women taking systemic chemotherapy and/or aromatase inhibitor therapy, non-postmenopausal women taking LH-RH agonist therapy, and non-postmenopausal women with persistent amenorrhea 1 year after chemotherapy completion. All women in these three categories should undergo an evaluation of bone health and receive interventions to combat risk factors for bone loss. Patients with a history of severe osteoporotic fracture and/or a T-score value <-2.5 should receive osteoporosis drug therapy. The FRAX® score should be used to guide treatment decisions in patients whose T-score is between -1 and -2.5. General osteoporosis prevention measures should be applied in patients without criteria for osteoporosis drug therapy, who should undergo bone mineral density measurements 18-24 months later if the baseline T-score is<-1 and 3-5 years later if the baseline T-score is>-1. The anti-tumor effect of bisphosphonates and denosumab was not considered when establishing these recommendations.

Cancer Treatment and Bone Health

Considerable advances in oncology over recent decades have led to improved survival, while raising concerns about long-term consequences of anticancer treatments. In patients with breast or prostate malignancies, bone health is a major issue due to the high risk of bone metastases and the frequent prolonged use of hormone therapies that alter physiological bone turnover, leading to increased fracture risk. Thus, the onset of cancer treatment-induced bone loss (CTIBL) should be considered by clinicians and recent guidelines should be routinely applied to these patients. In particular, baseline and periodic follow-up evaluations of bone health parameters enable the identification of patients at high risk of osteoporosis and fractures, which can be prevented by the use of bone-targeting agents (BTAs), calcium and vitamin D supplementation and modifications of lifestyle. This review will focus upon the pathophysiology of breast and prostate cancer treatment-induced bone loss and the most recent evidence about effective preventive and therapeutic strategies.

Evaluation and management of skeletal disease in cancer care

Recently, there have been considerable advancements in cancer therapies thereby prolonging the life of cancer survivors. However, these recent advancements present new challenges in the management of bone disease in cancer survivors. Bone acts as a fertile soil for cancer seeding and bone health is often compromised because of increased inflammatory cytokines in cancer, direct cancer metastasis and toxic effects of anti-cancer therapies. This effect is more pronounced in elderly population who already have compromised bone mineral density leading to increased skeletal related events and bone pain. Timely diagnosis and effective interventions are essential for reducing bone-related morbidity in cancer survivors. Also, a complex interdependence exists between cancer related bone disease and tumor growth, creating a vicious circle of extensive bone destruction and cancer progression. Hence, maintenance of bone health and integrity plays a pivotal role in comprehensive cancer care. The bone-targeted treatments have been shown to preserve bone health, and modify the course of the underlying cancer. Management of long-term bone health requires a broad knowledge base that endocrinologists, oncologists and other care team members should be aware of. The manuscript highlights the skeletal effects of cancer, adjuvant therapies used for hormone-responsive cancers, chemotherapy induced bone loss and steps for accurate diagnosis and management of bone disease in cancer survivors by bridging the gaps in the comprehensive cancer care.

Management of Aromatase Inhibitor-Associated Bone Loss (AIBL) in postmenopausal women with hormone sensitive breast cancer: Joint position statement of the IOF, CABS, ECTS, IEG, ESCEO IMS, and SIOG

BACKGROUND

Several guidelines have been reported for bone-directed treatment in women with early breast cancer (EBC) for averting fractures, particularly during aromatase inhibitor (AI) therapy. Recently, a number of studies on additional fracture related risk factors, new treatment options as well as real world studies demonstrating a much higher fracture rate than suggested by randomized clinical controlled trials (RCTs). Therefore, this updated algorithm was developed to better assess fracture risk and direct treatment as a position statement of several interdisciplinary cancer and bone societies involved in the management of AI-associated bone loss (AIBL).

PATIENTS AND METHODS

A systematic literature review identified recent advances in the management of AIBL. Results with individual agents were assessed based on trial design, size, follow-up, and safety.

RESULTS

Several fracture related risk factors in patients with EBC were identified. Although, the FRAX algorithm includes fracture risk factors (RF) in addition to BMD, it does not seem to adequately address the effects of AIBL. Several antiresorptive agents can prevent and treat AIBL. However, concerns regarding compliance and long-term safety remain. Overall, the evidence for fracture prevention is strongest for denosumab 60 mg s.c. every 6 months. Additionally, recent studies as well as an individual patient data meta-analysis of all available randomized trial data support additional anticancer benefits from adjuvant bisphosphonate treatment in postmenopausal women with a 34% relative risk reduction in bone metastasis and 17% relative risk decrease in breast cancer mortality that needs to be taken into account when advising on management of AIBL.

CONCLUSIONS

In all patients initiating AI treatment, fracture risk should be assessed and recommendation with regard to exercise and calcium/vitamin D supplementation given. Bone-directed therapy should be given to all patients with a T-score<-2.0 or with a T-score of <-1.5 SD with one additional RF, or with ≥2 risk factors (without BMD) for the duration of AI treatment. Patients with T-score>-1.5 SD and no risk factors should be managed based on BMD loss during the first year and the local guidelines for postmenopausal osteoporosis. Compliance should be regularly assessed as well as BMD on treatment after 12 - 24 months. Furthermore, because of the decreased incidence of bone recurrence and breast cancer specific mortality, adjuvant bisphosphonates are recommended for all postmenopausal women at significant risk of disease recurrence.

Toremifene in the treatment of breast cancer

Although more widespread screening and routine adjuvant therapy has improved the outcome for breast cancer patients in recent years, there remains considerable scope for improving the efficacy, safety and tolerability of adjuvant therapy in the early stage disease and the treatment of advanced disease. Toremifene is a selective estrogen receptor modifier (SERM) that has been widely used for decades in hormone receptor positive breast cancer both in early and late stage disease. Its efficacy has been well established in nine prospective randomized phase III trials compared to tamoxifen involving more than 5500 patients, as well as in several large uncontrolled and non-randomized studies. Although most studies show therapeutic equivalence between the two SERMs, some show an advantage for toremifene. Several meta-analyses have also confirmed that the efficacy of toremifene is at least as good as that of tamoxifen. In terms of safety and tolerability toremifene is broadly similar to tamoxifen although there is some evidence that toremifene is less likely to cause uterine neoplasms, serious vascular events and it has a more positive effect on serum lipids than does tamoxifen. Toremifene is therefore effective and safe in the treatment of breast cancer. It provides not only a useful therapeutic alternative to tamoxifen, but may bring specific benefits.

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.

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.

The role of antiresorptive therapies in improving patient care in early and metastatic breast cancer

Breast cancer is the second most common cancer among American women and has a high rate of metastasis to bone. Patients regularly undergo adjuvant therapy (chemotherapy or hormonal therapy) following surgical resection of the tumor. In addition to potential direct effects on bone cells, both chemotherapy and hormonal therapy induce ovarian dysfunction and dramatically decrease estrogen levels in both pre- and postmenopausal women. This leads to decreased bone mineral density and increased fracture risk. Antiresorptive therapies (e.g, zoledronic acid and denosumab) have demonstrated efficacy in preventing cancer therapy-induced bone loss in patients with breast cancer and are approved for the prevention of skeletal-related events in patients with bone metastases from breast cancer. This review will focus on the evolving role of these antiresorptive therapies in the care of women with early or metastatic breast cancer.

Guidelines for Osteoprotection in Breast Cancer Patients on an Aromatase Inhibitor

Postmenopausal women are at an increased risk of osteopenia and osteoporosis due to the physiologic loss of the bone protective effects of estrogen. Additionally, disease-related risk factors also contribute to the increased fracture risk. To further complicate matters, one of the most common and severe safety issues associated with cancer therapies for breast cancer patients is bone loss and the associated increased risk of fractures. These facts underscore the need to carefully monitor bone mineral density in patients with endocrine-responsive breast cancer, and to consider adjuvant therapy that may help manage and/or prevent bone loss and fracture. Aromatase inhibitors (AIs) are now in widespread clinical use for women with hormone receptor-positive breast cancer and have replaced tamoxifen as the gold standard of care. AIs target the estrogen biosynthetic pathway and deprive tumor cells of the growth-promoting effects of estrogen. These treatments provide significant benefit to patients in terms of improved disease-free and overall survival. Adversely, there is a concern of an increased risk of bone loss with prolonged therapy consequently leading to an increased fracture risk. This manuscript will review the recent literature pertaining to AI-associated bone loss and discuss suggested management and preventative approaches that may help patients remain on therapy to derive the most clinical benefits.

Lack of evidence for fracture prevention in early breast cancer bisphosphonate trials: a meta-analysis

OBJECTIVES

Recent data suggest that fractures might affect quality of life and survival in early breast cancer patients. Bisphosphonates are effective in treatment and prevention of cancer treatment-induced bone loss, but their value in the prevention of fractures is still investigational. Our aim was to evaluate the fracture rate in breast cancer patients receiving adjuvant bisphosphonates compared with those receiving no treatment or placebo.

METHODS

Our study is a systematic review and meta-analysis of randomized clinical trials. Trials were located through PubMed, ISI, Cochrane Library and major cancer scientific meetings searches. We identified 21 potentially eligible trials. Of these, 14 studies reported fracture data and were included in the analyses. Overall, 7461 early breast cancer patients were randomized, 3691 received bisphosphonates and 3770 received either placebo or no treatment.

RESULTS

Adjuvant breast cancer treatment with bisphosphonates did not reduce the fracture rate compared to placebo or no use either in intent to treat analysis (12 trials, OR=0.99, 95% CI=0.73-1.34, p=0.932) and in comprehensive analysis (all 14 trials included, OR=0.84, 95% CI=0.65-1.09 p=0.197). Treatment with bisphosphonates was not beneficial in postmenopausal patients (7 trials, OR=0.82, 95% CI=0.55-1.20 p=0.298) and in patients receiving aromatase inhibitors (6 trials, OR=0.79, 95% CI=0.53-1.17 p=0.242).

CONCLUSION

Our meta-analysis provides substantial evidence that bisphosphonates in the adjuvant setting among women with breast cancer do not decrease the number of fractures compared with placebo or no treatment.

Adjuvant bisphosphonates in endocrine-responsive breast cancer: what is their place in therapy?

Recent advances in the treatment of early breast cancer have improved clinical outcomes and prolonged survival, especially in women with endocrine-responsive disease. However, cancer therapies including cytotoxic chemotherapy, ovarian suppression, and aromatase inhibitors can drastically reduce circulating estrogen, increasing bone loss and fracture risk. Because most women with early breast cancer will live for many years, it is important to protect bone health during cancer therapy. Several recent clinical trials combining adjuvant endocrine therapy with bisphosphonates have demonstrated efficacy for preventing cancer treatment-induced bone loss in pre- and postmenopausal women with early breast cancer. The largest body of evidence supporting the use of adjuvant bisphosphonates comes from studies with zoledronic acid; however, studies with risedronate, ibandronate, and denosumab (a biologic agent) have also demonstrated efficacy for preventing bone loss. Adding zoledronic acid to endocrine therapy prevents bone loss and improves bone mineral density (BMD). In addition, preclinical studies suggest that bisphosphonates have direct and indirect antitumor activity, such as inducing tumor cell apoptosis, reducing tumor cell adhesion and invasion, reducing angiogenesis, activating immune responses, and synergy with chemotherapy agents, among others. Clinical trials have demonstrated significantly improved disease-free survival in patients receiving adjuvant endocrine therapy plus zoledronic acid compared with endocrine therapy alone. Ongoing studies will further define the role of adjuvant bisphosphonates in maintaining bone health and improving clinical outcomes. The available evidence suggests that pre- and postmenopausal patients may receive clinical benefit from including bisphosphonates as part of their adjuvant treatment regimen for endocrine-responsive early breast cancer.

Adverse bone effects during pharmacological breast cancer therapy

The improved survival and cure rate of breast cancer patients leads to increased diagnosis of later occurring side effects to therapy such as osteoporosis. Conventional chemotherapies such as CMF and CEF are known to induce premature menopause, which increases bone loss but these therapies have additional detrimental effects on bone. The loss in bone mass during chemotherapy is substantial and may lead to increased fracture risk. The influence of taxanes on bone is less well known. Whereas tamoxifen has a slight protective effect on bone loss the opposite is true for aromatase inhibitors. Adverse effect reportings show, that adjuvant treatment with aromatase inhibitors in postmenopausal women increases the risk of clinical fractures as compared to tamoxifen. The Danish Bone Society suggests that all women with operable breast cancer have their fracture risk evaluated including a BMD measurement prior to initiation of adjuvant aromatase inhibitor therapy as a part of the standard examination program. If osteoporosis is diagnosed, anti-osteoporosis therapies should be considered. Moreover, all women undergoing adjuvant chemotherapy and endocrine therapy should be informed of the risk of bone loss and should receive life style advice of how to preserve bone. Adjuvant regimens in breast cancer patients improve survival and cure rates. Therefore it is preferable to use such therapies although they increase risk of side effects such as osteoporosis.

Effect of Anastrozole on Bone Mineral Density: 5-Year Results From the Anastrozole, Tamoxifen, Alone or in Combination Trial 18233230

Purpose

The Arimidex, Tamoxifen, Alone or in Combination (ATAC) trial (median follow-up, 68 months) has shown that adjuvant anastrozole has superior efficacy and better tolerability than tamoxifen. However, anastrozole reduces circulating estrogen, and low estradiol levels are associated with decreased bone mineral density (BMD) and increased fracture risk. It is therefore important to understand the effects of long-term aromatase inhibitor therapy on BMD.

Patients and Methods

This prospective substudy of the ATAC trial assessed BMD changes in postmenopausal women with invasive primary breast cancer receiving anastrozole (1 mg/d) or tamoxifen (20 mg/d) as adjuvant therapy for 5 years. Lumbar spine and total hip BMD were assessed at baseline and after 1, 2, and 5 years.

Results

One hundred ninety-seven women from the monotherapy arms of the ATAC trial were recruited onto the bone substudy, and 108 were included in the primary analysis. Among anastrozole-treated patients, there was a decrease in median BMD from baseline to 5 years in lumbar spine (−6.08%) and total hip (−7.24%) compared with the tamoxifen group (lumbar spine, +2.77%; total hip, +0.74%). No patients with normal BMD at baseline became osteoporotic at 5 years.

Conclusion

Anastrozole is associated with accelerated bone loss over the 5-year treatment period. However, although patients with pre-existing osteopenia are likely to require monitoring and bone-protection strategies, patients with normal BMD would not appear to require monitoring beyond the recommendation for healthy postmenopausal women. The effect of anastrozole on bone should be weighed against its superior efficacy and better tolerability profile versus tamoxifen in the main ATAC trial.

Bone health in postmenopausal women with early breast cancer: How protective is tamoxifen?

Breast cancer is a leading threat to women's health. Tamoxifen, the most successful selective estrogen receptor modulator, has been used in hormonal therapy for three decades. Along with its therapeutic effect on breast cancer, tamoxifen also demonstrates potential benefits for bone health. However, the extent and quality of such benefits have not been systematically evaluated. We conducted a comprehensive literature search and identified 27 peer-reviewed articles investigating the relationship between tamoxifen and bone health in postmenopausal women with early stage breast cancer. The majority of studies reported that tamoxifen therapy alone protected against the loss of spinal bone mineral density. The bones in the hip also benefited from tamoxifen treatment while there was no evidence demonstrating tamoxifen's protection against bone loss in arms. When tamoxifen was combined with chemotherapy, it was found to partially prevent or reverse the bone loss resulting from chemotherapy. Patients with a history of hormone replacement therapy experienced bone loss while patients without the history had increased bone mineral density during tamoxifen therapy. Despite an apparent impact of tamoxifen on bone mineral density, the few available studies of tamoxifen and bone fractures appear to suggest no protective effect but an increase in fracture incidence. More investigation is necessary to clarify the discrepancy between bone mineral density and fracture in postmenopausal breast cancer patients treated with tamoxifen.

Cancer-treatment-induced bone loss, part 1

PURPOSE

The pathophysiology, frequency, sequelae, diagnosis, and treatment of cancer-treatment-induced bone loss (CTIBL) are discussed.

SUMMARY

CTIBL is a long-term complication associated with cancer therapies that can directly or indirectly affect bone metabolism. Although CTIBL can occur in any patient receiving a cancer therapy known to cause bone loss, CTIBL is most common in patients with breast or prostate cancer who receive chemotherapy, hormone therapy, or surgical castration, as these can cause hypogonadism and induce bone loss. CTIBL causes bone fragility and an increased susceptibility to fractures; therefore, prevention, early diagnosis, and treatment of CTIBL are essential to decrease the risk of fracture. Bone loss occurs more rapidly and tends to be more severe in patients with CTIBL compared with those with normal age-related bone loss. Fractures of the hip, vertebra, and wrist are the fractures most commonly associated with bone loss. CTIBL is diagnosed by measuring bone mass using bone densitometry. Treatment of CTIBL consists of changing diet and lifestyle such as optimizing calcium and vitamin D intake, exercising, modifying behaviors known to increase the risk of CTIBL and pharmacologic therapy with hormone replacement therapy (HRT), selective estrogen-receptor modifiers (SERMs), calcitonin, or a bisphosphonate.

CONCLUSION

Early identification and treatment of CTIBL are essential to prevent fractures. Patients should be instructed to optimize calcium and vitamin D intake, exercise regularly, and modify lifestyle behaviors known to cause bone loss. Patients with CTIBL should be treated with an oral or i.v. bisphosphonate; SERMs or HRT may be an option in some patients if contraindications do not exist.

Skeletal consequences of hormone therapy discontinuance: a systematic review

Although hormone therapy protects against bone loss after menopause, currently it is not recommended once menopausal symptoms have subsided. We reviewed randomized clinical trials to quantify bone loss after stopping hormone therapy and summarize treatment options for women who discontinue hormone treatment. We conducted a search of MEDLINE and EMBASE for randomized, controlled trials measuring bone mineral density (BMD) after hormone therapy discontinuation. Other known published and unpublished data were also included. Eleven studies fulfilled the search criteria. In each, bone loss was rapid after stopping hormone therapy, with BMD declines ranging from 2.3% to 6.2% in the first year. Increases in bone turnover markers also occurred rapidly when hormone therapy was stopped. Limited data addressing treatment after hormone therapy is stopped exist; only 2 studies specifically evaluated therapy to protect bone after hormone discontinuation. Taken together, these 2 studies demonstrate that alendronate produced significant increases relative to placebo in spine, hip, and total body BMD in women with low bone density who had discontinued hormone therapy within the past 3 months, preventing the rapid bone loss seen on discontinuation of hormone therapy. Among treatment options for preventing bone loss on discontinuation of hormone therapy for which randomized clinical trial data are available, alendronate prevented bone loss or increased bone density in postmenopausal women with low bone density. Women who are discontinuing hormone therapy should be counseled about potential bone loss and effective treatment options.

TARGET AUDIENCE

Obstetricians & Gynecologists, Family Physicians.

LEARNING OBJECTIVES

After completion of this article, the reader should be able to state that discontinuation of replacement menopausal hormone therapy, which protects against bone loss, is not recommended after menopause symptoms have subsided; recall that it may accelerate bone loss; and explain that there is bone loss preventive treatment for women after discontinuation of hormone therapy.

Bone mineral density and lipid changes during 5 years of follow-up in a study of prevention of breast cancer with toremifene in healthy, high-risk pre- and post-menopausal women

A double-blind, randomised, placebo-controlled pilot study was initiated to evaluate the feasibility of chemoprevention with toremifene 60 mg/day in healthy women at high risk for breast cancer. Enrolment in the study was terminated earlier than planned because of slow patient accrual, although 13% of patients continued for 5 years. The revised efficacy outcomes were change in bone mineral density (BMD) from baseline at four skeletal sites, plus effects on serum lipids. In premenopausal women there was a trend for sustained increase in BMD during toremifene therapy after year 1 in lumbar spine. In postmenopausal women, toremifene had little or no effect on BMD trends. Levels of total and low-density lipoprotein (LDL) cholesterol were largely unchanged from baseline in premenopausal women treated with toremifene but were often slightly lower than in the placebo group during follow-up. Total and LDL cholesterol levels declined slightly from baseline in the postmenopausal women and were, at several points during the first 3 years, significantly lower than in the corresponding placebo group (p < 0.01). We conclude that: (a) assessment of toremifene 60 mg/day in chemoprevention will require further clinical trials; (b) toremifene 60 mg/day has no substantive negative effects on BMD in pre- or postmenopausal women and may exert a minor favourable influence (in particular, the effects of toremifene 60 mg/day on BMD in premenopausal women may make the drug an attractive alternative to tamoxifen 20 mg/day for that patient subset); (c) lipid effects of toremifene 60 mg/day are, at minimum, neutral and may be modestly favourable for reducing cardiovascular risk.

Pilot studies of the effect of zoledronic acid (Zometa) on tumor-derived cells ex vivo in the ATP-based tumor chemosensitivity assay

There is debate regarding the direct effect of bisphosphonates against visceral metastases from solid tumors, despite their proven efficacy against the skeletal complications of metastasis. The aim of this study was to determine whether zoledronic acid showed direct activity against five ovarian cell lines and tumor-derived cells, and whether addition of zoledronic acid to cytotoxic agents increased their cytotoxicity. In this study we used a standardized ATP-based tumor chemosensitivity assay (ATP-TCA) to measure the activity of alendronate, clodronate and zoledronic acid in five ovarian carcinoma cell lines and human solid tumors (breast, lung, ovarian, unknown primary carcinoma, and cutaneous and uveal melanoma) (n=34). We also tested the combination of zoledronic acid with paclitaxel and cisplatin in tumor-derived cells. All five cell lines exhibited greater sensitivity to bisphosphonates than the tumor-derived cells and in all five the IC50 for zoledronic acid was less than 4 muM. In the tumor-derived cells, zoledronic acid showed concentration-dependent inhibition with a median IC50 for all tumors tested of 17 muM and evidence of apoptosis (caspase activation). Simultaneous addition of zoledronic acid to cisplatin or paclitaxel showed no major increase in cytotoxicity. We conclude that the activity of bisphosphonates was greater in cell lines than in tumor-derived cells. However, the pattern of activity of bisphosphonates was the same in cell lines and tumor derived cells. This study suggests a direct, or possibly an indirect, effect of zoledronic acid and other nitrogen-containing bisphosphonates against neoplastic cells, but simultaneous addition with cisplatin or paclitaxel does not substantially increase the activity of the cytotoxic agent.

Toremifene: an evaluation of its safety profile

Toremifene has been in clinical use for 8 years for the treatment of advanced hormone-sensitive breast cancer and the adjuvant treatment of early breast cancer. More than 350,000 patient treatment years have accumulated, sufficient to allow evaluation of its longer-term safety profile in comparison with tamoxifen and, where possible, with raloxifene and aromatase inhibitors. We reviewed all preclinical and clinical safety data from 1978 to 2004 and comparative clinical safety data between October 1995 and the end of 2004. Secondary endometrial cancer incidence was lower with toremifene than with tamoxifen and was similar to that with raloxifene. It is speculated that toremifene may unmask existing endometrial tumors rather than induce new events. The risk of stroke, pulmonary embolism, and cataract may be lower with toremifene than with tamoxifen and the risk of pulmonary embolism and deep vein thrombosis lower than with raloxifene. Beneficial estrogen agonistic effects were equivalent to those of tamoxifen regarding bone mineral density and superior regarding lipid profiles.

Management of menopausal symptoms in patients with breast cancer: an evidence-based approach

Increasing numbers of women have menopausal symptoms after treatment for breast cancer. These symptoms can result directly from cancer treatments (such as oophorectomy, ovarian suppression, chemotherapy-induced ovarian failure, and antioestrogens), as a spontaneous event, or after discontinuation of hormone-replacement therapy. The onset of menopausal symptoms after treatment for breast cancer can have a long-lasting effect on quality of life, body image, sexual function, and self esteem. Hormone-replacement therapy that contains oestrogen is the most effective treatment for menopausal symptoms in healthy women. However, evidence from one randomised controlled trial suggests that use of hormone replacement therapy after breast cancer raises the risk of recurrence and of new primary breast cancer. As the incidence of breast cancer increases and survival continues to improve, the number of women with menopausal symptoms will probably rise. Safe and effective non-hormonal treatments for severe menopausal symptoms after breast cancer are urgently needed. Few studies have addressed the management of menopausal symptoms after breast cancer, and the quality of studies is generally poor. Progestagens, and selective inhibitors of serotonin and norepinephrine reuptake seem to offer reasonable symptom palliation, but the long-term effectiveness and safety of these preparations is not known. We propose that the management of menopausal symptoms in patients with a history of cancer requires a patient-centred, but multidisciplinary, approach.

Changes in bone mineral density during and after 3 years' use of tamoxifen or toremifene

OBJECTIVES

To study the effects of tamoxifen and toremifene on bone mineral density (BMD) in postmenopausal women with breast cancer.

METHODS

Seventy patients with stage II-III breast cancer were randomized to start either tamoxifen (n = 36; 20 mg per day) or toremifene (n = 34; 40 mg per day) for 3 years. BMD in the lumbar spine and in the proximal femur was measured by dual-energy X-ray absorptiometry both before and during the treatment and 1 year after the discontinuation of the anti-estrogens.

RESULTS

The baseline BMD measurements were comparable between the groups. In 3 years, lumbar BMD decreased by 1.7% in tamoxifen (P = 0.048) and 3.0% in toremifene (P = 0.001) users (ns between the groups), and femoral neck BMD by 0.9% (P = 0.040) and 1.3% (P = ns), respectively. The use of hormone replacement therapy (HRT) until the diagnosis of breast cancer was associated with decreases in lumbar BMD during anti-estrogen regimen (4% at 3 years) in contrast to unchanged lumbar BMD in women with no previous use of HRT. During the 1st year after the cessation of anti-estrogen, lumbar BMD did not change at all in either group whereas femoral BMD decreased in both the groups at the rate of 1.5-3.2%, as expected.

CONCLUSIONS

We conclude that tamoxifen (20 mg) and toremifene (40 mg) have similar bone-sparing efficacy that in lumbar spine extends up to 1 year after the cessation of these regimens. This effect is not seen in lumbar spine BMD in those postmenopausal women who discontinue HRT at the time of breast cancer diagnosis.

Bone Health in Women with Early-Stage Breast Cancer

Bone health is an increasingly important concern in breast cancer survivors because in postmenopausal women, bone-sparing tamoxifen is being replaced by aromatase inhibitors, whereas in premenopausal women, ovarian suppression is playing an increasing role in adjuvant management. Estrogen reduction resulting from aromatase inhibition and ovarian suppression are associated with loss in bone mineral density (BMD) and an increase in fracture risk. These side effects must be placed in context of the overall risks and benefits seen with these interventions. The American Society of Clinical Oncology has outlined a management strategy for bone health maintenance in breast cancer survivors with early-stage disease that incorporates baseline and ongoing screening for BMD and treatment based on BMD results. Limited but consistent data suggest bisphosphonate therapy represents a treatment option for this condition. A variety of interventions to maintain bone health in breast cancer survivors are undergoing clinical evaluation and include the oral bisphosphonates risedronate and clodronate, the intravenous bisphosphonate zoledronic acid, the receptor activator of nuclear factor-kB ligand inhibitor AMG-162, and the hormonal agent tibolone. Current information suggests bone loss associated with estrogen reduction in breast cancer survivors may represent a preventable and treatable condition. Ongoing clinical trials will definitively evaluate this hypothesis.

American Society of Clinical Oncology technology assessment on the use of aromatase inhibitors as adjuvant therapy for postmenopausal women with hormone receptor-positive breast cancer: status report 2004

PURPOSE

To update the 2003 American Society of Clinical Oncology technology assessment on adjuvant use of aromatase inhibitors.

RECOMMENDATIONS

Based on results from multiple large randomized trials, adjuvant therapy for postmenopausal women with hormone receptor-positive breast cancer should include an aromatase inhibitor in order to lower the risk of tumor recurrence. Neither the optimal timing nor duration of aromatase inhibitor therapy is established. Aromatase inhibitors are appropriate as initial treatment for women with contraindications to tamoxifen. For all other postmenopausal women, treatment options include 5 years of aromatase inhibitors treatment or sequential therapy consisting of tamoxifen (for either 2 to 3 years or 5 years) followed by aromatase inhibitors for 2 to 3, or 5 years. Patients intolerant of aromatase inhibitors should receive tamoxifen. There are no data on the use of tamoxifen after an aromatase inhibitor in the adjuvant setting. Women with hormone receptor-negative tumors should not receive adjuvant endocrine therapy. The role of other biomarkers such as progesterone receptor and HER2 status in selecting optimal endocrine therapy remains controversial. Aromatase inhibitors are contraindicated in premenopausal women; there are limited data concerning their role in women with treatment-related amenorrhea. The side effect profiles of tamoxifen and aromatase inhibitors differ. The late consequences of aromatase inhibitor therapy, including osteoporosis, are not well characterized.

CONCLUSION

The Panel believes that optimal adjuvant hormonal therapy for a postmenopausal woman with receptor-positive breast cancer includes an aromatase inhibitor as initial therapy or after treatment with tamoxifen. Women with breast cancer and their physicians must weigh the risks and benefits of all therapeutic options.

Short-Term Intermittent Intravenous Clodronate in the Prevention of Bone Loss Related to Chemotherapy-Induced Ovarian Failure

Chemotherapy-induced ovarian failure causes rapid bone loss in premenopausal women with early breast cancer. The aim of the present study was to investigate the effect of intravenous intermittent clodronate during adjuvant chemotherapy in prevention of this rapid bone loss. 45 premenopausal women with early stage breast cancer were treated with adjuvant chemotherapy. In addition, all women were randomly allocated to receive either seven cycles of intravenous clodronate infusions (1500 mg each) parallel to the chemotherapy or no further therapy. The mean bone loss in the lumbar spine at 6 months was -0.5% in the clodronate group and -1.4% in the control group (p = 0.22) and, at 12 months, -3.9% and -3.6%, respectively (p = 0.62). Type I collagen metabolite PINP levels at six months were significantly lower in the clodronate group than in the control group: 22.6 microg/l (range 15.7-55.8 microg/l) and 44.0 microg/l (range 12.5-91.9 microg/l), respectively (p = 0.0001). At 12 months, no difference between the PINP levels in clodronate and control groups were seen. In conclusion, in this small study a short-term intermittent intravenous clodronate treatment did not seem to prevent clinically significantly the bone loss related to chemotherapy-induced ovarian failure in premenopausal women with early stage breast cancer, even though a significant reduction of a biochemical marker of bone turnover (PINP) was seen during the therapy.

American Society of Clinical Oncology 2003 update on the role of bisphosphonates and bone health issues in women with breast cancer

PURPOSE

To update the 2000 ASCO guidelines on the role of bisphosphonates in women with breast cancer and address the subject of bone health in these women.

RESULTS

For patients with plain radiographic evidence of bone destruction, intravenous pamidronate 90 mg delivered over 2 hours or zoledronic acid 4 mg over 15 minutes every 3 to 4 weeks is recommended. There is insufficient evidence supporting the efficacy of one bisphosphonate over the other. Starting bisphosphonates in women who demonstrate bone destruction through imaging but who have normal plain radiographs is considered reasonable treatment. Starting bisphosphonates in women with only an abnormal bone scan but without evidence of bone destruction is not recommended. The presence or absence of bone pain should not be a factor in initiating bisphosphonates. In patients with a serum creatinine less than 3.0 mg/dL (265 mumol/L), no change in dosage, infusion time, or interval is required. Infusion times less than 2 hours with pamidronate or less than 15 minutes with zoledronic acid should be avoided. Creatinine should be monitored before each dose of either agent in accordance with US Food and Drug Administration (FDA) labeling. Oncology professionals, especially medical oncologists, need to take an expanded role in the routine and regular assessment of the osteoporosis risk in women with breast cancer. The panel recommends an algorithm for patient management to maintain bone health.

CONCLUSION

Bisphosphonates provide a supportive, albeit expensive and non-life-prolonging, benefit to many patients with bone metastases. Current research is focusing on bisphosphonates as adjuvant therapy. Although new data addressing when to stop therapy, alternative doses or schedules for administration, and how to best coordinate bisphosphonates with other palliative therapies are needed, they are not currently being investigated.