Use of Adjuvant Bisphosphonates and Other Bone-Modifying Agents in Breast Cancer: A Cancer Care Ontario and American Society of Clinical Oncology Clinical Practice Guideline

Cancer Treatment-Induced Bone Loss (CTIBL): State of the Art and Proper Management in Breast Cancer Patients on Endocrine Therapy

OPINION STATEMENT

About 70-80% of early breast cancer (BC) patients receive adjuvant endocrine therapy (ET) for at least 5 years. ET includes in the majority of cases the use of aromatase inhibitors, as upfront or switch strategy, that lead to impaired bone health. Given the high incidence and also the high prevalence of BC, cancer treatment-induced bone loss (CTIBL) represents the most common long-term adverse event experimented by patients with hormone receptor positive tumours. CTIBL is responsible for osteoporosis occurrence and, as a consequence, fragility fractures that may negatively affect quality of life and survival expectancy. As recommended by main international guidelines, BC women on aromatase inhibitors should be carefully assessed for their fracture risk at baseline and periodically reassessed during adjuvant ET in order to early detect significant worsening in terms of bone health. Antiresorptive agents, together with adequate intake of calcium and vitamin D, should be administered in BC patients during all course of ET, especially in those at high risk of osteoporotic fractures, as calculated by tools available for clinicians. Bisphosphonates, such as zoledronate or pamidronate, and anti-RANKL antibody, denosumab, are the two classes of antiresorptive drugs used in clinical practice with similar efficacy in preventing bone loss induced by aromatase inhibitor therapy. The choice between them, in the absence of direct comparison, should be based on patients' preference and compliance; the different safety profile is mainly related to the route of administration, although both types of drugs are manageable with due care, since most of the adverse events are predictable and preventable. Despite advances in management of CTIBL, several issues such as the optimal time of starting antiresorptive agents and the duration of treatment remain unanswered. Future clinical trials as well as increased awareness of bone health are needed to improve prevention, assessment and treatment of CTIBL in these long-term survivor patients.

Breast Cancer Therapeutics and Biomarkers: Past, Present, and Future Approaches

Breast cancer (BC) is the leading cause of cancer death in women and the second-most common cancer. An estimated 281 550 new cases of invasive BC will be diagnosed in women in the United States, and about 43 600 will die during 2021. Continual research has shed light on all disease areas, including tumor classification and biomarkers for diagnosis/prognosis. As research investigations evolve, new classes of drugs are emerging with potential benefits in BC treatment that are covered in this manuscript. The initial sections present updated classification and terminology used for diagnosis and prognosis, which leads to the following topics, discussing the past and present treatments available for BC. Our review will generate interest in exploring the complexity of the cell cycle and its association with cancer biology as part of the plethora of target factors toward developing newer drugs and effective therapeutic management of BC.

Adjuvant bisphosphonate use in patients with early stage breast cancer: a physician survey

Purpose

Despite the increasing use of adjuvant bone-modifying agents (BMAs) such as zoledronate and clodronate in the treatment of patients with early stage breast cancer (EBC), little is known about real world practice patterns. A physician survey was performed to address this deficit and determine interest in clinical trials of alternative strategies for BMA administration.

Methods

Canadian oncologists treating patients with EBC were surveyed via an anonymized online survey. The survey collected information on: physician demographics, knowledge and interpretation of adjuvant bisphosphonate guidelines, and real world prescribing practices. Questions also determined thoughts around the design of future adjuvant BMA trials.

Results

Of 127 surveyed physicians, 53 eligible invitees responded (response rate 42%). The majority of physicians are offering high-risk postmenopausal patients adjuvant BMAs. The most common BMA regimen was adjuvant zoledronate (45/53, 85%) every 6 months for 3 years. Concerns around toxicities and repeated visits to the cancer centre were perceived as the greatest barriers to adjuvant bisphosphonate use. Respondents were interested in future trials of de-escalation of BMAs comparing a single infusion of zoledronate vs. 6-monthly zoledronate for 3 years. The most favoured primary endpoints for such a trial included disease recurrence and fragility fracture rates.

Conclusion

Questions around optimal use of adjuvant bisphosphonates in patients with EBC still exist. There is interest among physicians in performing trials of de-escalation of these agents. The results of this survey will assist in designing pragmatic clinical trials to address this question.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10549-021-06147-1.

Challenges in Adjuvant Therapy for Premenopausal Women Diagnosed With Luminal Breast Cancers

More than 90% of women with newly diagnosed breast cancer present with stage I to III disease and, with optimal multidisciplinary therapy, are likely to survive their disease. Of these patients, 70% are hormone receptor-positive and candidates for adjuvant endocrine therapy. The adoption of cumulatively better adjuvant treatments contributed to improved outcomes in patients with hormone receptor-positive, early-stage breast cancer. Premenopausal women with hormone receptor-positive breast cancer often present with complex disease and have inferior survival outcomes compared with their postmenopausal counterparts. Risk stratification strategies, including classic clinicopathologic features and newer gene expression assays, can assist in treatment decisions, including adjuvant chemotherapy use and type or duration of endocrine therapy. Gene expression assays may help identify patients who can safely forgo chemotherapy, although to a lesser extent among premenopausal patients, in whom they may play a role only in node-negative disease. Patients at lower risk of recurrence can be adequately treated with tamoxifen alone, whereas higher-risk patients benefit from ovarian function suppression with tamoxifen or an aromatase inhibitor. The role of adding newer therapies such as CDK4/6 inhibitors to adjuvant endocrine therapy is not yet clear. Breast cancer treatments are associated with several side effects, with major impact on patients' quality of life and treatment adherence, particularly in premenopausal women for whom these side effects may be more prominent as the result of the abrupt decrease in estrogen concentrations. Personalized management of treatment side effects, addressing patients' concerns, and health promotion should be an integral part of the care of premenopausal women diagnosed with luminal breast cancers.

Five-year follow-up results of aerobic and impact training on bone mineral density in early breast cancer patients

A 12-month exercise program reversibly prevented hip bone loss in premenopausal women with early breast cancer. The bone-protective effect was maintained for 2 years after the end of the program but was lost thereafter.

PURPOSE

Breast cancer survivors are at an increased risk for osteoporosis and fracture. This 5-year follow-up of a randomized impact exercise intervention trial evaluated the maintenance of training effects on bone among breast cancer patients.

METHODS

Five hundred seventy-three early breast cancer patients aged 35-68 years and treated with adjuvant therapy were allocated into a 12-month exercise program or a control group. Four hundred forty-four patients (77%) were included in the 5-year analysis. The exercise intervention comprised weekly supervised step aerobics, circuit exercises, and home training. Areal bone mineral density (aBMD) was measured by dual-energy X-ray absorptiometry. Physical activity was estimated in metabolic equivalent (MET) hours per week and physical performance assessed by 2-km walking and figure-8 running tests.

RESULTS

In premenopausal patients, the 12-month exercise program maintained femoral neck (FN) and total hip (TH) aBMD for 3 years, but the protective effect was lost thereafter. The mean FN aBMD change in the exercise and control groups was - 0.2% and - 1.5% 1 year, - 1.1% and - 2.1% 3 years and - 3.3% versus - 2.4% 5 years after the beginning of the intervention, respectively. Lumbar spine (LS) bone loss was not prevented in premenopausal women and no training effects on aBMD were seen in postmenopausal women. The main confounding element of the study was the unexpected rise in physical activity among patients in the control group. The physical performance improved among premenopausal women in the exercise group compared with the controls.

CONCLUSION

The 12-month exercise program prevented FN and TH bone loss in premenopausal breast cancer patients for 3 years. The bone-protective effect was reversible and lost thereafter.

From Theory to Practice: Bone Health in Women with Early Breast Cancer Treated with Aromatase Inhibitors

Aromatase inhibitors (AI) are extensively used as adjuvant endocrine therapy in post-menopausal women with hormone receptor-positive early breast cancer (HR+ EBC), but their impact on bone health is not negligible. This work aimed to assess bone loss, fracture incidence, and risk factors associated with these events, as well as the prognostic influence of fractures. We have conducted a retrospective cohort study of women with HR+ EBC under adjuvant therapy with AI, during a 3-year period. Four-hundred-and-fifty-one eligible women were reviewed (median age 68 years). Median time under AI was 40 months. A fracture event occurred in 8.4%, mostly in the radium and femoral neck and in older women (mean 74 vs. 68 years, p = 0.006). Age (OR 1.01, 95% CI 1.01-1.07, p = 0.024) and time under AI (OR 1.02, 95% CI 1.00-1.04, p = 0.037) were independent predictors of fracture, with a fair discrimination (AUC 0.71). Analysis of disease-free survival according to fracture event varied between groups, disfavoring the fracture cohort (at 73 months, survival 78.6%, 95% CI, 47.6-92.4 vs. 95.6%, 95% CI, 91.2-97.8, p = 0.027). The multivariate model confirmed the prognostic impact of fracture occurrence (adjusted HR of 3.17, 95% CI 1.10-9.11; p = 0.032). Bone health is often forgotten, despite its great impact in survivorship. Our results validate the pathophysiologic link between EBC and bone metabolism, which translates into EBC recurrence. Further research in this area may help refine these findings. Moreover, early identification of women at higher risk for fractures is warranted.

Adjuvant bisphosphonate use in patients with early stage breast cancer: Patient perspectives on treatment acceptability and potential de-escalation

Background

Despite the increasing use of adjuvant bisphosphonates for early stage breast cancer (EBC), little is known about the patient experience with such treatments. A patient survey was performed to identify current prescribing practices, perceptions around the role of treatment, the impact of treatment on patients' quality of life, and future trial designs.

Methods

EBC patients who had either completed or were currently receiving adjuvant bisphosphonates were sent an anonymized survey. The survey collected information on patient and disease characteristics, bisphosphonate scheduling, compliance, and tolerance. Questions also assessed patient interest in trials of de-escalated bisphosphonate therapy.

Results

A total of 255 patients were contacted, with 164 eligible respondents (eligible response rate 164/255, 64.3%). Median patient age was 52 years (range 28 to 82 years). The majority (111/163, 68.1%) were postmenopausal at the time of diagnosis, 23.3% (38/163) were premenopausal, and 7.4% (12/163) were perimenopausal. Most patients (78%) had received chemotherapy. Zoledronate was the most commonly used bisphosphonate (92%), with the majority receiving treatment every 6 months for 3 years (73%). While 66% (107/161) of respondents had experienced side effects with treatment, most had, or expected to, complete treatment (154/163, 94%). Provided there was no detriment in breast cancer outcomes, there was strong interest in future studies of de-escalating adjuvant bisphosphonate therapy.

Conclusion

While most patients tolerate their treatment, there is interest in performing trials of de-escalation of these agents.

Clodronate

Two early observations about the first generation bisphosphonate, clodronate, suggested that it would likely have clinical utility; specifically, it was a more potent anti-resorptive but a less potent inhibitor of mineralisation than its predecessor etidronate. The known mechanism of action differs from that of the later nitrogen-containing bisphosphonates, as clodronate is metabolised intracellularly to a toxic analog of adenosine triphosphate, AppCCl2p, which causes mitochondrial dysfunction, impaired cellular energy metabolism and osteoclast apoptosis. For pre-clinical studies in a variety of disease models, liposomal clodronate has become the agent of choice for macrophage depletion, for example in a recent study to enhance haematopoietic chimerism and donor-specific skin allograft tolerance in a mouse model. For clinical use, clodronate was developed in oral and injectable formulations; while poorly absorbed from the gastro-intestinal tract, its absorption at 1-3% of the administered dose is approximately three-fold higher than for nitrogen-containing bisphosphonates. Following an early setback due to an erroneous association with toxic adverse events, a number of successful clinical studies have established clodronate, predominantly in its oral formulations, as a highly successful treatment in Paget's disease, hypercalcaemia (benign and malignant), multiple myeloma, and early or metastatic breast cancer. Novel uses in other disease areas, including veterinary use, continue to be explored.

A randomised trial of 4- versus 12-weekly administration of bone-targeted agents in patients with bone metastases from breast or castration-resistant prostate cancer

BACKGROUND

Optimal dosing of bone-targeted agents (BTAs), in patients with bone metastases remains an important clinical question. This trial compared 4-weekly versus 12-weekly therapy.

PATIENTS AND METHODS

Patients with bone metastases from breast or castration-resistant prostate cancer (CRPC), who were going to start or already on BTAs, were randomised 1:1 to 4-weekly or 12-weekly BTA treatment for one year. Primary end point was change in health-related quality of life (HRQoL)-physical function European Organisation for Research and Treatment of Cancer (EORTC)-QLQ-C30). Secondary end points included pain (EORTC-QLQ-BM22), global health status (EORTC-QLQ-C30), symptomatic skeletal events (SSEs) rates and time to SSEs. Primary analysis was per protocol and a non-inferiority margin of 5 points was used.

RESULTS

Of 263 patients (160 breast cancer, 103 CRPC), 133 (50.6%) and 130 (49.4%) were randomised to the 4- and 12-weekly groups, respectively. BTAs included denosumab (56.3%), zoledronate (24.0%) and pamidronate (19.8%). Using repeated-measures analysis, across all time points, patients in the 4-weekly arm had a mean HRQL-physical subdomain score which was 1.2 (95% confidence interval: -1.6 to 4.0) higher than the 12-weekly arm. The study met the definition of non-inferiority for our primary outcome. Secondary outcomes showed no significant difference in scores for pain, global health status, SSE rates and SSE-free survival between arms. Subgroup analyses for cancer type, prior BTA use or BTA type showed no significant difference between arms.

CONCLUSION

These results in addition to those previously reported for de-escalating zoledronate and systematic reviews in both breast and prostate cancers, would support that de-escalation of commonly used BTAs is a reasonable treatment option.

Bone metastasis: mechanisms, therapies, and biomarkers

Skeletal metastases are frequent complications of many cancers, causing bone complications (fractures, bone pain, disability) that negatively affect the patient's quality of life. Here, we first discuss the burden of skeletal complications in cancer bone metastasis. We then describe the pathophysiology of bone metastasis. Bone metastasis is a multistage process: long before the development of clinically detectable metastases, circulating tumor cells settle and enter a dormant state in normal vascular and endosteal niches present in the bone marrow, which provide immediate attachment and shelter, and only become active years later as they proliferate and alter the functions of bone-resorbing (osteoclasts) and bone-forming (osteoblasts) cells, promoting skeletal destruction. The molecular mechanisms involved in mediating each of these steps are described, and we also explain how tumor cells interact with a myriad of interconnected cell populations in the bone marrow, including a rich vascular network, immune cells, adipocytes, and nerves. We discuss metabolic programs that tumor cells could engage with to specifically grow in bone. We also describe the progress and future directions of existing bone-targeted agents and report emerging therapies that have arisen from recent advances in our understanding of the pathophysiology of bone metastases. Finally, we discuss the value of bone turnover biomarkers in detection and monitoring of progression and therapeutic effects in patients with bone metastasis.

Feasibility outcomes of a randomised, multicentre, pilot trial comparing standard 6-monthly dosing of adjuvant zoledronate with a single one-time dose in patients with early stage breast cancer

•

Adjuvant bisphosphonates are an established standard in postmenopausal breast cancer.

•

Guidelines note the need to explore different agents, doses, and intervals of bisphosphonates.

•

Feasibility of randomizing to 6-monthly vs one dose of IV zoledronate was demonstrated.

Background

Adjuvant zoledronate is widely used in patients with early stage breast cancer (EBC), but its optimal duration and dosing interval is still unknown. While a single-dose of zoledronate can improve bone density for many years, a proper evaluation of its effects on breast cancer-related outcomes would require a large trial. In this pilot study we evaluated the feasibility of performing such a trial.

Methods

Eligible patients with EBC were randomised to receive either one dose of zoledronate or 7 doses (6-monthly dosing for 3 years). Feasibility was assessed by a combination of primary outcomes including: activation of at least 6 Ontario sites within a year, active participation (i.e. approaching eligible patients for study participation) of at least half of the medical oncologists, and enrolment of at least 100 patients across all sites within 9 months of the sixth site being activated.

Results

All 6 sites were activated within 1 year and of 47 medical oncologists, 27 (57%) approached patients. Between November 2018 and April 2020, 211 eligible patients were randomised, 106 (50.2%) to a single dose of zoledronate and 105 (49.8%) to 6-monthly dosing. Baseline characteristics of randomised patients included; median age 59 (range 36–88), ER and/or PR positive (85%), Her2 positive (23%), menopausal status (premenopausal [19%], perimenopausal [6.7%] and postmenopausal [74%]) and 74% received neo/adjuvant chemotherapy.

Conclusions

All study feasibility endpoints were met in this trial comparing alternative schedules for adjuvant zoledronate. We will now seek funding for performing a larger efficacy trial.

Trial registration: NCT03664687.

Updates on the treatment of invasive breast cancer: Quo Vadimus?

Breast cancer is a common malignancy among women. Despite an increase in incidence, breast cancer mortality has drastically dropped over the last 20 years. This change has been attributed to advances in screening, diagnosis, and treatment. This review summarises recent updates in the clinical approach to breast cancer. Advances in genetics have facilitated the stratification of the risk of recurrence in early-stage breast cancer. Advances in biology have led to the development of novel therapies (poly-ADP-ribose polymerase inhibitors, cyclin-dependent kinase 4/6 inhibitors, HER2 targeted agents). Their combination with endocrine (tamoxifen, aromatase inhibitors, GnRH-analogues, fulvestrant) and systematic therapy (anthracyclines, taxanes) in early and advanced disease have improved clinical outcomes. In the near future, neoadjuvant strategies in specific breast cancer subgroups (triple-negative breast cancers) and novel strategies (immune-modulatory agents) could further improve histopathological responses and survival. Radical mastectomies have been widely replaced by breast-conserving operations, while the traditional axillary dissection is being replaced with sentinel node techniques. Breast cancer therapeutics represents a great challenge due to patients' heterogeneous molecular and clinical characteristics, while the identification of reliable and easily reproducible predictive factors could further improve individualized treatment.

Breast Cancer and Microcalcifications: An Osteoimmunological Disorder?

The presence of microcalcifications in the breast microenvironment, combined with the growing evidences of the possible presence of osteoblast-like or osteoclast-like cells in the breast, suggest the existence of active processes of calcification in the breast tissue during a woman’s life. Furthermore, much evidence that osteoimmunological disorders, such as osteoarthritis, rheumatoid arthritis, or periodontitis influence the risk of developing breast cancer in women exists and vice versa. Antiresorptive drugs benefits on breast cancer incidence and progression have been reported in the past decades. More recently, biological agents targeting pro-inflammatory cytokines used against rheumatoid arthritis also demonstrated benefits against breast cancer cell lines proliferation, viability, and migratory abilities, both in vitro and in vivo in xenografted mice. Hence, it is tempting to hypothesize that breast carcinogenesis should be considered as a potential osteoimmunological disorder. In this review, we compare microenvironments and molecular characteristics in the most frequent osteoimmunological disorders with major events occurring in a woman’s breast during her lifetime. We also highlight what the use of bone anabolic drugs, antiresorptive, and biological agents targeting pro-inflammatory cytokines against breast cancer can teach us.

Bisphosphonates and breast cancer - From cautious palliation to saving lives

Bone metastases are common in breast cancer and may cause considerable morbidity including fractures, severe pain, nerve compression and hypercalcaemia. Alongside developments in the multidisciplinary management for patients with metastatic breast cancer, the use of bisphosphonates, and more recently denosumab, has transformed the course of advanced breast cancer for many patients resulting in a major reduction in skeletal complications, reduced bone pain and improved quality of life. Additionally, because the bone marrow microenvironment is so intimately involved in the metastatic processes required for cancer dissemination, the use of adjuvant bisphosphonates has been studied extensively over the past 25 years in many randomised trials. We now have clear evidence that bisphosphonates significantly reduce both metastasis to bone and mortality in postmenopausal women with early breast cancer. Efficacy seems similar across different biological subgroups of postmenopausal breast cancer with the use of either a nitrogen-containing bisphosphonate such as intravenous zoledronate or daily oral ibandronate as well as the non-nitrogen containing agent, daily oral clodronate. In this overview of evolving role of bisphosphonates in breast cancer, focussing particularly on pamidronate and zoledronate, the long winding development road from the 1970s through to the present day is described and some of the serendipitous findings, "lucky breaks" and regulatory decisions along the way outlined.

Osteoporosis: A Long-Term and Late-Effect of Breast Cancer Treatments

Simple Summary

Osteoporosis is a prevalent condition affecting 200 million individuals world-wide. Estimates are about one in three women will experience a fragility fracture of hip, spine or wrist. Common breast cancer treatments, such as aromatase inhibitors in postmenopausal women and chemotherapy-induced ovarian failure in premenopausal women, cause bone loss that in some women will lead to osteoporosis and fragility fractures. Fragility fractures cause morbidity and mortality and are entirely preventable. Prevention or treatment of osteoporosis includes lifestyle modifications (e.g., reducing smoking and excessive alcohol consumption, and increasing physical activity), taking calcium and vitamin D3, screening for osteoporosis with dual-energy absorptiometry, and treatment, if clinically indicated, with ether oral bisphosphonates, intravenous zoledronic acid, or subcutaneous denosumab. This chapter reviews the pathogenesis of osteoporosis, the magnitude of bone loss related to common breast cancer treatments, osteoporosis risk factor assessment and screening, and the specific drugs to treat or prevent osteoporosis.

Abstract

Osteoporosis is both a long-term effect (occurs during treatment and extends after treatment) and a late-effect (occurs after treatment ends) of breast cancer treatments. The worldwide prevalence of osteoporosis is estimated to be some 200 million patients. About one in three postmenopausal women will experience an osteoporotic (or fragility) fracture of the hip, spine, or wrist. breast cancer treatments, including gonadotropin-releasing hormone (GnRH) agonists, chemotherapy-induced ovarian failure (CIOF), and aromatase inhibitors (AIs), cause bone loss and increase the risks of osteoporosis. Also, breast cancer is a disease of aging, and most of the “one in eight” lifetime risks of breast cancer are in women in their sixth, seventh, and eighth decades. The majority of women diagnosed with breast cancers today will be long-term survivors and experience personal cures. It is the coalescence of osteoporosis with breast cancer, two common and age-related conditions that make osteoporosis relevant in women with breast cancer throughout the continuum from diagnosis, treatment, and survivorship. It is critical to remember that women (and men) will lose bone after age thirty years. However, only certain women will lose bone of sufficient magnitude to merit treatment with anti-osteoporosis drugs. The narrative review is intended for medical, surgical, radiation oncologists, and other mid-level providers, and provides an overview of bone loss and the prevention and treatment of osteoporosis.

Landmark trials in the medical oncology management of early stage breast cancer

With the advent of breast cancer screening programs, the majorities of patients with newly diagnosed breast cancer are diagnosed with early stage disease and are likely to experience cure with proper treatment. Significant advances have been made in the management of early-stage breast cancer to personalize treatment according to disease biology. This progress has led to improvement in survival outcomes and quality of life for our patients. In this review, we discuss landmark clinical trials in medical oncology that have shaped the current standard of care for early stage ER-positive, HER2-positive, and triple negative breast cancer.

Shared decision making in breast cancer treatment guidelines: Development of a quality assessment tool and a systematic review

BACKGROUND

It is not clear whether clinical practice guidelines (CPGs) and consensus statements (CSs) are adequately promoting shared decision making (SDM).

OBJECTIVE

To evaluate the recommendations about SDM in CPGs and CSs concerning breast cancer (BC) treatment.

SEARCH STRATEGY

Following protocol registration (Prospero no.: CRD42018106643), CPGs and CSs on BC treatment were identified, without language restrictions, through systematic search of bibliographic databases (MEDLINE, EMBASE, Web of Science, Scopus, CDSR) and online sources (12 guideline databases and 51 professional society websites) from January 2010 to December 2019.

INCLUSION CRITERIA

CPGs and CSs on BC treatment were selected whether published in a journal or in an online document.

DATA EXTRACTION AND SYNTHESIS

A 31-item SDM quality assessment tool was developed and used to extract data in duplicate.

MAIN RESULTS

There were 167 relevant CPGs (139) and CSs (28); SDM was reported in only 40% of the studies. SDM was reported more often in recent publications after 2015 (42/101 (41.6 %) vs 46/66 (69.7 %), P = .0003) but less often in medical journal publications (44/101 (43.5 %) vs 17/66 (25.7 %), P = .009). In CPGs and CSs with SDM, only 8/66 (12%) met one-fifth (6 of 31) of the quality items; only 14/66 (8%) provided clear and precise SDM recommendations.

DISCUSSION AND CONCLUSIONS

SDM descriptions and recommendations in CPGs and CSs concerning BC treatment need improvement. SDM was more frequently reported in CPGs and CSs in recent years, but surprisingly it was less often covered in medical journals, a feature that needs attention.

Challenges in Preventing Bone Loss Induced by Aromatase Inhibitors

CONTEXT

Aromatase inhibitors have become a mainstay in the adjuvant treatment regimen in postmenopausal women with hormone receptor-positive breast cancer. While many of these patients have an excellent long-term prognosis, adverse effects on bone represent an emerging complication of aromatase inhibitor treatment, resulting in substantial bone loss and fragility fractures. Treatment approaches to prevent aromatase inhibitor-induced bone loss typically consist of an antiresorptive approach with bisphosphonates or the RANKL antibody denosumab. However, different guidelines vary with respect to treatment thresholds, duration, and dosing. The choice of antiresorptive regime is further complicated by comorbidities and potential disease-modifying effects of individual agents.

OBJECTIVE

This review summarizes the evidence of how aromatase inhibitors affect bone health and provides an update of clinical approaches to preserve bone strength in affected women. (J Clin Endocrinol Metab XX: 0-0, 2020).

Quality and reporting of clinical guidelines for breast cancer treatment: A systematic review

BACKGROUND

High-quality, well-reported clinical practice guidelines (CPGs) and consensus statements (CSs) underpinned by systematic reviews are needed. We appraised the quality and reporting of CPGs and CSs for breast cancer (BC) treatment.

METHODS

Following protocol registration (Prospero no: CRD42020164801), CPGs and CSs on BC treatment were identified, without language restrictions, through a systematic search of bibliographic databases (MEDLINE, EMBASE, Web of Science, Scopus, CDSR) and online sources (12 guideline databases and 51 professional society websites) from January 2017 to June 2020. Data were extracted in duplicate assessing overall quality using AGREE II (% of maximum score) and reporting compliance using RIGHT (% of total 35 items); reviewer agreement was 98% and 96% respectively.

RESULTS

There were 59 relevant guidance documents (43 CPGs, 16 CSs), of which 20 used systematic reviews for evidence synthesis. The median overall quality was 54.0% (IQR 35.9-74.3) and the median overall reporting compliance was 60.9% (IQR 44.5-84.4). The correlation between quality and reporting was 0.9. Compared to CSs, CPGs had better quality (55.4% vs 44.2%; p = 0.032) and reporting (67.18% vs 44.5%; p = 0.005). Compared to subjective methods of evidence analysis, guidance documents that used systematic reviews had better quality (76.3% vs 51.4%; p = 0.001) and reporting (87.1% vs 59.4%; p = 0.001).

CONCLUSION

The quality and reporting of CPGs and CSs in BC treatment were moderately strong. Systematic reviews should be used to improve the quality and reporting of CPGs and CSs.

Risk factors for bisphosphonate-associated osteonecrosis of the jaw in the prospective randomized trial of adjuvant bisphosphonates for early-stage breast cancer (SWOG 0307)

PURPOSE

Bisphosphonates reduce bone metastases in postmenopausal women with early-stage breast cancer but carry the risk of bisphosphonate-related osteonecrosis of the jaw (BRONJ). We describe risk factors for BRONJ and compare BRONJ provoked by infection or trauma with spontaneous lesions, which carry a better prognosis.

METHODS

SWOG 0307 randomized women with stage I-III breast cancer to receive zoledronic acid (ZA), clodronate (CL), or ibandronate (IB) for 3 years, implemented BRONJ prevention guidelines, and collected information about dental health and development of BRONJ. All statistical tests were two-sided.

RESULTS

Of 6018 women, 48 developed BRONJ. Infection was present in 21 (43.8%). Median time to BRONJ was 2.1 years for ZA, 2.0 years for IB, and 3.4 years for clodronate (p = 0.04). BRONJ was associated with bisphosphonate type (28/2231 (1.26%) for ZA, 8/2235 (0.36%) for CL, 12/1552 (0.77%) for IB), dental calculus (OR 2.03), gingivitis (OR 2.11), moderate/severe periodontal disease (OR 2.87), and periodontitis > 4 mm (OR 2.20) (p < 0.05). Of 57 lesions, BRONJ occurred spontaneously in 20 (35.1%) and was provoked by dental extraction in 20 (35.1%), periodontal disease in 14 (24.6%), denture trauma in 6 (10.5%), and dental surgery in 2 (3.5%). Spontaneous BRONJ occurred more frequently at the mylohyoid ridge. There were no differences in dental disease, infection, or bisphosphonate type between spontaneous and provoked BRONJ.

CONCLUSION

ZA and worse dental health were associated with increased incidence of BRONJ, with a trend toward additive risk when combined. BRONJ incidence was lower than in similar studies, with prevention strategies likely linked to this.

CLINICAL TRIAL NUMBER

NCT00127205 REGISTRATION DATE: July 2005.

Impact of mastectomy for breast cancer on spinal curvature: Considerations when treating patients with scoliosis

OBJECTIVE

Mastectomy has been shown to influence body posture in women; however, there are limited data outlining changes in spine curvature after mastectomy in patients with scoliosis. We sought to quantify changes in spine curvature after mastectomy for breast cancer.

METHODS

We conducted a retrospective review of 62 patients with scoliosis who underwent mastectomy for breast cancer at a single institution between 1995 and 2018. Preoperative and postoperative radiographs were used to measure Cobb angles to assess lateral spinal curvature. Changes in Cobb angle were compared using paired two-tailed t-tests. The relationship between mass of breast removed and changes in Cobb angle was modeled using a linear regression.

RESULTS

The median follow-up after mastectomy was 7.9 years (range 0.9-21.5). Median age was 62 years (range 30-85). Of 62 patients, 10 (16%) expressed that their back pain became worse after mastectomy. Nineteen patients had evaluable radiographs before and after mastectomy. In these patients, the average change in Cobb angle was 4.7° (range -0.2-12.2). Cobb angle significantly increased after mastectomy (P < .0001). Although not statistically significant, average Cobb angle was greater for patients who underwent unilateral compared to bilateral mastectomy (P = .09). Mass of breast removed significantly correlated with the difference in Cobb angle for patients who underwent unilateral mastectomy (P = .0006), but not for bilateral mastectomy (P = .55).

CONCLUSIONS

In this understudied patient population, mastectomy significantly increased the change in spine curvature. Further care should be taken to assess patient-reported pain and quality of life in patients with spine morbidity who undergo mastectomy for breast cancer.

Key steps for effective breast cancer prevention

Despite decades of laboratory, epidemiological and clinical research, breast cancer incidence continues to rise. Breast cancer remains the leading cancer-related cause of disease burden for women, affecting one in 20 globally and as many as one in eight in high-income countries. Reducing breast cancer incidence will likely require both a population-based approach of reducing exposure to modifiable risk factors and a precision-prevention approach of identifying women at increased risk and targeting them for specific interventions, such as risk-reducing medication. We already have the capacity to estimate an individual woman's breast cancer risk using validated risk assessment models, and the accuracy of these models is likely to continue to improve over time, particularly with inclusion of newer risk factors, such as polygenic risk and mammographic density. Evidence-based risk-reducing medications are cheap, widely available and recommended by professional health bodies; however, widespread implementation of these has proven challenging. The barriers to uptake of, and adherence to, current medications will need to be considered as we deepen our understanding of breast cancer initiation and begin developing and testing novel preventives.

Management of hormone receptor-positive, HER2-negative early breast cancer

The majority of breast cancers are diagnosed at an early stage and are hormone receptor (HR)-positive and human epidermal growth factor receptor 2 (HER2)-negative. Significant advances have been made in the management of early stage HR-positive, HER2-negative breast cancer, resulting in improved survival outcomes. In this review, we discuss important factors to consider in the management of this disease. In particular, we discuss the role of adjuvant endocrine therapy, specific endocrine therapy agents, the duration of adjuvant endocrine therapy, treatment-related side effects, and the role of genomic assays and other biomarkers when considering treatment recommendations for individuals with HR-positive, HER2-negative early breast cancer. Finally, we address emerging data to individualize therapeutic decision-making and provide future considerations.

Phase III Randomized Trial of Bisphosphonates as Adjuvant Therapy in Breast Cancer: S0307

BACKGROUND

Adjuvant bisphosphonates, when given in a low-estrogen environment, can decrease breast cancer recurrence and death. Treatment guidelines include recommendations for adjuvant bisphosphonates in postmenopausal patients. SWOG/Alliance/Canadian Cancer Trials Group/ECOG-ACRIN/NRG Oncology study S0307 compared the efficacy of three bisphosphonates in early-stage breast cancer.

METHODS

Patients with stage I-III breast cancer were randomly assigned to 3 years of intravenous zoledronic acid, oral clodronate, or oral ibandronate. The primary endpoint was disease-free survival (DFS) with overall survival as a secondary outcome. All statistical tests were two-sided.

RESULTS

A total of 6097 patients enrolled. Median age was 52.7 years. Prior to being randomly assigned, 73.2% patients indicated preference for oral vs intravenous formulation. DFS did not differ across arms in a log-rank test (P = .49); 5-year DFS was 88.3% (zoledronic acid: 95% confidence interval [CI] = 86.9% to 89.6%), 87.6% (clodronate: 95% CI = 86.1% to 88.9%), and 87.4% (ibandronate: 95% CI = 85.6% to 88.9%). Additionally, 5-year overall survival did not differ between arms (log rank P = .50) and was 92.6% (zoledronic acid: 95% CI = 91.4% to 93.6%), 92.4% (clodronate: 95% CI = 91.2% to 93.5%), and 92.9% (ibandronate: 95% CI = 91.5% to 94.1%). Bone as first site of recurrence did not differ between arms (P = .93). Analyses based on age and tumor subtypes showed no treatment differences. Grade 3/4 toxicity was 8.8% (zoledronic acid), 8.3% (clodronate), and 10.5% (ibandronate). Osteonecrosis of the jaw was highest for zoledronic acid (1.26%) compared with clodronate (0.36%) and ibandronate (0.77%).

CONCLUSIONS

We found no evidence of differences in efficacy by type of bisphosphonate, either in overall analysis or subgroups. Despite an increased rate of osteonecrosis of the jaw with zoledronic acid, overall toxicity grade differed little across arms. Given that patients expressed preference for oral formulation, efforts to make oral agents available in the United States should be considered.

The limitations of today’s clinical guidance: Atypical femoral fracture and long-term bone-modifying agents in the oncology setting

While bone-modifying agents such as bisphosphonates and denosumab are crucial to preventing skeletal-related events in patients with bone metastases, the optimal duration remains undefined. Extended duration may be associated with adverse effects such as osteonecrosis of the jaw and atypical femoral fracture. Although uncommon, atypical femoral fracture represents a serious consequence of prolonged bone-modifying agent use and are characterized by a prodrome and distinct radiographic findings. The oncology setting encompasses a unique set of atypical femoral fracture risk factors and considerations, with hormonal therapy in early stage disease, bone metastases in the advanced setting, and new targeted agents that may affect bone homeostasis. As outcomes in cancer treatment continue to improve, the questions of risks versus benefits of long-term bone-modifying agents and how to mitigate atypical femoral fracture risk become increasingly pertinent.

Survival in older women with early stage breast cancer receiving low-dose bisphosphonates or denosumab

BACKGROUND

Bisphosphonates and denosumab, as adjuvant therapy in breast cancer, have been associated in some studies with improved cancer outcomes. The potential benefits of these drugs used at the lower doses commonly given for osteoporosis have not been established. The objective of this study was to investigate the association between therapy with bone-modifying agents (BMAs) and survival in older women with early breast cancer.

METHODS

The authors conducted a retrospective cohort study of women aged ≥66 years with breast cancer who were included in the Surveillance, Epidemiology, and End Results and Texas Cancer Registry Medicare-linked databases. Associations were examined between the receipt of BMAs at dosages indicated for osteoporosis within 2 years after diagnosis and overall and breast cancer-specific survival. Cox proportional hazards models and propensity score adjustment and matching were used for the analyses.

RESULTS

Of the 37,724 women included, 7925 (21%) received at least 6 months of a BMA within the first 2 years of breast cancer diagnosis, including bisphosphonates only in 6898 women (80.7%), denosumab only in 1204 (15.2%), and both classes of BMAs in 323 (4.1%). The median follow-up was 64 months. The receipt of a bisphosphonate was associated with improved overall survival (hazard ratio [HR], 0.87; 95% CI, 0.82-0.93) and breast cancer-specific survival (HR, 0.77; 95% CI, 0.64-0.92) after multivariable adjustment. Benefits were primarily seen for patients who had stage II and III disease. No benefits were observed with denosumab (stage II: HR, 1.05 [95% CI, 0.90-1.22]; stage III: HR, 1.09 [95% CI, 0.66-1.82]).

CONCLUSIONS

Bisphosphonates at the doses recommended for osteoporosis are associated with improved survival in older postmenopausal women with early breast cancer.

ESO-ESMO 4th International Consensus Guidelines for Breast Cancer in Young Women (BCY4)

The 4th International Consensus Conference for Breast Cancer in Young Women (BCY4) took place in October 2018, in Lugano, Switzerland, organized by the European School of Oncology (ESO) and the European Society of Medical Oncology (ESMO). Consensus recommendations for the management of breast cancer in young women were updated from BCY3 with incorporation of new evidence to inform the guidelines. Areas of research priorities were also identified. This article summarizes the ESO-ESMO international consensus recommendations, which are also endorsed by the European Society of Breast Specialists (EUSOMA).

Management of osteoporosis in women with breast cancer

The screening, prevention and treatment of osteoporosis are similar in women with or without breast cancer. Breast cancer treatments, such as aromatase inhibitors, chemotherapy-induced ovarian failure and gonadotropin-releasing hormone antagonists all decrease estrogen levels, which in turn causes net bone resorption and bone loss. Bone loss over time will be of sufficient magnitude to cause some women to experience fractures. Thus, osteoporosis is an equation; the peak bone mass achieved by age 30 years minus the age-related and menopausal bone loss. Women should have their bone density measured by dual x-ray absorptiometry scans every 2 years. As clinically indicated, women should receive anti-osteoporosis drugs such as zoledronic acid, denosumab or oral bisphosphonates.

Cost-effectiveness analysis of endocrine therapy alone versus partial-breast irradiation alone versus combined treatment for low-risk hormone-positive early-stage breast cancer in women aged 70 years or older

PURPOSE

We performed a cost-effectiveness analysis of three strategies for the adjuvant treatment of early breast cancer in women age 70 years or older: an aromatase inhibitor (AI-alone) for 5 years, a 5-fraction course of accelerated partial-breast irradiation using intensity-modulated radiation therapy (APBI-alone), or their combination.

METHODS

We constructed a patient-level Markov microsimulation from the societal perspective. Effectiveness data (local recurrence, distant metastases, survival), and toxicity data were obtained from randomized trials when possible. Costs of side effects were included. Costs were adjusted to 2019 US dollars and extracted from Medicare reimbursement data. Quality-adjusted life-years (QALY) were calculated using utilities extracted from the literature.

RESULTS

The strategy of AI-alone ($12,637) was cheaper than both APBI-alone ($13,799) and combination therapy ($18,012) in the base case. All approaches resulted in similar QALY outcomes (AI-alone 7.775; APBI-alone 7.768; combination 7.807). In the base case, AI-alone was the cost-effective strategy and dominated APBI-alone, while combined therapy was not cost-effective when compared to AI-alone ($171,451/QALY) or APBI-alone ($107,932/QALY). In probabilistic sensitivity analyses, AI-alone was cost-effective at $100,000/QALY in 50% of trials, APBI-alone in 28% and the combination in 22%. Scenario analysis demonstrated that APBI-alone was more effective than AI-alone when AI compliance was lower than 26% at 5 years.

CONCLUSIONS

Based on a Markov microsimulation analysis, both AI-alone and APBI-alone are appropriate options for patients 70 years or older with early breast cancer with small cost differences noted. A prospective trial comparing the approaches is warranted.

Clinical benefits of bone targeted agents in early breast cancer

Through their profound effects on the bone microenvironment, bone targeted treatments can potentially modify the process of metastasis and have important effects on disease outcomes as well as on bone health. The Early Breast Cancer Trialists Collaborative Group (EBCTCG) evaluated the effect of adjuvant bisphosphonates in early breast cancer by performing a meta-analysis of individual patient data (n = 18,766) from all available randomized trials initiated between the early 1990s until 2006. In postmenopausal women, bisphosphonates reduced bone recurrence (RR = 0.72; 95%CI 0.60-0.86, 2p = 0.0002) and breast cancer mortality (0.82; 95%CI 0.73-0.93, 2p = 0.002); no effects on disease outcomes could be identified in premenopausal women. Somewhat surprisingly, these effects could not be reproduced in the large adjuvant trial of denosumab (DCARE). In this study, neither bone metastasis free survival (the primary endpoint) or disease-free survival were improved by the addition of this targeted antibody inhibitor of osteoclast activity. Efforts are ongoing to try to understand the biologic implications of these results. For now, the use of denosumab in early cancers is limited to its use for fracture prevention using the 60mg every 6 months dosing schedule.

Role of Bone Targeting Agents in the Prevention of Bone Metastases from Breast Cancer

Breast cancer (BC) is the most common malignancy in women worldwide and leads, in more than 70% of patients with advanced disease, to skeleton colonization and formation of bone metastases (BM). This condition implies a severe disability and deterioration of the quality of life, with consequent additional social costs. In recent decades, several studies explored the role of agents acting within the bone microenvironment to counteract BM development, and several bone-targeting agents (BTAs) have been introduced in the clinical practice to manage bone lesions and reduce the risk of skeletal complications. However, long-term exposure to these agents is not free from potential toxicities and needs careful monitoring. In this context, the potential capability to prevent BM onset in selected BC patients, through the early administration of BTAs, has been explored by several researchers, with the belief that “prevention is better than cure” and that, ultimately, metastatic BC is an incurable condition. Here, we revised the mechanisms of BM development in BC as well as the strategies for selecting high-risk patients suitable for early BTA treatment.

Correlation Analysis of Morphological Changes of Structural and Functional Areas of Mesenteric Lymph Nodes with Cytokines of Lymph of Thoracic Lymphatic Duct in Experimental Breast Cancer

We performed a correlation analysis of the morphometric parameters of mesenteric lymph nodes and cytokine content in the lymph of thoracic duct in rats with chemically induced breast cancer. The study showed that activity of the local immune response in the lymph nodes in breast cancer is aimed at antitumor protection. In breast cancer, the area of the paracortical zone remained at the level of the intact group, while the area of lymphoid nodules with germinative centers and the area of medullary substance increased; the number of macrophages in the thymus-dependent zone and zone responsible for humoral immunity also increased. The following positive correlations were revealed: in germinative centers and medullary substance, number of mitotic cells correlated with cytokine IL-5 content and the number of medium lymphocytes correlated with the content of chemokine MIP-1α; in the germinative centers, the number of immunoblasts correlated with the level of cytokine GRO/KC, in the paracortical zone, the number of macrophages correlated with the level of chemokine MCP-1, the number of reticular cells correlated with IL-6 and M-CSF content; in medullary substance, the number of small lymphocytes and mature cells plasma cells (their content was reduced) correlated with the level of chemokine GRO/KC, which can be caused by their migration from the lymph node.

Endocrine Therapy-related Endocrinopathies-Biology, Prevalence and Implications for the Management of Breast Cancer

Nearly 270,000 new breast cancer cases are predicted to be diagnosed in the USA in 2019 with more than 70% being estrogen receptor positive and treated using endocrine therapy. The suppression of estrogen biosynthesis or action via the use of ovarian suppression, aromatase inhibitors and selective estrogen receptor modulators/degraders, respectively, is effective in approximately 70% of women. The systemic inhibition of estrogen during breast cancer treatment is also associated with side effects due to the important endocrine functions of this steroid hormone, including its role in the maintenance of energy homeostasis and bone health. The current work will present perspectives of the impact of endocrine therapy from the point of view of breast medical oncology, endocrinology, and basic science.

Impact of ovarian function suppression in premenopausal women with estrogen receptor-positive early breast cancer

PURPOSE OF REVIEW

This manuscript aims at providing an updated overview on the role of adding ovarian function suppression to tamoxifen or an aromatase inhibitor as adjuvant endocrine therapy in premenopausal women with estrogen receptor-positive early breast cancer.

RECENT FINDINGS

Until recently, tamoxifen alone was the only recommended adjuvant treatment option for premenopausal women with estrogen receptor-positive disease. However, recent important evidence has contributed to significantly modify the endocrine treatment landscape in this setting.

SUMMARY

With the only exception of patients with low-risk clinical-pathological features characterized by excellent survival outcomes with tamoxifen alone, the use of ovarian function suppression is to be considered standard of care for most of premenopausal women with estrogen receptor-positive disease. Regarding the choice of its best partner as endocrine agent, the available data suggest that the higher the risk of disease recurrence the larger benefit can be observed with a more profound estrogen deprivation that can be obtained with ovarian function suppression and an aromatase inhibitor as compared to ovarian function suppression and tamoxifen. Despite the significant improvement in our understanding on the role of ovarian function suppression in this setting, several unanswered questions remain and further research efforts are needed in the field.

Adjuvant bisphosphonate therapy in early-stage breast cancer-Treating the soil to kill the seed

Bisphosphonates alter the tumor microenvironment, possibly preventing cancer cell growth in the bone. Analyses of data from numerous clinical trials and a large individual patient-level data meta-analysis have suggested an anti-tumor effect for bisphosphonates in patients with early-stage breast cancer who are postmenopausal. The absolute benefit from the use of bisphosphonates on breast cancer-related mortality reduction mirrors that seen with the use of anthracycline-based chemotherapy versus a first-generation chemotherapy regimen (CMF). In this review, we discuss the evidence base for the use of adjuvant bisphosphonates in early-stage breast cancer and provide recommendations for clinical use.

Adjuvant denosumab in early breast cancer (D-CARE): an international, multicentre, randomised, controlled, phase 3 trial

BACKGROUND

Denosumab is a fully human monoclonal antibody that binds to, and inhibits, the receptor activator of RANKL (TNFSF11) and might affect breast cancer biology, as shown by preclinical evidence. We aimed to assess whether denosumab combined with standard-of-care adjuvant or neoadjuvant systemic therapy and locoregional treatments would increase bone metastasis-free survival in women with breast cancer.

METHOD

In this international, double-blind, randomised, placebo-controlled, phase 3 study (D-CARE), patients were recruited from 389 centres in 39 countries. We enrolled women (aged ≥ 18 years) with histologically confirmed stage II or III breast cancer and an Eastern Cooperative Oncology Group performance status of 0 or 1. On eligibility confirmation, investigators at each site telephoned an interactive voice response system to centrally randomly assign patients (1:1) based on a fixed stratified permuted block randomisation list (block size 4) to receive either denosumab (120 mg) or matching placebo subcutaneously every 3-4 weeks, starting with neoadjuvant or adjuvant chemotherapy, for about 6 months and then every 12 weeks for a total duration of 5 years. Stratification factors were breast cancer therapy, lymph node status, hormone receptor and HER2 status, age, and geographical region. The primary endpoint was the composite endpoint of bone metastasis-free survival. This trial is registered with ClinicalTrials.gov, NCT01077154.

FINDINGS

Between June 2, 2010, and Aug 24, 2012, 4509 women were randomly assigned to receive denosumab (n=2256) or placebo (n=2253) and included in the intention-to-treat analysis. The primary analysis of the study was done when all patients had the opportunity to complete 5 years of follow-up with an analysis data cutoff date of Aug 31, 2017. The primary endpoint of bone metastasis-free survival was not significantly different between the groups (median not reached in either group; hazard ratio 0·97, 95% CI 0·82-1·14; p=0·70). The most common grade 3 or worse treatment-emergent adverse events, reported in patients who had at least one dose of the investigational product (2241 patients with denosumab vs 2218 patients with placebo), were neutropenia (340 [15%] vs 328 [15%]), febrile neutropenia (112 [5%] vs 142 [6%]), and leucopenia (62 [3%] vs 61 [3%]). Positively adjudicated osteonecrosis of the jaw occurred in 122 (5%) of 2241 patients treated with denosumab versus four (<1%) of 2218 patients treated with placebo; treatment-emergent hypocalcaemia occurred in 152 (7%) versus 82 (4%). Two treatment-related deaths occurred in the placebo group due to acute myeloid leukaemia and depressed level of consciousness.

INTERPRETATION

Despite preclinical evidence suggesting RANKL inhibition might delay bone metastasis or disease recurrence in patients with early-stage breast cancer, in this study, denosumab did not improve disease-related outcomes for women with high-risk early breast cancer.

FUNDING

Amgen.

Toronto Workshop on Late Recurrence in Estrogen Receptor-Positive Breast Cancer: Part 1: Late Recurrence: Current Understanding, Clinical Considerations

Disease recurrence (locoregional, distant) exerts a significant clinical impact on the survival of estrogen receptor-positive breast cancer patients. Many of these recurrences occur late, more than 5 years after original diagnosis, and represent a major obstacle to the effective treatment of this disease. Indeed, methods to identify patients at risk of late recurrence and therapeutic strategies designed to avert or treat these recurrences are lacking. Therefore, an international workshop was convened in Toronto, Canada, in February 2018 to review the current understanding of late recurrence and to identify critical issues that require future study. In this article, the major issues surrounding late recurrence are defined and current approaches that may be applicable to this challenge are discussed. Specifically, diagnostic tests with potential utility in late-recurrence prediction are described as well as a variety of patient-related factors that may influence recurrence risk. Clinical and therapeutic approaches are also reviewed, with a focus on patient surveillance and the implementation of extended endocrine therapy in the context of late-recurrence prevention. Understanding and treating late recurrence in estrogen receptor-positive breast cancer is a major unmet clinical need. A concerted effort of basic and clinical research is required to confront late recurrence and improve disease management and patient survival.

BOne HEalth ManagEment in Patients with Early Breast Cancer: A Retrospective Italian Osteoncology Center "Real-Life" Experience (BOHEME Study)

Background: We assessed the real-life clinical impact of bone health management in patients with breast cancer (BC) receiving adjuvant endocrine therapy at an Italian Osteoncology Center. Methods: Pre- and post-menopausal women undergoing adjuvant endocrine therapy for early-stage BC who came to our institute for their first bone health evaluation from January 2011 to June 2016 were considered in this retrospective observational study. Results: 1125 pre- and post-menopausal early-stage BC patients (209 and 916, respectively) were evaluated. Median age was 61 years (range 26–88). In the pre-menopausal group, spinal x-ray revealed that 10 patients (4.7%) had a morphometric vertebral fracture. Higher age (OR: 1.14; 95% CI: 1.01–1.29) and bone mineral density (BMD) ≤ −2.5 (OR: 14.45; 95% CI: 1.70–122.67) were associated with a higher risk of bone fracture. The overall frequency of bone fracture was 17.6% (n = 161) in post-menopausal patients and a lower risk for bone fractures was associated with tamoxifen or other treatments (OR: 0.25; 95% CI: 0.12–0.53), presence of back pain (OR: 1.65; 95% CI: 1.16–2.36), lower BMD (OR: 2.09 in patients with T-score ≤ 2.5; 95% CI: 1.21–3.59) and lower vitamin D levels (OR: 1.57 in patients with ≤ 10 ng/mL; 95% CI: 1.05–2.34) in univariate analysis. Conclusion: Our findings confirm that bone health management should be an integral part of long-term cancer care.

Bisphosphonates-much more than only drugs for bone diseases

α,α-Bisphosphonates (BPs) are well established in the treatment of bone diseases such as osteoporosis and Paget's disease. Their successful application originates from their high affinity to hydroxyapatite. While the initially appreciated features of BPs are already beneficial to many patients, recent developments have further expanded their pleiotropic applications. This review describes the background of the interactions of BPs with bone cells that form the basis of the classical treatment. A better understanding of the mechanism behind their interactions allows for the parallel application of BPs against bone cancer and metastases followed by palliative pain relief. Targeted therapy with bone-seeking BPs coupled with a diagnostic agent in one particle resulted in theranostics which is also described here. For example, in such a system, BP moieties are bound to contrast agents used in magnetic resonance imaging or radionuclides used in positron emission tomography. In addition, another example of the pleiotropic function of BPs which involves targeting the imaging agents to bone tissues accompanied by pain reduction is presented in this work.

Fracture Risk in Women with Breast Cancer Initiating Aromatase Inhibitor Therapy: A Registry-Based Cohort Study

BACKGROUND

Aromatase inhibitors (AIs) used in breast cancer induce loss in bone mineral density (BMD) and are reported to increase fracture risk.

MATERIALS AND METHODS

Using a population-based BMD registry, we identified women aged at least 40 years initiating AIs for breast cancer with at least 12 months of AI exposure (n = 1,775), women with breast cancer not receiving AIs (n = 1,016), and women from the general population (n = 34,205). Fracture outcomes were assessed to March 31, 2017 (mean, 6.2 years for AI users).

RESULTS

At baseline, AI users had higher body mass index (BMI), higher BMD, lower osteoporosis prevalence, and fewer prior fractures than women from the general population or women with breast cancer without AI use (all p < .001). After adjusting for all covariates, AI users were not at significantly greater risk for major osteoporotic fractures (hazard ratio [HR], 1.15; 95% confidence interval [CI], 0.93-1.42), hip fracture (HR, 0.90; 95% CI, 0.56-1.43), or any fracture (HR, 1.06; 95% CI, 0.88-1.28) compared with the general population.

CONCLUSION

Higher baseline BMI, BMD, and lower prevalence of prior fracture at baseline may offset the adverse effects of AI exposure. Although confirmatory data from large cohort studies are required, our findings challenge the view that all women with breast cancer initiating AI therapy should be considered at high risk for fractures.

IMPLICATIONS FOR PRACTICE

In a population-based observational registry that included 1,775 patients initiating long-term aromatase inhibitor therapy, risk for major osteoporotic fracture, hip fracture, or any fracture was similar to the general population. Higher baseline body mass index, bone mineral density, and lower prevalence of prior fracture at baseline may offset the adverse effects of aromatase inhibitor exposure.

Management of Osteoporosis in Survivors of Adult Cancers With Nonmetastatic Disease: ASCO Clinical Practice Guideline

PURPOSE

The aim of this work is to provide evidence-based guidance on the management of osteoporosis in survivors of adult cancer.

METHODS

ASCO convened a multidisciplinary Expert Panel to develop guideline recommendations based on a systematic review of the literature.

RESULTS

The literature search of the 2018 systematic review by the US Preventive Services Task Force in the noncancer population was used as the evidentiary base upon which the Expert Panel based many of its recommendations. A total of 61 additional studies on topics and populations not covered in the US Preventive Services Task Force review were also included. Patients with cancer with metastatic disease and cancer survival outcomes related to bone-modifying agents are not included in this guideline.

RECOMMENDATIONS

Patients with nonmetastatic cancer may be at risk for osteoporotic fractures due to baseline risks or due to the added risks that are associated with their cancer therapy. Clinicians are advised to assess fracture risk using established tools. For those patients with substantial risk of osteoporotic fracture, the clinician should obtain a bone mineral density test. The bone health of all patients may benefit from optimizing nutrition, exercise, and lifestyle. When a pharmacologic agent is indicated, bisphosphonates or denosumab at osteoporosis-indicated dosages are the preferred interventions.

Dental care for patients taking antiresorptive drugs: a literature review

Antiresorptive drugs (ARDs), such as bisphosphonates or denosumab, that prevent bone resorption are widely used in patients with osteoporosis or with cancer that has metastasized to the bones. Although osteonecrosis of the jaw (ONJ) is a well-documented complication of ARD use, the benefits ARDs outweigh the complication. Thus, research has focused on finding ways to prevent or reduce the risk of developing ONJ. Dentists, as part of a multi-professional team, have a critical role in preventing ONJ. However, many dentists tend to hesitate to provide dental care to patients with ONJ, or tend to think that it is a problem to be dealt with by oral surgeons. This review gives an overview of ARD-related ONJ and provides the guidelines for dental care in patients taking ARDs to lower the risk of developing ONJ.

Improving Adjuvant Endocrine Treatment Tailoring in Premenopausal Women With Hormone Receptor-Positive Breast Cancer

The Oncology Grand Rounds series is designed to place original reports published in the Journal into clinical context. A case presentation is followed by a description of diagnostic and management challenges, a review of the relevant literature, and a summary of the authors' suggested management approaches. The goal of this series is to help readers better understand how to apply the results of key studies, including those published in Journal of Clinical Oncology, to patients seen in their own clinical practice.