Bone-related complications and quality of life in advanced breast cancer: results from a randomized phase III trial of denosumab versus zoledronic acid

Treatment Patterns of Bone-targeting Agents Among Solid Tumor Patients With Bone Metastases: An Analysis of Electronic Health Record Data in the United States From 2014 to 2018

OBJECTIVES

This study evaluated real-world treatment patterns of approved bone-targeting agents (BTAs) with various mechanisms of action-pamidronate, zoledronic acid, and denosumab-for the prevention of skeletal-related events in patients with bone metastases (BM) from solid tumors.

METHODS

Adult patients with BM secondary to solid tumors between January 1, 2014, and December 31, 2018, were identified from the Flatiron Health Oncology Services Comprehensive Electronic Records database and categorized by BTA use and therapy type. Time from diagnosis to initiation, persistence (mean time on treatment), and compliance (≥12 administrations/year) with BTA with up to 4 years of follow-up were examined.

RESULTS

This study included 27,268 patients with BM (breast cancer, 32.7%; lung cancer, 16.5%; prostate cancer, 17.2%; and other solid tumors, 33.6%); of these, 41.4% initiated denosumab after BM diagnosis; 21.3%, zoledronic acid; 0.6%, pamidronate; and 36.7% had no treatment record. Mean (SD) time to initiation for denosumab or zoledronic acid was 68.6 (157.0) days (denosumab, 70.3 (160.4) days; zoledronic acid, 65.2 [150.2] days). Mean persistence and compliance (first year of treatment) were significantly higher for denosumab than for zoledronic acid (22.0 vs. 14.9 mo [ P <0.0001] and 42.3% vs. 34.8% [ P <0.0001], respectively). Treatment compliance was the highest in patients with breast cancer (denosumab, 48.2%; zoledronic acid, 39.1%).

CONCLUSION

Real-world BTA treatment patterns in the United States suggest that over one-third of patients with BM secondary to solid tumors remain untreated and less than 50% of the patients received ≥12 administrations/year of BTA therapy.

Quality of life issues in patients with bone metastases: A systematic review

INTRODUCTION

Bones are frequent sites of metastatic disease, observed in 30-75% of advanced cancer patients. Quality of life (QoL) is an important endpoint in studies evaluating the treatments of bone metastases (BM), and many patient-reported outcome tools are available. The primary objective of this systematic review was to compile a list of QoL issues relevant to BM and its interventions. The secondary objective was to identify common tools used to assess QoL in patients with BM, and the QoL issues they fail to address.

METHODS

A search was conducted on Ovid MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials databases between 1946 and 27 January 2023 with the keywords "bone metastases", "quality of life", and "patient reported outcomes". Specific QoL issues in original research studies and the QoL tools used were extracted.

RESULTS

The review identified the QoL issues most prevalent to BM in the literature. Physical and functional issues observed in patients included pain, interference with ambulation and daily activities, and fatigue. Psychological symptoms, such as helplessness, depression, and anxiety were also common. These issues interfered with patients' relationships and social activities. Items not mentioned in existing QoL tools were related to newer treatments of BM, such as pain flare, flu-like symptoms, and jaw pain due to osteonecrosis.

CONCLUSIONS

This systematic review highlights that QoL issues for patients with BM have expanded over time due to advances in BM-directed treatments. If they are relevant, additional treatment-related QoL issues identified need to be validated prospectively by patients and added to current assessment tools.

Bone-Targeted Therapy Regimen and Skeletal-Related Events in Patients Surviving Longer Than 2 Years With Metastatic Breast Cancer and Bone Metastasis

BACKGROUND

Bone-targeted therapy (BTT) including zoledronic acid (ZA) and denosumab decreases the risk of skeletal-related events (SREs) in patients with metastatic breast cancer (MBC) and bone metastasis. The impacts from prolonged BTT on SREs and BTT-associated harms are unknown and are becoming important to understand as these patients survive for longer periods.

METHODS AND MATERIALS

We conducted a retrospective study of 224 patients with MBC and bone metastasis who survived for more than 2 years after diagnosis and received treatment at our institution between 2016 and 2021. We defined 3 BTT patterns: (1) ZA only, (2) denosumab only, (3) both ZA and denosumab. The association between these BTT patterns and SREs and harms was assessed using Fisher exact test and logistic regression.

RESULTS

Rates of SREs overall were 21.2% of patients given ZA only, 8.8% of those given denosumab only, and 20% of those given both, without statistically significant differences (p = .32). However, those treated with denosumab only had significantly fewer compression fractures (0.7%) (p = .02). BTT-associated harm was observed in 5.8% of the ZA-only group, 11.7% of the denosumab-only group, and 14.3% of the group given both, without statistically significant differences (p = .37).

CONCLUSION

Oncologists may have increased flexibility regarding the frequency of administration of BTT along with their choice of agent. Our study showed no significant difference in the prevention of overall SRE or development of BTT-associated harms between the BTT regimens evaluated.

RANK pathway in cancer: underlying resistance and therapeutic approaches

Cancer remains one of the deadliest diseases despite advances in treatment. Metastatic cancers are the leading cause of death for advanced cancer patients. Those with advanced cancer with osteolytic-type bone metastases have a significantly lower quality of life. A novel treatment plan is needed now more than ever for breast cancer patients with bone metastases. There are shreds of evidence that cancer cells in the bloodstream interact with the bone microenvironment and that this interaction is a contributing component to breast cancer progression. Preventing any stage of this cycle can result in anti-metastasis effects. Since RANKL interacts with its receptor RANK and plays an important role in the vicious cycle, it has proven to be a successful therapeutic target in cancer treatment. As a result, we have presented a complete overview of the RANK pathway in cancer and discussed RANK signaling and tumor microenvironment, and potential therapeutic approaches in this review.

Prevalence of Precursory Signs of Atypical Femoral Fractures in Patients Receiving Bone-Modifying Agents for Bone Metastases: A Cross-Sectional Study

Patients on bone-modifying agents (BMAs) for bone metastases are at risk of atypical femoral fractures (AFFs), which can lead to a sudden deterioration in performance status. In this study, we sought to determine the prevalence of radiographic precursory signs of AFF in patients on oncologic BMAs. Forty-two patients (23 men, 19 women; mean age 68.8 ± 10.0 years) on oncologic BMAs (zoledronate for >3 years and/or denosumab for >1 year) and without clinical symptoms were enrolled between 2019 and 2021. All patients were receiving denosumab at enrollment and 5 had previously used zoledronate. The mean duration of BMA use was 31.2 ± 18.5 months. Radiographs of both femurs were screened for precursory signs of AFF (e.g., thickening of the lateral cortex). The patients were divided into two groups according to thickening status and compared by duration of BMA use. They were also divided into three groups by duration of BMA use (12-23 months, n = 18; 24-59 months, n = 19; ≥60 months, n = 5), and the prevalence of apparent thickenings was examined. As a result, 18 patients (42.9%) showed minute local or diffuse thickening and 10 (23.8%) showed apparent local thickening. The duration of BMA use was significantly longer in patients with apparent thickening than in those without (47.3 ± 23.6 months [n = 10] versus 26.2 ± 13.5 months [n = 32]; p < 0.05). The prevalence of apparent thickening increased with increasing duration of BMA use (12-23 months, 5.6%; 24-59 months, 31.6%; ≥60 months, 60.0%). In conclusion, radiographic precursory signs of AFF are common in patients on oncologic BMAs. Radiographic screening for AFF could be relevant in patients who have been on long-term oncologic BMAs, even if asymptomatic. © 2023 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Multicenter study on atypical femoral fractures in patients with bone metastases taking bone- modifying agents

Bone-modifying agents (BMAs), with bone-resorptive inhibitory effects, such as zoledronic acid and denosumab, are widely used at higher doses for bone-related events caused by bone metastasis of malignant tumors. These drugs have been suggested to be associated with atypical femoral fractures (AFFs), and the relationship between BMAs and AFFs has attracted attention. To investigate the clinical features including bone union time of AFFs in patients administered BMA for bone metastasis, we conducted a retrospective multicenter study. Thirty AFFs from 19 patients were enrolled in this study. Thirteen patients had bilateral AFFs, and nineteen AFFs had prodromal symptoms. Eighteen AFFs underwent surgery after complete fracture, three failed to achieve bone union and required nonunion surgery, and 11 AFFs that achieved bone union had an average period until bone union of 16.2 months, which was much longer than that previously reported for ordinary AFFs. Seven patients discontinued the BMAs, but not due to AFFs. Stopping BMAs in patients with bone metastasis would make it difficult to secure their performance of activities of daily living, and AFF with BMA administration might require a longer time for union. Therefore, it would be important to prevent incomplete AFF from becoming complete AFF via prophylactic internal fixation.

Current comprehensive understanding of denosumab (the RANKL neutralizing antibody) in the treatment of bone metastasis of malignant tumors, including pharmacological mechanism and clinical trials

Denosumab, a fully humanized monoclonal neutralizing antibody, inhibits activation of the RANK/RANKL/OPG signaling pathway through competitive binding with RANKL, thereby inhibiting osteoclast-mediated bone resorption. Denosumab inhibits bone loss; therefore, it is used to treat metabolic bone diseases (including postmenopausal osteoporosis, male osteoporosis, and glucocorticoid-induced osteoporosis), in clinical practice. Since then, multiple effects of denosumab have been discovered. A growing body of evidence suggests that denosumab has a variety of pharmacological activities and broad potential in clinical diseases such as osteoarthritis, bone tumors, and other autoimmune diseases. Currently, Denosumab is emerging as a treatment for patients with malignancy bone metastases, and it also shows direct or indirect anti-tumor effects in preclinical models and clinical applications. However, as an innovative drug, its clinical use for bone metastasis of malignant tumors is still insufficient, and its mechanism of action needs to be further investigated. This review systematically summarizes the pharmacological mechanism of action of denosumab and the current understanding and clinical practice of the use of denosumab for bone metastasis of malignant tumors to help clinicians and researchers deepen their understanding of denosumab.

Management of bone metastasis with zoledronic acid: A systematic review and Bayesian network meta-analysis

Background

While considered the mainstay of treatment for specific bone metastases, ZA is used predominantly to treat osteolytic lesions. The purpose of this network meta-analysis is to compare ZA to other treatment options in its ability to improve specific clinical outcomes in patients with bone metastases secondary to any primary tumor.

Methods

PubMed, Embase and Web of Science were systematically searched from inception to May 5th, 2022. Keywords used were solid tumor, lung neoplasm, kidney neoplasm, breast neoplasm, prostate neoplasm, ZA and bone metastasis. Every randomized controlled trial and non-randomized quasi-experimental study of systemic ZA administration for patients with bone metastases and any comparator were included. A Bayesian network meta-analysis was done on the primary outcomes including number of SREs, time to developing a first on-study SRE, overall survival, and disease progression-free survival. Secondary outcome was pain at 3, 6 and 12 months after treatment.

Results

Our search yielded 3861 titles with 27 meeting inclusion criteria. For the number of SRE, ZA in combination with chemotherapy or hormone therapy was statistically superior to placebo (OR 0.079; 95 % CrI: 0.022-0.27). For the time to the first on study SRE, the relative effectiveness of ZA 4 mg was statistically superior to placebo (HR 0.58; 95 % CrI:0.48-0.77). At 3 and 6 months, ZA 4 mg was significantly superior to placebo for reducing pain with a SMD of -0.85 (95 % CrI:-1.6, -0.0025) and -2.6 (95 % CrI:-4.7, -0.52) respectively.

Conclusions

This systematic review shows the benefits of ZA in decreasing the incidence of SREs, increasing the time to the first on-study SRE, and reducing the pain level at 3 and 6 months.

AAOS Clinical Practice Guideline Summary: Treatment of Metastatic Carcinoma and Myeloma of the Femur

The Musculoskeletal Tumor Society, in partnership with American Society of Clinical Oncology and American Society for Radiation Oncology, has developed a clinical practice guideline to assist providers with the care of patients with metastatic carcinoma and myeloma of the femur. The guideline was developed by an Expert Panel consisting of representatives of all three organizations by American Academy of Orthopaedic Surgeons (AAOS) methodologists using the AAOS standardized guideline development process. A systematic review of the available evidence was conducted, and the identified evidence was rated was rated for quality and potential for bias. Recommendations were developed based on this evidence in a standardized fashion. The guideline was approved by the guideline approval bodies of all three organizations. Thirteen recommendations were synthesized covering relevant subtopics such as imaging, use of bone-modifying agents, radiation therapy, and surgical reconstruction. The consensus of the expert panel was that bone-modifying agents may assist in reducing the incidence of femur fracture, regardless of tumor histology. The panel recommended the use of radiation therapy to decrease the rate of femur fractures for patients considered at increased risk. The panel recommended arthroplasty be considered to improve patient function and decrease the need of postoperative radiation therapy in patients with pathologic fractures in the femur.

TOR1B: a predictor of bone metastasis in breast cancer patients

Recent therapeutic advances in breast cancer (BC) have improved survival outcomes; however, the prognosis for patients with bone metastasis (BM) remains poor. Hence, novel clinical biomarkers are needed to accurately predict BC BM as well as to promote personalized medicine. Here, we discovered a novel biomarker, TOR1B, for BM in BC patients via analysis of BC gene expression data and clinical information downloaded from open public databases. In cancer cells, we found high expression levels of TOR1B in the nucleus and endoplasmic reticulum. Regarding gene expression, the level of TOR1B was significantly upregulated in BC patients with BM (p < 0.05), and the result was externally validated. In addition, gene expression clearly demonstrated two distinct types of prognoses in ER- and PR-positive patients. In multivariate regression, the gene could be an independent predictor of BM in BC patients, i.e., a low expression level of TOR1B was associated with delayed metastasis to bone in BC patients (HR, 0.28; 95% CI 0.094-0.84). Conclusively, TOR1B might be a useful biomarker for predicting BM; specifically, patients with ER- and PR-positive subtypes would benefit from the clinical use of this promising prognostic biomarker.

Validation of Algorithms to Identify Bone Metastases Using Administrative Claims Data in a Japanese Hospital

BACKGROUND

Validated coding algorithms are essential to generate high-quality, real-world evidence from claims data studies.

OBJECTIVE

We aimed to evaluate the validity of the algorithms to identify patients with bone metastases using claims data from a Japanese hospital.

PATIENTS AND METHODS

This study used administrative claims data and electronic medical records at Juntendo University Hospital from April 2017 to March 2019. We developed two candidate claims-based algorithms to detect bone metastases, one based on diagnosis codes alone (Algorithm 1) and the other based on the combination of diagnosis and imaging test codes (Algorithm 2). Of the patients identified by Algorithm 1, 100 patients were randomly sampled. Among these 100 patients, 88 patients met the conditions of Algorithm 2; further, 12 additional patients were randomly sampled from those identified by Algorithm 2, thus obtaining a total of 100 patients for Algorithm 2. They were evaluated for their true diagnosis using the patient chart review as the gold standard. The positive predictive value (PPV) was calculated to assess the accuracy of each algorithm.

RESULTS

For Algorithm 1, 82 patients were analyzed after excluding 18 patients without diagnostic imaging reports. Of these, 69 patients were true positive by chart review, resulting in a PPV of 84.1% (95% confidence interval (CI) 74.5-90.6). For Algorithm 2, 92 patients were analyzed after excluding eight patients whose diagnoses were not judged by chart review. Of these, 76 patients were confirmed positive by chart review, yielding a PPV of 82.6% (95% CI 73.4-89.1).

CONCLUSION

Both claims-based algorithms yielded high PPVs of approximately 85%, with no improvement in PPV by adding imaging test conditions. The diagnosis code-based algorithm is sufficient and valid for identifying bone metastases in this Japanese hospital.

Hypercalcemia: A Review

IMPORTANCE

Hypercalcemia affects approximately 1% of the worldwide population. Mild hypercalcemia, defined as total calcium of less than 12 mg/dL (<3 mmol/L) or ionized calcium of 5.6 to 8.0 mg/dL (1.4-2 mmol/L), is usually asymptomatic but may be associated with constitutional symptoms such as fatigue and constipation in approximately 20% of people. Hypercalcemia that is severe, defined as total calcium of 14 mg/dL or greater (>3.5 mmol/L) or ionized calcium of 10 mg/dL or greater (≥2.5 mmol/L) or that develops rapidly over days to weeks, can cause nausea, vomiting, dehydration, confusion, somnolence, and coma.

OBSERVATIONS

Approximately 90% of people with hypercalcemia have primary hyperparathyroidism (PHPT) or malignancy. Additional causes of hypercalcemia include granulomatous disease such as sarcoidosis, endocrinopathies such as thyroid disease, immobilization, genetic disorders, and medications such as thiazide diuretics and supplements such as calcium, vitamin D, or vitamin A. Hypercalcemia has been associated with sodium-glucose cotransporter 2 protein inhibitors, immune checkpoint inhibitors, denosumab discontinuation, SARS-CoV-2, ketogenic diets, and extreme exercise, but these account for less than 1% of causes. Serum intact parathyroid hormone (PTH), the most important initial test to evaluate hypercalcemia, distinguishes PTH-dependent from PTH-independent causes. In a patient with hypercalcemia, an elevated or normal PTH concentration is consistent with PHPT, while a suppressed PTH level (<20 pg/mL depending on assay) indicates another cause. Mild hypercalcemia usually does not need acute intervention. If due to PHPT, parathyroidectomy may be considered depending on age, serum calcium level, and kidney or skeletal involvement. In patients older than 50 years with serum calcium levels less than 1 mg above the upper normal limit and no evidence of skeletal or kidney disease, observation may be appropriate. Initial therapy of symptomatic or severe hypercalcemia consists of hydration and intravenous bisphosphonates, such as zoledronic acid or pamidronate. In patients with kidney failure, denosumab and dialysis may be indicated. Glucocorticoids may be used as primary treatment when hypercalcemia is due to excessive intestinal calcium absorption (vitamin D intoxication, granulomatous disorders, some lymphomas). Treatment reduces serum calcium and improves symptoms, at least transiently. The underlying cause of hypercalcemia should be identified and treated. The prognosis for asymptomatic PHPT is excellent with either medical or surgical management. Hypercalcemia of malignancy is associated with poor survival.

CONCLUSIONS AND RELEVANCE

Mild hypercalcemia is typically asymptomatic, while severe hypercalcemia is associated with nausea, vomiting, dehydration, confusion, somnolence, and coma. Asymptomatic hypercalcemia due to primary hyperparathyroidism is managed with parathyroidectomy or observation with monitoring, while severe hypercalcemia is typically treated with hydration and intravenous bisphosphonates.

Radiodynamic therapy with acridine orange local administration as a new treatment option for primary and secondary bone tumours

AIMS

Acridine orange (AO) demonstrates several biological activities. When exposed to low doses of X-ray radiation, AO increases the production of reactive radicals (radiodynamic therapy (AO-RDT)). We elucidated the efficacy of AO-RDT in breast and prostate cancer cell lines, which are likely to develop bone metastases.

METHODS

We used the mouse osteosarcoma cell line LM8, the human breast cancer cell line MDA-MB-231, and the human prostate cancer cell line PC-3. Cultured cells were exposed to AO and radiation at various concentrations followed by various doses of irradiation. The cell viability was then measured. In vivo, each cell was inoculated subcutaneously into the backs of mice. In the AO-RDT group, AO (1.0 μg) was locally administered subcutaneously around the tumour followed by 5 Gy of irradiation. In the radiation group, 5 Gy of irradiation alone was administered after macroscopic tumour formation. The mice were killed on the 14th day after treatment. The change in tumour volume by AO-RDT was primarily evaluated.

RESULTS

The viability of LM8, MDA-MB-231, and PC-3 cells strongly decreased at AO concentration of 1.0 μg/ml and a radiation dose of 5 Gy. In xenograft mouse model, the AO-RDT also showed a strong cytocidal effect on tumour at the backside in osteosarcoma, breast cancer, and prostate cancer. AO-RDT treatment was more effective for tumour control than radiotherapy in breast cancer.

CONCLUSION

AO-RDT was effective in preventing the proliferation of osteosarcoma, breast cancer, and prostate cancer cell lines in vitro. The reduction in tumour volume by AO-RDT was also confirmed in vivo.Cite this article: Bone Joint Res 2022;11(10):685-692.

Epidemiology of spinal metastases, metastatic epidural spinal cord compression and pathologic vertebral compression fractures in patients with solid tumors: A systematic review

•

The clinical incidence of spinal metastases is 15.67%, two thirds are metastases from breast-, prostate- or lung cancer.

•

9.6% of patients with spinal metastases develop metastatic epidural spinal cord compression.

•

1 out of 8 (12.6%) of patients with spinal metastases suffer of pathologic vertebral compression fractures.

Introduction

Spinal metastases (SM) are a frequent complication of cancer and may lead to pathologic vertebral compression fractures (pVCF) and/or metastatic epidural spinal cord compression (MESCC). Based on autopsy studies, it is estimated that about one third of all cancer patients will develop SM. These data may not provide a correct estimation of the incidence in clinical practice.

Objective

This systematic review (SR) aims to provide a more accurate estimation of the incidence of SM, MESCC and pVCF in a clinical setting.

Methods

We performed a SR of papers regarding epidemiology of SM, pVCF, and MESCC in patients with solid tumors conform PRISMA guidelines. A search was conducted in the PubMed and Web of Science database using the terms epidemiology, prevalence, incidence, global burden of disease, cost of disease, spinal metastas*, metastatic epidural spinal cord compression, pathologic fracture, vertebral compression fracture, vertebral metastas* and spinal neoplasms. Papers published between 1975 and august 2021 were included. Quality was evaluated by the STROBE criteria.

Results

While 56 studies were included, none of them reports the actual definition used for MESCC and pVCF, inevitably introducing heterogenity. The overall cumulative incidence of SM and MESCC is 15.67% and 2.84% respectively in patients with a solid tumor. We calculated a mean cumulative incidence in patients with SM of 9.56% (95% CI 5.70%-13.42%) for MESCC and 12.63% (95% CI 7.00%-18.25%) for pVCF. Studies show an important delay between onset of symptoms and diagnosis.

Conclusions

While the overall cumulative incidence for clinically diagnosed SM in patients with a solid tumor is 15.67%, autopsy studies reveal that SM are present in 30% by the time they die, suggesting underdiagnosing of SM. Approximately 1 out of 10 patients with SM will develop MESCC and another 12.6% will develop a pVCF. Understanding these epidemiologic data, should increase awareness for first symptoms, allowing early diagnosis and subsequent treatment, thus improving overall outcome.

Quality-of-life methodology in hormone receptor-positive advanced breast cancer: Current tools and perspectives for the future

Health-related quality of life (HRQOL) is increasingly recognized as important when evaluating cancer treatments. The use, reporting, and analysis of patient-reported outcome measures (PROMs), however, are not standardized in clinical trials and are often poorly implemented in clinical practice. We report the results of a systematic literature review (PubMed search: January 1, 2000 to August 15, 2020) of PROM use, reporting, and analysis in phase 3 clinical trials of hormone receptor-positive (HR+) advanced breast cancer (ABC). Further inspection of cyclin-dependent kinase 4/6 (CDK4/6) inhibitor publications was performed to examine PROMs in the HR+/human epidermal growth factor receptor 2-negative setting. A total of 88 results were identified in the initial search; 32 were included in the final analysis. Among included studies, most (66%) had been published in the last 5 years (2015 to 2020). CDK4/6 inhibitors (38%) were the most common agents reported. No clear standard for PROM use, reporting, or analysis was found. The most common PROMs were European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire Core 30 (EORTC QLQ-C30; 59%) and the Functional Assessment of Cancer Therapy-Breast (FACT-B; 34%). Important differences, among studies that reported them, ranged from 5 to 10 points for the EORTC QLQ-C30 and 8 points for the FACT-B total score. This review showed that a lack of clear consistency remains for PROM use, reporting, and analysis in phase 3 clinical trials of HR+ ABC. However, HRQOL is of high interest in the literature, including for CDK4/6 inhibitors.

Risk factors associated with onset of medication-related osteonecrosis of the jaw in patients treated with denosumab

Objectives

While risk factors of bisphosphonate (BP) associated osteonecrosis of the jaw have been properly analyzed, studies focusing on risk factors associated with denosumab (DNO) are sparse. The purpose of this study was to identify risk factors influencing the onset of medication-related osteonecrosis of the jaw (MRONJ) in patients receiving antiresorptive treatment (ART) with DNO by comparing patients suffering from MRONJ and patients without MRONJ. Multiple variables were evaluated including the impact of a previous BP intake.

Materials and methods

A retrospective single-center cohort study with patients receiving DNO was conducted. One-hundred twenty-eight patients were included and divided into three groups: I (control, n = 40) receiving DNO with absence of MRONJ; group II (Test 1, n = 46), receiving DNO with presence of MRONJ; and group III (Test 2, n = 42) sequentially receiving BP and DNO with presence of MRONJ. Patients’ medical history, focusing on the identification of MRONJ risk factors, was collected and evaluated. Parameters were sex, age, smoking habit, alcohol consumption, underlying disease (cancer type, osteoporosis), internal diseases, additional chemo/hormonal therapy, oral inflammation, and trauma.

Results

The following risk factors were identified to increase MRONJ onset significantly in patients treated with DNO: chemo/hormonal therapy (p = 0.02), DNO dosage (p < 0.01), breast cancer (p = 0.03), intake of corticosteroids (p = 0.04), hypertension (p = 0.02), diabetes mellitus (p = 0.04), periodontal disease (p = 0.03), apical ostitis (p = 0.02), and denture use (p = 0.02). A medication switch did not affect MRONJ development (p = 0.86).

Conclusions

Malignant diseases, additional chemotherapy, DNO dosage, and oral inflammations as well as diabetes mellitus and hypertension influence MRONJ onset in patients treated with DNO significantly.

Clinical relevance

Patients receiving ART with DNO featuring aforementioned risk factors have a higher risk of MRONJ onset. These patients need a sound and regular prophylaxis in order to prevent the onset of MRONJ under DNO treatment.

Bone Metastatic Breast Cancer: Advances in Cell Signaling and Autophagy Related Mechanisms

Bone metastasis is a frequent complication of breast cancer with nearly 70% of metastatic breast cancer patients developing bone metastasis during the course of their disease. The bone represents a dynamic microenvironment which provides a fertile soil for disseminated tumor cells, however, the mechanisms which regulate the interactions between a metastatic tumor and the bone microenvironment remain poorly understood. Recent studies indicate that during the metastatic process a bidirectional relationship between metastatic tumor cells and the bone microenvironment begins to develop. Metastatic cells display aberrant expression of genes typically reserved for skeletal development and alter the activity of resident cells within the bone microenvironment to promote tumor development, resulting in the severe bone loss. While transcriptional regulation of the metastatic process has been well established, recent findings from our and other research groups highlight the role of the autophagy and secretory pathways in interactions between resident and tumor cells during bone metastatic tumor growth. These reports show high levels of autophagy-related markers, regulatory factors of the autophagy pathway, and autophagy-mediated secretion of matrix metalloproteinases (MMP's), receptor activator of nuclear factor kappa B ligand (RANKL), parathyroid hormone related protein (PTHrP), as well as WNT5A in bone metastatic breast cancer cells. In this review, we discuss the recently elucidated mechanisms and their crosstalk with signaling pathways, and potential therapeutic targets for bone metastatic disease.

Denosumab for Effective Tumor Size Reduction in Patients With Giant Cell Tumors of the Bone: A Systematic Review and Meta-Analysis

BACKGROUND

Denosumab is a human monoclonal antibody that has been used successfully in the treatment of giant cell tumors of bone. These tumors are rare and, in principle, benign, but they are highly aggressive, locally advanced, osteolytic bone tumors that can metastasize to the lungs. Denosumab is an effective treatment when these tumors cannot be surgically removed or when surgical resection is likely to lead to severe morbidity (eg, loss of limbs or joints). The aim of this systematic review and meta-analysis was to investigate patients with giant cell tumors of bone who experienced tumor progression during treatment with denosumab and to compare them with patients who experienced reduction of their giant cell tumors of bone during treatment with denosumab.

METHODS

Embase, Cochrane Library, and MEDLINE/PubMed databases were searched for trials submitted by January 7, 2020, that reported the efficacy and safety of denosumab in patients with giant cell tumors of bone.

RESULTS

Sixty studies were reviewed, involving a total of 1074 patients who had giant cell tumors of bone and were treated with denosumab. Of the 60 studies, 58% of the patients were from case series studies, 39% from open-label phase II studies, and 3% from case reports. The response rate for denosumab as a treatment for giant cell tumors of bone was 97.5%, with statistical significance (P < .0001). Pain in the limbs was statistically the most common adverse event for denosumab treatment in case series studies (P < .0001). No treatment-related deaths occurred in the reviewed studies.

CONCLUSION

Cumulative evidence supports the addition of surgery to optimal medical therapy with denosumab to reduce tumor size, clinical symptoms, and mortality among patients with giant cell tumors of bone.

Prognostic effects of cytokine levels on patients treated with taxane and zoledronic acid for metastatic breast cancer in bone (BEAT-ZO) (KCSG BR 10-13)

Advanced breast cancer frequently metastasizes to the skeleton causing major mobility issues and hazards to quality of life. To manage osteolytic bone metastasis, bone-modifying agents and chemotherapy are recommended as the standard of care. Here, we investigated serologic biomarkers that might be associated with prognosis in breast cancer patients treated with zoledronic acid (ZA) and taxane-based chemotherapy. We collected serum samples from breast cancer patients with bone metastasis who received taxane plus ZA as palliative treatment. Fourteen biomarkers of angiogenesis, immunogenicity, and apoptosis were assessed, and the correlation between serum cytokine levels and patient's prognosis was statistically analyzed. Sixty-six patients were enrolled, and samples from 40 patients were analyzed after laboratory quality control. Patients with low baseline PDGF-AA, high IFN-γ, low MCP-2, low TGF-β1, and low TNF-α were significantly associated with longer progression-free survival (PFS). Decreasing VEGF and TNF-α and increasing FGF-2 and PDGF-AA in the early treatment phase indicated longer PFS. In univariate and multivariate analyses, low TGF-β1 and TNF-α and high IFN-γ at baseline were associated with a significantly low hazard ratio for disease progression. Further, we designed a risk score with TGF-β1, TNF-α, and IFN-γ levels, which could prognosticate patients for PFS. In conclusion, serum cytokine level, such as TGF-β1, TNF-α, and IFN-γ, could be a potential prognostic biomarker for breast cancer patients with bone metastasis treated with ZA and taxane-based chemotherapy.

Targeting cancer metastasis with antibody therapeutics

Cancer metastasis, the spread of disease from a primary to a distal site through the circulatory or lymphatic systems, accounts for over 90% of all cancer related deaths. Despite significant progress in the field of cancer therapy in recent years, mortality rates remain dramatically higher for patients with metastatic disease versus those with local or regional disease. Although there is clearly an urgent need to develop drugs that inhibit cancer spread, the overwhelming majority of anticancer therapies that have been developed to date are designed to inhibit tumor growth but fail to address the key stages of the metastatic process: invasion, intravasation, circulation, extravasation, and colonization. There is growing interest in engineering targeted therapeutics, such as antibody drugs, that inhibit various steps in the metastatic cascade. We present an overview of antibody therapeutic approaches, both in the pipeline and in the clinic, that disrupt the essential mechanisms that underlie cancer metastasis. These therapies include classes of antibodies that indirectly target metastasis, including anti-integrin, anticadherin, and immune checkpoint blocking antibodies, as well as monoclonal and bispecific antibodies that are specifically designed to interrupt disease dissemination. Although few antimetastatic antibodies have achieved clinical success to date, there are many promising candidates in various stages of development, and novel targets and approaches are constantly emerging. Collectively, these efforts will enrich our understanding of the molecular drivers of metastasis, and the new strategies that arise promise to have a profound impact on the future of cancer therapeutic development. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease.

Non-opioid Analgesics and Emerging Therapies

Pain is a common and debilitating symptom of cancer. Cancer-related pain can occur at any point along the continuum from diagnosis to treatment to survivorship¹. A systematic review published in 2016 estimated the prevalence of cancer pain to be 55% in those undergoing antineoplastic treatment, 66.4% in advanced cancer, and 39.3% in the post-treatment population. Thirty-eight percent of cancer patients in this pooled analysis experienced moderate to severe pain².

The safety profile of denosumab in oncology beyond the safety of denosumab as an anti-osteoporotic agent: still more to learn

INTRODUCTION

Initially endorsed as an antiosteoporotic agent, denosumab ‒ human monoclonal antibody inhibiting the receptor activator of nuclear factor kappa-B ligand (RANKL)‒ has currently shown an anticancer potential, rationalizing its exploitation in oncology. A prerequisite for leveraging denosumab in oncology is a favorable safety profile.

AREAS COVERED

The present review provides an overview of the adverse events of denosumab in oncology, with a focus on hypocalcemia, medication-related osteonecrosis of the jaw, atypical femoral fracture(s), post-denosumab vertebral fractures, increased risk of infections, and excess of second primary cancer. Representative studies addressing the safety and efficacy of denosumab compared to bisphosphonates in oncology are summarized. Critical gaps in the literature concerning the safety of denosumab in oncology are highlighted as opposed to plenty of available safety data on denosumab as an antiosteoporotic agent.

EXPERT OPINION

Despite the generally acceptable safety profile of denosumab in oncology, many issues remain unresolved. Further research is mandatory to counteract current challenges, namely: (i) validation of risk factors for adverse events; (ii) elucidation of the pathophysiology of the adverse events in search of actionable molecular pathways; (iii) illumination of the association of denosumab with increased risk of infections and/or second primary cancer; (iv) establishment of optimal diagnostic, and therapeutic protocols.

Meta-analysis of clinical trials to assess denosumab over zoledronic acid in bone metastasis

Background Bone metastases-induced skeletal complications result in reduced patient survival, lower quality of life, and an increase in healthcare costs. Previously, zoledronic acid (ZA) was the standard choice of treatment for bone metastases, but another drug, denosumab, has also shown promise. However, the clinical utility of these two drugs requires further exploration. Aim of the review Due to the lack of direct comparisons regarding the efficacy of these drugs in both solid tumors and multiple myeloma (MM), we herein tried to conduct a meta-analysis to compare their efficacy in parallel for bone metastases treatment in both solid tumor and MM patients. Methods Multiple databases including Cochrane Library, MEDLINE, EMBASE, and Web of Science were searched to identify randomized controlled trials (RCTs) reported up to March 2019 directly comparing denosumab with ZA in solid tumors and MM. Information about the following events was primarily searched: time to first on-study skeletal-related event (SRE), time to first and subsequent SREs, and overall survival. Information about secondary outcomes including disease progression, pain, health-related quality of life, and adverse events was also recorded. Results Overall, we analyzed data from four distinct RCTs including 7441 patients, and our analysis revealed that patients in the denosumab group had a significantly delayed incidence to the first and subsequent SREs. In addition, denosumab resulted in a higher incidence of hypocalcemia and osteonecrosis of the jaw (ONJ), and a lower incidence of renal toxicity and acute phase reactions, in comparison to ZA. Conclusion Overall, denosumab showed superiority in delaying the first and subsequent SREs, and hence seems to be a promising choice for managing bone metastases in both solid tumors and MM. However, it can induce a higher incidence of ONJ and hypocalcaemia, but these are preventable and manageable effects.

Denosumab for cancer-related bone loss

INTRODUCTION

Prolonged use of anti-cancer treatments in breast and prostate tumors alters physiological bone turnover leading to adverse skeletal related events, such as osteoporosis, loss of bone mass, and increased risk of fractures. These complications known as cancer treatment-induced bone loss (CTIBL) should be managed with bone targeting agents such as the bisphosphonates and denosumab. The latter is a monoclonal antibody against the receptor activator of nuclear factor-kB ligand (RANKL) that suppresses osteoclasts function and survival increasing bone mass.

AREAS COVERED

This review will focus on the mechanisms associated with bone loss induced by cancer treatments and the most recent evidence about the use of denosumab as preventive and therapeutic strategy to protect bone health. Moreover, we will discuss several key aspects regarding the clinical practical use of denosumab to optimize the management of CTLIB in breast and prostate cancer.

EXPERT OPINION

Denosumab treatment strongly prevents cancer therapies-related skeletal issues in breast and prostate cancer with a good safety profile. Adjuvant six-monthly denosumab delays the time to first fracture onset in early stage breast cancer patients with normal or altered bone mineral density (BMD). Similarly, denosumab treatment is able to prevent fractures and BMD loss in nonmetastatic prostate cancer patients.

Spine and Non-spine Bone Metastases - Current Controversies and Future Direction

Bone is a common site of metastases in advanced cancers. The main symptom is pain, which increases morbidity and reduces quality of life. The treatment of bone metastases needs a multidisciplinary approach, with the main aim of relieving pain and improving quality of life. Apart from systemic anticancer therapy (hormonal therapy, chemotherapy or immunotherapy), there are several therapeutic options available to achieve palliation, including analgesics, surgery, local radiotherapy, bone-seeking radioisotopes and bone-modifying agents. Long-term use of non-steroidal analgesics and opiates is associated with significant side-effects, and tachyphylaxis. Radiotherapy is effective mainly in localised disease sites. Bone-targeting radionuclides are useful in patients with multiple metastatic lesions. Bone-modifying agents are beneficial in reducing skeletal-related events. This overview focuses on the role of surgery, including minimally invasive treatments, conventional radiotherapy in spinal and non-spinal bone metastases, bone-targeting radionuclides and bone-modifying agents in achieving palliation. We present the clinical data and their associated toxicity. Recent advances are also discussed.

Practical update for the use of bone-targeted agents in patients with bone metastases from metastatic breast cancer or castration-resistant prostate cancer

Bone metastases are a significant source of morbidity and mortality for patients with breast and prostate cancer. In this review, we discuss key practical themes regarding the use of bone-targeted agents (btas) such as bisphosphonates and denosumab for managing bony metastatic disease. The btas both delay the onset and reduce the incidence of skeletal-related events (sres), defined as any or all of a need for radiation therapy or surgery to bone, pathologic fracture, spinal cord compression, or hypercalcemia of malignancy. They have more modest benefits for pain and other quality-of-life measures. Regardless of the benefits of btas, it should always be remembered that the palliative management of metastatic bone disease is multimodal and multidisciplinary. The collaboration of all disciplines is essential for optimal patient care. Special consideration is given to these key questions: ■ What are btas, and what is their efficacy?■ What are their common toxicities?■ When should they be initiated?■ How do we choose the appropriate bta?■ What is the appropriate dose, schedule, and duration of btas?

Incidence of atypical femoral fractures in the treatment of bone metastasis: An alert report

•

Oncologic use of bone-modifying agents (BMAs) has been dramatically increasing.

•

Long-term BMA use is a risk factor for atypical femoral fracture (AFF).

•

We reviewed 721 patients with bone metastasis in a Japanese university hospital.

•

The incidence of critical AFF (n = 5) was 0.9% among 529 BMA-exposed patients.

•

The incidence was 6.6% when limited to breast cancer patients alone.

Background

As the life expectancy of cancer-bearing patients has increased, more patients with bone metastasis are receiving long-term treatment with bone-modifying agents (BMAs; e.g., zoledronate and denosumab), which are a risk factor for developing atypical femoral fracture (AFF). In this study, we surveyed the risk of iatrogenic AFF using a clinical database on treatment of bone metastasis in the past 10 years.

Methods

From April 2011 through October 2019, 721 patients with bone metastasis (436 men, 285 women; mean age, 65.7 ± 12.4 years) were registered under the bone metastasis consultation system, which has been run by orthopaedic surgeons since 2011, at a university hospital in Japan. We retrospectively reviewed the database to identify patients who had received BMAs for treatment of bone metastasis, and we investigated the incidence of critical skeletal-related events (including AFF) which required surgical interventions by orthopaedic surgeons.

Results

BMAs were administered to 529 patients (73.4%). Orthopaedic surgery for the treatment of skeletal-related events was performed in 36 patients (5.0%): femur, 13 (1.8%); others, 23 (3.2%). Eight AFFs in 5 patients (breast cancer, n = 4; prostate cancer, n = 1), who all had prior exposure to zoledronate or denosumab before onset of AFF, were treated with internal fixation using intramedullary nailing. In 192 patients with no BMA exposure, critical (surgically treated) AFF was not detected. In summary, the incidence of critical AFF was 0.9% among 529 patients who received BMAs for treatment of bone metastasis, and the incidence was 6.6% when limited to breast cancer patients (4 of 61).

Conclusion

In treatment of bone metastasis using BMAs, especially for breast cancer patients, attention should be paid to the risk of developing AFFs. Routine radiographic screening for AFF might be necessary in patients with prolonged BMA use for bone metastasis, even if asymptomatic. This report alerts all physicians and surgeons involved in the management of cancer patients, especially those with bone metastasis, regarding the risk of AFF following BMA use.

Incidence of and risk factors for medication-related osteonecrosis of the jaw in women with breast cancer with bone metastasis: a population-based study

OBJECTIVE

The aim of this study was to prospectively determine the incidence of medication-related osteonecrosis of the jaw (MRONJ) and define risk factors in patients with metastatic breast cancer treated with zoledronic acid and/or denosumab.

STUDY DESIGN

In a prospective cohort study performed in Region Skåne, Sweden, from January 1, 2012, until December 31, 2015, all patients with breast cancer who had radiographic evidence of bone metastases and were treated with zoledronic acid or denosumab were included and followed up until May 31, 2018.

RESULTS

Of the 242 patients, MRONJ developed in 16 (6.6%) during the 77 months of study. The incidence of MRONJ in patients treated with zoledronic acid was 4.1%, and in patients treated with denosumab, it was 13.6%. The risk of MRONJ was higher in patients on denosumab than in those treated with zoledronic acid (P = .011). Corticosteroid use was associated with a decreased risk of MRONJ (P = .008), and diabetes was associated with an increased risk of MRONJ (P = .02).

CONCLUSIONS

The incidence of MRONJ is 13.6% (>3 times higher) in denosumab-treated patients with breast cancer compared with that in patients treated with zoledronic acid (4.1%). Corticosteroid use decreased the risk of MRONJ.

Incidence of patients with bone metastases at diagnosis of solid tumors in adults: a large population-based study

Background

Bones are one of the most common metastatic sites for solid malignancies. Bone metastases can significantly increase mortality and decrease the quality of life of cancer patients. In the United States, around 350,000 people die each year from bone metastases. This study aimed to analyze and update the incidence and prognosis of bone metastases with solid tumors at the time of cancer diagnosis and its incidence rate for each solid cancer.

Methods

We used the Surveillance, Epidemiology, and End Results (SEER) database to find patients diagnosed with solid cancers originating from outside the bones and joints between 2010 and 2016. Data were stratified by age, sex, and race. Patients with a tumor in situ or with an unknown bone metastases stage were excluded. We then selected most of the sites where cancer often occurred, leaving 2,207,796 patients for the final incidence analysis. For the survival analysis, patients were excluded if they were diagnosed at their autopsy or on their death certificate, or had unknown follow-ups. The incidence of bone metastases and overall survival was compared between patients with different primary tumor sites.

Results

We identified 2,470,634 patients, including 426,594 patients with metastatic disease and 113,317 patients with bone metastases, for incidence analysis. The incidence of bone metastases among the metastatic subset was 88.74% in prostate cancer, 53.71% in breast cancer, and 38.65% in renal cancer. In descending order of incidence, there were patients with other cancers in the genitourinary system (except for renal, bladder, prostate, and testicular cancer) (37.91%), adenocarcinoma of the lung (ADC) (36.86%), other gynecologic cancers (36.02%), small-cell lung cancer (SCLC) (34.56%), non-small cell lung cancer not otherwise specified and others [NSCLC (NOS/others)] (33.55%), and bladder (31.08%) cancers. The rate of bone metastases is 23.19% in SCLC, 22.50% in NSCLC (NOS/others), 20.28% in ADC, 8.44% in squamous cell carcinoma of the lung (SCC), and 4.11% in bronchioloalveolar carcinoma [NSCLC (BAC)]. As for the digestive system, the overall bone metastases rate was 7.99% in the esophagus, 4.47% in the gastric cancer, 4.42% in the hepatobiliary cancer, 3.80% in the pancreas, 3.26% in other digestive organs, 1.24% in the colorectum, and 1.00% in the anus. Overall, the incidence rate of bone metastases among the entire cohort in breast and prostate cancer was 3.73% and 5.69%, respectively.

Conclusions

The results of this study provide population-based estimates for the incidence rates of patients with bone metastases at initial diagnosis of their solid tumor. The findings can help clinicians to early detect bone metastases by bone screening to anticipate the occurrence of symptoms and favorably improve the prognosis.

RANKL/RANK System-Based Mechanism for Breast Cancer Bone Metastasis and Related Therapeutic Strategies

Breast cancer remains one of the most life-threatening tumors affecting women. Most patients with advanced breast cancer eventually develop metastatic diseases, which cause significant morbidity and mortality. Approximately two-thirds of patients with advanced breast cancer exhibit osteolytic-type bone metastasis, which seriously reduce the quality of life. Therefore, development of novel therapeutic strategies for treating breast cancer patients with bone metastasis is urgently required. The "seed and soil" theory, which describes the interaction between the circulating breast cancer cells (seeds) and bone microenvironment (soil), is widely accepted as the mechanism underlying metastasis. Disruption of any step in this cycle might have promising anti-metastasis implications. The interaction of receptor activator of nuclear factor-κB ligand (RANKL) and its receptor RANK is fundamental in this vicious cycle and has been shown to be a novel effective therapeutic target. A series of therapeutic strategies have been developed to intervene in this cross-talk. Therefore, in this review, we have systematically introduced the functions of the RANKL/RANK signaling system in breast cancer and discussed related therapeutic strategies.

Tumor dormancy in bone

Background

Bone marrow is a common site of metastasis for a number of tumor types, including breast, prostate, and lung cancer, but the mechanisms controlling tumor dormancy in bone are poorly understood. In breast cancer, while advances in drug development, screening practices, and surgical techniques have dramatically improved survival rates in recent decades, metastatic recurrence in the bone remains common and can develop years or decades after elimination of the primary tumor.

Recent Findings

It is now understood that tumor cells disseminate to distant metastatic sites at early stages of tumor progression, leaving cancer survivors at a high risk of recurrence. This review will discuss mechanisms of bone lesion development and current theories of how dormant cancer cells behave in bone, as well as a number of processes suspected to be involved in the maintenance of and exit from dormancy in the bone microenvironment.

Conclusions

The bone is a complex microenvironment with a multitude of cell types and processes. Many of these factors, including angiogenesis, immune surveillance, and hypoxia, are thought to regulate tumor cell entry and exit from dormancy in different bone marrow niches.

Atypical femoral fracture in patients with bone metastasis receiving denosumab therapy: a retrospective study and systematic review

BACKGROUND

While denosumab has been shown to prevent skeletal-related events in patients with bone metastasis, there is a concern that it may cause atypical femoral fracture (AFF). While AFF has been reported in patients with osteoporosis receiving denosumab, data are scarce in the context of AFF occurring in patients with bone metastasis receiving monthly denosumab therapy.

METHODS

To analyze the incidence of AFF in patients with bone metastasis, we reviewed the medical records of patients who had received monthly denosumab (120 mg) treatment from May 2012 to June 2017 at any of the three participant institutions.

RESULTS

The study population consisted of 277 patients who had received a median of 10 doses (range, 1-79) of denosumab. Five patients were diagnosed as having AFF or symptomatic atypical femoral stress reaction (AFSR) needing surgical intervention, representing an incidence rate of 1.8% (95% confidence interval, 0.77-4.2). These patients had received 15, 45, 45, 46 or 47 doses of denosumab, respectively. Four of the patients had received prior zoledronic acid treatment. The results of our analysis suggested that long-term use of denosumab, especially for more than 3.5 years, and prior use of zoledronic acid were risk factors for the development of AFF.

CONCLUSIONS

We found the AFF events in 5 patients (1.8%) among 277 cancer patients who had received monthly denosumab (120 mg) treatment. Long-term denosumab treatment and prior zoledronic acid treatment were identified as risk factors for the development of AFF.

Adult Cancer Pain, Version 3.2019, NCCN Clinical Practice Guidelines in Oncology

In recent years, the NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for Adult Cancer Pain have undergone substantial revisions focusing on the appropriate and safe prescription of opioid analgesics, optimization of nonopioid analgesics and adjuvant medications, and integration of nonpharmacologic methods of cancer pain management. This selection highlights some of these changes, covering topics on management of adult cancer pain including pharmacologic interventions, nonpharmacologic interventions, and treatment of specific cancer pain syndromes. The complete version of the NCCN Guidelines for Adult Cancer Pain addresses additional aspects of this topic, including pathophysiologic classification of cancer pain syndromes, comprehensive pain assessment, management of pain crisis, ongoing care for cancer pain, pain in cancer survivors, and specialty consultations.

Multiple actions of parathyroid hormone-related protein in breast cancer bone metastasis

The sequence similarity within the amino-terminal regions of parathyroid hormone (PTH) and PTH-related protein (PTHrP) allows the two to share actions at a common site, the PTH1 receptor. A number of biological activities have been ascribed to actions of other domains within PTHrP. PTHrP production by late stage breast cancer has been shown to contribute to bone metastasis formation through promotion of osteoclast formation and bone resorption by action through PTH1 receptors. There is evidence also for a role for PTHrP early in breast cancer that is protective against tumour progression. No signalling pathway has been identified for this effect. PTHrP has also been identified as a factor promoting the emergence of breast cancer cells from dormancy in bone. In that case, PTHrP does not function through activation of PTH1 receptors, despite having very substantial effects on transcriptional activity of the breast cancer cells. This indicates actions of PTHrP that are non-canonical, that is, mediated through domains other than the amino-terminal. It is concluded that PTHrP has several distinct paracrine, autocrine, and intracrine actions in the course of breast cancer pathophysiology. Some are mediated through action at PTH1 receptors and others are controlled by other domains within PTHrP. LINKED ARTICLES: This article is part of a themed issue on The molecular pharmacology of bone and cancer-related bone diseases. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v178.9/issuetoc.

Prediction of Bone Metastasis in Inflammatory Breast Cancer Using a Markov Chain Model

BACKGROUND

Inflammatory breast cancer (IBC) is a rare yet aggressive variant of breast cancer with a high recurrence rate. We hypothesized that patterns of metastasis differ between IBC and non-IBC. We focused on the patterns of bone metastasis throughout disease progression to determine statistical differences that can lead to clinically relevant outcomes. Our primary outcome of this study is to quantify and describe this difference with a view to applying the findings to clinically relevant outcomes for patients.

SUBJECTS, MATERIALS, AND METHODS

We retrospectively collected data of patients with nonmetastatic IBC (n = 299) and non-IBC (n = 3,436). Probabilities of future site-specific metastases were calculated. Spread patterns were visualized to quantify the most probable metastatic pathways of progression and to categorize spread pattern based on their propensity to subsequent dissemination of cancer.

RESULTS

In patients with IBC, the probabilities of developing bone metastasis after chest wall, lung, or liver metastasis as the first site of progression were high: 28%, 21%, and 21%, respectively. For patients with non-IBC, the probability of developing bone metastasis was fairly consistent regardless of initial metastasis site.

CONCLUSION

Metastatic patterns of spread differ between patients with IBC and non-IBC. Selection of patients with IBC with known liver, chest wall, and/or lung metastasis would create a population in whom to investigate effective methods for preventing future bone metastasis.

IMPLICATIONS FOR PRACTICE

This study demonstrated that the patterns of metastasis leading to and following bone metastasis differ significantly between patients with inflammatory breast cancer (IBC) and those with non-IBC. Patients with IBC had a progression pattern that tended toward the development of bone metastasis if they had previously developed metastases in the liver, chest wall, and lung, rather than in other sites. Selection of patients with IBC with known liver, chest wall, and/or lung metastasis would create a population in whom to investigate effective methods for preventing future bone metastasis.

Oncogenic osteomalacia and metastatic breast cancer: a case report and review of the literature

Objectives

Oncogenic osteomalacia is a rare paraneoplastic metabolic syndrome that is characterised by severe hypophosphataemia, hyperphosphaturia and osteomalacia secondary to renal loss of phosphate. It is commonly caused by overproduction of fibroblast growth factor-23 (FGF23) from benign tumours of mesenchymal origin. Currently, there is no clear evidence on the management of oncogenic osteomalacia in patients with metastatic solid tumours.

Methods

We report a case of breast cancer-induced oncogenic osteomalacia and discuss its diagnosis and management.

Results

A 71-year-old woman with advanced breast cancer developed symptomatic oncogenic osteomalacia with raised FGF23, severe hypophosphataemia and hypocalcaemia. The electrolytic disturbances were exacerbated after the administration of bisphosphonates in the context of her oncological treatment. Systemic chemotherapy and maintenance endocrine treatment along with phosphate and calcium supplementation reduced the activity of oncogenic osteomalacia and resolved the electrolytic imbalances.

Conclusions

To our knowledge, this is the first reported case of oncogenic osteomalacia in a patient with breast cancer. Oncogenic osteomalacia constitutes a diagnostic and therapeutic challenge. Pre-clinical and clinical evidence suggest that a possible underlying mechanism is the presence of molecular alterations in the FGF/FGFR signalling pathway leading to overexpression of FGF23. In metastatic setting, anticancer treatment can potentially lead to the normalisation of the electrolytic disturbances and reduction of the activity of oncogenic osteomalacia. The use of antiresorptive therapy in patients with bone metastases can potentially trigger FGF23 overexpression. Its use should be guided by the patients' risk of skeletal-related events and electrolytic disturbances as well as the degree of activity of oncogenic osteomalacia.

Denosumab versus zoledronic acid for preventing symptomatic skeletal events in Asian postmenopausal women with oestrogen-receptor-positive advanced breast cancer: an outcome analyses with a mean follow-up of 3 years

Background

The purpose of this study was to evaluate the efficacy of denosumab or zoledronic acid (ZA) using symptomatic skeletal events (SSEs) as the primary endpoint in Asian postmenopausal women with oestrogen-receptor-positive advanced breast cancer.

Methods

Asian postmenopausal women with oestrogen-receptor-positive advanced breast cancer receiving subcutaneous denosumab 120 mg Q4W, or intravenous ZA 4 mg Q4W until the primary analysis cut-off date were retrospectively analysed in the Hong Kong Practice-Based Cancer Research Center(HKCRC) from March 2011 to March 2013. The time to first on-study SSE that was assessed either clinically or through routine radiographic scans was the primary endpoint.

Results

242 patients received denosumab or ZA treatment (n = 120, mean age of 64.9 years (SD 3.01) and n = 122, 65.4 years (3.44), respectively). The median times to first on-study SSE were 14.7 months (12.9–45.6) and 11.7 months (9.9–45.6) for denosumab and ZA, respectively (hazard ratio, HR 0.44, 95% CI 0.71–2.95; p = 0·0002). Compared with the ZA group, denosumab-treated patients had a significantly delayed time to first SSE (HR 0.65 [95% CI 0.29–1.45], p < 0.0001). An increased incidence of SSE was found in the 16-month follow-up with rates of 2.1 and 10.7% for denosumab and ZA, respectively (P = 0.033). The difference persisted with time with rates of 8.3 and 17.2% at the final follow-up, respectively (P < 0.05).

Conclusion

In postmenopausal women aged ≥60 years with oestrogen-receptor-positive advanced breast cancer, denosumab significantly reduced the risk of developing SSEs compared with ZA. The findings of this pilot trial justify a larger study to determine whether the result is more generally applicable to a broader population.

Prognostic Factors in Patients with Metastatic Breast Cancer with Bone-Only Metastases

This article describes the association between pain attributable to bone metastasis and location, as well as number and type of bone metastases at time of bone metastasis diagnosis in metastatic breast cancer patients with bone‐only metastases. The resulting outcomes analysis should allow for earlier interventions or identification for clinical trial involvement.

Background.

Patients with metastatic breast cancer with bone‐only metastases (BOM) are a unique patient population without consensus regarding high‐risk characteristics, which we sought to establish.

Methods.

We identified 1,445 patients with BOM followed for at least 6 months at MD Anderson Cancer Center from January 1, 1997, to December 31, 2015.

Results.

Seventy‐one percent (n = 936) of the 1,325 patients with BOM with available pain characterization were symptomatic at time of BOM diagnosis. Pain was more common in patients with lytic compared with blastic or sclerotic metastases (odds ratio [OR], 1.79; 95% confidence interval [CI,] 1.26–2.53) and multiple versus single bone metastases (OR, 1.37; 95% CI, 1.03–1.83). Poorer overall survival (OS) was also noted in patients with multiple bone metastases (median OS, 4.80 years; 95% CI, 4.49–5.07) compared with single bone metastasis (median OS, 7.54 years; 95% CI, 6.28–10.10) and in patients with metastases in both the axial and appendicular skeleton (median OS, 4.58 years; 95% CI, 4.23–4.96) compared with appendicular‐only (median OS, 6.78 years; 95% CI, 5.26–7.96) or axial‐only metastases (median OS, 5.62 years; 95% CI, 4.81–6.69). Black/non‐Hispanic patients had poorer outcomes, and patients aged 40–49 years at time of breast cancer diagnosis had significantly better OS compared with both younger and older patient groups.

Conclusion.

Overall, several risk features for decreased OS were identified, including multiple bone metastases and both axial and appendicular skeleton involvement. Multiple bone metastases and lytic bone metastases were associated with increased pain.

Implications for Practice.

Patients with metastatic breast cancer and bone‐only metastases (BOM) represent a poorly characterized patient subset. The ability to identify unique patient characteristics at time of BOM diagnosis associated with increased morbidity or mortality would allow for recognition of patients who would benefit from more aggressive therapy. In this study, the largest sample of patients with BOM thus far reported is characterized, highlighting several higher‐risk BOM groups, including those with multiple bone metastases and bone metastases in both the axial and appendicular skeleton at time of BOM diagnosis. In addition to tailoring current practices for these high‐risk patients, ongoing studies of these patients are indicated.

Incidence proportions and prognosis of breast cancer patients with bone metastases at initial diagnosis

INTRODUCTION

Population-based data on the incidence and prognosis of bone metastases at diagnosis of breast cancer are currently limited. Hence, we conducted this study to analyze the incidence proportions and prognostic factors of patients with breast cancer and bone metastases at the time of cancer diagnosis.

MATERIALS AND METHODS

Patients with primary invasive breast cancer and bone metastases at initial diagnosis between 2010 and 2014 were identified using the Surveillance, Epidemiology, and End Results (SEER) dataset and Fudan University Shanghai Cancer Center (FUSCC) cohort. Multivariable logistic regression was performed to identify predictors of the presence of bone metastases at diagnosis. Univariate and multivariate analyses were performed to determine the effects of each variable on survival.

RESULTS

Of 229, 195 patients from SEER database included in the analysis, 8295 patients had bone metastases at initial diagnosis, reflecting 3.6% of the entire study population, and 65.1% of the subset with metastatic disease to any distant site. Patients with hormone receptor (HR)-positive human epidermal growth factor receptor 2 (HER2)-negative represented the highest incidence proportions among patients with metastatic disease (73.9%). Among entire cohort, multivariable logistic regression identified eight factors as predictors of the presence of bone metastases at diagnosis. Median OS for the patients with bone metastases in SEER and FUSCC cohorts was 30.0 and 68.2 months, respectively. Patients with HR-positive HER2-positive subtype had the longest median OS, and patients with triple-negative subtype showed the shortest median OS. Multivariable Cox model in SEER cohort confirmed age, histology, grade, tumor subtype, extraosseous metastatic sites, history of primary surgery, insurance status, marital status, and income as independent prognostic factors for both OS and BCSS.

CONCLUSIONS

The findings of this study provide population-based estimates of the incidence and prognosis for patients with bone metastases at initial diagnosis of breast cancer.

Denosumab versus bisphosphonates in patients with advanced cancers-related bone metastasis: systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Bone metastasis is reported to be associated with poor quality of life, and increased risk of hospitalization. We aim to synthesize evidence from published randomized controlled trials (RCTs) which compared the efficacy of denosumab versus bisphosphonates in patients with advanced cancers.

METHODS

We searched for all published RCTs in the following electronic databases: PubMed, Scopus, Web of Science, and Cochrane Central. Retrieved records were screened for eligibility. Time-to-event data were pooled as hazard ratio (HR) using the generic inverse-variance method and dichotomous data were pooled as relative risk (RR) in a random-effect model. We used Review Manager 5.3 for windows.

RESULTS

Six unique RCTs with a total of 7722 patients were included. Overall effect estimates favored denosumab group in comparison to intravenous (IV) bisphosphonates in the following terms: time to first skeletal-related events (HR 0.92, 95% CI [0.86, 0.98], p = 0.01), time to subsequent skeletal-related event (RR 0.92, 95% CI [0.86, 0.99], p = 0.03), and radiation to bone (RR 0.81, 95% CI [0.71, 0.92], p = 0.02). Denosumab group was associated with increased risk of grade 3 or 4 hypocalcaemia (RR 1.99, 95% CI [1.11, 3.54], p = 0.02) and reduced risk of renal impairment or toxicity (RR 0.75, 95% CI [0.61, 0.91], p = 0.003) in comparison to IV bisphosphonates group. Pooled studies were homogenous.

CONCLUSION

Denosumab showed a favorable significant impact on delaying the time to first skeletal-related event and reducing the incidence of radiation to the bone event in comparison to bisphosphonates, with similar efficacy regarding overall survival and time to disease progression. Further large-scale and long-term studies are needed to clarify the long-term efficacy and safety of both regimens.

Role of Bone-Modifying Agents in Metastatic Breast Cancer: An American Society of Clinical Oncology–Cancer Care Ontario Focused Guideline Update

Purpose

To update, in collaboration with Cancer Care Ontario (CCO), key recommendations of the American Society of Clinical Oncology (ASCO) guideline on the role of bone-modifying agents (BMAs) in metastatic breast cancer. This focused update addressed the new data on intervals between dosing and the role of BMAs in control of bone pain.

Methods

A joint ASCO-CCO Update Committee conducted targeted systematic literature reviews to identify relevant studies.

Results

The Update Committee reviewed three phase III noninferiority trials of dosing intervals, one systematic review and meta-analysis of studies of de-escalation of BMAs, and two randomized trials of BMAs in control of pain secondary to bone metastases.

Recommendations

Patients with breast cancer who have evidence of bone metastases should be treated with BMAs. Options include denosumab, 120 mg subcutaneously, every 4 weeks; pamidronate, 90 mg intravenously, every 3 to 4 weeks; or zoledronic acid, 4 mg intravenously every 12 weeks or every 3 to 4 weeks. The analgesic effects of BMAs are modest, and they should not be used alone for bone pain. The Update Committee recommends that the current standard of care for supportive care and pain management—analgesia, adjunct therapies, radiotherapy, surgery, systemic anticancer therapy, and referral to supportive care and pain management—be applied. Evidence is insufficient to support the use of one BMA over another. Additional information is available at www.asco.org/breast-cancer-guidelines and www.asco.org/guidelineswiki .

In Vitro Study of the Effects of Denosumab on Giant Cell Tumor of Bone: Comparison with Zoledronic Acid

Giant cell tumor of bone (GCTB) is a locally aggressive primary bone tumor that contains numerous osteoclasts formed from marrow-derived precursors through receptor activator of nuclear factor κ-B ligand (RANKL), an osteoclast differentiation factor expressed in neoplastic cells of GCTB. Denosumab, a fully human monoclonal antibody targeting RANKL, has recently been used for the treatment of GCTB, and superior treatment effects have been reported. The aim of this work was to elucidate the mechanism of action of denosumab, and the differences between denosumab and zoledronic acid at the level of GCTB cells. We isolated GCTB cells from 3 patients and separated them into osteoclasts, osteoclast precursors and proliferating spindle-shaped stromal cells (the true neoplastic component), and examined the action of denosumab on differentiation, survival and bone resorption activity of osteoclasts. Denosumab and zoledronic acid inhibited osteoclast differentiation from mononuclear cells containing osteoclast precursors. Zoledronic acid inhibited osteoclast survival, whereas an inhibitory effect of denosumab on osteoclast survival was not observed. The inhibitory effect on bone resorption by both agents was confirmed in culture on dentin slices. Furthermore, zoledronic acid showed dose-dependent inhibition of cell growth of neoplastic cells whereas denosumab had no inhibitory effect on these cells. Denosumab has an inhibitory effect on osteoclast differentiation, but no inhibitory effects on survival of osteoclasts or growth of neoplastic cells in GCTBs.

Bisphosphonates and other bone agents for breast cancer

BACKGROUND

Bone is the most common site of metastatic disease associated with breast cancer (BC). Bisphosphonates inhibit osteoclast-mediated bone resorption, and novel targeted therapies such as denosumab inhibit other key bone metabolism pathways. We have studied these agents in both early breast cancer and advanced breast cancer settings. This is an update of the review originally published in 2002 and subsequently updated in 2005 and 2012.

OBJECTIVES

To assess the effects of bisphosphonates and other bone agents in addition to anti-cancer treatment: (i) in women with early breast cancer (EBC); (ii) in women with advanced breast cancer without bone metastases (ABC); and (iii) in women with metastatic breast cancer and bone metastases (BCBM).

SEARCH METHODS

In this review update, we searched Cochrane Breast Cancer's Specialised Register, CENTRAL, MEDLINE, Embase, the World Health Organization's International Clinical Trials Registry Platform (WHO ICTRP) and ClinicalTrials.gov on 19 September 2016.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) comparing: (a) one treatment with a bisphosphonate/bone-acting agent with the same treatment without a bisphosphonate/bone-acting agent; (b) treatment with one bisphosphonate versus treatment with a different bisphosphonate; (c) treatment with a bisphosphonate versus another bone-acting agent of a different mechanism of action (e.g. denosumab); and (d) immediate treatment with a bisphosphonate/bone-acting agent versus delayed treatment of the same bisphosphonate/bone-acting agent.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data, and assessed risk of bias and quality of the evidence. The primary outcome measure was bone metastases for EBC and ABC, and a skeletal-related event (SRE) for BCBM. We derived risk ratios (RRs) for dichotomous outcomes and the meta-analyses used random-effects models. Secondary outcomes included overall survival and disease-free survival for EBC; we derived hazard ratios (HRs) for these time-to-event outcomes where possible. We collected toxicity and quality-of-life information. GRADE was used to assess the quality of evidence for the most important outcomes in each treatment setting.

MAIN RESULTS

We included 44 RCTs involving 37,302 women.In women with EBC, bisphosphonates were associated with a reduced risk of bone metastases compared to placebo/no bisphosphonate (RR 0.86, 95% confidence interval (CI) 0.75 to 0.99; P = 0.03, 11 studies; 15,005 women; moderate-quality evidence with no significant heterogeneity). Bisphosphonates provided an overall survival benefit with time-to-event data (HR 0.91, 95% CI 0.83 to 0.99; P = 0.04; 9 studies; 13,949 women; high-quality evidence with evidence of heterogeneity). Subgroup analysis by menopausal status showed a survival benefit from bisphosphonates in postmenopausal women (HR 0.77, 95% CI 0.66 to 0.90; P = 0.001; 4 studies; 6048 women; high-quality evidence with no evidence of heterogeneity) but no survival benefit for premenopausal women (HR 1.03, 95% CI 0.86 to 1.22; P = 0.78; 2 studies; 3501 women; high-quality evidence with no heterogeneity). There was evidence of no effect of bisphosphonates on disease-free survival (HR 0.94, 95% 0.87 to 1.02; P = 0.13; 7 studies; 12,578 women; high-quality evidence with significant heterogeneity present) however subgroup analyses showed a disease-free survival benefit from bisphosphonates in postmenopausal women only (HR 0.82, 95% CI 0.74 to 0.91; P < 0.001; 7 studies; 8314 women; high-quality evidence with no heterogeneity). Bisphosphonates did not significantly reduce the incidence of fractures when compared to placebo/no bisphosphonates (RR 0.77, 95% CI 0.54 to 1.08, P = 0.13, 6 studies, 7602 women; moderate-quality evidence due to wide confidence intervals). We await mature overall survival and disease-free survival results for denosumab trials.In women with ABC without clinically evident bone metastases, there was no evidence of an effect of bisphosphonates on bone metastases (RR 0.96, 95% CI 0.65 to 1.43; P = 0.86; 3 studies; 330 women; moderate-quality evidence with no heterogeneity) or overall survival (RR 0.89, 95% CI 0.73 to 1.09; P = 0.28; 3 studies; 330 women; high-quality evidence with no heterogeneity) compared to placebo/no bisphosphonates however the confidence intervals were wide. One study reported a trend towards an extended period of time without a SRE with bisphosphonate compared to placebo (low-quality evidence). One study reported quality of life and there was no apparent difference in scores between bisphosphonate and placebo (moderate-quality evidence).In women with BCBM, bisphosphonates reduced the SRE risk by 14% (RR 0.86, 95% CI 0.78 to 0.95; P = 0.003; 9 studies; 2810 women; high-quality evidence with evidence of heterogeneity) compared with placebo/no bisphosphonates. This benefit persisted when administering either intravenous or oral bisphosphonates versus placebo. Bisphosphonates delayed the median time to a SRE with a median ratio of 1.43 (95% CI 1.29 to 1.58; P < 0.00001; 9 studies; 2891 women; high-quality evidence with no heterogeneity) and reduced bone pain (in 6 out of 11 studies; moderate-quality evidence) compared to placebo/no bisphosphonate. Treatment with bisphosphonates did not appear to affect overall survival (RR 1.01, 95% CI 0.91 to 1.11; P = 0.85; 7 studies; 1935 women; moderate-quality evidence with significant heterogeneity). Quality-of-life scores were slightly better with bisphosphonates than placebo at comparable time points (in three out of five studies; moderate-quality evidence) however scores decreased during the course of the studies. Denosumab reduced the risk of developing a SRE compared with bisphosphonates by 22% (RR 0.78, 0.72 to 0.85; P < 0.001; 3 studies, 2345 women). One study reported data on overall survival and observed no difference in survival between denosumab and bisphosphonate.Reported toxicities across all settings were generally mild. Osteonecrosis of the jaw was rare, occurring less than 0.5% in the adjuvant setting (high-quality evidence).

AUTHORS' CONCLUSIONS

For women with EBC, bisphosphonates reduce the risk of bone metastases and provide an overall survival benefit compared to placebo or no bisphosphonates. There is preliminary evidence suggestive that bisphosphonates provide an overall survival and disease-free survival benefit in postmenopausal women only when compared to placebo or no bisphosphonate. This was not a planned subgroup for these early trials, and we await the completion of new large clinical trials assessing benefit for postmenopausal women. For women with BCBM, bisphosphonates reduce the risk of developing SREs, delay the median time to an SRE, and appear to reduce bone pain compared to placebo or no bisphosphonate.

Denosumab for the treatment of bone disease in solid tumors and multiple myeloma

Bone is a common site for malignant involvement, either as a site of metastasis, especially in breast or prostate cancer, or as a defining characteristic of the disease, as in multiple myeloma. Bone disease is a major source of morbidity, and half of patients with bone involvement develop skeletal-related events such as pathological fractures or cord compression requiring surgery and/or radiation. Skeletal involvement also increases mortality, as pathologic fractures increase the risk of dying by 20-40%. Osteoclast inhibition with bisphosphonates such as zoledronic acid and recently denosumab has been a significant improvement for bone disease. This review will focus on denosumab in the treatment of bone metastases and highlight the recent findings in multiple myeloma.

The skeletal-related events of denosumab versus zoledronic acid in patients with bone metastases: A meta-analysis of randomized controlled trials

Objective

The meta-analysis was used to evaluate the skeletal-related events (SREs) and efficacy of denosumab versus zoledronic acid (ZA) in patients with bone metastases.

Methods

The data of this meta-analysis study were searched from PUBMED, EMBASE, Cochrane Library, Web of Science with Conference Proceedings, Elsevier and China National Knowledge Infrastructure (CNKI) databases till August 2017. Two independent reviewers reviewed the reference lists of relevant articles. The fixed-effects model and random-effects model were used to summarize relative estimates and 95% confidence intervals (CIs) according to the heterogeneity of the included studies.

Results

Three randomized controlled trials (RCTs) including 4050 patients were identified in this meta-analysis study. The pooled analysis showed that denosumab could significantly reduce SREs, series SREs [Odds Ratio (OR) = 0.84; 95% CI, 0.74–0.95, I² = 0%, P = 0.008] in patients with bone metastases as compared with ZA. Similar results of spinal cord compression SRE and surgery to bone SRE were obtained with (OR = 0.84; 95% CI, 0.70–1.01, I² = 0%, P = 0.07) and (OR = 0.92; 95% CI, 0.78–1.08, I² = 0%, P = 0.28) separately, radiation to bone SRE (OR = 0.72; 95% CI, 0.46–1.10, I² = 11%, P = 0.13) and pathological fracture SRE (OR = 0.78; 95% CI, 0.35–1.73, I² = 25%, P = 0.54) showed similar results, there were no significant difference between denosumab and ZA in patients with bone metastases.

Conclusion

Denosumab was more effective than ZA in reducing the incidence of SRE in patients with bone metastases.

Low calcium diet increases 4T1 mammary tumor carcinoma cell burden and bone pathology in mice

Breast cancer metastasizes to bone in the majority of patients with advanced disease. We investigated the effects of inadequate dietary calcium (Ca) on bone turnover, tumor growth, and bone response to tumor in tibia inoculated with 4T1 mammary carcinoma cells. Nine-month-old female Balb/c mice were placed on an adequate Ca (5 g/kg diet, n = 30) or low Ca (80 mg/kg diet, n = 31) diet for 14 days, then injected intratibially with 1,000 4T1 cells (transfected with luciferase for bioluminescence imaging), and sacrificed at 5, 10, or 21 days post-inoculation (n = 7–10 mice/group). Control mice (n = 6/group) were injected with carrier and sacrificed at 10 days post-inoculation. Tibiae with muscle intact were excised and evaluated by microcomputed tomography and histology. In vivo bioluminescent imaging revealed that 4T1 cells metastasized to lung. Therefore, lungs were removed for quantification of tumor. Mice fed low Ca exhibited higher bone turnover and higher tibial lesion scores than mice fed adequate Ca. Lesion severity, manifested as cortical osteolysis and periosteal woven bone formation, and tumor cell infiltration to muscle, increased with time, irrespective of diet. However, for most skeletal endpoints the rates of increase were greater in mice consuming low Ca compared to mice consuming adequate Ca. Infiltration of tumor cells into adjacent muscle, but not metastasis to lung, was also greater in mice consuming low Ca diet. The findings suggest that high bone turnover due to Ca insufficiency results in greater local mammary tumor cell growth, cortical osteolysis, woven bone formation, and invasion to muscle in mice.

Risk stratification for predicting symptomatic skeletal events (SSEs) in breast cancer patients with bone metastases

BACKGROUND

Symptomatic skeletal events (SSEs) affect many patients with bone metastases from breast cancer. However, predictive models of SSEs in patients with bone metastases from breast cancer have not been established for clinical use. The purpose of this study is to examine risk factors for SSEs in those patients and by combining these risk factors patients are classified into several groups. With this risk-stratification model, we can identify patients at higher risk of SSEs and require close follow-up to maintain ADL.

METHODS

Participants included 189 female patients with bone metastases from breast cancer and treated in our institute between 2009 and 2012. To assess risk factors for the first SSEs, clinical data at the time of registration were assessed. To estimate the effects of covariates, we used cause-specific hazard modeling.

RESULTS

Multivariate analysis revealed that a high number of metastasized vertebral bodies (≥20) (p < 0.001) and elevated carcinoembryonic antigen (CEA) level (>5 ng/mL) (p = 0.003) were risk factors for SSEs. Patients were classified into four subgroups according to the combination of the number of vertebral metastases and CEA level: patients with CEA level > 5 ng/mL and ≥20 vertebral metastases; patients with CEA level ≤ 5 ng/mL and ≥20 vertebral metastases; patients with CEA level > 5 ng/mL and <20 vertebral metastases; and patients with CEA level ≤ 5 ng/mL and <20 vertebral metastases. Cumulative incidences of SSEs in these four subgroups at 6 months were 35.6%, 15.6%, 9.3%, and 3.7%, respectively.

CONCLUSIONS

Patients with elevated CEA level (>5 ng/mL) and extensive vertebral metastases (≥20) should be closely monitored in routine clinical care, to allow prevention of pathological fracture or paraplegia with the intervention of orthopedists or radiologists.