Management of bone metastases in breast cancer

Short-term outcomes after spinal surgery for metastatic breast cancer: A single-center analysis

Background

Advances in detection and breast cancer treatment lead to higher survival rates, with more patients living with spine metastases. Those surgeries are palliative; however, they can improve the quality of life (QOL).

Objective

The aim of this study is to report pain and neurological function outcomes after surgery for spinal metastatic disease of breast cancer patients of a single institution. Complications were recorded.

Materials and Methods

A retrospective, single-center, single-arm study was performed. Consecutive patients who underwent spinal surgery were included. We analyzed demographic, surgical, histopathological, and clinical data.

Results

Seventeen women were included. Three patients (17.6%) did not present pre- and postoperative pain (n = 3), 6 (35.3%) had pain in both situations, and 8 (47.1%) were pain-free postoperatively (P = 0.013). Ten (58.8%) patients had preoperative deficits: 3 (30%) did not improve and 7 (70%) improved after surgery. Six cases (35.2%) did not present preoperative deficits and did not get worse (n = 6). The Frankel classification after the following time showed that 11 patients (64.7%) remained stable after surgery and 5 patients (29.4%) got better. A single patient (5.6%) had deterioration of strength. Two patients (11.7%) had intraoperative complications.

Conclusions

Pain was significantly improved by surgery, with also a possibly positive effect on functionality. Considering the low complication rates, surgery is still a useful tool in the management of spinal metastases in breast cancer patients and may be related to better QOL.

The effect of zoledronic acid and denosumab on the mandible and other bones: a 18F-NaF-PET study

OBJECTIVES

The primary purpose of this study was to determine whether both zoledronic acid (ZA) and denosumab (Dmab) equally suppress bone remodeling of the normal mandible, and the secondary purpose was to determine the influence of ZA and Dmab on other normal bones.

METHODS

¹⁸F-sodium fluoride-positron-emission-tomography (¹⁸F-NaF-PET) was used to perform quantitative analysis of the bone metabolism in various parts. The end points of the study were the mean standardized uptake value (SUV) of each member of the ZA group (n = 9), the Dmab group (n = 16), and the Control group (n = 23).

RESULTS

The SUV at the thoracic vertebrae in the ZA group were significantly lower than those of the Dmab and Control group (p < 0.05) In addition, the mean SUVs of the cervical vertebrae in the ZA group were significantly lower than those in the Control group (p < 0.05). There was no significant difference among ZA, Dmab and Control group in the other sites. There was no significant difference between the Dmab and Control groups at all sites.

CONCLUSIONS

The remodeling of mandible was not suppressed due to the treatment with anti-resorptive agents. Differences in the mechanisms of action between the BP and Dmab caused the specificity of the effect on the metabolism of normal bone.

Progress in Targeted Alpha-Particle-Emitting Radiopharmaceuticals as Treatments for Prostate Cancer Patients with Bone Metastases

Bone metastasis remains a major cause of death in cancer patients, and current therapies for bone metastatic disease are mainly palliative. Bone metastases arise after cancer cells have colonized the bone and co-opted the normal bone remodeling process. In addition to bone-targeted therapies (e.g., bisphosphonate and denosumab), hormone therapy, chemotherapy, external beam radiation therapy, and surgical intervention, attempts have been made to use systemic radiotherapy as a means of delivering cytocidal radiation to every bone metastatic lesion. Initially, several bone-seeking beta-minus-particle-emitting radiopharmaceuticals were incorporated into the treatment for bone metastases, but they failed to extend the overall survival in patients. However, recent clinical trials indicate that radium-223 dichloride (223RaCl2), an alpha-particle-emitting radiopharmaceutical, improves the overall survival of prostate cancer patients with bone metastases. This success has renewed interest in targeted alpha-particle therapy development for visceral and bone metastasis. This review will discuss (i) the biology of bone metastasis, especially focusing on the vicious cycle of bone metastasis, (ii) how bone remodeling has been exploited to administer systemic radiotherapies, and (iii) targeted radiotherapy development and progress in the development of targeted alpha-particle therapy for the treatment of prostate cancer bone metastasis.

Dickkopf-1 (Dkk1) protein expression in breast cancer with special reference to bone metastases

Dysregulation of the Wnt inhibitor dickkopf-1 protein (Dkk1) has been reported in a variety of cancers. In addition, it has been linked to the progression of malignant bone disease by impairing osteoblast activity. This study investigated serum- and tissue levels of Dkk1 in breast cancer patients with- or without bone metastases. Serum Dkk1 levels were measured by ELISA in 89 breast cancer patients and 86 healthy women. Tissue levels of Dkk1 and β-catenin, a major downstream component of Wnt transduction pathway, were tested with immunohistochemical staining in 143 different tissues, including adjacent non-tumoral breast tissues, primary breast tumours, lymph nodes metastases, and bone metastases. Serum levels of Dkk1 were significantly increased in breast cancer patients without metastases compared with healthy controls and even more increased in patients with bone metastases. Tissue expression of Dkk1 was positive in 70% of tested primary breast cancer tissues and demonstrated significant correlation with histological type and PR status. Less frequent expression of Dkk1 was found in lymph nodes metastases and bone metastases compared with adjacent non-tumoral breast tissues and primary breast tumours. Tissue expression of β-catenin was positive in the vast majority of all tested tissue types indicating activated Wnt/β-catenin signalling. Our results suggested that Wnt/β-catenin signalling in breast tumours and their secondary lymph nodes- and bone metastases is dysregulated and this could be related to aberrant Dkk1 expression levels. Hence, Dkk1 protein might provide insights into the continued development of novel comprehensive and therapeutic strategies for breast cancer and its bone metastases.

The Effect of Gabapentin and Tramadol in Cancer Pain Induced by Glioma Cell in Rat Femur

Preclinical Research The presence of pain as part of the cancer process is variable. Glioblastoma multiform (GBM) can produce bone metastasis, a condition that involves other pathological phenotypes including neuropathic and inflammatory pain. Tramadol and gabapentin are drugs used in the treatment of neuropathic pain. However, there are no studies evaluating their analgesic effects in bone metastasis. We produced a pain model induced by the inoculation of glioma cells (10⁵ ) into the rat femur, by perforating the intercodiloid fossa. Painful behavior was evaluated by measuring mechanical allodynia using the Von Frey test while thermal hyperalgesia was assessed in the plantar test. Histopathological features were evaluated and antinociceptive responses were compared using tramadol and gabapentin. The inoculation of cells inside the right femur produced nociceptive behaviors. Tramadol and gabapentin produced an anti-allodynic effect in this condition, but tramadol did not produce an anti-hyperalgesic response. The development of this model will allow us to perform tests to elucidate the pathology of bone metastasis, cancer pain, and in particular the pain produced by glioma. Drug Dev Res 78 : 173-183, 2017. © 2017 Wiley Periodicals, Inc.

Biomechanical properties of bone treated by magnetic resonance-guided focused ultrasound - an in vivo porcine model study

The magnetic resonance-guided focused ultrasound (MRgFUS) system uses MR imaging for real-time aiming of thermal ablation of bone and soft tissue tumors. Past clinical studies showed no increase in fracture rate after MRgFUS treatment. The purpose of this study was to determine the effect of MRgFUS treatment on mechanical properties of bone and correlate the effect to histological findings of treated bone. Four fully grown mini-pigs were treated by MRgFUS. Six consecutive right normal ribs were treated in each animal, and the left corresponding ribs served as controls. The animals were sacrificed at pre-set intervals (0, 2, 6 and 12weeks after treatment), and the treated and control bones were extracted. Mechanical properties of each bone were examined using three points bending studies for comparing treated bones to the corresponding controls. Histologic properties using Masson and hematoxylin-eosin stains were also compared. The ratio between treated and control biomechanical properties showed reduction in bone biomechanical properties at 6weeks post-MRgFUS treatment. The mean±SD yield load ratio and maximum ratios were 0.69±0.11 and 0.71±0.13, respectively (both p=0.031). These findings showed some recovery trend at 12weeks after treatment. Histological analysis showed a reduction in mean osteon size at 2weeks after treatment (0.58×10(-3)±0.1×10(-3)mm and 0.16×10(-3)±0.017×10(-3)mm) in control vs. treated bones, respectively (p=0.005). Treatment with the MRgFUS system resulted in a ~30% reduction in mechanical strength at 6weeks post-treatment. The reduction showed a reversible trend, with a 25%-20% decrease in strength at 12weeks post-treatment.

Cost analysis of skeletal-related events in Spanish patients with bone metastases from solid tumours

PURPOSE

To estimate the cost per skeletal-related event (SRE) in patients with bone metastases secondary to solid tumours in the Spanish healthcare setting.

METHODS

Patients diagnosed with bone metastases secondary to breast, prostate or lung cancer were included in this multicentre, observational study. SREs are defined as pathologic fracture (vertebral and non-vertebral fracture), radiation to bone, spinal cord compression or surgery to bone. Health resource utilisation associated with these events (inpatient stays, outpatient, emergency room and home health visits, nursing home stays and procedures) were collected retrospectively for all SREs that occurred in the 97 days prior to enrolment and prospectively during follow-up. Unit costs were obtained from the 2010 eSalud healthcare costs database.

RESULTS

A total of 93 Spanish patients with solid tumours were included (31 had breast cancer, 21 prostate cancer and 41 lung cancer), contributing a total of 143 SREs to this cost analysis. Inpatient stays (between 9.0 and 29.9 days of mean length of stay per inpatient stay by SRE type) and outpatient visits (between 1.7 and 6.4 mean visits per SRE type) were the most frequently reported types of health resources utilised. The mean cost per SRE was between <euro>2,377.79 (radiation to bone) and <euro>7,902.62 (spinal cord compression).

CONCLUSION

SREs are associated with a significant consumption of healthcare resources that generate a substantial economic burden for the Spanish healthcare system.

Use of bisphosphonates in metastatic breast cancer: single institution review at the Dr. H. Bliss Murphy Cancer Centre

PURPOSE

Bone metastases occur in 65-75% of patients with metastatic breast cancer. These patients are at risk of developing skeletal-related events (SREs). SREs are defined as any pathological fracture, spinal cord compression, hypercalcemia, and surgery or radiation required for treatment of bone metastases. Bisphosphonates are used to prevent the development of SREs. The purpose of this study is to review the incidence of SREs in metastatic breast cancer patients with bony disease in Newfoundland and Labrador and to determine if there is an association between SREs and the type of bisphosphonate therapy given.

METHODS

This retrospective chart review includes all metastatic breast cancer patients with bony disease treated at the Dr. H. Bliss Murphy Cancer Centre from 2008 to 2010. Patient demographics, treatment received, and treatment changes were collected. Patients at the Centre received bisphosphonate, pamidronate or zolendronic acid to prevent SREs. The prescribing pattern of bisphosphonates was collected. The occurrences of SREs were then compared to the type of treatment received.

RESULTS

Sixty-five patients with breast cancer and bony metastasis were identified using the provincial tumor registry, three patients were excluded from the review as their charts could not be located. Following the initial diagnosis of bone metastasis, 8 patients (12.7%) were started on zolendronic acid, 50 patients (80.6%) were started on pamidronate, and 4 (6.4%) received no treatment. Six patients (75%) on zolendronic acid experienced one SRE; however, none experienced multiple SREs. Thirty-one patients (62%) on pamidronate experienced one SRE, and ten (20%) had multiple SREs. Of the 31 patients on pamidronate with an SRE, 4 (12.9%) were switched to zolendronic acid. Three of the four (75%) had multiple SREs despite treatment changes. Of the six patients on zolendronic acid with SREs, none were switched to pamidronate.

CONCLUSION

Our results show that the majority of patients with breast cancer, who develop bony metastases in Newfoundland and Labrador, are initially treated with the bisphosphonate, pamidronate. Over 60% of these patients experienced at least one SRE, and 20% had more than two SREs. A small proportion of the patients were initially started on zolendronic acid, and this group had better outcomes with fewer SREs and none had more than two SREs. It appears that zolendronic acid is superior to pamidronate in preventing SREs; however, zolendronic acid is being used primarily as second-line in Newfoundland and Labrador.

Surgical treatment of sacral metastases: indications and results

OBJECT

Hematogenous metastases to the sacrum can produce significant pain and lead to spinal instability. The object of this study was to evaluate the palliative benefit of surgery in patients with these metastases.

METHODS

The authors retrospectively reviewed all cases involving patients undergoing surgery for metastatic disease to the sacrum at a single tertiary cancer center between 1993 and 2005.

RESULTS

Twenty-five patients (21 men, 4 women) were identified as having undergone sacral surgery for hematogenous metastatic disease during the study period. Their median age was 57 years (range 25-71 years). The indications for surgery included palliation of pain (in 24 cases), need for diagnosis (in 1 case), and spinal instability (in 3 cases). The most common primary disease was renal cell carcinoma. Complications occurred in 10 patients (40%). The median overall survival was 11 months (95% CI 5.4-16.6 months). The median time from the initial diagnosis to the diagnosis of metastatic disease in the sacrum was 14 months (95% CI 0.0-29.3 months). The numerical pain scores (scale 0-10) were improved from a median of 8 preoperatively to a median of 3 postoperatively at 90 days, 6 months, and 1 year (p < 0.01). Postoperative modified Frankel grades improved in 8 cases, worsened in 3 (due to disease progression), and remained unchanged in 14 (p = 0.19). Among patients with renal cell carcinoma, the median overall survival was better in those in whom the sacrum was the sole site of metastatic disease than in those with multiple sites of metastatic disease (16 vs 9 months, respectively; p = 0.053).

CONCLUSIONS

Surgery is effective to palliate pain with acceptable morbidity in patients with metastatic disease to the sacrum. In the subgroup of patients with renal cell carcinoma, those with the sacrum as their solitary site of metastatic disease demonstrated improved survival.

Pharmacoeconomics of bisphosphonates for skeletal-related event prevention in metastatic non-breast solid tumours

Bisphosphonates reduce the risk of skeletal-related events (SREs; i.e. spinal cord compression, pathological fracture, radiation or surgery to the bone, and hypercalcaemia) in patients with metastatic cancer. A number of analyses have been conducted to assess the cost effectiveness of bisphosphonates in patients with bone metastases secondary to breast cancer, but few in other solid tumours. This is a review of cost-effectiveness analyses in patients with non-breast solid tumours and bone metastases. A literature search was conducted to identify cost-effectiveness analyses reporting the cost per QALY gained of bisphosphonates in patients with metastatic bone disease secondary to non-breast solid tumours. Four analyses met inclusion criteria. These included two in prostate cancer (one of which used a global perspective but expressed results in $US, and the other reported from a multiple country perspective: France, Germany, Portugal and the Netherlands). The remaining analyses were in lung cancer (in the UK, France, Germany, Portugal and the Netherlands), and renal cell carcinoma (in the UK, France and Germany). In each analysis, the cost effectiveness of zoledronic acid versus placebo was analysed. Zoledronic acid was found to be cost effective in all European countries across all three indications but not in the sole global prostate cancer analysis. Across countries and indications, assumptions regarding patient survival, drug cost and baseline utility (i.e. patient utility with metastatic disease but without an SRE) were the most robust drivers of modelled estimates. Assumptions of SRE-related costs were most often the second strongest cost driver. Further review indicated that particular attention should be paid to the inclusion or exclusion of nonsignificant survival benefits, whether health state utilities were elicited from community or patient samples or author assumptions, delineation between symptomatic and asymptomatic SREs, and the methods with which SRE disutility was modelled over time. While the field of cost-effectiveness analysis in solid tumours other than breast cancer is still evolving, outcomes will likely continue to be driven by drug cost and assumptions regarding treatment benefits. Although considerations such as adverse events and administration costs are important, they were not found to influence cost-effectiveness estimates greatly. As zoledronic acid will lose patent protection in 2013 and subsequently be greatly reduced in price, it is likely that the field of cost effectiveness will change with regard to SRE-limiting agents. Meanwhile, research should be conducted to improve our understanding of the impact on quality of life and medical costs of preventing SREs.

Estimated number of prevalent cases of metastatic bone disease in the US adult population

BACKGROUND

The prevalence of metastatic bone disease in the US population is not well understood. We sought to estimate the current number of US adults with metastatic bone disease using two large administrative data sets.

METHODS

Prevalence was estimated from a commercially insured cohort (ages 18-64 years, MarketScan database) and from a fee-for-service Medicare cohort (ages ≥65 years, Medicare 5% database) with coverage on December 31, 2008, representing approximately two-thirds of the US population in each age group. We searched for claims-based evidence of metastatic bone disease from January 1, 2004, using a combination of relevant diagnosis and treatment codes. The number of cases in the US adult population was extrapolated from age- and sex-specific prevalence estimated in these cohorts. Results are presented for all cancers combined and separately for primary breast, prostate, and lung cancer.

RESULTS

In the commercially insured cohort (mean age = 42.3 years [SD = 13.1]), we identified 9505 patients (0.052%) with metastatic bone disease. Breast cancer was the most common primary tumor type (n = 4041). In the Medicare cohort (mean age = 75.6 years [SD = 7.8]), we identified 6427 (0.495%) patients with metastatic bone disease. Breast (n = 1798) and prostate (n = 1862) cancers were the most common primary tumor types. We estimate that 279,679 (95% confidence interval: 274,579-284,780) US adults alive on December 31, 2008, had evidence of metastatic bone disease in the previous 5 years. Breast, prostate, and lung cancers accounted for 68% of these cases.

CONCLUSION

Our findings suggest that approximately 280,000 US adults were living with metastatic bone disease on December 31, 2008. This likely underestimates the true frequency; not all cases of metastatic bone disease are diagnosed, and some diagnosed cases might lack documentation in claims data.

The role of surgery in metastatic breast cancer

Some of the patients who present with breast cancer already have distant metastatic disease. According to recent literature, these patients may benefit from resection of the breast tumour. One explanation for the effect of this resection is that reducing the tumour load influences metastatic growth. Results of future randomised controlled trials should indicate whether surgery of the breast tumour truly improves survival. Selected patients could even benefit from metastasectomy of liver and lung metastases; survival seems to improve and these procedures seldom lead to major complications. When metastasectomy is not possible, minimally invasive techniques can be used in selected patients for the treatment of breast cancer liver metastases, radiofrequency ablation (RFA) being discussed most in the literature. Patients with locally advanced breast cancer are treated multidisciplinarily and with curative intent. Part of the treatment is surgery to reduce tumour load. Regarding treatment of the axilla, in a clinically negative axilla sentinel node biopsy is advised before neoadjuvant treatment; an axillary lymph node dissection is not warranted. In local recurrence, surgery is the primary treatment. Axillary staging can be done in patients with a previous negative sentinel node biopsy. Regional recurrence after breast-conserving surgery or mastectomy is treated with surgery followed by radiotherapy.

MR-guided high-intensity focused ultrasound for noninvasive cancer treatment

Magnetic resonance (MR)-high-intensity focused ultrasound (HIFU) is an innovative, noninvasive tumour ablation technique. MR imaging and focused ultrasound are combined allowing real-time anatomic guidance and temperature mapping during treatment. Recently, the volumetric ablation approach has been introduced in order to reduce treatment length and provide more homogeneous tumour ablation. After successful treatment of uterine fibroids, MR-HIFU is currently being investigated for the treatment of malignant tumours. Palliative treatment of painful bone metastases is already applied in clinical practice. Several issues need to be further investigated for successful cancer treatment with MR-HIFU, including patient selection criteria, definition of treatment margins and optimal transducer technology.

The hospital burden of disease associated with bone metastases and skeletal-related events in patients with breast cancer, lung cancer, or prostate cancer in Spain

POCKETT R.D., CASTELLANO D., MCEWAN P., OGLESBY A., BARBER B.L. & CHUNG K. (2010) European Journal of Cancer Care19, 755–760 The hospital burden of disease associated with bone metastases and skeletal-related events in patients with breast cancer, lung cancer, or prostate cancer in Spain

Metastatic bone disease (MBD) is the most common cause of cancer pain and of serious skeletal-related events (SREs) reducing quality of life. Management of MBD involves a multimodal approach aimed at delaying the first SRE and reducing subsequent SREs. The objective of the study was to characterise the hospital burden of disease associated with MBD and SREs following breast, lung and prostate cancer in Spain. Patients admitted into a participating hospital, between 1 January 2003 and 31 December 2003, with one of the required cancers were identified and selected for inclusion into the study. The index admission to hospital, incidence of patients admitted and hospital length of stay were analysed. There were 28 162 patients identified with breast, lung and prostate cancer. The 3 year incidence rates of hospital admission due to MBD were 95 per 1000 for breast cancer, 156 per 1000 for lung cancer and 163 per 1000 for prostate cancer. For patients admitted following an SRE, the incidence rates were 211 per 1000 for breast cancer, 260 per 1000 for lung cancer and 150 per 1000 for prostate cancer. This study has shown that cancer patients consume progressively more hospital resources as MBD and subsequent SREs develop.

The promise of bone cancer proteomics

Mass spectrometric analysis of the low-molecular-weight (LMW) range of the serum/plasma proteome is revealing the existence of large numbers of previously unknown peptides and protein fragments, predicted to be derived from circulating low-abundance proteins. While genomics and proteomics are the primary discovery research tool, recent innovations in high-throughput proteomics are now standard practice for biomarker and target discovery. Surface-enhanced laser desorption/ionization time-of-flight (SELDI-TOF) mass spectrometry (MS) is the current mainstay for serum or plasma analysis, although other methods are emerging as alternative high-throughput approaches. From a proteomics perspective, the bone cancers, such as myeloma, breast and prostate cancer bony metastases, and osteosarcoma, are likely among the least studied. As recent advances in proteomic technology have thrust the bone cancer field into the era of proteomics, a review of the current status of the proteome as it relates to the skeletal consequences of malignancy seems reasonable.

Emerging therapeutic targets in breast cancer bone metastasis

In the past decade, our understanding of the molecular mechanisms that underlie breast cancer pathology and progression has dramatically improved. Using this knowledge, we have identified additional targets and developed novel therapeutic interventions in breast cancer. Together, these translational research efforts are helping to usher us into an age of personalized cancer therapy. Metastasis to bone is a common and devastating consequence of breast cancer. Bisphosphonates, which represent the current gold standard in bone metastasis therapies, are being improved with newer and more efficacious generations of these compounds being developed. Breast cancer growth in the bone requires activation of various signaling pathways in both cancer cells and stromal cells, including those that are stimulated by TGF-β and RANKL, and mediated through the Src tyrosine kinase. Bone cells and cancer cells alike express promising targets for therapeutic intervention, including Cathepsin K, CXCR4 and GPNMB. In this article we discuss the molecular mechanisms behind these pro-metastatic molecules and review the most recent findings in the clinical development of their associated targeted therapies.

Treatment Options for Breast Cancer and Bone Metastases

The most common destination for breast cancer metastases is bone. If bone metastases are detected, treatment algorithms should include the continuation of cytoreductive therapy with the addition of treatment to counter skeletal-related events, including bone pain. The range of current treatment options includes bisphosphonates, surgical intervention to improve structural integrity and palliative focal radiotherapy. This article focuses on the role of bisphosphonate therapy in metastatic breast cancer. Bisphosphonate therapy significantly reduces the impact of skeletal-related events, reduces bone pain and increases patient quality of life. Our current understanding is that bisphosphonates may also disrupt the metastatic process and reduce the development of bone lesions. Ultimately, this may lead to further expansion of bisphosphonate-based therapy in the future.

Effect of bisphosphonates on pain and quality of life in patients with bone metastases

Bone is the most common organ for tumor metastasis, especially in patients with cancers of the breast or prostate. Bone metastases disrupt skeletal metabolism and result in considerable skeletal morbidity, including intractable, chronic bone pain, hypercalcemia of malignancy, pathologic fracture and spinal-cord compression. In addition to the chronic pain caused by bone metastases, skeletal-related events (SREs) such as pathologic fractures and spinal-cord compression can result in acute increases in pain. These effects can severely impair mobility and contribute to a general decrease in quality of life. Palliative options to treat bone metastases include radiotherapy, analgesics, surgery and bisphosphonates. These drugs bind to the surface of the bone and impair osteoclast-mediated bone resorption, and reduce the tumor-associated osteolysis that is initiated by the development of skeletal metastases. In addition to preventing SREs, bisphosphonates can palliate bone pain caused by a variety of solid tumors. This Review summarizes the clinical trial data of bisphosphonates for the prevention of SREs and the palliation of bone pain. Among these agents, nitrogen-containing bisphosphonates are recognized as the most effective, and zoledronic acid has demonstrated the broadest clinical utility.

Impact of skeletal complications on patients' quality of life, mobility, and functional independence

INTRODUCTION

Skeletal-related events (SREs) from malignant bone disease cause considerable morbidity and can dramatically reduce patients' quality of life.

DISCUSSION

Pathologic fractures often require surgical intervention and palliative radiotherapy. Thus, patients suffer impaired mobility, loss of functional independence, and diminished health-related quality of life (HRQOL). Bisphosphonates can delay the onset and reduce the incidence of SREs and have become the standard of care for the treatment of malignant bone disease; however, minimal information on the effects of bisphosphonate treatment on HRQOL is available. Targeted HRQOL assessments for patients with malignant bone disease are currently under development and are discussed herein.

Magnetic resonance guided focused ultrasound surgery. Ablation of soft tissue at bone-muscle interface in a porcine model

BACKGROUND

Pain management treatments of patients with bone metastases have either efficacy problems or significant side effects. Percutaneous radiofrequency ablation has recently proved to be of palliative value. Magnetic resonance guided focused ultrasound surgery (MRgFUS) uses focused ultrasonic energy to non-invasively create a heat-coagulated lesion deep within the body in a controlled, accurate manner. The surgeon can monitor and control energy deposition in real time. This technology represents a potential treatment modality in oncological surgery. We investigated the ability of two MRgFUS methods to accurately and safely target and ablate soft tissue at its interface with bone.

MATERIALS AND METHODS

Heat-ablated lesions were created by MRgFUS at the bone-muscle interface of 15 pigs. Two different methods of energy delivery were used. Temperature rise at the target adjacent to bone was monitored by real time MR thermal images. Results were evaluated by MRI (magnetic resonance imaging), nuclear scanning and by histopathological evaluation.

RESULTS

Soft tissue lesion sizes by both methods were in the range of 1-2 cm in diameter. Targeting the focus 'behind' the bone, achieved the same result with a single sonication only. Follow up MRI and histopathological examination of all lesions showed focal damage at its interface with bone and localized damage to the outer cortex on the side closer to the targeted tissue. There was no damage to non-targeted tissue.

CONCLUSION

MRgFUS by both energy deposition methods can be used to produce controlled well-localized damage to soft tissue in close proximity to bone, with minimal collateral damage.

Biology of bone metastases: causes and consequences

Breast cancer is a highly osteotropic neoplasm, and as many as 75% of patients with metastatic disease will have involvement of the bony skeleton. On radiologic examination, these metastases are predominantly osteolytic but can be osteoblastic or mixed. The mechanisms by which metastases are formed are complex, involving many steps that include angiogenesis, invasion, and proliferation in the bone microenvironment. Tumor cells in the bone microenvironment produce a large number of cytokines that stimulate osteoclastic activity. Increased osteoclastic activity, in turn, leads to production of a variety of lymphokines and growth factors that can increase tumor cell proliferation. Thus, a cytokine network is established, which results in an imbalance of the processes of bone formation and bone resorption. As tumor burden in bone increases, osteoclast-mediated bone resorption is accelerated, resulting in loss of bone strength, fractures, pain, and other morbidities. Tumor cells metastatic to bone can also secrete growth factors, leading to increased osteoblastic activity. Osteoblasts lay down an excess of new bone that is structurally weak. There is considerable crosstalk between osteoclasts, osteoblasts, macrophages, and other cellular elements within the bone environment. The increasing understanding of the biology of bone metastases has opened the door to improved management of this important clinical problem. Current treatment strategies include approaches to reduce tumor burden and developing treatments that directly inhibit osteoclast function. The bisphosphonates are a class of drugs that inhibit osteoclast recruitment and function. Several highly potent bisphosphonates are now available for clinical use and represent an important adjunct in the management of bone metastases from breast cancer, multiple myeloma, and several other types of malignancies. Some newer therapeutic approaches include agents designed to inhibit the osteoclast-osteoblast signaling interactions or alter processes of adhesion and invasion.

Proteomic analysis of bone cancer: a review of current and future developments

The ability of sophisticated proteomic approaches to scrutinize the dynamic nature of protein expression, cellular and subcellular protein distribution, post-translational modifications, and protein-protein interactions has culminated in the identification of many potential new therapeutic targets and an abundance of cancer-related biomarkers. From a proteomics perspective, amongst the most under-studied diseases are bone cancers, such as myeloma, osteosarcoma and breast and prostate cancer bony metastases. This review focuses on the recent advances in proteomic technology that have thrust the skeletal cancer field into this exciting age of proteomics, and highlights the future work that is required to adapt this technology to specifically interrogate the skeletal consequences of malignancy.

In vitro synergistic cytoreductive effects of zoledronic acid and radiation on breast cancer cells

Introduction

Bisphosphonates are mostly used in the treatment of bone metastases. They have been shown to act synergistically with other chemotherapeutic agents. It is not known, however, whether similar synergistic effects exist with radiation on breast cancer cells.

Methods

Human MCF-7 breast cancer cells were treated with up to 100 μM zoledronic acid, were irradiated with up to 800 cGy or were exposed to combinations of both treatments to determine the antiproliferative effects of zoledronic acid and radiation.

Results

Zoledronic acid and radiation caused a dose-dependent and time-dependent decrease in cell viability (approximate 50% growth inhibition values were 48 μM and 20 μM for 24 hours and 72 hours, respectively, for zoledronic acid and 500 cGy for radiation). A synergistic cytotoxic effect of the combination of zoledronic acid and radiation was confirmed by isobologram analysis.

Conclusion

These data constitute the first in vitro evidence for synergistic effects between zoledronic acid and radiation. This combination therapy might thus be expected to be more effective than either treatment alone in patients with metastatic breast carcinoma.

The circadian rhythm of biochemical markers of bone resorption is normally synchronized in breast cancer patients with bone lytic metastases independently of tumor load

BACKGROUND

Bone metastases are devastating events resulting in disruption of local bone remodeling processes. Physiological bone turnover has a circadian rhythm. No data are available on the circadian pattern of bone turnover markers in patients with bone metastases.

METHODS

Twenty post-menopausal women with breast cancer (BC) at first disease relapse and at least one bone metastasis were consecutively recruited. Twenty healthy women served as controls. Patients were free from concomitant chemotherapy/endocrine therapy. Throughout a 24-h period, urine samples were collected at 4-h intervals, and blood samples were collected at 4-h intervals between 08:00 and 24:00, and at 2-h intervals between 24:00 and 08:00. Serum osteocalcin (OC), total and bone-alkaline phosphatase (tALP and bALP, respectively) and C-terminal telopeptide of type I collagen (CTX), and urinary NTX and free deoxypyridinoline (fDPD) were measured together with serum parathyroid hormone (PTH) and serum and urinary calcium and phosphorus. Temporal variations of measured analytes were assessed by ANOVA and the COSINOR model.

RESULTS

At 08:00, patients had higher levels of bone resorption indices (NTX, CTX and fDPD) than controls (p<0.0001). tALP and bALP, but not OC, were higher in patients than controls (p<0.001). PTH, serum and urinary calcium and urinary phosphorus did not differ between groups; serum phosphorus was higher in controls (p<0.0001). A circadian rhythm was evident for CTX and fDPD values in both patients and controls. A circadian rhythm in NTX, OC, phosphorus and PTH was apparent in controls only. However, it was detected also in patients when percent changes from MESOR were considered. Serum phosphorus showed a circadian rhythm, while no rhythm was detected for tALP, bALP, serum and urinary calcium. The rhythmicities in cancer patients were normally synchronized, and rhythmic parameters were independent of tumor load in the skeleton, age and menopausal status.

CONCLUSIONS

This is the first study to yield information on the maintenance of the temporal program of bone turnover in bone metastatic cancer patients. Whether administration of bisphosphonates in the nighttime leads to a different outcome with respect to the current administration in the morning is a matter of future research.

MR-guided focused ultrasound surgery (MRgFUS) for the palliation of pain in patients with bone metastases--preliminary clinical experience

BACKGROUND

Magnetic resonance-guided focused ultrasound surgery (MRgFUS) is a noninvasive thermal ablation technique, shown to be clinically effective in the treatment of uterine fibroids and is being evaluated as a method of thermal ablation of benign and malignant breast tumors. To evaluate the safety and initial efficacy of MRgFUS for the palliation of pain caused by bone metastases, in patients for whom other treatments are either not effective or not feasible.

MATERIALS AND METHODS

Thirteen patients suffering from symptomatic bone metastases underwent MRgFUS procedure. Treatment safety was evaluated by assessing the incidence and severity of device-related complications up to 6 months after treatment. Effectiveness of pain palliation was evaluated by visual analog scale, pain questionnaires and changes in the patients' medication.

RESULTS

Fifteen procedures were carried out. Mean follow-up was 59 days. Twelve patients received adequate treatment and were available for follow-up. Two patients died due to disease progression during the first month after treatment. No severe adverse events were recorded. The remaining 10 patients reported prolonged improvement in pain score and/or reduced analgesic dosage.

CONCLUSION

MRgFUS may provide a safe and effective noninvasive alternative for the palliation of pain, caused by bone metastases.

Bone integrity and bone metastases in breast cancer

Individuals with a history of early-stage breast cancer may be at increased risk of osteoporosis related to adjuvant therapy, and those with metastatic breast cancer may experience skeletal-related complications from the cancer affecting the bone. Maintaining bone strength is critical in the care of both early- and late-stage breast cancer patients because fractures are associated with morbidity and mortality. This article reviews the maintenance of bone integrity in women with breast cancer.

Bosentan® inhibits tumor vascularization and bone metastasis in an immunocompetent skin-fold chamber model of breast carcinoma cell metastasis

Angiogenic factors including endothelin-1 (ET-1) play a key role in the progression of breast metastases to bone. We investigated the impact of ET-1 on the development of bone metastases in an immunocompetent murine skin-fold chamber model. Murine mammary carcinoma 4T1 was injected in a skin-fold chamber implanted on CB6 mice along with bone explants. Furthermore, mice were treated with or without a dual selective antagonist of both ET-1 receptors. The progression of the vascularization within the chamber was monitored over time by intravital microscopy (IVM). The tumor growth and the development of bone metastases were assessed by cytokeratin-19 gene expression and histological studies. Results indicate that this new model associated with IVM allows for the continuous monitoring of the change in vascularization associated with the development of bone metastases. Additionally, treatment with an antagonist of both ET-1 receptors was associated with the presence of significantly less vessels near the tumor mass compared to control mice. These changes were correlated with smaller tumor masses and reduced bone invasion (P < 0.05). Thus, in an immunocompetent murine model of breast carcinoma metastases to bone, our data support the hypothesis that vascularization plays a role in tumor development and progression and that ET-1 specifically modulates the angiogenesis associated with breast metastases to the bone.

Genes Associated With Breast Cancer Metastatic to Bone

Purpose

The biology of tumors relapsing to bone is poorly understood. In this study, we initiated a search for genes that are implicated in tumors relapsing to bone in breast cancer.

Patients and Methods

We analyzed 107 primary breast tumors in patients who were all lymph node negative at the time of diagnosis and all had experienced relapse. Total RNA isolated from frozen tumor samples was used to gather gene expression data using oligo microarrays.

Results

A panel of 69 genes was found significantly differentially expressed between patients who experienced relapse to bone versus those who experienced relapse elsewhere in the body. The most differentially expressed gene, TFF1, was confirmed by quantitative reverse transcriptase polymerase chain reaction in an independent cohort (n = 122; P = .0015). Our differentially expressed genes, combined with a recently reported gene set relevant to tumors relapsing to bone in an animal model system, pointed to the involvement of the fibroblast growth factor receptor signaling pathway in preference of tumor cells that relapse to bone. Given that patients who experience relapse to bone may benefit from bisphosphonate therapy, we developed a classifier of 31 genes, which in an independent validation set correctly predicts all tumors relapsing to bone with a specificity of 50%.

Conclusion

Our study identifies a panel of genes relevant to bone metastasis in breast cancer. The subsequently developed classifier of tumors relapsing to bone could, after thorough confirmation on an extended number of independent samples, and in combination with our previously developed high-risk profile, provide a diagnostic tool for the recommendation of adjuvant bisphosphonate therapy in addition to endocrine therapy or chemotherapy.

Kinetics of metastatic breast cancer cell trafficking in bone

PURPOSE

In vivo studies have focused on the latter stages of the bone metastatic process (osteolysis), whereas little is known about earlier events, e.g., arrival, localization, and initial colonization. Defining these initial steps may potentially identify the critical points susceptible to therapeutic intervention.

EXPERIMENTAL DESIGN

MDA-MB-435 human breast cancer cells engineered with green fluorescent protein were injected into the cardiac left ventricle of athymic mice. Femurs were analyzed by fluorescence microscopy, immunohistochemistry, real-time PCR, flow cytometry, and histomorphometry at times ranging from 1 hour to 6 weeks.

RESULTS

Single cells were found in distal metaphyses at 1 hour postinjection and remained as single cells up to 72 hours. Diaphyseal arrest occurred rarely and few cells remained there after 24 hours. At 1 week, numerous foci (2-10 cells) were observed, mostly adjacent to osteoblast-like cells. By 2 weeks, fewer but larger foci (> or =50 cells) were seen. Most bones had a single large mass at 4 weeks (originating from a colony or coalescing foci) which extended into the diaphysis by 4 to 6 weeks. Little change (<20%) in osteoblast or osteoclast numbers was observed at 2 weeks, but at 4 to 6 weeks, osteoblasts were dramatically reduced (8% of control), whereas osteoclasts were reduced modestly (to approximately 60% of control).

CONCLUSIONS

Early arrest in metaphysis and minimal retention in diaphysis highlight the importance of the local milieu in determining metastatic potential. These results extend the Seed and Soil hypothesis by demonstrating both intertissue and intratissue differences governing metastatic location. Ours is the first in vivo evidence that tumor cells influence not only osteoclasts, as widely believed, but also eliminate functional osteoblasts, thereby restructuring the bone microenvironment to favor osteolysis. The data may also explain why patients receiving bisphosphonates fail to heal bone despite inhibiting resorption, implying that concurrent strategies that restore osteoblast function are needed to effectively treat osteolytic bone metastases.