The skeletal metastatic complications of renal cell carcinoma

Differences at diagnosis between long-term survivors and not long-term survivors in metastatic renal cell carcinoma initially treated with TKI

INTRODUCTION

In recent years, significant advancements in the treatment of metastatic renal cell carcinoma (mRCC) have notably extended overall survival (OS) times, particularly with the introduction of tyrosine kinase inhibitors (TKIs) and combination immunotherapy. However, survival outcomes in mRCC remain highly variable.

MATERIALS AND METHODS

This study retrospectively analyzed clinical and demographic factors at diagnosis in patients treated for mRCC to identify predictors of long-term survival (defined as OS ≥ 48 months). Patients were categorized into long-term survivors (LTS) and non-long-term survivors (nLTS).

RESULTS

The analysis revealed that factors such as better Karnofsky Performance Status (KPS), normal baseline laboratory values (e.g., hemoglobin, calcium), and the presence of lung-only metastases were significantly associated with longer survival. Conversely, comorbid conditions like hypertension and dyslipidemia, poorer KPS, and certain adverse laboratory findings were more common in the nLTS group.

CONCLUSION

These findings underscore the importance of baseline prognostic factors in predicting survival outcomes and emphasize the need for personalized treatment strategies in mRCC.

Metastatic sites and clinical outcomes in renal cell carcinoma patients receiving immune-based combinations: the MOUSEION-08 study

Immune-based combinations have significantly improved the treatment of metastatic renal cell carcinoma (mRCC); however, immunotherapy has reported varying degrees of efficacy across different metastatic sites, with liver and bone metastases traditionally considered more challenging to treat. In MOUSEION-08 study, we aimed to investigate the association between lung, liver, and bone metastases and clinical outcomes such as Overall Survival (OS) and Progression- Free Survival (PFS) in mRCC patients receiving immune-based combinations. The present systematic review and study-level meta-analysis was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA). PFS and OS were measured as Hazard Ratios (HRs) and 95% confidence intervals (CIs). The protocol was registered with PROSPERO, Registration number: CRD42024581488. Our search resulted in the identification of 2364 potentially relevant reports, which were subsequently restricted to three. The pooled HRs for OS and PFS in patients with lung metastases receiving immune-based combinations versus sunitinib were 0.61 (95% CI, 0.51-0.72) and 0.47 (95% CI, 0.38-0.59), respectively. In patients with liver metastases, the pooled HRs for OS and PFS were 0.56 (95% CI, 0.42-0.75) and 0.48 (95% CI, 0.34-0.67), while the pooled HRs for OS and PFS in patients with bone metastases were 0.64 (95% CI, 0.49-0.84) and 0.36 (95% CI, 0.27-0.49), respectively. According to our findings, the analyses reported similar HRs for OS and PFS, something that further underlines the role of immune-based combinations in this setting, regardless of metastatic sites, such as lung, liver, and bone metastases. Ongoing research and clinical trials are destined to refine and improve immunotherapeutic strategies for mRCC, aiming to enhance efficacy across all metastatic sites and to define predictive biomarkers.

Brown Tumor From Secondary Hyperparathyroidism Mimicking Metastatic Renal Cell Carcinoma in a Patient With End-Stage Renal Disease

Brown tumors (also known as osteitis fibrosa cystica) are rare complications of end-stage renal disease (ESRD) and secondary hyperparathyroidism (HPT), characterized by focal bone lesions that resemble neoplasms. They are often misdiagnosed as metastatic bone disease, especially in patients with a history of malignancy. We present a case of a 60-year-old man with a history of renal cell carcinoma (RCC), and ESRD on hemodialysis (HD), who developed diffuse bone lesions on imaging with osteolytic/osteoblastic appearance concerning metastases, but on further workup was found to have brown tumors. We discuss the treatment and outcome and briefly review the relevant medical literature.

Extracellular vesicles secreted from bone metastatic renal cell carcinoma promote angiogenesis and endothelial gap formation in bone marrow in a time-dependent manner in a preclinical mouse model

Introduction

Bone is a major metastatic site of renal cell carcinoma (RCC). Recently, it is well recognized that bone metastatic tumor cells remodel bone marrow vasculature. However, the precise mechanism underlying cell-cell communication between bone metastatic RCC and the cells in bone marrow remains unknown. Extracellular vesicles (EVs) reportedly play crucial roles in intercellular communication between metastatic tumor cells and bone marrow. Therefore, we conducted the current study to clarify the histological alteration in vascular endothelium in bone marrow induced by EVs secreted from bone metastatic RCC cells as well as association between angiogenesis in bone marrow and bone metastasis formation.

Materials and methods

We established a bone metastatic RCC cell line (786-O BM) by in vivo selection and observed phenotypic changes in tissues when EVs were intravenously injected into immunodeficient mice. Proteomic analysis was performed to identify the protein cargo of EVs that could contribute to histological changes in bone. Tissue exudative EVs (Te-EVs) from cancer tissues of patients with bone metastatic RCC (BM-EV) and those with locally advanced disease (LA-EV) were compared for in vitro function and protein cargo.

Results

Treatment of mice with EVs from 786-O BM promoted angiogenesis in the bone marrow in a time-dependent manner and increased the gaps of capillary endothelium. 786-O BM EVs also promoted tube formation in vitro. Proteomic analysis of EVs identified aminopeptidase N (APN) as a candidate protein that enhances angiogenesis. APN knockdown in 786-O BM resulted in reduced angiogenesis in vitro and in vivo. When parental 786-O cells were intracardially injected 12 weeks after treatment with786-O BM EVs, more bone metastasis developed compared to those treated with EVs from parental 786-O cells. In patient samples, BM-EVs contained higher APN compared to LA-EV. In addition, BM-EVs promoted tube formation in vitro compared to LA-EVs.

Conclusion

EVs from bone metastatic RCC promote angiogenesis and gap formation in capillary endothelium in bone marrow in a time-dependent manner.

Bone metastasis risk and prognosis assessment models for kidney cancer based on machine learning

Background

Bone metastasis is a common adverse event in kidney cancer, often resulting in poor survival. However, tools for predicting KCBM and assessing survival after KCBM have not performed well.

Methods

The study uses machine learning to build models for assessing kidney cancer bone metastasis risk, prognosis, and performance evaluation. We selected 71,414 kidney cancer patients from SEER database between 2010 and 2016. Additionally, 963 patients with kidney cancer from an independent medical center were chosen to validate the performance. In the next step, eight different machine learning methods were applied to develop KCBM diagnosis and prognosis models while the risk factors were identified from univariate and multivariate logistic regression and the prognosis factors were analyzed through Kaplan-Meier survival curve and Cox proportional hazards regression. The performance of the models was compared with current models, including the logistic regression model and the AJCC TNM staging model, applying receiver operating characteristics, decision curve analysis, and the calculation of accuracy and sensitivity in both internal and independent external cohorts.

Results

Our prognosis model achieved an AUC of 0.8269 (95%CI: 0.8083-0.8425) in the internal validation cohort and 0.9123 (95%CI: 0.8979-0.9261) in the external validation cohort. In addition, we tested the performance of the extreme gradient boosting model through decision curve analysis curve, Precision-Recall curve, and Brier score and two models exhibited excellent performance.

Conclusion

Our developed models can accurately predict the risk and prognosis of KCBM and contribute to helping improve decision-making.

Bone metastases from renal cell carcinoma: 4 years after aggressive surgeries and anti-angiogenic therapy

Management of bone metastases from renal cell carcinoma (RCC) has significantly changed after the era of targeted therapy that improved the overall survival (OS). Surgical decision-making remains a subject of controversy. We report a case of pelvic bone metastasis from RCC, 2 months after nephrectomy and surgery of a revealing clavicular metastasis.

Impact of Bone Metastases on Patients with Renal Cell Carcinoma or Melanoma Treated with Combotherapy Ipilimumab Plus Nivolumab

(1) Background: Ipilimumab plus nivolumab (combo-ICI) improves overall survival (OS) in patients with advanced renal cell carcinoma (RCC) or melanoma. The impact of bone metastases (BM) on survival outcomes of combo-ICI-treated patients is unknown. (2) Methods: This single-center retrospective observational study involved 36 combo-ICI-treated patients with advanced RCC and 35 with melanoma. Clinical and laboratory data preceding the initiation of combo-ICI were collected. Univariate and multivariate Cox proportional hazard models were used to assess the effect of BM on overall survival (OS) and progression-free survival (PFS). (3) Results: zNine RCC and 11 melanoma patients had baseline BM. In unadjusted analysis, baseline BM was associated with a poorer OS in the RCC cohort. Baseline BM did not have any impact on survival outcomes in melanoma patients. After adjustment on baseline performance status and on neutrophil-to-lymphocyte ratio (NLR), the impact of BM was no longer significant, but a NLR ≥ 3 was significantly associated with a poorer OS in the RCC cohort. (4) Conclusions: The presence of baseline BM seems to be associated with worse outcomes in RCC combo-ICI-treated patients, while its effect might not be independent from the inflammatory state (approximated by the NLR). BM seems to have no impact on the outcomes of melanoma combo-ICI-treated patients.

Establishment and Validation of a Machine Learning Prediction Model Based on Big Data for Predicting the Risk of Bone Metastasis in Renal Cell Carcinoma Patients

PURPOSE

Since the prognosis of renal cell carcinoma (RCC) patients with bone metastasis (BM) is poor, this study is aimed at using big data to build a machine learning (ML) model to predict the risk of BM in RCC patients.

METHODS

A retrospective study was conducted on 40,355 RCC patients in the SEER database from 2010 to 2017. LASSO regression and multivariate logistic regression analysis was performed to determine independent risk factors of RCC-BM. Six ML algorithm models, including LR, GBM, XGB, RF, DT, and NBC, were used to establish risk models for predicting RCC-BM. The prediction performance of ML models was weighed by 10-fold cross-validation.

RESULTS

The study investigated 40,355 patients diagnosed with RCC in the SEER database, where 1,811 (4.5%) were BM patients. Independent risk factors for BM were tumor grade, T stage, N stage, liver metastasis, lung metastasis, and brain metastasis. Among the RCC-BM risk prediction models established by six ML algorithms, the XGB model showed the best prediction performance (AUC = 0.891). Therefore, a network calculator based on the XGB model was established to individually assess the risk of BM in patients with RCC.

CONCLUSION

The XGB risk prediction model based on the ML algorithm performed a good prediction effect on BM in RCC patients.

All bone metastases are not created equal: Revisiting treatment resistance in renal cell carcinoma

Renal cell carcinoma (RCC) is the most common malignancy of the kidney, representing 80-90% of renal neoplasms, and is associated with a five-year overall survival rate of approximately 74%. The second most common site of metastasis is bone. As patients are living longer due to new RCC targeting agents and immunotherapy, RCC bone metastases (RCCBM) treatment failure is more prevalent. Bone metastasis formation in RCC is indicative of a more aggressive disease and worse prognosis. Osteolysis is a prominent feature and causes SRE, including pathologic fractures. Bone metastasis from other tumors such as lung, breast, and prostate cancer, are more effectively treated with bisphosphonates and denosumab, thereby decreasing the need for palliative surgical intervention. Resistance to these antiresportives in RCCBM reflects unique cellular and molecular mechanisms in the bone microenvironment that promote progression via inhibition of the anabolic reparative response. Identification of critical mechanisms underlying RCCBM induced anabolic impairment could provide needed insight into how to improve treatment outcomes for patients with RCCBM, with the goals of minimizing progression that necessitates palliative surgery and improving survival.

A Multi-institutional, Retrospective Analysis of Patients with Metastatic Renal Cell Carcinoma to Bone Treated with Combination Ipilimumab and Nivolumab

BACKGROUND

Bone metastases (BM) in renal cell carcinoma (RCC) patients are associated with poor outcomes. There are limited published data on outcomes in these patients with immunotherapy agents. We present a multi-institutional, retrospective analysis of metastatic RCC patients with BM treated with ipilimumab and nivolumab (I + N).

OBJECTIVE

Patient, tumor, and treatment-related variables were retrospectively collected from electronic medical records of patients with a histologically confirmed diagnosis of RCC and at least one radiographically confirmed BM prior to initiation of I + N. Best objective response was assessed by clinical chart review, imaging reports, and treating physician evaluation; progression-free survival (PFS) and overall survival (OS) were recorded as of 31 December 2020. Descriptive statistics were used to summarize patient characteristics and BM-related variables. Kaplan-Meier method and Mantel-Haenszel log-rank test were used to compare survival among groups. Cox regression univariable and multivariable models were used to correlate patient- and treatment-related variables to outcomes.

RESULTS

Eighty patients with RCC and BM treated with I + N were identified. Patients were predominantly male and Caucasian presenting primarily with IMDC intermediate or poor-risk clear-cell RCC. Best response to I + N was progressive disease (46%), stable disease (28%), partial response (21%), and not evaluable (5%). Median PFS was 6.1 months (95% CI 3.8-8.9 months) with the majority of patients (65%) discontinuing I + N due to disease progression. Median OS was 25.6 months (95% CI 14.9-NA) with median follow-up of 25.2 months. A multivariable regression model for PFS showed several variables to be significantly associated with worse PFS including female gender [p = 0.02; hazard ratio (HR) 2.16; 95% CI 1.14-4.12], metastases to other sites (p = 0.006; HR 2.12; 95% CI 1.24-3.62) and presence of BM to ribs (p = 0.0007; HR 2.61; 95% CI 1.50-4.52). A multivariable Cox model of OS showed no prior radiation therapy to BM (p = 0.02; HR 2.17; 95% CI 1.13-4.17) and presence of liver metastases (p = 0.0006; HR 3.19; 95% CI 1.65-6.19) to be significantly associated with worse OS.

CONCLUSION

RCC patients with ≥ 1 BM who received I + N therapy had a relatively low response rate, PFS, and OS. Strategies to improve outcomes in this subset of patients are needed.

Antiresorptive agent-related osteonecrosis of the jaw (ARONJ) in urological malignancies: a multi-center retrospective study

INTRODUCTION

We evaluated the incidence and risk factors for antiresorptive agent-related osteonecrosis of the jaw (ARONJ) in prostate and kidney cancer patients.

MATERIALS AND METHODS

We retrospectively reviewed the clinical data of 547 patients from 13 hospitals. Prostate and kidney cancer patients with bone metastases who were treated with a bone-modifying agent (BMA) between January 2012 and February 2019 were enrolled. Exclusion criteria were BMA use for hypercalcemia, a lack of clinical data, a follow-up period of less than 28 days and a lack of evaluation by dentists before BMA administration. The diagnosis and staging of ARONJ were done by dentists.

RESULTS

Two-hundred eighteen patients were finally enrolled in the study, including 168 prostate cancer patients and 50 kidney cancer patients. Of them, 49 (29%) prostate cancer patients and 18 (36%) kidney cancer patients needed tooth extraction prior to BMA initiation. The mean follow-up period after BMA initiation was 552.9 ± 424.7 days (mean ± SD). In the cohort, 23% of the patients were diagnosed with ARONJ in the follow-up period. The 1-year cumulative incidences of ARONJ were 9.4% and 15.4% in prostate and kidney cancer patients, respectively. Multivariate analysis indicated that kidney cancer, tooth extraction before BMA and a body mass index (BMI) ≥ 25 kg/m² were significant predictors for ARONJ.

CONCLUSION

ARONJ is not a rare adverse event in urological malignancies. Especially, kidney cancer, high BMI patients and who needed tooth extraction before BMA were high risk for developing ARONJ.

Bone Metastasis in Renal Cell Carcinoma Patients: Risk and Prognostic Factors and Nomograms

Background

Bone metastasis (BM) is one of the common sites of renal cell carcinoma (RCC), and patients with BM have a poorer prognosis. We aimed to develop two nomograms to quantify the risk of BM and predict the prognosis of RCC patients with BM.

Methods

We reviewed patients with diagnosed RCC with BM in the Surveillance, Epidemiology, and End Results (SEER) database from 2010 to 2015. Multivariate logistic regression analysis was used to determine independent factors to predict BM in RCC patients. Univariate and multivariate Cox proportional hazards regression analyses were used to determine independent prognostic factors for BM in RCC patients. Two nomograms were established and evaluated by calibration curve, receiver operating characteristic (ROC) curve, and decision curve analysis (DCA).

Results

The study included 37,554 patients diagnosed with RCC in the SEER database, 537 of whom were BM patients. BM's risk factors included sex, tumor size, liver metastasis, lung metastasis, brain metastasis, N stage, T stage, histologic type, and grade in RCC patients. Currently, independent prognostic factors for RCC with BM included grade, histologic type, N stage, surgery, brain metastasis, and lung metastasis. The calibration curve, ROC curve, and DCA showed good performance for diagnostic and prognostic nomograms.

Conclusions

Nomograms were established to predict the risk of BM in RCC and the prognosis of RCC with BM, separately. These nomograms strengthen each patient's prognosis-based decision making, which is critical in improving the prognosis of patients.

Development of a highly pulmonary metastatic orthotopic renal cell carcinoma murine model

The incidence of renal cell carcinoma (RCC) is high, and its outcomes remain poor. Mortality is attributable largely to metastatic disease and a dearth of effective therapeutic interventions. The lungs are the most common metastatic site. To elucidate the biological mechanisms underlying pulmonary metastasis and identify superior therapeutic strategies, we developed a novel and clinically relevant murine RCC model exhibiting enhanced pulmonary metastasis. Mice underwent intrarenal implantation using luciferase-expressing Renca, a murine renal adenocarcinoma cell line. Primary renal tumor progression and development of metastatic lung lesions were monitored in live mice using bioluminescent imaging, followed by post-mortem organ assessment. Cells were isolated from pulmonary metastases for reimplantation, followed by repeat monitoring and assessment. This process was repeated once more for a total of two in vivo passages to select for pulmonary metastatic Renca cell subpopulations. However, a single round of in vivo selection was sufficient to produce a near-maximally metastatic subpopulation. Relative to Renca cell-implanted mice, subpopulation-implanted mice exhibited shorter implantation-metastasis intervals (5 days), shorter implantation-moribundity intervals (sacrificed at 18.6±2.9 versus 22.3±1.1 days), a higher number of metastatic lung lesions at 23 days (183.9±39.0 versus 172.6±38.2) and poorer survival. Implantation of cells derived from the second round of in vivo selection produced no further significant differences in the above metrics. This model consistently and efficiently recapitulates RCC pulmonary metastasis while allowing in vivo monitoring of tumor progression, thereby facilitating elucidation of the molecular mechanisms underlying pulmonary metastasis and evaluation of therapeutic modalities.

Modeling Neoplastic Growth in Renal Cell Carcinoma and Polycystic Kidney Disease

Renal cell carcinoma (RCC) and autosomal dominant polycystic kidney disease (ADPKD) share several characteristics, including neoplastic cell growth, kidney cysts, and limited therapeutics. As well, both exhibit impaired vasculature and compensatory VEGF activation of angiogenesis. The PI3K/AKT/mTOR and Ras/Raf/ERK pathways play important roles in regulating cystic and tumor cell proliferation and growth. Both RCC and ADPKD result in hypoxia, where HIF-α signaling is activated in response to oxygen deprivation. Primary cilia and altered cell metabolism may play a role in disease progression. Non-coding RNAs may regulate RCC carcinogenesis and ADPKD through their varied effects. Drosophila exhibits remarkable conservation of the pathways involved in RCC and ADPKD. Here, we review the progress towards understanding disease mechanisms, partially overlapping cellular and molecular dysfunctions in RCC and ADPKD and reflect on the potential for the agile Drosophila genetic model to accelerate discovery science, address unresolved mechanistic aspects of these diseases, and perform rapid pharmacological screens.

c-Met expression in renal cell carcinoma with bone metastases

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Bone is a common metastatic site in renal cell carcinoma (RCC).

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HGF/c-Met pathway is particularly relevant in tumors with bone metastases.

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c-Met/HGF pathway is involved in RCC progression, conferring poor prognosis.

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Several c-Met targeting therapies are currently in clinical development.

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c-Met expression is an important therapeutic target in RCC with bone metastases.

Hepatocyte growth factor (HGF)/c-Met pathway is implicated in embryogenesis and organ development and differentiation. Germline or somatic mutations, chromosomal rearrangements, gene amplification, and transcriptional upregulation in MET or alterations in autocrine or paracrine c-Met signalling have been associated with cancer cell proliferation and survival, including in renal cell carcinoma (RCC), and associated with disease progression. HGF/c-Met pathway has been shown to be particularly relevant in tumors with bone metastases (BMs). However, the efficacy of targeting c-Met in bone metastatic disease, including in RCC, has not been proven. Therefore, further investigation is required focusing the particular role of HGF/c-Met pathway in bone microenvironment (BME) and how to effectively target this pathway in the context of bone metastatic disease.

Radiographical efficacy of systemic treatment for bone metastasis from renal cell carcinoma

Enlarged bone metastasis from renal cell carcinoma (RCC) can cause skeletal-related events, and thus treatment to inhibit the growth of bone metastases is often required. Although radiotherapy for RCC bone metastases can achieve a certain degree of local control, evidence is lacking regarding the effects of systemic therapy to improve bone metastasis. The present study aimed to assess the treatment efficacy of targeted therapy and immune checkpoint inhibitors, and to determine whether systemic therapy without radiotherapy can shrink bone metastases of RCC. The present study retrospectively reviewed 44 patients with RCC with bone metastases treated via systemic therapy, including targeted therapy or immune checkpoint inhibitors. Patients were divided into two groups: Those who underwent systemic therapy with radiotherapy for bone lesions (n=29); and those who underwent systemic therapy without radiotherapy for bone lesions (n=15). The radiographical efficacy of systemic therapy and the time to progression of bone metastases were compared between groups. The overall response rate of systemic therapy with radiotherapy was 44%, and in total, 13 patients demonstrated a partial response. Only one patient (6%) had a partial response among those who were treated via systemic therapy without radiotherapy. The time to progression of bone metastasis was 9.5 and 2.1 months in patients treated with and without radiotherapy, respectively (P<0.0001). Collectively, the present results suggested that targeted therapy or immune checkpoint inhibitors without radiotherapy had only a slight effect on bone metastasis control.

Molecular mechanisms and clinical management of cancer bone metastasis

As one of the most common metastatic sites of malignancies, bone has a unique microenvironment that allows metastatic tumor cells to grow and flourish. The fenestrated capillaries in the bone, bone matrix, and bone cells, including osteoblasts and osteoclasts, together maintain the homeostasis of the bone microenvironment. In contrast, tumor-derived factors act on bone components, leading to subsequent bone resorption or excessive bone formation. The various pathways involved also provide multiple targets for therapeutic strategies against bone metastases. In this review, we summarize the current understanding of the mechanism of bone metastases. Based on the general process of bone metastases, we specifically highlight the complex crosstalk between tumor cells and the bone microenvironment and the current management of cancer bone metastases.

Personal Medicine and Bone Metastases: Biomarkers, Micro-RNAs and Bone Metastases

Bone metastasis is a major cause of morbidity within solid tumours of the breast, prostate, lung and kidney. Metastasis to the skeleton is associated with a wide range of complications including bone fractures, spinal cord compression, hypercalcaemia and increased bone pain. Improved treatments for bone metastasis, such as the use of anti-bone resorptive bisphosphonate agents, within post-menopausal women have improved disease-free survival; however, these treatments are not without side effects. There is thus a need for biomarkers, which will predict the risk of developing the spread to bone within these cancers. The application of molecular profiling techniques, together with animal model systems and engineered cell-lines has enabled the identification of a series of potential bone-metastasis biomarker molecules predictive of bone metastasis risk. Some of these biomarker candidates have been validated within patient-derived samples providing a step towards clinical utility. Recent developments in multiplex biomarker quantification now enable the simultaneous measurement of up to 96 micro-RNA/protein molecules in a spatially defined manner with single-cell resolution, thus enabling the characterisation of the key molecules active at the sites of pre-metastatic niche formation as well as tumour-stroma signalling. These technologies have considerable potential to inform biomarker discovery. Additionally, a potential future extension of these discoveries could also be the identification of novel drug targets within cancer spread to bone. This chapter summarises recent findings in biomarker discovery within the key bone metastatic cancers (breast, prostate, lung and renal cell carcinoma). Tissue-based and circulating blood-based biomarkers are discussed from the fields of genomics, epigenetic regulation (micro-RNAs) and protein/cell-signalling together with a discussion of the potential future development of these markers towards clinical development.

TGF-β and microRNA Interplay in Genitourinary Cancers

Genitourinary cancers (GCs) include a large group of different types of tumors localizing to the kidney, bladder, prostate, testis, and penis. Despite highly divergent molecular patterns, most GCs share commonly disturbed signaling pathways that involve the activity of TGF-β (transforming growth factor beta). TGF-β is a pleiotropic cytokine that regulates key cancer-related molecular and cellular processes, including proliferation, migration, invasion, apoptosis, and chemoresistance. The understanding of the mechanisms of TGF-β actions in cancer is hindered by the "TGF-β paradox" in which early stages of cancerogenic process are suppressed by TGF-β while advanced stages are stimulated by its activity. A growing body of evidence suggests that these paradoxical TGF-β actions could result from the interplay with microRNAs: Short, non-coding RNAs that regulate gene expression by binding to target transcripts and inducing mRNA degradation or inhibition of translation. Here, we discuss the current knowledge of TGF-β signaling in GCs. Importantly, TGF-β signaling and microRNA-mediated regulation of gene expression often act in complicated feedback circuits that involve other crucial regulators of cancer progression (e.g., androgen receptor). Furthermore, recently published in vitro and in vivo studies clearly indicate that the interplay between microRNAs and the TGF-β signaling pathway offers new potential treatment options for GC patients.

An interdisciplinary consensus on the management of bone metastases from renal cell carcinoma

Bone is a major site of haematogenous tumour cell spread in renal cell carcinoma (RCC), and most patients with RCC will develop painful and functionally disabling bone metastases at advanced disease stages. The prognosis of these patients is generally poor and the treatment is, therefore, aimed at palliation. However, RCC-associated bone metastases can be curable in select patients. Current data support a multimodal management strategy that includes wide resection of lesions, radiotherapy, systemic therapy, and other local treatment options, which can improve quality of life and survival. Nevertheless, the optimal approach for metastatic bone disease in RCC has not yet been defined and practical recommendations are rare. To improve the management and outcomes of patients with RCC and bone metastases, the International Kidney Cancer Coalition and the interdisciplinary working group on renal tumours of the German Cancer Society convened a meeting of experts with a global perspective to perform an unstructured review and elaborate on current treatment strategies on the basis of published data and expertise. The panel formulated recommendations for the diagnosis and treatment of patients with RCC and metastasis to the bone. Furthermore, the experts summarized current challenges and unmet patient needs that should be addressed in the future.

In this Expert Consensus, Grünwald et al. summarize their recommendations for the diagnosis and treatment of patients with renal cell carcinoma and metastasis to the bone. They also outline current challenges and unmet patient needs that should be addressed in the future.

Complete Remission of Bone Metastases in Renal Cell Carcinoma with Nivolumab

A 60-year-old female, who presented with abdominal discomfort, was noted to have an enhancing left renal mass, with central necrosis on a CT scan. She underwent radical nephrectomy and biopsy revealed clear cell renal cell carcinoma, Fuhrman grade 4. After 1.5 years of her surgery, she developed metastatic disease with pulmonary nodules and was started on sunitinib. She had disease progression with development of a new 8.2 x 7.6 cm expansile, lytic bony lesion with a complete destruction of the left scapula and 5th left rib lesion. She was treated with Nivolumab for three years. Scans revealed complete resolution of the left scapular metastasis, left rib lesion and the pulmonary nodules. The patient experienced no skeletal-related event (SRE), and no bisphosphonates or receptor activator of nuclear factor-kappa B ligand (RANKL) inhibitor was used. The patient remains in complete remission, three years out of treatment. This case highlights the importance of exploring this particular class of drugs for renal cell carcinoma (RCC) with bone metastasis.

The Value of 18F-FDG PET in the Diagnosis of Intertrabecular Vertebral Metastasis in a Small Cell Lung Cancer Patient with a High Serum CEA Level

We encountered a small cell lung cancer (SCLC) patient with intertrabecular vertebral metastasis (IVM). A 59-year-old man was admitted to our hospital with weight loss. 18F-fluorodeoxyglucose positron emission tomography (FDG PET)-CT demonstrated the uptake of fluorodeoxyglucose in the hilum of the left lung and whole-body bones. Despite intensive support, the patient died within a month. Subsequent autopsy revealed a small lesion consisting of small round cells in the left lung. The cancer cells were found to have spread through the replacement of the bone marrow cells while sparing the trabecular bone. This case demonstrated the potential of 18F-FDG PET for detecting IVM in SCLC patients.

Solitary Metastatic Lesion of the Tibia from Clear Cell Renal Carcinoma: A Case Report of Segmental Skeletal Resection, Intercalary Allograft Over Reamed Nailing and Soleus Flap Interposition

BACKGROUND Renal cell carcinoma (RCC) is the most common malignancy of the kidney, with clear cell (ccRCC) subtype identified in 85% of the cases; one-third of these patients experience synchronous metastatic disease, while 20-30% of the remaining patients develop metachronous metastatic RCC. The axial skeleton (pelvis and sacrum) is the second most common location (following the lungs), with a reported incidence of 35%. Diaphysis of the long bones is rarely involved, with the tibia being an even rarer site of metastasis. CASE REPORT We present a rare case of solitary diaphyseal tibial metachronous metastasis from RCC in a 54-year-old male that appeared 8 years after nephrectomy without any previous evidence of disease. He underwent segmental skeletal resection, intercalary allograft over locked reamed intramedullary nailing, and soleus flap coverage. Thirty months later he presented with hardware failure and nonunion at the distal part of the allograft site. He was successfully treated with exchange nailing, fibular osteotomy, and bone grafting, showing excellent clinical and radiological outcome without any evidence of recurrence 5 years after the index operation. CONCLUSIONS Wide resection and biological reconstruction using intramedullary nailing and incorporated allograft is a good option for metachronous solitary RCC tumors.

Incidence of bone metastasis and factors contributing to its development and prognosis in newly diagnosed renal cell carcinoma: a population-based study

Purpose

The purpose of this study was to assess the incidence of and the risk factors and prognostic factors for bone metastasis (BM) in initial metastatic renal cell carcinoma (RCC) based on a large population analysis.

Patients and methods

Data were obtained for a total of 45,824 RCC patients recorded in the database of the Surveillance, Epidemiology, and End Results program of the National Cancer Institute between 2010 and 2014. Multivariate logistic and Cox regression analyses were used to identify the risk factors and prognostic factors associated with BM in RCC patients. Kaplan-Meier analysis was used to estimate the overall survival of RCC patients, and the difference between the survival curves was tested by log-rank tests.

Results

A total of 1,509 (3.29%) patients were diagnosed with bone metastases at initial diagnosis. Male gender, higher T stage, lymph node involvement, poor tumor grade, presence of lung, liver, and brain metastases, and the collecting duct type of RCC were positively associated with BM occurrence. The median survival time for RCC patients with bone metastases was 12.0 (95% confidence interval [CI]: 10.69-13.31) months, and the survival time for those with collecting duct, clear-cell, papillary, and chromophobe subtypes of RCC were 3 (95% CI: 0.23-5.77), 13 (95% CI: 11.60-14.40), 8 (95% CI: 5.09-10.91), and 11 (95% CI: 5.02-16.98) months; these differences were significantly different (P<0.01). Older age, higher T stage, lymph node involvement, poor tumor grade, the presence of lung, liver, and brain metastases, collecting duct RCC, and the absence of surgical treatments were the factors associated with worse prognoses.

Conclusion

BM was highly prevalent and significantly decreased the survival rate of RCC patients. A number of factors associated with the development and prognosis of BM were identified, and these insights provide preventive guidelines for screening and treatment of BM in RCC patients.

Calcium-sensing receptor (CaSR) promotes development of bone metastasis in renal cell carcinoma

Bone metastasis is an important prognostic factor in renal cell carcinoma (RCC). The calcium-sensing receptor (CaSR) has been associated with bone metastasis in several different malignancies. We analyzed the impact of CaSR in bone metastasis in RCC in vitro and in vivo. The RCC cell line 786-O was stably transfected with the CaSR gene and treated with calcium alone or in combination with the CaSR antagonist NPS2143. Afterwards migration, adhesion, proliferation and prominent signaling molecules were analyzed. Calcium treated CaSR-transfected 768-O cells showed an increased adhesion to endothelial cells and the extracellular matrix components fibronectin and collagen I, but not to collagen IV. The chemotactic cell migration and proliferation was also induced by calcium. The activity of SHC, AKT, ERK, P90RSK and JNK were enhanced after calcium treatment of CaSR-transfected cells. These effects were abolished by NPS2143. Development of bone metastasis was evaluated in vivo in a mouse model. Intracardiac injection of CaSR-transfected 768-O cells showed an increased rate of bone metastasis. The results indicate CaSR as an important component in the mechanism of bone metastasis in RCC. Therefore, targeting CaSR might be beneficial in patients with bone metastatic RCC with a high CaSR expression.

Role of RPLND and Metastasectomy in the Management of Oligometastatic Renal Cell Carcinoma

Although lymphadenectomy is currently accepted as most accurate and reliable staging procedure for lymph node metastases, its therapeutic benefit in renal cell carcinoma (RCC) still remains controversial. Although the new, targeted therapy paradigms have changed the treatment of patients with advanced RCC and offer prolonged survival, cure is extremely uncommon in the absence of surgical resections. In this paper, the current role of metastasectomy is reviewed. Review the available literature concerning the role of retroperitoneal lymph node dissection and metastasectomy in outcome of oligometastatic RCC. A PubMed search was conducted to identify original articles, review articles, and editorials addressing the role of retroperitoneal lymph node dissection and metastasectomy in outcome of oligometastatic RCC. Keywords included renal tumors, renal cell cancer, kidney cancer, lymphadenectomy, metastasectomy, and oligometastases. While there is no randomized study available, recent large observational studies have better defined the prognosis of patients with metastatic RCC with or without metastasectomy and RPLND. To date, the available evidence suggests that RPLND and metastasectomy may be beneficial when technically feasible in patients with locally advanced (unfavorable clinical and pathologic characteristics) and oligometastatic disease. A proportion of patients will achieve long-term survival with aggressive surgical resection.

Skeletal metastasis in renal cell carcinoma: A review

Background

Renal cell carcinoma account for 3% of all cancers, with peak incidence between 60 and 70 years of age predominantly affecting male population. Renal carcinoma is the most common malignancy of kidney constitutes for 80–90% of renal neoplasm with an overall 45% five years survival rate. Majority are diagnosed incidentally during investigation for other disease process of abdomen. Classical triad of gross hematuria, pain and palpable mass in abdomen is rare accounting to only 6–10%. Treatment of early stages of disease i.e. localized disease is partial or radical nephrectomy. Most common metastasis in RCC occurs to lung, followed by bone involvement in 20–35%, lymph nodes, liver, adrenal gland and brain. In metastatic disease median survival rate of patient is about eight months with 50% mortality rate within first year of life, five years survival rate is 10%. Skeletal metastasis are very destructive in patients with renal cell carcinoma compromising bone integrity leading to skeletal related events including pains, impending fractures, nerve compressions, hypercalcemia and even pathological fractures which may require surgical interventions and other therapy. In addition to skeletal complications, presence of bone metastases in RCC has negative impact on progression free survival and overall survival of patients treated with systemic therapies.

Objective

In this review we discuss pathophysiology of tumor metastasis, diagnosis, management and Case examples of metastatic renal cell carcinoma.

Conclusion

Incidence of metastatic renal carcinoma is increasing. Overall prognosis of patient with advanced RCC is poor, emphasizing the importance of early detection and prompt treatment of primary lesion in its early stage. Advancement in targeted therapy in recent decades had made some improvement in treatment of SREs and has helped in improving patent's quality of life but still we are in need of further improvement in treatment modalities to cure disease thereby decreasing morbidity and mortality.

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Renal cell carcinoma account for 3% of all cancers.

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It is a very destructive that may compromise bone integrity.

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Most common metastasis in renal cell carcinoma occurs to lung, followed by bone , lymph nodes, liver, adrenal gland and brain.

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Most common metastasis in renal cell carcinoma occurs to lung, followed by bone involvement in 20–35%, lymph nodes, liver, adrenal gland and brain.

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In metastatic disease median survival rate of patient is about eight months with 50% mortality rate within first year of life, five years survival rate is 10.

Comparative efficacy and safety of bone-modifying agents for the treatment of bone metastases in patients with advanced renal cell carcinoma: a systematic review and meta-analysis

OBJECTIVE

To determine the comparative efficacy and safety of all available bone-modifying agents (BMAs) for the treatment of bone metastases in patients with advanced renal cell carcinoma (RCC).

RESULTS

Three studies (259 patients) were identified for the systematic review. Two studies that compared zoledronic acid with placebo or no zoledronic acid showed that zoledronic acid reduced the risk of skeletal-related events (SREs) by 68% (pooled hazard ratio [HR]: 0.32; 95% confidence interval [CI]: 0.19-0.55). The quality of evidence was moderate. The incidence of serious adverse events (AEs) was identical (80%) for both treatment arms in one study and not reported in the other study. In the third study that compared denosumab and zoledronic acid among patients with solid tumors or myeloma, a post-hoc subgroup analysis with individual patient data (155 patients) showed an HR of 0.71 (95% CI: 0.43-1.17) for SREs and a risk ratio of 0.86 (95% CI: 0.68-1.08) for serious AEs for denosumab compared to zoledronic acid.

MATERIALS AND METHODS

We searched the MEDLINE database, Cochrane Library, WHO International Clinical Trials Registry Platform, and ClinicalTrials.gov database up to January 2017 without language restriction. Only randomized controlled trials were included. When relevant data were missing, we contacted the investigators of the original study. The Grading of Recommendation Assessment, Development, and Evaluation approach was used to assess the evidence certainty.

CONCLUSIONS

Our moderate-quality evidence indicates that zoledronic acid significantly reduces SREs risk among patients with bone metastases of RCC.

Renal Cell Carcinoma with Unusual Skeletal Metastasis to Tibia and Ankle: A Case Report and Review of Literature

Renal Cell Carcinoma (RCC) accounts for 5% of the epithelial malignancies worldwide with clear cell carcinoma accounting for 85% of these malignancies. One third of these patients experience synchronous metastatic disease and 20-30% of the remaining patients experience metachronous metastatic RCC. Bony metastasis accounts for 20% of metastatic RCC. They most commonly affect the axial skeleton and rarely the long bones or the small bones of the hands and feet. Bone metastases from RCC are predominantly osteolytic in nature, leading to significant patient morbidity due to the associated Skeletal Related Events (SRE). SREs may significantly decrease patient quality of life. Bone pain is most common SRE and radiotherapy is most common form of treatment. Only 2% of the patients require surgery. Here we present a case of advanced RCC with tibial and ankle metastasis who presented to us after one year of radical nephrectomy with severe pain and inability to walk and underwent above knee amputation.

Metastatic lesions: A diagnostic dilemma-retrospective study, Srinagar, Jammu and Kashmir, India

BACKGROUND

Renal clear cell carcinoma (RCC) accounts for about 3% of adult malignancies and about 90% of neoplasms of the kidney. It is most common in men aged 50 to 60 years old. RCC has different manifestations, including metastasis in uncommon sites and paraneoplastic syndromes.

AIMS

To evaluate the clinicopathological pattern of RCC.

MATERIALS AND METHODS

This study was conducted in the Department of Pathology, Government Medical College, Srinagar. It was a retrospective study done over a period of 5 years, November 2009 to November 2014.

RESULTS

The study was done to evaluate the clinicopathological pattern of 6 cases of RCC diagnosed at a tertiary care hospital. All patients were males, presenting with submandibular swellings without any other symptom. Radiological and histopathological examination proved the lesion as metastasis of renal cell carcinoma to the mandible.

CONCLUSION

Being a rare presentation in the head and neck region, metastatic renal cell carcinoma needs to be considered in the differential diagnosis of submandibular swellings even in patients younger than 40 years.

Bone Metastasis from Renal Cell Carcinoma

About one-third of patients with advanced renal cell carcinoma (RCC) have bone metastasis that are often osteolytic and cause substantial morbidity, such as pain, pathologic fracture, spinal cord compression and hypercalcemia. The presence of bone metastasis in RCC is also associated with poor prognosis. Bone-targeted treatment using bisphosphonate and denosumab can reduce skeletal complications in RCC, but does not cure the disease or improve survival. Elucidating the molecular mechanisms of tumor-induced changes in the bone microenvironment is needed to develop effective treatment. The “vicious cycle” hypothesis has been used to describe how tumor cells interact with the bone microenvironment to drive bone destruction and tumor growth. Tumor cells secrete factors like parathyroid hormone-related peptide, transforming growth factor-β and vascular endothelial growth factor, which stimulate osteoblasts and increase the production of the receptor activator of nuclear factor κB ligand (RANKL). In turn, the overexpression of RANKL leads to increased osteoclast formation, activation and survival, thereby enhancing bone resorption. This review presents a general survey on bone metastasis in RCC by natural history, interaction among the immune system, bone and tumor, molecular mechanisms, bone turnover markers, therapies and healthcare burden.

Prognostic significance of intensive local therapy to bone lesions in renal cell carcinoma patients with bone metastasis

We evaluated the prognostic roles of local therapy to bone metastasis (BM) in metastatic renal cell carcinoma (mRCC) patients with BM. This retrospective study included 71 mRCC patients with BM. Local therapy to BM included en bloc resection, curettage, and radiotherapy (RT). RT was classified into RT with biological effective dose (BED) ≥85 Gy and <85 Gy by its therapeutic intensity. Local therapy to BM was given for 64 patients (90 %): en bloc resection, curettage, and RT for 16, 10, and 38 patients, respectively. Fifteen patients received RT with BED ≥85 Gy. The median overall survival (OS) was 25 months (median follow-up 16 months). For 46 patients with solitary BM, patients treated with en bloc resection, curettage, and RT with BED ≥85 Gy showed significantly better OS than those treated with RT with BED <85 Gy or no local therapy (P = 0.006). Because OS was comparable among patients treated with en bloc resection, curettage, and RT with BED ≥85 Gy, these three treatment modalities were defined as "intensive local therapy". Intensive local therapy to BM was also associated with favorable OS with marginal significance (P = 0.052) in a cohort of 25 patients with multiple BM. A multivariate analysis in the whole cohort revealed that intensive local therapy to BM was independently associated with favorable OS (hazard ratio 0.23, P < 0.001) along with Memorial-Sloan Kettering Cancer Center risk category (P < 0.001). Thus, intensive local therapy to BM might improve OS in mRCC patients with BM including multiple BM.

Bone metastases affect prognosis but not effectiveness of third-line targeted therapies in patients with metastatic renal cell carcinoma

INTRODUCTION

Treatment of metastatic renal cell carcinoma (mRCC) has improved with the use of targeted therapies, but bone metastases continue to be negative prognostic factor.

METHODS

Patients with mRCC treated with everolimus (EV) or sorafenib (SO) after two previous lines of targeted therapies were included in the analysis. Overall survival (OS) and progression-free survival (PFS) were assessed based on the presence of bone metastases and type of therapy; they were also adjusted based on prognostic criteria.

RESULTS

Of the 233 patients with mRCC, 76 had bone metastases. Of the 233 patients, EV and SO were administered in 143 and 90 patients, respectively. Median OS was 10.4 months in patients with BMs and 17.4 months in patients without bone metastases (p = 0.002). EV decreased the risk of death by 18% compared to SO (adjusted hazard ratio [HR] 0.82, 95% confidence interval [CI] 0.74-0.91; p < 0.001), with comparable effects in patients with or without bone metastases. In the same manner, EV decreased the risk of progression by 12% compared to SO (adjusted HR 0.88, 95% CI 0.82-0.96; p = 0.002), but this difference was not significant in patients without bone metastases. The major limitations of the study are its retrospective nature, the heterogeneity of the methods to detect bone metastases, and the lack of data about patients treated with bisphosphonates.

CONCLUSIONS

The relative benefit of targeted therapies in mRCC is not affected by the presence of bone metastases, but patients without bone metastases have longer response to therapy and overall survival.

Animal Models of Bone Metastasis

Bone is one of the most common sites of cancer metastasis in humans and is a significant source of morbidity and mortality. Bone metastases are considered incurable and result in pain, pathologic fracture, and decreased quality of life. Animal models of skeletal metastases are essential to improve the understanding of the molecular pathways of cancer metastasis and growth in bone and to develop new therapies to inhibit and prevent bone metastases. The ideal animal model should be clinically relevant, reproducible, and representative of human disease. Currently, an ideal model does not exist; however, understanding the strengths and weaknesses of the available models will lead to proper study design and successful cancer research. This review provides an overview of the current in vivo animal models used in the study of skeletal metastases or local tumor invasion into bone and focuses on mammary and prostate cancer, lymphoma, multiple myeloma, head and neck squamous cell carcinoma, and miscellaneous tumors that metastasize to bone.

Case report demonstrating effectiveness of sorafenib in multiple lung and bone metastases of renal cell carcinoma

The current study presents the case of a 59-year-old male with advanced-stage renal cell carcinoma and bone metastases in the proximal femur and ilium (cT3aN3M1; stage IV). Resection of the primary renal cell cancer and palliative surgery with a γ-nail for an impending fracture of the right proximal femur were performed, followed by radiotherapy. Sorafenib, a multi-kinase inhibitor that blocks the raf and tyrosine kinases of the vascular endothelial and platelet-derived growth factor receptors, was administered for 9 months, resulting in a marked improvement in the metastatic ilium and a reduction in the extent of the lung metastases. The patient suffered minor adverse effects, including a skin rash and mild diarrhea, but remained alive at the time of follow-up at 36 months post-surgery. Sorafenib demonstrated efficacy against the bone metastasis of metastatic renal cell carcinoma.

Palliative effects and adverse events of strontium-89 for prostate cancer patients with bone metastasis

The aim of the present study was to evaluate the palliative effects and adverse events of strontium-89 (Sr-89) in patients with bone metastasis from prostate cancer. A total of 18 patients with prostate cancer and painful bone metastases, as diagnosed on bone scintigraphy, who were treated with Sr-89 at the National Kyushu Cancer Center between February, 2008 and April, 2014 were reviewed. Of the 18 subjects, 13 (72.2%) achieved a pain response, whereas 5 were classified as pain non-responders (27.8%). According to a logistic regression analysis, the pre-administration characteristics, including age, prostate-specific antigen (PSA), alkaline phosphatase (ALP), history of bone-modifying agent administration, opioid use or palliative radiation therapy, time after the combined androgen blockade nadir and time since the pain onset, were not found to be significant predictors of the pain response. Similarly, the post-administration characteristics, including pain flares and the PSA and ALP response, were not found to be significant predictors of the pain response. Although no patients exhibited leukocyte toxicities, 2 patients experienced myelosuppression, involving anemia and thrombocytopenia, requiring transfusion of red cell or platelet concentrate following Sr-89 treatment. Of the 18 patients, 5 (27.8%) reported pain flares, all of whom were successfully treated with rescue drugs alone. According to the logistic regression analysis, of the pre-administration characteristics, only ALP was identified as a significant predictor of bone marrow suppression in the univariate and multivariate analyses (P=0.006). Therefore, Sr-89 treatment was found to be effective in ameliorating bone pain associated with metastasis from prostate cancer. Although it is difficult to identify the patients who will receive pain relief prior to Sr-89 administration, this drug should be administered during the early stages due to the potential for bone marrow suppression in patients with high ALP levels.

Bone-targeted therapies for elderly patients with renal cell carcinoma: current and future directions

Bone metastases are very common in advanced renal cell carcinoma (RCC) and can have a huge impact on quality of life by leading to skeletal-related events (SREs), including pain, pathologic fractures and spinal cord compression with need for surgery or radiotherapy. Because of their osteolytic aspect and biologic behaviour, these SREs are more common in patients with bone metastases from RCC than from other malignancies. As overall survival is increased by new anti-angiogenic drugs like tyrosine kinase inhibitors and mammalian target of rapamycin inhibitors, the incidence of SREs is rising, making the clinical management of bone metastases in RCC ever more important, especially in the more vulnerable elderly patient. In this review we discuss the current advances and future directions in bone-targeted therapies in patients with RCC with a special focus on the elderly population. Recently, two bone-targeted agents have been approved in the prevention of SREs in advanced RCC: zoledronic acid and denosumab. To date, there is no specific data on the use of bisphosphonates or denosumab in the elderly and specific studies in this setting are warranted. We compare the available evidence for the use and implications of both agents in the elderly patient and give general information on safety concerns that could be more important in these patients.

High calcium concentration in bones promotes bone metastasis in renal cell carcinomas expressing calcium-sensing receptor

Background

The prognosis for renal cell carcinoma (RCC) is related to a high rate of metastasis, including 30% of bone metastasis. Characteristic for bone tissue is a high concentration of calcium ions. In this study, we show a promoting effect of an enhanced extracellular calcium concentration on mechanisms of bone metastasis via the calcium-sensing receptor (CaSR) and its downstream signaling molecules.

Methods

Our analyses were performed using 33 (11/category) matched specimens of normal and tumor tissue and 9 (3/category) primary cells derived from RCC patients of the 3 categories: non-metastasized, metastasized into the lung and metastasized into bones during a five-year period after nephrectomy. Expression of CaSR was determined by RT-PCR, Western blot analyses and flow cytometry, respectively. Cells were treated by calcium and the CaSR inhibitor NPS 2143. Cell migration was measured in a Boyden chamber with calcium (10 μM) as chemotaxin and proliferation by BrdU incorporation. The activity of intracellular signaling mediators was quantified by a phospho-kinase array and Western blot.

Results

The expression of CaSR was highest in specimens and cells of patients with bone metastases. Calcium treatment induced an increased migration (19-fold) and proliferation (2.3-fold) exclusively in RCC cells from patients with bone metastases. The CaSR inhibitor NPS 2143 elucidated the role of CaSR on the calcium-dependent effects. After treatment with calcium, the activity of AKT, PLCγ-1, p38α and JNK was clearly enhanced and PTEN expression was almost completely abolished in bone metastasizing RCC cells.

Conclusions

Our results indicate a promoting effect of extracellular calcium on cell migration and proliferation of bone metastasizing RCC cells via highly expressed CaSR and its downstream signaling pathways. Consequently, CaSR may be regarded as a new prognostic marker predicting RCC bone metastasis.

Cadherin-11 in renal cell carcinoma bone metastasis

Bone is one of the common sites of metastases from renal cell carcinoma (RCC), however the mechanism by which RCC preferentially metastasize to bone is poorly understood. Homing/retention of RCC cells to bone and subsequent proliferation are necessary steps for RCC cells to colonize bone. To explore possible mechanisms by which these processes occur, we used an in vivo metastasis model in which 786-O RCC cells were injected into SCID mice intracardially, and organotropic cell lines from bone, liver, and lymph node were selected. The expression of molecules affecting cell adhesion, angiogenesis, and osteolysis were then examined in these selected cells. Cadherin-11, a mesenchymal cadherin mainly expressed in osteoblasts, was significantly increased on the cell surface in bone metastasis-derived 786-O cells (Bo-786-O) compared to parental, liver, or lymph node-derived cells. In contrast, the homing receptor CXCR4 was equivalently expressed in cells derived from all organs. No significant difference was observed in the expression of angiogenic factors, including HIF-1α, VEGF, angiopoeitin-1, Tie2, c-MET, and osteolytic factors, including PTHrP, IL-6 and RANKL. While the parental and Bo-786-O cells have similar proliferation rates, Bo-786-O cells showed an increase in migration compared to the parental 786-O cells. Knockdown of Cadherin-11 using shRNA reduced the rate of migration in Bo-786-O cells, suggesting that Cadherin-11 contributes to the increased migration observed in bone-derived cells. Immunohistochemical analysis of cadherin-11 expression in a human renal carcinoma tissue array showed that the number of human specimens with positive cadherin-11 activity was significantly higher in tumors that metastasized to bone than that in primary tumors. Together, these results suggest that Cadherin-11 may play a role in RCC bone metastasis.

Natural history of malignant bone disease in renal cancer: final results of an Italian bone metastasis survey

BACKGROUND

Bone metastasis represents an increasing clinical problem in advanced renal cell carcinoma (RCC) as disease-related survival improves. There are few data on the natural history of bone disease in RCC.

PATIENTS AND METHODS

Data on clinicopathology, survival, skeletal-related events (SREs), and bone-directed therapies for 398 deceased RCC patients (286 male, 112 female) with evidence of bone metastasis were statistically analyzed.

RESULTS

Median time to bone metastasis was 25 months for patients without bone metastasis at diagnosis. Median time to diagnosis of bone metastasis by MSKCC risk was 24 months for good, 5 months for intermediate, and 0 months for poor risk. Median number of SREs/patient was one, and 71% of patients experienced at least one SRE. Median times to first, second, and third SRE were 2, 5, and 12 months, respectively. Median survival was 12 months after bone metastasis diagnosis and 10 months after first SRE. Among 181 patients who received zoledronic acid (ZOL), median time to first SRE was significantly prolonged versus control (n = 186) (3 months vs 1 month for control; P<0.05).

CONCLUSIONS

RCC patients with bone metastasis are at continuous risk of SREs, and in this survey ZOL effectively reduced this risk.

An unusual cause of shoulder pain in an elderly woman: a case report

INTRODUCTION

Stress fracture of the clavicle is a rare entity. It can manifest itself with an atypical shoulder pain. The clavicle is vulnerable to pathological fractures from several causes such as neoplasm, infection and rarely metabolic bone disease.

CASE PRESENTATION

We report a case of a bone insufficiency fracture of the clavicle, in a 67-year-old Moroccan woman patient with several risk factors of bone insufficiency including osteoporosis, osteomalacia and primary hyperparathyroidism.

CONCLUSION

The diagnosis of bone insufficiency-related fracture of the clavicle can be challenging. It should be considered in the differential diagnosis of shoulder or clavicle pain.

Invasion and metastasis of renal cell carcinoma

Renal cell carcinoma (RCC) represents over 80% of kidney cancer, and about 30% of the patients with RCC develop metastasis after the surgery. Invasion of basement membrane (BM) and extracellular matrix (ECM) is an essential event in tumor invasion and metastasis. Matrix metalloproteinases (MMPs), which digest the main components of BM and ECM, are expressed in RCC. Heparanase, which degrades heparan sulfate proteoglycans, is predominantly expressed in high-grade RCCs with a positive correlation with pathological tumor stage and poor prognosis. Bone metastasis is common among the patients with RCC, and increased osteoclastic activity was observed at metastatic sites. Receptor activator of nuclear factor κB ligand (RANKL), which plays an important role in osteoclastogenesis, is predominantly expressed in high-grade RCC and its expression level is associated with bone metastasis and prognosis. Epithelial-mesenchymal transition (EMT), a switch of epithelial cells to sarcomatoid phenotype, is considered to be critical step during metastasis, and Snail, a major regulator of EMT, is predominantly expressed in high-grade RCC, and high Snail expression is a worse prognostic factor. Accordingly, heparanase, RANKL and Snail may be targets for the development of anti-tumor therapies for RCCs.

Treatment of Renal Cell Carcinoma with 2-Stage Total en bloc Spondylectomy after Marked Response to Molecular Target Drugs

Metastatic renal cell carcinoma of the bone occurs at a high rate, and the prognosis is poor. In general, total en bloc spondylectomy is considered when there is only one vertebral metastasis and the primary disease is treated. However, palliative surgery is selected when the primary disease is not being treated or metastasis occurs to an important organ. We encountered a patient in whom lung and vertebra metastases were already present at the time of the first examination at our department and the prognosis was considered poor. However, molecular targeted therapy was markedly effective and enabled 2-stage total en bloc spondylectomy. As of one year after total en bloc spondylectomy, the condition has improved to cane gait, and surgery for lung metastasis is planned. Molecular target drugs might markedly change the current therapeutic strategy for renal cell carcinoma.

Biochemical markers of bone turnover and clinical outcome in patients with renal cell and bladder carcinoma with bone metastases following treatment with zoledronic acid: The TUGAMO study

Background:

Levels of bone turnover markers (BTM) might be correlated with outcome in terms of skeletal-related events (SRE), disease progression, and death in patients with bladder cancer (BC) and renal cell carcinoma (RCC) with bone metastases (BM). We try to evaluate this possible correlation in patients who receive treatment with zoledronic acid (ZOL).

Methods:

This observational, prospective, and multicenter study analysed BTM and clinical outcome in these patients. Serum levels of bone alkaline phosphatase (BALP), procollagen type I amino-terminal propeptide (PINP), and beta-isomer of carboxy-terminal telopeptide of type I collagen (β-CTX) were analysed.

Results:

Patients with RCC who died or progressed had higher baseline β-CTX levels and those who experienced SRE during follow-up showed high baseline BALP levels. In BC, a poor rate of survival was related with high baseline β-CTX and BALP levels, and new SRE with increased PINP levels. Cox univariate analysis showed that β-CTX levels were associated with higher mortality and disease progression in RCC and higher mortality in BC. Bone alkaline phosphatase was associated with increased risk of premature SRE appearance in RCC and death in BC.

Conclusion:

Beta-isomer of carboxy-terminal telopeptide of type I collagen and BALP can be considered a complementary tool for prediction of clinical outcomes in patients with BC and RCC with BM treated with ZOL.

Zoledronic acid sensitizes renal cell carcinoma cells to radiation by downregulating STAT1

Zoledronic acid (ZOL), a third-generation bisphosphonate that strongly inhibits osteoclast activity, is widely used for the treatment of bone metastasis from a variety of malignancies, including renal cell carcinoma (RCC). We previously reported that zoledronic acid (ZOL) clinically potentiates antitumor effects of radiotherapy (RT) on bone metastases from RCC. To date, however, it remains unknown whether ZOL radiosensitizes RCC and if it does, how. Here, we demonstrated that ZOL directly radiosensitizes RCC cells independent of osteoclast activity by potentiating the caspase-3-mediated apoptosis pathway. The radiosensitization by ZOL was observed in 786-O, A-498, and ACHN cells but not in Caki-1 cells. As its underlying molecular mechanism, we found that the signal transducer and activator of transcription 1 (STAT1) plays a key role. The three RCC cell lines, in which ZOL exerted a radiosensitizing effect, expressed STAT1 abundantly but Caki-1 cells did not. ZOL downregulated endogenous STAT1 expression in 786-O, A-498, and ACHN cells by a post-transcriptional modification. We confirmed that knockdown of endogenous STAT1 by siRNA sensitized 786-O cells to RT equivalently to ZOL, and that introduction of exogenous STAT1 rendered Caki-1 cells more RT-resistant. This is the first study to clarify the molecular mechanism by which ZOL directly radiosensitizes tumor cells. Because tumor cells commonly overexpress STAT1 and ZOL reportedly radiosensitizes various types of tumor cells, ZOL warrants further clinical and translational studies as a potent radiosensitizer against RT-resistant tumors overexpressing STAT1.

Zoledronic acid in genitourinary cancer

Bone metastases are a common complication of advanced prostate cancer and while they are less common in non-prostate genitourinary (GU) malignances, they have been reported in up to 35 % of patients with advanced renal cell carcinoma and bladder cancer. Furthermore, they may occur in more than two-thirds of those patients with bladder cancer who develop distant metastases. In the absence of bone-targeted therapies, approximately 50 % of all patients with metastatic bone disease from GU cancers experience at least one skeletal-related event within their lifetime. Zoledronic acid is a bisphosphonate that has been shown to delay or prevent the development of skeletal complications in patients with bone metastases and reduce bone pain in these patients. Furthermore, zoledronic acid has also demonstrated the ability to prevent osteopenia, which may occur with the prolonged use of some pharmacological interventions in patients with cancer.

Concomitant oral tyrosine kinase inhibitors and bisphosphonates in advanced renal cell carcinoma with bone metastases

BACKGROUND

The presence of bone metastases in patients with metastatic renal cell carcinoma treated with oral tyrosine kinase inhibitors (TKIs) is associated with poorer outcome as compared with patients without bone involvement. Concomitant bisphosphonates could probably improve outcomes but also induce osteonecrosis of the jaw (ONJ).

METHODS

Retrospective study on all the renal cell carcinoma patients with bone metastases treated with sunitinib or sorafenib between November 2005 and June 2012 at the University Hospitals Leuven and AZ Groeninge in Kortrijk.

RESULTS

Seventy-six patients were included in the outcome analysis: 49 treated with concomitant bisphosphonates, 27 with TKI alone. Both groups were well balanced in terms of prognostic and predictive markers. Response rate (38% vs 16% partial responses, P=0.028), median progression-free survival (7.0 vs 4.0 months, P=0.0011) and median overall survival (17.0 vs 7.0 months, P=0.022) were significantly better in patients receiving bisphosphonates. The incidence of ONJ was 10% in patients treated with TKI and bisphosphonates.

CONCLUSION

Concomitant use of bisphosphonates and TKI in renal cell carcinoma patients with bone involvement probably improves treatment efficacy, to be confirmed by prospective studies, but is associated with a high incidence of ONJ.