Skeletal metastasis in renal cell carcinoma: current and future management options

BIGH3 mediates apoptosis and gap junction failure in osteocytes during renal cell carcinoma bone metastasis progression

Renal cell carcinoma (RCC) bone metastatis progression is driven by crosstalk between tumor cells and the bone microenvironment, which includes osteoblasts, osteoclasts, and osteocytes. RCC bone metastases (RCCBM) are predominantly osteolytic and resistant to antiresorptive therapy. The molecular mechanisms underlying pathologic osteolysis and disruption of bone homeostasis remain incompletely understood. We previously reported that BIGH3/TGFBI (transforming growth factor-beta-induced protein ig-h3, shortened to BIGH3 henceforth) secreted by colonizing RCC cells drives osteolysis by inhibiting osteoblast differentiation, impairing healing of osteolytic lesions, which is reversible with osteoanabolic agents. Here, we report that BIGH3 induces osteocyte apoptosis in both human RCCBM tissue specimens and in a preclinical mouse model. We also demonstrate that BIGH3 reduces Cx43 expression, blocking gap junction (GJ) function and osteocyte network communication. BIGH3-mediated GJ inhibition is blocked by the lysosomal inhibitor hydroxychloroquine (HCQ), but not osteoanabolic agents. Our results broaden the understanding of pathologic osteolysis in RCCBM and indicate that targeting the BIGH3 mechanism could be a combinational strategy for the treatment of RCCBM-induced bone disease that overcomes the limited efficacy of antiresorptives that target osteoclasts.

Development and validation of an early diagnosis model for bone metastasis in non-small cell lung cancer based on serological characteristics of the bone metastasis mechanism

Background

Bone metastasis significantly impact the prognosis of non-small cell lung cancer (NSCLC) patients, reducing their quality of life and shortening their survival. Currently, there are no effective tools for the diagnosis and risk assessment of early bone metastasis in NSCLC patients. This study employed machine learning to analyze serum indicators that are closely associated with bone metastasis, aiming to construct a model for the timely detection and prognostic evaluation of bone metastasis in NSCLC patients.

Methods

The derivation cohort consisted of 664 individuals with stage IV NSCLC, diagnosed between 2015 and 2018. The variables considered in this study included age, sex, and 18 specific serum indicators that have been linked to the occurrence of bone metastasis in NSCLC. Variable selection used multivariate logistic regression analysis and Lasso regression analysis. Six machine learning methods were utilized to develop a bone metastasis diagnostic model, assessed with Area Under the Curve (AUC), Decision Curve Analysis (DCA), sensitivity, specificity, and validation cohorts. External validation used 113 NSCLC patients from the Medical Alliance (2019-2020). Furthermore, a prospective validation study was conducted on a cohort of 316 patients (2019-2020) who were devoid of bone metastasis, and followed-up for at least two years to assess the predictive capabilities of this model. The model's prognostic value was evaluated using Kaplan-Meier survival curves.

Findings

Through variable selection, 11 serum indictors were identified as independent predictive factors for NSCLC bone metastasis. Six machine learning models were developed using age, sex, and these serum indicators. A random forest (RF) model demonstrated strong performance during the training and internal validation cohorts, achieving an AUC of 0.98 (95% CI 0.95-0.99) for internal validation. External validation further confirmed the RF model's effectiveness, yielding an AUC of 0.97 (95% CI 0.94-0.99). The calibration curves demonstrated a high level of concordance between the anticipated risk and the observed risk of the RF model. Prospective validation revealed that the RF model could predict the occurrence of bone metastasis approximately 10.27 ± 3.58 months in advance, according to the results of the SPECT. An online computing platform (https://bonemetastasis.shinyapps.io/shiny_cls_1model/) for this RF model is publicly available and free-to-use by doctors and patients.

Interpretation

This study innovatively employs age, gender, and 11 serological markers closely related to the mechanism of bone metastasis to construct an RF model, providing a reliable tool for the early screening and prognostic assessment of bone metastasis in NSCLC patients. However, as an exploratory study, the findings require further validation through large-scale, multicenter prospective studies.

Funding

This work is supported by the National Natural Science Foundation of China (NO.81974315); Shanghai Municipal Science and Technology Commission Medical Innovation Research Project (NO.20Y11903300); Shanghai Municipal Health Commission Health Industry Clinical Research Youth Program (NO.20204Y034).

Advanced renal cell carcinoma management: the Latin American Cooperative Oncology Group (LACOG) and the Latin American Renal Cancer Group (LARCG) consensus update

PURPOSE

Renal cell carcinoma is an aggressive disease with a high mortality rate. Management has drastically changed with the new era of immunotherapy, and novel strategies are being developed; however, identifying systemic treatments is still challenging. This paper presents an update of the expert panel consensus from the Latin American Cooperative Oncology Group and the Latin American Renal Cancer Group on advanced renal cell carcinoma management in Brazil.

METHODS

A panel of 34 oncologists and experts in renal cell carcinoma discussed and voted on the best options for managing advanced disease in Brazil, including systemic treatment of early and metastatic renal cell carcinoma as well as nonclear cell tumours. The results were compared with the literature and graded according to the level of evidence.

RESULTS

Adjuvant treatments benefit patients with a high risk of recurrence after surgery, and the agents used are pembrolizumab and sunitinib, with a preference for pembrolizumab. Neoadjuvant treatment is exceptional, even in initially unresectable cases. First-line treatment is mainly based on tyrosine kinase inhibitors (TKIs) and immune checkpoint inhibitors (ICIs); the choice of treatment is based on the International Metastatic Database Consortium (IMCD) risk score. Patients at favourable risk receive ICIs in combination with TKIs. Patients classified as intermediate or poor risk receive ICIs, without preference for ICI + ICIs or ICI + TKIs. Data on nonclear cell renal cancer treatment are limited. Active surveillance has a place in treating favourable-risk patients. Either denosumab or zoledronic acid can be used for treating metastatic bone disease.

CONCLUSION

Immunotherapy and targeted therapy are the standards of care for advanced disease. The utilization and sequencing of these therapeutic agents hinge upon individual risk scores and responses to previous treatments. This consensus reflects a commitment to informed decision-making, drawn from professional expertise and evidence in the medical literature.

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.

Reoperation after surgery for bone metastasis of renal cell carcinoma

BACKGROUND AND OBJECTIVE

The prognosis of metastatic renal cell carcinoma (RCC) has markedly improved with the advent of molecular targeted therapies and immune checkpoint inhibitors. However, the therapeutic response in patients with bone metastasis remains low; therefore, surgery still plays a significant role in treatment of bone metastasis. It is important to maintain quality of life for patients with bone metastasis from RCC and avoid reoperation after surgery for bone metastasis. Therefore, we investigated the risk factors for reoperation after surgery in patients with bone metastasis from RCC.

METHODS

We retrospectively studied 103 bones of 97 patients who underwent surgery for bone metastasis of RCC from 2001 to 2023 at our institutions.

RESULTS

Reoperation was performed in 10 (9.7%) of 103 bones. There was no correlation between reoperation-free survival and any of the following variables: preoperative and postoperative radiotherapy, site of bone metastasis, indication for surgery (solitary bone metastasis or impending or pathologic fractures), surgical method (intramedullary nailing fixation, curettage, or en bloc resection), preoperative embolization, or survival.

CONCLUSION

The risk of reoperation for bone metastasis of RCC does not appear to be based on the surgical method.

Role of Surgery in Metastatic Renal Cell Carcinoma

Surgery has historically been the mainstay of treatment for metastatic renal cell carcinoma (mRCC), but recent clinical trials demonstrated that contemporary systemic therapies alone are non-inferior to cytoreductive nephrectomy (CN). Thus, the current role of surgery is not precisely defined. CN remains an appropriate upfront treatment for the palliation of severe symptoms, select cases of metastatic non-clear cell renal cell carcinoma, for consolidation following systemic therapy, and in the setting of oligometastatic disease. Metastasectomy is ideally utilized to achieve a disease-free state when there is minimal morbidity associated with surgery. Given the heterogenous nature of mRCC, the decision for systemic therapy and surgery should be made through a multidisciplinary approach tailored to each individual patient.

Stereotactic body radiotherapy and tyrosine kinase inhibitors in patients with oligometastatic renal cell carcinoma: a multi-institutional study

PURPOSE

Few studies have determined the viability of stereotactic body radiotherapy (SBRT) and tyrosine kinase inhibitors (TKIs) in the treatment of metastatic renal cell carcinoma (mRCC). We examined the results of RCC patients who had five or fewer lesions and were treated with TKI and SBRT.

METHODS

The clinical data of 42 patients with 96 metastases treated between 2011 and 2020 were retrospectively evaluated. The prognostic factors predicting overall survival (OS) and progression-free survival (PFS) were assessed in uni- and multivariable analyses.

RESULTS

Median follow-up and time between TKI therapy and SBRT were 62.3 and 3.7 months, respectively. The 2‑year OS and PFS rates were 58.0% and 51.3%, respectively, and 2‑year local control rate was 94.1% per SBRT-treated lesion. In univariable analysis, the time between TKI therapy and SBRT and treatment response were significant prognostic factors for OS and PFS. In multivariable analysis, a time between TKI therapy and SBRT of less than 3 months and complete response were significant predictors of better OS and PFS. Only 12 patients (28.6%) had a systemic treatment change at a median of 18.2 months after SBRT, mostly in patients with a non-complete treatment response after this therapy. Two patients (4.8%) experienced grade III toxicity, and all side effects observed during metastasis-directed therapy subsided over time.

CONCLUSION

We demonstrated that SBRT in combination with TKIs is an effective and safe treatment option for RCC patients with ≤ 5 metastases. However, distant metastasis was observed in 60% of the patients, indicating that distant disease control still has room for improvement.

A practical dynamic nomogram model for predicting bone metastasis in patients with thyroid cancer

PURPOSE

The aim of this study was to established a dynamic nomogram for assessing the risk of bone metastasis in patients with thyroid cancer (TC) and assist physicians to make accurate clinical decisions.

METHODS

The clinical data of patients with TC admitted to the First Affiliated hospital of Nanchang University from January 2006 to November 2016 were included in this study. Demographic and clinicopathological parameters of all patients at primary diagnosis were analyzed. Univariate and multivariate logistic regression analysis was applied to build a predictive model incorporating parameters. The discrimination, calibration, and clinical usefulness of the nomogram were evaluated using the C-index, ROC curve, calibration plot, and decision curve analysis. Internal validation was evaluated using the bootstrapping method.

RESULTS

A total of 565 patients were enrolled in this study, of whom 25 (4.21%) developed bone metastases. Based on logistic regression analysis, age (OR=1.040, P=0.019), hemoglobin (HB) (OR=0.947, P<0.001) and alkaline phosphatase (ALP) (OR=1.006, P=0.002) levels were used to construct the nomogram. The model exhibited good discrimination, with a C-index of 0.825 and good calibration. A C-index value of 0.815 was achieved on interval validation analysis. Decision curve analysis showed that the nomogram was clinically useful when intervention was decided at a bone metastases possibility threshold of 1%.

CONCLUSIONS

This dynamic nomogram, with relatively good accuracy, incorporating age, HB, and ALP, could be conveniently used to facilitate the prediction of bone metastasis risk in patients with TC.

Bone Metabolism Effects of Medical Therapy in Advanced Renal Cell Carcinoma

The medical therapy of advanced renal cell carcinoma (RCC) is based on the use of targeted therapies, such as tyrosine kinase inhibitors (TKI) and immune-checkpoint inhibitors (ICI). These therapies are characterized by multiple endocrine adverse events, but the effect on the bone is still less known. Relatively few case reports or small case series have been specifically focused on TKI and ICI effects on bone metabolism. However, the importance to consider these possible side effects is easily intuitable because the bone is one of the most frequent metastatic sites of RCC. Among TKI used in RCC, sunitinib and sorafenib can cause hypophosphatemia with increased PTH levels and low-normal serum calcium levels. Considering ICI, nivolumab and ipilimumab, which can be used in association in a combination strategy, are associated with an increased risk of hypocalcemia, mediated by an autoimmune mechanism targeted on the calcium-sensing receptor. A fearsome complication, reported for TKI and rarely for ICI, is osteonecrosis of the jaw. Awareness of these possible side effects makes a clinical evaluation of RCC patients on anticancer therapy mandatory, especially if associated with antiresorptive therapy such as bisphosphonates and denosumab, which can further increase the risk of these complications.

Prediction of bone metastasis in non-small cell lung cancer based on machine learning

OBJECTIVE

The purpose of this paper was to develop a machine learning algorithm with good performance in predicting bone metastasis (BM) in non-small cell lung cancer (NSCLC) and establish a simple web predictor based on the algorithm.

METHODS

Patients who diagnosed with NSCLC between 2010 and 2018 in the Surveillance, Epidemiology and End Results (SEER) database were involved. To increase the extensibility of the research, data of patients who first diagnosed with NSCLC at the First Affiliated Hospital of Nanchang University between January 2007 and December 2016 were also included in this study. Independent risk factors for BM in NSCLC were screened by univariate and multivariate logistic regression. At this basis, we chose six commonly machine learning algorithms to build predictive models, including Logistic Regression (LR), Decision tree (DT), Random Forest (RF), Gradient Boosting Machine (GBM), Naive Bayes classifiers (NBC) and eXtreme gradient boosting (XGB). Then, the best model was identified to build the web-predictor for predicting BM of NSCLC patients. Finally, area under receiver operating characteristic curve (AUC), accuracy, sensitivity and specificity were used to evaluate the performance of these models.

RESULTS

A total of 50581 NSCLC patients were included in this study, and 5087(10.06%) of them developed BM. The sex, grade, laterality, histology, T stage, N stage, and chemotherapy were independent risk factors for NSCLC. Of these six models, the machine learning model built by the XGB algorithm performed best in both internal and external data setting validation, with AUC scores of 0.808 and 0.841, respectively. Then, the XGB algorithm was used to build a web predictor of BM from NSCLC.

CONCLUSION

This study developed a web predictor based XGB algorithm for predicting the risk of BM in NSCLC patients, which may assist doctors for clinical decision making.

Effect of Bisphosphonates on Skeletal Related Events in Long Bone Metastases of Renal Cell Carcinoma: A Systematic Review

Bone metastases (BMs) in patients with renal cell carcinoma (RCC) are lytic lesions which are prone to skeletal related events (SREs) such as (pending) pathological fractures or bone pain requiring radiotherapy or surgery. The aim of this review is to assess whether the use of bisphosphonates in patients with RCC and BMs in the long bones results in reduced SRE rate. A systematic review of literature was conducted, using PubMed, Embase, Medline, Web of Science, Cochrane, and Google Scholar (date 1971 till June 2021). All clinical studies on bisphosphonates in patients with RCC and BMs in long bones were retrieved. Primary outcome measure was SRE rate of BMs in long bones. Secondary outcome was fracture rate of BMs in long bones. Fourteen relevant articles were selected. Bisphosphonates reduced the mean skeletal morbidity rate by 0.4-0.95 SREs/year and had a pooled SRE rate of 38.3% (95% confidence interval [CI] 28.4%-49.3%). When bisphosphonates were added to radiotherapy the pooled SRE rate was 18.4% (95% CI, 10.5%-30.3%). In addition, pooled effect sizes showed a significant SRE risk reduction (RR 0.45, 95% CI, 0.24-0.85) in the bisphosphonates combined with radiotherapy group. There was limited reported data on rate of pathological fractures. In general, bisphosphonates reduce the SRE rate in RCC patients with BMs. The level of evidence for the effect of bisphosphonates on the rate of pathological fractures in patients with long BMs of RCC is low.

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-only oligometastatic renal cell carcinoma patients treated with stereotactic body radiotherapy: a multi-institutional study

PURPOSE

This study aimed to analyze the prognostic factors associated with overall survival (OS) and progression-free survival (PFS) in patients with bone-only metastatic renal cell carcinoma (RCC) who have five or fewer lesions treated with stereotactic body radiotherapy (SBRT).

METHODS

The clinical data of 54 patients with 70 bone metastases undergoing SBRT treated between 2013 and 2020 with a dose of at least 5 Gy per fraction and a biologically effective dose (BED) of at least 90 Gy were retrospectively evaluated.

RESULTS

The majority of lesions were located in the spine (57.4%) and had only one metastasis (64.8%). After a median follow-up of 22.4 months, the 1‑ and 2‑year OS rates were 84.6% and 67.3%, respectively, and median OS was 43.1 months. The 1‑ and 2‑year PFS rates and median PFS were 63.0%, 38.9%, and 15.3 months, respectively. In SBRT-treated lesions, the 1‑year local control (LC) rate was 94.9%. Age, metastasis localization, and number of fractions of SBRT were significant prognostic factors for OS in univariate analysis. In multivariate analysis, patients with spinal metastasis had better OS compared to their counterparts, and patients who received single-fraction SBRT had better PFS than those who did not. No patient experienced acute or late toxicities of grade 3 or greater.

CONCLUSION

Despite excellent LC at the oligometastatic site treated with SBRT, disease progression was observed in nearly half of patients 13 months after metastasis-directed local therapy, particularly as distant disease progression other than the treated lesion, necessitating an effective systemic treatment to improve treatment outcomes.

Urological cancer organoids, patients' avatars for precision medicine: past, present and future

Urological cancers are common malignant cancers worldwide, with annually increasing morbidity and mortality rates. For decades, two-dimensional cell cultures and animal models have been widely used to study the development and underlying molecular mechanisms of urological cancers. However, they either fail to reflect cancer heterogeneity or are time-consuming and labour-intensive. The recent emergence of a three-dimensional culture model called organoid has the potential to overcome the shortcomings of traditional models. For example, organoids can recapitulate the histopathological and molecular diversity of original cancer and reflect the interaction between cancer and surrounding cells or stroma by simulating tumour microenvironments. Emerging evidence suggests that urine-derived organoids can be generated, which could be a novel non-invasive liquid biopsy method that provides new ideas for clinical precision therapy. However, the current research on organoids has encountered some bottlenecks, such as the lack of a standard culture process, the need to optimize the culture medium and the inability to completely simulate the immune system in vivo. Nonetheless, cell co-culture and organoid-on-a-chip have significant potential to solve these problems. In this review, the latest applications of organoids in drug screening, cancer origin investigation and combined single-cell sequencing are illustrated. Furthermore, the development and application of organoids in urological cancers and their challenges are summarised.

Preoperative Embolization of a Delayed Femoral Metastasis of Renal Cell Carcinoma: A Case Report

Preoperative embolization of hypervascular bone metastasis is an effective measure for reducing blood loss during open orthopedic surgery. When the clinician is experienced with the procedure, the risks of the procedure are minimal and final outcomes are typically good.

In this study, we report a case of a 50-year-old female patient who presented with a delayed metastatic renal cell tumor in the left proximal femur one year after radical nephrectomy. The patient underwent an effective preoperative embolization, which resulted in a remarkable absence of bleeding and a successful response subsequent to surgical fixation.

Risk Factors, Prognostic Factors, and Nomograms for Bone Metastasis in Patients with Newly Diagnosed Clear Cell Renal Cell Carcinoma: A Large Population-Based Study

Background

This study aimed to investigate risk factors and prognostic factors in patients with clear cell renal cell carcinoma (ccRCC) with bone metastasis (BM) and establish nomograms to provide a quantitative prediction of the risk of BM and survival probability.

Methods

The clinicopathological characteristics of patients with ccRCC between January 2010 and December 2015 were obtained from the Surveillance, Epidemiology and End Results (SEER) database. Independent factors for BM in ccRCC patients were identified using univariate and multivariate logistic regression analyses. Prognostic factors for predicting cancer-specific death were evaluated using univariate and multivariate analyses based on a competing risk regression model. We then constructed a diagnostic nomogram and a prognostic nomogram. The two nomograms were evaluated using calibration curves, receiver operating characteristic curves, and decision curve analysis.

Results

Our study included 34,659 patients diagnosed with ccRCC in the SEER database, with 1,415 patients who presented with bone metastasis. Risk factors for BM in patients with ccRCC included age, stage T, stage N, brain metastasis, liver metastasis, lung metastasis, tumor size, and laterality. Independent prognostic factors for patients with ccRCC patients with BM were Fuhrman grade, tumor size, T stage, N stage, brain metastases, lung metastasis, and surgery. For the diagnostic nomogram, the area under the curve values in the training and testing cohorts were 0.863 (95% CI, 0.851–0.875) and 0.859 (95% CI, 0.839–0.878), respectively. In the prognostic cohort, the area under the curve values for 1-, 2-, and 3-year cancer-specific survival rates in the training cohort were 0.747, 0.774, and 0.780, respectively, and 0.671, 0.706, and 0.696, respectively, in the testing cohort. Through calibration curves and decision curve analyses, the nomograms displayed excellent performance.

Conclusions

Several factors related to the development and prognosis of BM in patients with ccRCC were identified. The nomograms constructed in this study are expected to become effective and precise tools for clinicians to improve cancer management.

Evolving cancer-niche interactions and therapeutic targets during bone metastasis

Many cancer types metastasize to bone. This propensity may be a product of genetic traits of the primary tumour in some cancers. Upon arrival, cancer cells establish interactions with various bone-resident cells during the process of colonization. These interactions, to a large degree, dictate cancer cell fates at multiple steps of the metastatic cascade, from single cells to overt metastases. The bone microenvironment may even influence cancer cells to subsequently spread to multiple other organs. Therefore, it is imperative to spatiotemporally delineate the evolving cancer-bone crosstalk during bone colonization. In this Review, we provide a summary of the bone microenvironment and its impact on bone metastasis. On the basis of the microscopic anatomy, we tentatively define a roadmap of the journey of cancer cells through bone relative to various microenvironment components, including the potential of bone to function as a launch pad for secondary metastasis. Finally, we examine common and distinct features of bone metastasis from various cancer types. Our goal is to stimulate future studies leading to the development of a broader scope of potent therapies.

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.

Metastatic Lesion of the Tibia from Renal Cell Carcinoma

Introduction

Renal cell carcinoma is responsible for 3% of all cancers, with the highest incidence occurring in Western countries. Additionally, in patients with osseous metastasis, only 3% occur within the tibia. Rarely, a patient presents with a primary complaint of lower limb pain in advanced metastatic renal cell carcinoma. Case Presentation. The patient arrived at the emergency department with a primary complaint of left ankle pain. Ankle X-rays demonstrated a lytic lesion involving the medial malleolus with possible metastatic disease. CT scan confirmed a tumor within the right kidney. The patient was treated with a laparoscopic radical nephrectomy with histopathologic confirmation of clear cell renal cell carcinoma. Biopsy was then performed of the tibial lesion, confirming metastatic clear cell renal cell carcinoma. The tibial lesion was treated with local radiotherapy, and because of the progression of the tibia lesion, a decision was made to amputate the leg. Additionally, the patient was enrolled to sunitinib treatment and was disease free at one year of follow-up. 13 months after diagnosis of cancer, she was suffering a major stroke of the brain that caused her to die.

Conclusion

The treatment of patients with osseous metastases of renal cell cancer depends on the number of metastases, location of metastases, and overall health of the patient. We performed an overview of available literature and provided a summary regarding the use of cytoreductive nephrectomy, local therapy, target therapy, and bone-targeting agents in the treatment of metastatic renal cell cancer.

Metastatic Renal Cell Carcinoma to the Spine: Outcomes and Morbidity: Single-Center Experience

BACKGROUND

Renal cell carcinoma with metastases to the spine (RCCMS) requires a multidisciplinary approach. We reviewed our institutional experience with RCCMS patients undergoing spinal surgery in order to identify factors that may affect clinical outcomes, survival, and complications.

METHODS

Patients with RCCMS who underwent operative intervention from 2007 to 2020 were reviewed retrospectively.

RESULTS

Forty-four patients with the diagnosis of RCCMS were identified. Pain was the most common symptom, and neurologic dysfunction was present in one third of cases. Thoracic spine was the most common location (N = 27), followed by the lumbar (N = 12) and cervical (N = 5) regions. The overall survival from diagnosis of renal cell carcinoma was 25 (2 - 194) months and 8 (0.3 - 92) months after spinal surgery. Gender, age, spinal level, postoperative radiation, and nephrectomy had no bearing on survival. Survival for patients with a Tokuhashi score of 0 - 8, 9 - 11, and 12 - 15 was 6.5 (1.5 - 23.5), 8.9 (0.3 - 91.6), and 23.4 (2.5 - 66) months, respectively (P = 0.03). The postoperative American Spinal Cord Injury Association score of E (hazard ratio 0.109 [95% confidence interval 0.022 - 0.534, P = 0.006) also bore a significant influence on survival. There was a total of 10 complications in 7 of 44 (16%) patients.

CONCLUSIONS

Median postoperative survival of patients with RCCMS was 8 (0.3 - 92) months. Higher Tokuhashi score and ASIA E score at follow-up correlated with improved overall survival. Complication rate was 16%. Spinal surgery in RCCMS is indicated for the preservation of function and prevention of neurologic deterioration. Multimodality therapy with improved chemotherapy and stereotactic spinal radiation is expected to impact quality and length of survival positively.

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.

Machine learning for the prediction of bone metastasis in patients with newly diagnosed thyroid cancer

OBJECTIVES

This study aimed to establish a machine learning prediction model that can be used to predict bone metastasis (BM) in patients with newly diagnosed thyroid cancer (TC).

METHODS

Demographic and clinicopathologic variables of TC patients in the Surveillance, Epidemiology, and End Results database from 2010 to 2016 were retrospectively analyzed. On this basis, we developed a random forest (RF) algorithm model based on machine-learning. The area under receiver operating characteristic curve (AUC), accuracy score, recall rate, and specificity are used to evaluate and compare the prediction performance of the RF model and the other model.

RESULTS

A total of 17,138 patients were included in the study, with 166 (0.97%) developed bone metastases. Grade, T stage, histology, race, sex, age, and N stage were the important prediction features of BM. The RF model has better predictive performance than the other model (AUC: 0.917, accuracy: 0.904, recall rate: 0.833, and specificity: 0.905).

CONCLUSIONS

The RF model constructed in this study could accurately predict bone metastases in TC patients, which may provide clinicians with more personalized clinical decision-making recommendations. Machine learning technology has the potential to improve the development of BM prediction models in TC patients.

Percutaneous thermal ablation alone or in combination with cementoplasty for renal cell carcinoma osseous metastases: Pain palliation and local tumour control

INTRODUCTION

To evaluate the safety and efficacy of minimally invasive percutaneous thermal ablation alone or in combination with cementoplasty for pain palliation and local tumour control of renal cell carcinoma osseous metastases.

METHODS

Imaging-guided thermal ablation was performed in 59 renal cell carcinoma osseous metastatic tumours in 23 patients (concomitant cementoplasty in 43 tumours) selected following multidisciplinary consultations to achieve local tumour control and pain palliation (75%, 44/59) or pain palliation alone (25%, 15/59) in this retrospective study. Tumour characteristics, procedural details and complications were documented. Pain palliation was assessed using pre- and post-procedural Numeric Rating Scale scores at 1-week, 1-month, 3-month and 6-month time intervals. Pre- and post-procedural cross-sectional imaging was reviewed to assess local tumour control rates at 3-month, 6-month, and 12-month post-treatment time intervals.

RESULTS

All procedures were technically successful and performed as pre-operatively planned. The median pre- and post-procedural Numeric Rating Scale scores were 8.0 and 3.0 (at all time intervals), respectively (P < 0.001). Local tumour control rates were 100% (40/40), 100% (36/36) and 85% (28/33) at ≥3 months, ≥6 months and ≥12 months post-procedural time intervals, respectively. There was 1 minor complication (1.7%, 1/59).

CONCLUSIONS

Percutaneous thermal ablation alone or in combination with cementoplasty is safe and effective for pain palliation and local tumour control of renal cell carcinoma osseous metastases.

Cabozantinib Reverses Renal Cell Carcinoma-mediated Osteoblast Inhibition in Three-dimensional Coculture In Vitro and Reduces Bone Osteolysis In Vivo

Renal cell carcinoma bone metastases (RCCBM) are typically osteolytic. We previously showed that BIGH3 (beta Ig-h3/TGFBI), secreted by 786-O renal cell carcinoma, plays a role in osteolytic bone lesion in RCCBM through inhibition of osteoblast (OSB) differentiation. To study this interaction, we employed three-dimensional (3D) hydrogels to coculture bone-derived 786-O (Bo-786) renal cell carcinoma cells with MC3T3-E1 pre-OSBs. Culturing pre-OSBs in the 3D hydrogels preserved their ability to differentiate into mature OSB; however, this process was decreased when pre-OSBs were cocultured with Bo-786 cells. Knockdown of BIGH3 in Bo-786 cells recovered OSB differentiation. Furthermore, treatment with bone morphogenetic protein 4, which stimulates OSB differentiation, or cabozantinib (CBZ), which inhibits VEGFR1 and MET tyrosine kinase activities, also increased OSB differentiation in the coculture. CBZ also inhibited pre-osteoclast RAW264.7 cell differentiation. Using RCCBM mouse models, we showed that CBZ inhibited Bo-786 tumor growth in bone. CBZ treatment also increased bone volume and OSB number, and decreased osteoclast number and blood vessel density. When tested in SN12PM6 renal cell carcinoma cells that have been transduced to overexpress BIGH3, CBZ also inhibited SN12PM6 tumor growth in bone. These observations suggest that enhancing OSB differentiation could be one of the therapeutic strategies for treating RCCBM that exhibit OSB inhibition characteristics, and that this 3D coculture system is an effective tool for screening osteoanabolic agents for further in vivo studies.

Does Bone-targeted Therapy Benefit Patients with Metastatic Renal Cell Carcinoma?

INTRODUCTION

In metastatic renal cell carcinoma (mRCC), the bone is the second most common site of metastasis and is associated with increased morbidity and poorer quality of life. Bone-targeted therapies (BTTs) such as denosumab and zoledronic acid may prevent skeletal-related events (SREs). However, the benefit of BTTs in combination with tyrosine kinase inhibitors (TKIs) remains unclear.

METHODS

We performed a retrospective chart review at the Urologic Cancer Centre for Research and Innovation. Patients with mRCC were included if they had bone metastases treated with TKIs between 2010 and 2017. Our primary outcome was overall survival (OS), defined as the time elapsed from clinical diagnosis of mRCC to death, and modelled using the Kaplan-Meier method. Secondary outcomes included the median time to SRE and the analysis of prognostic factors of OS using Cox proportional hazards regression.

RESULTS

In total, 230 patients with mRCC were identified; of which, 46 had bone metastases treated with TKIs and were included in the study (TKI-only, n = 37; TKI + BTT, n = 9). In the TKI + BTT cohort, patients received either denosumab (n = 5) or zoledronic acid (n = 4). At the time of analysis, 63% of patients were deceased. We observed an OS trend favouring the TKI + BTT cohort (13.8 months [95% confidence interval {CI}: 12.3-15.2] vs. 29.6 months [95% CI: 7.2-51.9], hazard ratio [HR]: 1.66 (95% CI: 0.62-4.45), P = 0.31). When patients in the TKI + BTT cohort were stratified by type of therapy (denosumab or zoledronic acid), the median time to SRE was similar between the groups (4.2 months [95% CI: 2.28-6.14] vs. 2.2 months [95% CI: not available], P = 0.71]. On univariate or multivariate analysis, it was found that age, gender, comorbidities, International metastatic RCC database consortium (IMDC) prognostic group and pathologic tumour grade were not significant predictors of worse OS. Pathologic stage 3 or 4 was an independent predictor of worse OS (HR: 5.8, 95% CI: 1.41-24.03, P = 0.015).

CONCLUSION

BTTs may have a continued role in the era of targeted therapy and immunotherapy. Further prospective data are required to validate our findings.

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.

mTOR inhibitor and bone-targeted drugs break the vicious cycle between clear-cell renal carcinoma and osteoclasts in an in vitro co-culture model

The skeleton is one of the most common sites of metastatic spread from advanced clear-cell renal carcinoma (ccRCC). Most of the bone lesions observed in RCC patients are classified as osteolytic, causing severe pain and morbidity due to pathological bone destruction. Nowadays, it is well known that cancer induced bone loss in lytic metastasis is caused by the triggering of a vicious cycle between cancer and bone resident cells that leads to an imbalance between bone formation and degradation. Targeting the mammalian target of rapamycin (mTOR) is an efficient treatment option for metastatic renal carcinoma patients. Moreover, bone targeted therapy could benefit bone metastatic cancer patients caused by advanced RCC. However, more data is needed to support the hypothesis of the beneficial effect of a combined therapy. The aim of this work is to investigate the effect of targeting mTOR and the sequential combination with bone targeted therapy as a strategy to break the vicious cycle between ccRCC cells and osteoclasts. A previously optimized fully human co-culture model is used to mimic the crosstalk between Caki-2 cells (ccRCC) and osteoclasts. Cells are treated at fixed timing with everolimus, zoledronic acid and denosumab as single or sequential combined treatment. We show that Caki-2 cells can induce osteoclast cells differentiation from isolated human monocytes, as demonstrated by specific tartrate-resistant acid phosphatase (TRAP) staining and f-actin ring formation, in a statistically significant manner. Moreover, differentiated osteoclasts proved to be functionally active by pit formation assay. Caki-2 cells co-cultured with osteoclasts acquire a more aggressive phenotype based on gene expression analysis. Interestingly, the sequential combined treatment of everolimus and zoledronic acid is the most effective in the inhibition of both Caki-2 cells survival and osteoclastogenic potential, making it an effective strategy to inhibit the vicious cycle of bone metastasis. At preclinical level, this observation confirms the value of our co-culture model as a useful tool to mimic the bone microenvironment and to assess drug sensitivity in vitro. A better understanding of the molecular mechanisms involved in tumor-bone cells crosstalk will be investigated next.

Clear cell renal cell carcinoma bone metastasis: What should be considered in prognostic evaluation

INTRODUCTION

Knowledge of clear cell renal cell carcinoma bone metastasis (ccRCC-BM) remains scarce. This study depicts clinical, pathological and outcome features of the disease and provides suggestions to establish prognosis prediction system more appropriate for ccRCC-BM.

MATERIALS AND METHODS

Patients with ccRCC-BM had clinical, pathological data collected. Kaplan-Meier survival analysis was used for outcome profiles. Prognostic risks were evaluated using MSKCC/Motzer score. Univariate and multivariate logistic regression were performed to investigate association between clinical, pathological features and prognosis.

RESULTS

In the series containing 106 ccRCC-BM patients with 4:1 male predominance, 44.3% of them had synchronous bone metastasis and 28.3% had multi-organ metastasis. Axial bone was prone to bone metastasis and the incidence of severe skeletal-related events was 54.7%. Curative bone lesion resection was performed in 70.7% patients. The median overall survival (mOS) time was 45 months for all and 32 months for those in unfavorable risk stratification. Shorter time to bone metastasis (TTBM) [OR 1.019, 95% CI (1.007, 1.031)], elderly age [OR 1.040, 95% CI (1.001, 1.080)], concomitant multi-organ metastasis [OR 3.883, 95% CI (1.375, 10.967)] and carbonic anhydrase (CA)-IX expression loss [OR 58.824, 95% CI (2.653, 1000)] were associated with poor prognosis.

CONCLUSION

The outcome of ccRCC-BM remained poor in unfavorable risk stratification. Bone lesion resection accompanied by systematic therapy for selected patient could improve prognosis. Shorter TTBM, elderly age, concomitant multi-organ metastasis and the expression loss of CA-IX along with gender-bias, feasibility for surgical treatment are suggested to be incorporated in modified ccRCC-BM-specific prognosis prediction system.

Denosumab Toxicity When Combined With Anti-angiogenic Therapies on Patients With Metastatic Renal Cell Carcinoma: A GETUG Study

BACKGROUND

About one-third of patients with renal cell carcinoma (RCC) have detectable metastases at diagnosis. Among them, bone is the second most frequent metastatic site. Treatment of metastatic RCC mostly relies on anti-angiogenic (AA) therapies and, more recently, immunotherapy. Skeletal-related events (SREs) can be prevented with bone-targeted therapies such as denosumab (Dmab), which has demonstrated superiority when compared with zoledronic acid in solid tumors. However, there is limited available data on Dmab toxicity in combination with AA therapies in patients with kidney cancer. The objective of this study was to retrospectively analyze the toxicity profile (mainly osteonecrosis of the jaw [ONJ] and hypocalcemia) in patients with metastatic renal cell carcinoma (mRCC) treated with Dmab and AA therapy combination.

PATIENTS AND METHODS

We conducted a multicenter retrospective study among centers from the French Groupe d'Etudes des Tumeurs Uro Genitales (GETUG). Patients with bone metastases who received concurrently or sequentially AA therapy and Dmab were included in this study.

RESULTS

A total of 41 patients with mRCC were enrolled. Although no patient presented with severe hypocalcemia, ONJ occurred in 7 (17%) of 41 patients. Interestingly, all patients with ONJ received the Dmab and AA combination in the first line of treatment; among these patients, 3 patients had no risk factor other than the Dmab and AA combination.

CONCLUSION

The incidence of ONJ was high in this real-life population of patients with mRCC treated with AA therapies combined with Dmab. This toxicity signal should warn physicians about this combination in the mRCC population.

A simple selection-free method for detecting disseminated tumor cells (DTCs) in murine bone marrow

Bone metastasis is a lethal and incurable disease. It is the result of the dissemination of cancer cells to the bone marrow. Due to the difficulty in sampling and detection, few techniques exist to efficiently and consistently detect and quantify disseminated tumor cells (DTCs) in the bone marrow of cancer patients. Because mouse models represent a crucial tool with which to study cancer metastasis, we developed a novel method for the simple selection-free detection and quantification of bone marrow DTCs in mice. We have used this protocol to detect human and murine DTCs in xenograft, syngeneic, and genetically engineered mouse models. We are able to detect and quantify bone marrow DTCs in mice that do not have overt bone metastasis. This protocol is amenable not only for detection and quantification purposes but also to study the expression of markers of numerous biological processes or tissue-specificity.

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.

Cabozantinib, a New Standard of Care for Patients With Advanced Renal Cell Carcinoma and Bone Metastases? Subgroup Analysis of the METEOR Trial

Purpose Cabozantinib, an inhibitor of tyrosine kinases including MET, vascular endothelial growth factor receptors, and AXL, increased progression-free survival (PFS), overall survival (OS), and objective response rate (ORR) in patients with advanced renal cell carcinoma (RCC) after previous vascular endothelial growth factor receptor-targeted therapy in the phase III METEOR trial. Because bone metastases are associated with increased morbidity in patients with RCC, bone-related outcomes were analyzed in METEOR. Patients and Methods Six hundred fifty-eight patients were randomly assigned 1:1 to receive 60 mg cabozantinib or 10 mg everolimus. Prespecified subgroup analyses of PFS, OS, and ORR were conducted in patients grouped by baseline bone metastases status per independent radiology committee (IRC). Additional end points included bone scan response per IRC, skeletal-related events, and changes in bone biomarkers. Results For patients with bone metastases at baseline (cabozantinib [n = 77]; everolimus [n = 65]), median PFS was 7.4 months for cabozantinib versus 2.7 months for everolimus (hazard ratio, 0.33 [95% CI, 0.21 to 0.51]). Median OS was also longer with cabozantinib (20.1 months v 12.1 months; hazard ratio, 0.54 [95% CI, 0.34 to 0.84]), and ORR per IRC was higher (17% v 0%). The rate of skeletal-related events was 23% with cabozantinib and 29% with everolimus, and bone scan response per IRC was 20% versus 10%, respectively. PFS, OS, and ORR were also improved with cabozantinib in patients without bone metastases. Changes in bone biomarkers were greater with cabozantinib than with everolimus. The overall safety profiles of cabozantinib and everolimus in patients with bone metastases were consistent with those observed in patients without bone metastases. Conclusion Cabozantinib treatment was associated with improved PFS, OS, and ORR when compared with everolimus treatment in patients with advanced RCC and bone metastases and represents a good treatment option for these patients.

Risk factors for bone metastasis from renal cell cancer

Objective

The prognosis for renal cell carcinoma (RCC) is related to a high rate of metastasis, including 30% of bone metastasis. In this study, we investigate the correlation between diverse clinical factors and bone metastases secondary from renal cell cancer (RCC), and to identify potential risk factors for bone metastasis in newly diagnosed patients and those who have already received treatment.

Methods

The clinical data of 372 patients with RCC were reviewed from January 2000 to August 2016. The correlations between age, gender, histopathologic types, alkaline phosphotase (ALP), CEA, AFP, CA-125, CA-153, CA-199, calcium, hemoglobin (HB) and bone metastases were analyzed. And the risk factors for bone metastases in RCC were identified by multivariate logistic regression analysis. The cutoff value, sensitivity and specificity of the independent correlation factors were calculated by receiver operating characteristic (ROC) curve.

Results

The bone is the second to the lung as a distant metastasis target site in patients with RCC. Thirty eight individuals were identified with bone metastases. Of these patients, significantly higher levels of ALP, calcium, HB were found than those without bone metastasis (P < 0.05, respectively). No significant differences were detected in CEA, AFP, CA-125, CA-153, CA-199, age, gender and histopathologic types between patients with and without bone metastases (P > 0.05, respectively). Multivariate logistic regression analysis indicated that ALP, calcium and HB were independent risk factors correlated with bone metastasis (P < 0.05, respectively). ROC curves demonstrated these factors had comparable accuracy at predicting bone metastasis (AUC were 0.749, 0.633 and 0.665, respectively). The cutoff values of ALP, calcium and HB were 105.5 U/L, 2.615 mmol/L and 111.5 g/L, respectively. The sensitivities of them were 57.9%, 36.8% and 71.1% for predicting bone metastasis, with specificities of 83.5%, 95.2% and 65.3%, respectively.

Conclusion

Based on our study, the concentrations of ALP, calcium and HB were potentially risk factors for bone metastasis in patients with RCC. For newly diagnosed patients, if the values of ALP>105.5 U/L, calcium>2.615 mmol/L and HB<111.5 g/L were detected, intensive monitoring and bone scanning are warranted for them.

Outcomes of Patients With Metastatic Renal Cell Carcinoma and Bone Metastases in the Targeted Therapy Era

BACKGROUND

Bone metastases (BMs) occur commonly in patients with metastatic renal cell carcinoma (mRCC). Tyrosine kinase inhibitors (TKIs) have improved the outcomes for patients with mRCC. However, data on the outcomes of mRCC patients with BMs treated with TKIs are limited. We describe the outcomes of patients with BMs treated with TKI therapy and compare them with the outcomes from a pre-TKI group.

PATIENTS AND METHODS

Using an institutional tumor registry, a retrospective review of patients with mRCC from 2002 to 2003 and 2006 to 2007 was performed. The baseline characteristics were analyzed, and overall survival (OS) was estimated using the Kaplan-Meier method. The predictors of OS were analyzed using Cox regression analysis.

RESULTS

The data from 375 patients were reviewed. Of these patients, 188 (50%) started treatment with TKIs and 187 (50%) had started treatment in the pre-TKI era. The distribution of patient characteristics was similar. The sites of organ metastases were equally distributed, including BMs in 48% of the patients in each cohort. The median OS for the patients treated in the TKI era was 22 months (95% confidence interval [CI], 17-25 months) compared with 14 months (95% CI, 10-19 months; P < .01) for the historical controls. A subset analysis of patients with BM in the TKI era demonstrated a median OS of 24 months (95% CI, 17-28 months) compared with 18 months (95% CI, 10-21 months; P < .01) in pre-TKI era. The predictors of shorter OS were a higher Memorial Sloan Kettering Cancer Center score; liver, lung, and brain metastases; and multiple sites of BMs (hazard ratio, 1.38; 95% CI, 1.02-1.91; P = .04). The rate of new BM development was the same in the pre- and post-TKI era.

CONCLUSION

The rate of BM development was the same in the pre- and post-TKI era. The management of BMs in patients with mRCC remains challenging.

Osteonecrosis of the Jaw in Patients With Metastatic Renal Cell Cancer Treated With Bisphosphonates and Targeted Agents: Results of an Italian Multicenter Study and Review of the Literature

Osteonecrosis of the jaw (ONJ) associated with the use of bisphosphonates has been rarely reported in metastatic renal cell cancer (RCC) patients. Since the introduction of combined therapies consisting of nitrogen-containing bisphosphonates (NBPs) and targeted agents, an increasing number of RCC patients were reported to develop ONJ, suggesting that therapeutic angiogenesis suppression might increase the risk of ONJ in NBPs users. We performed a multicenter retrospective study and reviewed literature data to assess the occurrence and to investigate the nature of ONJ in RCC patients taking NBPs and targeted agents. Nine Italian Centers contributed to the data collection. Patients with exposed and nonexposed ONJ were eligible for the study if they had been taking NBPs and were receiving targeted agents at the time of ONJ diagnosis. Forty-four RCC patients were studied. Patients were mostly male (82%), with a median age of 63 years (range, 45-85 years). Zoledronic acid (93%) and sunitinib (80%) were the most frequently used NBP and antiangiogenic agent, respectively. Other agents included Pamidronate, ibandronate, sorafenib, bevacizumab, mammalian target of rapamycin inhibitors. Forty-nine sites of ONJ were encountered, with the mandible being the preferred site of ONJ (52%); both jaws were affected in 5 cases (12%). The most common precipitating event was dental/periodontal infection (34%), followed by tooth extraction (30%). Oral triggers of ONJ were missing in 10 cases (23%). This unexpectedly high number of ONJ cases, in comparison with literature data, suggests that frequency of ONJ in RCC patients might be largely underestimated and suggests a potential role for targeted agents in the incremental risk of ONJ.

Three-dimensional (3D) culture of bone-derived human 786-O renal cell carcinoma retains relevant clinical characteristics of bone metastases

Bone metastases from renal cell carcinoma (RCC) are typically lytic, destructive, and resistant to treatment regimens. Current in vitro models for studying metastasis introduce artifacts that limit their usefulness. Many features of tumors growing in bone are lost when human RCC cells are cultured in two-dimensional (2D) plastic substrata. In this study, we established that RCC spheroids, consisting of aggregates of cells, can be grown in a three-dimensional (3D) hyaluronate hydrogel-based culture system. The bone-derived human 786-O RCC subline proliferated and survived long term in these hydrogels. Additionally, RCC spheroids in 3D hydrogels demonstrated lower proliferation rates than their counterparts grown in 2D. Overall, gene expression patterns of RCC spheroids in 3D more closely mimicked those observed in vivo than did those of cells grown in 2D. Of particular importance, selected adhesion molecules, angiogenesis factors, and osteolytic factors that have been shown to be involved in RCC bone metastasis were found to be expressed at higher levels in 3D than in 2D cultures. We propose that the 3D culture system provides an improved platform for RCC bone metastasis studies compared with 2D systems.

The Impact of Immune System in Regulating Bone Metastasis Formation by Osteotropic Tumors

Bone metastases are frequent and debilitating consequence for many tumors, such as breast, lung, prostate, and kidney cancer. Many studies report the importance of the immune system in the pathogenesis of bone metastasis. Indeed, bone and immune system are strictly linked to each other because bone regulates the hematopoietic stem cells from which all cells of the immune system derive, and many immunoregulatory cytokines influence the fate of bone cells. Furthermore, both cytokines and factors produced by immune and bone cells promote the growth of tumor cells in bone, contributing to supporting the vicious cycle of bone metastasis. This review summarizes the current knowledge on the interactions among bone, immune, and tumor cells aiming to provide an overview of the osteoimmunology field in bone metastasis from solid tumors.

Alterations in enhancer of zeste homolog 2, matrix metalloproteinase-2 and tissue inhibitor of metalloproteinase-2 expression are associated with ex vivo and in vitro bone metastasis in renal cell carcinoma

Renal cell carcinoma (RCC) has a high potential for bone metastasis; however, the molecular mechanisms underlying this metastasis have remained to be elucidated. The present study aimed to explore the expression levels of enhancer of zeste homolog 2 (EZH2), matrix metalloproteinase-2 (MMP2) and tissue inhibitor of metalloproteinase-2 (TIMP2) as determinants of RCC-associated bone metastasis. Their expression was evaluated in a newly generated RCC cell subline that has a high potential for bone metastasis, in tissue specimens from metastasized bone tissues from patients with RCC and in RCC tissues without metastasis. A total of 25 RCC tissue specimens without metastasis and 13 RCC tissue specimens with bone metastasis were acquired for immunohistochemical analysis of EZH2, MMP2 and TIMP2 protein expression. The expression levels of EZH2, MMP2 and TIMP2 mRNA and protein were analyzed in the ACHN and ACHN-BO5 cell lines using western blot and reverse transcription polymerase chain reaction (PCR) analyses. Methylation-specific PCR was also used to analyze TIMP2 promoter methylation. EZH2 and MMP2 proteins were found to be expressed at higher levels in tissues from patients where RCC had metastasized to the bone as compared with those in RCC patients without metastasis, whereas there was no significant difference in the expression of TIMP2 protein between the two tissues. Furthermore, the expression of EZH2 protein was correlated with MMP2 expression, but there was no significant correlation between the expression of EZH2 and TIMP2 proteins. The in vitro results using cell lines confirmed the ex vivo findings, indicating that the expression levels of EZH2 and MMP2 protein and mRNA were higher in ACHN-BO5 cells than those in ACHN cells. By contrast, TIMP2 protein and mRNA expression levels were lower in ACHN-BO5 cells than those in the parental ACHN cells. The TIMP2 promoter was highly methylated in ACHN-BO5 cells compared with that in ACHN cells. Upregulation of EZH2, MMP2 and TIMP2 expression was correlated with metastasis of RCC to bone tissues ex vivo and in vitro. Further studies are required in order to elucidate the mechanism underlying the altered expression of these genes.

Bone turnover markers in serum and urine as diagnostic, prognostic and monitoring biomarkers of bone metastasis

Bone metastases are characterized by increased osteoblastic and/or osteolytic processes depending on the tumor type. The altogether destructive effect of metastasis formation promoted by increased metabolic activity raises the release of components from the osseous metabolism into the blood stream. These components are either enzymes directly involved in the alteration processes, metabolites/proteins that develop during this or bone matrix proteins released during this. These biomarkers are categorized in relation to their involvement in the bone formation or resorption as bone formation and resorption markers. Based on a PubMed literature search, a critical appraisal of the various biomarkers for diagnostic, prognostic, and monitoring purposes is given for patients with skeletal metastases caused by breast, prostate, lung, or renal cell carcinomas.

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.

Development of a realistic in vivo bone metastasis model of human renal cell carcinoma

About one-third of patients with advanced renal cell carcinoma (RCC) have bone metastases. The incidence of RCC is increasing and bone metastatic RCC merits greater focus. Realistic preclinical bone metastasis models of RCC are lacking, hampering the development of effective therapies. We developed a realistic in vivo bone metastasis model of human RCC by implanting precision-cut tissue slices under the renal capsule of immunodeficient mice. The presence of disseminated cells in bone marrow of tissue slice graft (TSG)-bearing mice was screened by human-specific polymerase chain reaction and confirmed by immunohistology using human-specific antibody. Disseminated tumor cells in bone marrow of TSG-bearing mice derived from three of seven RCC patients were detected as early as 1 month after tissue implantation at a high frequency with close resemblance to parent tumors (e.g., CAIX expression and high vascularity). The metastatic patterns of TSGs correlated with disease progression in patients. In addition, TSGs retained capacity to metastasize to bone at high frequency after serial passaging and cryopreservation. Moreover, bone metastases in mice responded to Temsirolimus treatment. Intratibial injections of single cells generated from TSGs showed 100 % engraftment and produced X-ray-visible tumors as early as 3 weeks after cancer cell inoculation. Micro-computed tomography (μCT) and histological analysis revealed osteolytic characteristics of these lesions. Our results demonstrated that orthotopic RCC TSGs have potential to develop bone metastases that respond to standard therapy. This first reported primary RCC bone metastasis model provides a realistic setting to test therapeutics to prevent or treat bone metastases in RCC.

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.