Implications of bone metastasis on response to systemic therapy in patients with advanced renal cell carcinoma: A systematic literature review.

INTRODUCTION: Bone metastases negatively affect prognosis in patients with advanced renal cell carcinoma (aRCC). We conducted a systematic literature review to identify clinical trial publications including patients with aRCC with and without bone metastases. METHODS: The review was conducted according to Preferred Reporting Items for Systematic Reviews and Meta­Analyses (PRISMA) guidelines and registered with PROSPERO (CRD42022355436). MEDLINE and Embase databases were searched (September 2, 2022) to identify publications reporting efficacy and safety outcomes for patients with/without bone metastasis from clinical trials of systemic RCC therapies. Risk of bias was assessed using Grading of Recommendations Assessment, Development and Evaluation (GRADE). RESULTS: Of 526 publications screened, 19 were eligible: seven (from five studies) reported phase 3 trials, six reported phase 2 trials, one reported phase 1b/2 trials, and five were pooled analyses. Five publications reported moderate-quality evidence, while 14 were graded as low- or very low-quality evidence, suggesting a high potential for uncertainty. Five studies reported benefits of investigational therapies versus comparators in patients with and without bone metastases; these studies included cabozantinib, nivolumab, cabozantinib plus nivolumab, and lenvatinib plus pembrolizumab treatment arms. Data were also available for nivolumab plus ipilimumab. Bone metastases were consistently associated with poor prognosis in patients with aRCC. Preliminary data support the hypothesis that therapies targeting pathways implicated in the development of bone metastases may be beneficial, and warrant further investigation. However, data to support treatment decision-making are lacking. CONCLUSION: Our findings highlight the need for clinical data to assist in defining the optimal treatment for patients with aRCC and bone metastasis.

CEACAM6 Promotes Lung Metastasis via Enhancing Proliferation, Migration and Suppressing Apoptosis of Prostate Cancer Cells.

BACKGROUND/AIM: Metastatic prostate cancer (mPCa) results in high morbidity and mortality. Visceral metastases in particular are associated with a shortened survival. Our aim was to unravel the molecular mechanisms that underly pulmonary spread in mPCa. MATERIALS AND METHODS: We performed a comprehensive transcriptomic analysis of PCa lung metastases, followed by functional validation of candidate genes. Digital gene expression analysis utilizing the NanoString technology was performed on mRNA extracted from formalin-fixed, paraffin-embedded (FFPE) tissue from PCa lung metastases. The gene expression data from primary PCa and PCa lung metastases were compared, and several publicly available bioinformatic analysis tools were used to annotate and validate the data. RESULTS: In PCa lung metastases, 234 genes were considerably up-regulated, and 78 genes were significantly down-regulated when compared to primary PCa. Carcinoembryonic antigen-related cell adhesion molecule 6 (CEACAM6) was identified as suitable candidate gene for further functional validation. CEACAM6 as a cell adhesion molecule has been implicated in promoting metastatic disease in several solid tumors, such as colorectal or gastric cancer. We showed that siRNA knockdown of CEACAM6 in PC-3 and LNCaP cells resulted in decreased cell viability and migration as well as enhanced apoptosis. Comprehensive transcriptomic analyses identified several genes of interest that might promote metastatic spread to the lung. CONCLUSION: Functional validation revealed that CEACAM6 might play an important role in fostering metastatic spread to the lung of PCa patients via enhancing proliferation, migration and suppressing apoptosis in PC-3 and LNCaP cells. CEACAM6 might pose an attractive therapeutic target to prevent metastatic disease.

Bone Metastases in Non-Seminomatous Germ Cell Tumors: A 20-Year Retrospective Analysis.

Background: Non-seminomatous germ cell tumors (NSGCTs) represent a rare yet the most prevalent malignancy among young men. Bone metastases (BMs) are exceedingly uncommon in this neoplasm, and available data regarding the initial disease presentation, survival outcomes, and prognostic significance of BMs are limited. Methods: We conducted a retrospective analysis of 40 NSGCT patients with BMs treated between 2001 and 2021 in our tertiary care center. The cohort was stratified into synchronous (n = 29) and metachronous (n = 11) groups based on the presence of BM at diagnosis or only at relapse, respectively. We assessed overall survival (OS), progression-free survival (PFS), disease presentation, and treatments. Results: After a median follow-up of 93 months, the 5-year PFS and OS rates were 37.6% and 53.9% in the synchronous group and 18.2% and 36.4% in the metachronous group, respectively. At the initial diagnosis, most patients were classified into the IGCCCG poor prognostic group (n = 34, 85%). BMs were mostly asymptomatic (n = 23, 57.5%), involved the spine (n = 37, 92.5%), and could become visible only after disease response (n = 4, 10%). A pathological examination of resected bone lesions after first-line treatment revealed necrosis (n = 5, 71.4%), teratoma, or seminoma (both n = 1, 14.3%). At first relapse, eight patients in the synchronous group did not experience bone recurrence, while eight patients experienced recurrence at the initial affected bone site. Conclusions: In NSGCT patients, BMs often present asymptomatically and may initially be unnoticed. However, these patients may have a poorer prognosis compared to those in the IGCCCG poor prognostic group. Further studies including control groups are needed to assess the independent prognostic significance of BMs.

Site-Specific Response and Resistance Patterns in Patients with Advanced Non-Small-Cell Lung Cancer Treated with First-Line Systemic Therapy.

Patients with advanced NSCLC have heterogenous responses to immune checkpoint inhibitors (ICIs) with or without chemotherapy. In NSCLC, the impact of the distribution of metastatic sites and the response to systemic therapy combinations remain poorly understood. In a retrospective cohort study of patients with unresectable stage III/IV NSCLC who received first-line systemic therapy, we sought to assess the association between the site of metastases with patterns of response and progression. Data regarding demographics, tumour characteristics (including site, size, and volume of metastases), treatment, and outcomes were examined at two cancer care centres. The endpoints included organ site-specific response rate, objective response rate (ORR), progression-free survival (PFS), and overall survival (OS). Two-hundred and eighty-five patients were included in the analysis. In a multivariate analysis, patients with bone metastases had a reduced ORR, PFS, and OS. Primary resistance was also more likely in patients with bone metastases. Patients with bone or liver metastases had a shorter OS when receiving ICIs with or without chemotherapy, but not with chemotherapy alone, suggesting an immunological basis for therapeutic resistance. A directed assessment of the tumour microenvironment in these locations and a deeper understanding of the drivers of organ-specific resistance to immunotherapy are critical to optimise novel combination therapies and sequencing in these patients.

IL-23 inhibitor enhances the effects of PTEN DNA-loaded lipid nanoparticles for metastatic CRPC therapy.

Introduction: Metastatic castration-resistant prostate cancer (mCRPC) patients face challenges due to limited treatment options. About 50% of patients with mCRPC have a functional loss of phosphatase and tensin homology deleted on chromosome 10 (PTEN), leading to tumor progression, metastasis, and immune suppression. Moreover, elevated IL-23 produced by myeloid-derived suppressor cells (MDSCs) is found in CRPC patients, driving tumor progression. Therefore, a combination strategy based on PTEN restoration and IL-23 inhibition may block CRPC progression and metastasis. Methods: The antitumor effect of restoring PTEN expression combined with the IL-23 inhibitor Apilimod was studied in a mouse model of bone metastasis CRPC and mouse prostate cancer RM-1 cells. To verify the targeting ability of PTEN DNA coated with lipid nanoparticles (LNP@PTEN) in vitro and in vivo. In addition, RT-qPCR and flow cytometry were used to investigate the related mechanisms of the antitumor effect of LNP@PTEN combined with Apilimod. Results: LNPs exhibited significant tumor-targeting and tumor accumulation capabilities both in vitro and in vivo, enhancing PTEN expression and therapeutic efficacy. Additionally, the combination of LNP@PTEN with the IL-23 inhibitor Apilimod demonstrated enhanced inhibition of tumor growth, invasion, and metastasis (particularly secondary organ metastasis) compared to other groups, and extended the survival of mice to 41 days, providing a degree of bone protection. These effects may be attributed to the PTEN function restoration combined with IL-23 inhibition, which help reverse immune suppression in the tumor microenvironment by reducing MDSCs recruitment and increasing the CD8+/CD4+ T cell ratio. Discussion: In summary, these findings highlight the potential of LNPs for delivering gene therapeutic agents. And the combination of LNP@PTEN with Apilimod could achieve anti-tumor effects and improve tumor microenvironment. This combinational strategy opens new avenues for the treatment of mCRPC.

Prognostic factors of patients with thyroid cancer and bone metastasis at presentation.

Objective: While bone metastases (BMs) are present in a minority of thyroid cancer (TC) patients at the time of initial diagnosis, there has been growing concern regarding their impact on life expectancy and quality of life. The aim of this study was to identify prognostic factors associated with overall survival (OS) and cancer-specific survival (CSS) in these patients and provide therapeutic recommendations based on the findings. Methods: In this retrospective cohort study, we included 82 patients diagnosed as TC with BM received treatment in our department from 2011.03 to 2023.03 (average follow-up duration was 3.02 years). The retrospective study was performed according to the inclusion and exclusion criteria. Kaplan-Meier analysis was used to estimate the OS and CSS, while the univariate and multivariate Cox proportional hazard models were employed to determine prognostic factors associated with OS and CSS. Also, 287 patients' data were collected from the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) database between 2010 and 2015 to confirm the prognostic factors identified in the retrospective study. Results: The average survival time of the 82 patients was estimated to be 5.818 years (with a 95% confidence interval (CI) of 4.767 to 6.868 years). The cox regression analysis showed that older age (hazard ratio (HR) = 1.045, 95% CI: 1.001-1.092, P = 0.047), larger tumor size (>5cm, HR = 11.087, 95% CI: 3.728 - 32.976, P = 0.000), and the presence of extraosseous metastasis (HR = 3.247, 95% CI: 1.376 - 7.665, P = 0.007) were statistically significant factors associated with worse CSS. The results were furtherly confirmed in 287 SEER-sourced patients (age (HR = 1.020, 95% CI: 1.006 - 1.034, P = 0.006), tumor size (HR = 2.917, 95% CI: 2.044 - 4.161, P = 0.000), and extraosseous metastasis (HR = 3.726, 95% CI: 2.571 - 5.398, P = 0.000)). Conclusions: These results offer a population-based assessment of prognostic factors for patients with TC and BMs, revealing that age, primary tumor size (>5cm), and presence of extraosseous metastases are independent prognostic factors that correlate with worse survival. Accordingly, treatment for such patients ought to concentrate on systemic integrative therapy instead of surgical intervention.

Re-treatment of bone metastases for pain control: 2023 ASTRO education panel.

Bone metastases are a common and debilitating consequence of advanced cancer, often necessitating palliative radiation therapy (RT) for pain relief. Reirradiation (reRT) of bone metastases is often considered after lack of pain relief following an initial course of RT, after a partial but unsatisfying pain response to an initial course of radiotherapy, or after pain recurrence following a complete or partial pain response to an initial course of RT. The NCIC CTG SC.20 trial, a landmark multicenter, randomized, non-blinded, controlled non-inferiority trial, addressed the critical question of optimal dose fractionation for reRT in this patient population. This trial compared the efficacy and toxicity of a single 8 Gy fraction to multiple fractions totaling 20 Gy in 850 patients with painful bone metastases requiring reRT. The primary endpoint was overall pain response at 2 months, with secondary endpoints of quality of life (QoL) measures, functional interference, and toxicity profiles assessed using patient-reported questionnaires and the European Organisation for Research and Treatment of Cancer (EORTC) QLQ-C30. The intention-to-treat analysis revealed no significant difference in pain response between the two arms, meeting the pre-specified non-inferiority criteria. The per-protocol analysis suggested a potential benefit for a subset of patients receiving multiple fractions, although this was not statistically robust. Acute toxicities were more prevalent in the multiple fractions arm, with implications for patient comfort and healthcare utilization. Importantly, responders to reRT reported significant improvements in functional interference and QoL. The trial's findings support the use of a patient-centric approach to palliative RT, highlighting the viability of a single 8 Gy fraction as a less toxic and more convenient treatment option, albeit with consideration for individual patient circumstances. These results have significant implications for clinical practice, potentially reducing healthcare burdens while optimizing patient convenience during palliative care for painful bone metastases.

Quality of palliative radiotherapy assessed using quality indicators: a multicenter survey†.

We sought to identify potential evidence-practice gaps in palliative radiotherapy using quality indicators (QIs), previously developed using a modified Delphi method. Seven QIs were used to assess the quality of radiotherapy for bone metastases (BoM) and brain metastases (BrM). Compliance rate was calculated as the percentage of patients for whom recommended medical care was conducted. Random effects models were used to estimate the pooled compliance rates. Of the 39 invited radiation oncologists, 29 (74%) from 29 centers participated in the survey; 13 (45%) were academic and 16 (55%) were non-academic hospitals. For the QIs, except for BoM-4, the pooled compliance rates were higher than 80%; however, for at least some of the centers, the compliance rate was lower than these pooled rates. For BoM-4 regarding steroid use concurrent with radiotherapy for malignant spinal cord compression, the pooled compliance rate was as low as 32%. For BoM-1 regarding the choice of radiation schedule, the compliance rate was higher in academic hospitals than in non-academic hospitals (P = 0.021). For BrM-3 regarding the initiation of radiotherapy without delay, the compliance rate was lower in academic hospitals than in non-academic hospitals (P = 0.016). In conclusion, overall, compliance rates were high; however, for many QIs, practice remains to be improved in at least some centers. Steroids are infrequently used concurrently with radiotherapy for malignant spinal cord compression.

Practical management of renal cell carcinoma: integrating current approaches with advances in bone metastasis treatment.

Renal cell carcinoma (RCC) is a common type of tumor that can develop in the kidney. It is responsible for around one-third of all cases of neoplasms. RCC manifests itself in a variety of distinct subtypes. The most frequent of which is clear cell RCC, followed by papillary and chromophobe RCC. RCC has the potential for metastasis to a variety of organs; nevertheless, bone metastases are one of the most common and potentially fatal complications. These bone metastases are characterized by osteolytic lesions that can result in pathological fractures, hypercalcemia, and other complications, which can ultimately lead to a deterioration in quality of life and an increase morbidity. While nephrectomy remains a foundational treatment for RCC, emerging evidence suggests that targeted therapies, including tyrosine kinase inhibitors and T cell checkpoint inhibitors, may offer effective alternatives, potentially obviating the need for adjuvant nephrectomy in certain cases of metastatic RCC Bone metastases continue to be a difficult complication of RCC, which is why more research is required to enhance patient outcome.

Retrospective Evaluation of Bone Turnover Markers in Serum for the Prediction of Metastases Development in Breast Cancer Patients: A Cohort Study.

BACKGROUND: Serum bone turnover markers might play a role in the prediction of the development of bone metastases in breast cancer (BC) patients. We conducted a retrospective cohort study to address the association of serum bone turnover markers with oncologic outcomes. METHODS: We included 80 women with BC, who were operated on at the Department of Gynecology, Obstetrics and Reproductive Medicine, Homburg/Saar, Germany. Serum samples were obtained prior to surgery and were used for estimation of the concentration of tumor and bone turnover markers using enzyme-linked immunosorbent assay (ELISA) and radioimmunoassay (RIA). RESULTS: At baseline, pyridinoline cross-linked carboxy-terminal telopeptide of type-1 collagen (ICTP) concentrations were higher in nodal positive vs. negative tumors (Mann-Whitney test p = 0.04). After a median follow-up of 79.4 months, 17 patients developed metastases, with 9 demonstrating, among other organs, osseous metastases. ICTP demonstrated the best area under the curve in the predection of osseous metastases in our cohort (AUC = 0.740, DeLong Test p = 0.005). Univariable Cox proportional hazard models failed to demonstrate significant associations between serum bone turnover markers and oncologic outcomes (progression-free survival, overall survival). CONCLUSIONS: Serum bone turnover markers (e.g., ICTP) were able to predict the development of osseous metastases but were not associated with oncologic outcomes. Further investigation and validation are required for the use of such markers in clinical practice.

Development of a predictive model to predict postoperative bone metastasis in pathological I-II non-small cell lung cancer.

Background: Bone is a common metastatic site in postoperative metastasis, but related risk factors for early-stage non-small cell lung cancer (NSCLC) remain insufficiently investigated. Thus, the study aimed to identify risk factors for postoperative bone metastasis in early-stage NSCLC and construct a nomogram to identify high-risk individuals. Methods: Between January 2015 and January 2021, we included patients with resected stage I-II NSCLC at the Department of Thoracic Surgery, West China Hospital. Univariable and multivariable Cox regression analyses were used to identify related risk factors. Additionally, we developed a visual nomogram to forecast the likelihood of bone metastasis. Evaluation of the model involved metrics such as the area under the curve (AUC), C-index, and calibration curves. To ensure reliability, internal validation was performed through bootstrap resampling. Results: Our analyses included 2,106 eligible patients, with 54 (2.56%) developing bone metastasis. Multivariable Cox analyses showed that tumor nodules with solid component, higher pT stage, higher pN stage, and histologic subtypes especially solid/micropapillary predominant types were considered as independent risk factors of bone metastasis. In the training set, the developed model demonstrated AUCs of 0.807, 0.769, and 0.761 for 1-, 3-, and 5-year follow-ups, respectively. The C-index, derived from 1,000 bootstrap resampling, showed values of 0.820, 0.793, and 0.777 for 1-, 3-, and 5-year follow-ups. The calibration curve showed that the model was well calibrated. Conclusions: The predictive model is proven to be valuable in estimating the probability of bone metastasis in early-stage NSCLC following surgery. Leveraging four easy-to-acquire clinical parameters, this model effectively identifies high-risk patients and enables individualized surveillance strategies for better patient care.

Microenvironment-Responsive Targeted Nanomedicine for a Collaborative Integration of Tumor Theranostics and Bone Defect Repair.

Despite advancements in breast cancer treatment, bone metastases remain a significant concern for advanced breast cancer patients. Current theranostics strategies face challenges in integrating tumor theranostics and bone formation. Herein, this work develops an activatable targeted nanomedicine AuMnCO@BSA-N3 (AMCBN) to enable a novel collaborative integration of second near-infrared (NIR-II) fluorescence imaging guided precise theranostics for breast cancer bone metastases and osteogenic microenvironment remolding. This strategy employs a chemical coordination between noble metal complex and metal carbonyl (MnCO), with surface modification of azide groups to enhance tumor affinity through passive and active targeting. The initiated respondent behavior of AMCBN by tumor microenvironment accelerate the degradation of coordinated MnCO, resulting in a rapid release of multifunctional agents for efficient chemodynamic therapy (CDT)/gas synergistic therapy. Meanwhile, the exceptional bone-binding properties enable the efficient and controlled release of Mn2+ ions and carbon monoxide (CO) in the bone microenvironment, thereby facilitating the expression of osteogenesis-related proteins and establishing a novel synchronous theranostics process for tumor-bone repair.

Myonecrosis as a rare side effect of stereotactic body radiotherapy for bone metastases: Report of two cases and a comprehensive literature review.

Stereotactic body radiotherapy is a highly effective form of radiation therapy for palliation of bone metastases, but it can also lead to rare but severe side effects, such as myonecrosis. According to the literature, the incidence of myonecrosis after stereotactic body radiotherapy is low and mostly dose dependent. It is crucial to consider the potential impact of immunotherapy and other systemic therapies in the assessment. The course of radiation myonecrosis can vary, and corticosteroids or vascular endothelial growth factor inhibitors may potentially play a role in its treatment. Herein, we report two patients presenting with myonecrosis after stereotactic body radiotherapy for bone metastasis.

Multimodal Treatment of Metastatic Rectal Cancer in a Young Patient: Case Report and Literature Review.

Metastatic colorectal cancer requires a multidisciplinary and individualized approach. Herein, we reported the case of a young woman diagnosed with metastatic rectal cancer who received an individualized multimodal treatment strategy that resulted in a remarkable survival. There were several particular aspects of this case, such as the early onset of the disease, the successful use of conversion therapy, the application of liquid biopsy to guide treatment, and the specific nature of the bone metastasis. To offer more insights for navigating such challenges in patients with metastatic colorectal cancer, we have conducted a literature review to find more data related to the particularities of this case. The incidence of early onset colorectal cancer is on the rise. Data suggests that it differs from older-onset colorectal cancer in terms of its pathological, epidemiological, anatomical, metabolic, and biological characteristics. Conversion therapy and surgical intervention provide an opportunity for cure and improve outcomes in metastatic colorectal cancer. It is important to approach each case individually, as every patient with limited liver disease should be considered as a candidate for secondary resection. Moreover, liquid biopsy has an important role in the individualized management of metastatic colorectal cancer patients, as it offers additional information for treatment decisions.

Incidence, Risk Factors, and Survival of Bone Metastases and Skeletal-Related Events in Melanoma Patients: A Systematic Review and Quality Assessment of 29 Studies.

Background: Skeletal metastases make up 17% of all metastases from advanced-stage melanoma. Bone metastases are associated with increased morbidity and mortality and decreased quality of life due to their association with skeletal-related events (SREs), including pathological fracture, spinal cord compression, hypercalcemia, radiotherapy, and surgery. The study aimed to determine the incidence of bone metastases and SREs in melanoma, identify possible risk factors for the development of bone metastases and SREs, and investigate survival rates in this patient population. Methods: A computer-based literature search was conducted using Pubmed, Embase, and Cochrane Central Register of Controlled Trials up to July 2023. The Newcastle-Ottawa Quality Assessment Scale (NOS) was utilized for quality assessment. Study characteristics, patient information, risk factors for developing bone metastases and SREs, and characteristics for survival were recorded. Results: We included 29 studies. The average bone metastasis-free interval ranged from four to 72 months. Incidence of bone metastases varied from 2 % to 49 % across 14 studies. 69 % (20/29) of studies described the location of bone metastases, with 24 % (7/29) focusing solely on spinal metastases. In one study, 129 SREs were recorded in 71 % (59/83) of the patient cohort, with various manifestations. The use of bone-directed agents was independently associated with lower risk of SREs. Survival after detection of bone metastasis ranged from three to 13 months. Factors associated with survival included clinical, tumor-related, and treatment features. Conclusion: This review highlights the notable prevalence and risk factors of developing bone metastases and subsequent SREs in patients with melanoma. The surge in bone metastases poses a challenge in complication management, given the high prevalence of SREs. While this study offers a comprehensive overview of the incidence, risk factors, and outcomes associated with bone metastases and SREs in melanoma patients that may guide patient and physician decision-making, a notable gap lies in the limited availability of high-quality data and the heterogeneous design of the existing literature. Future research should address predictive factors for bone metastases and SREs in melanoma to facilitate patient and physician decision-making and ultimately improve outcomes in this patient population.

From Tumor to Bone: Growth Factor Receptors as Key Players in Cancer Metastasis.

This review article explores the intricate correlation between growth factors and bone metastases, which play a crucial role in the development of several types of malignancies, namely breast, prostate, lung, and renal cancers. The focal point of our discussion is on crucial receptors for growth factors, including Epidermal Growth Factor Receptor (EGFR), Transforming Growth Factor-ß (TGFß), Vascular Endothelial Growth Factor Receptor (VEGFR), and Fibroblast Growth Factor Receptor (FGFR). These receptors, which are essential for cellular activities including growth, differentiation, and survival, have important involvement in the spread of cancer and the interactions between tumors and the bone environment. We discuss the underlying mechanisms of bone metastases, with a specific emphasis on the interaction between growth factor receptors and the bone microenvironment. EGFR signaling specifically enhances the process of osteoclast development and the formation of osteolytic lesions, especially in breast and lung malignancies. TGFß receptors have a role in both osteolytic and osteoblastic metastases by releasing TGFß, which attracts cancer cells and promotes bone remodeling. This is a crucial element in the spread of prostate cancer to the bones. The functions of FGFR and VEGFR in the processes of bone formation and tumor angiogenesis, respectively, highlight the complex and diverse nature of these interactions. The review emphasizes the possibility of targeted therapeutics targeting these receptors to interrupt the cycle of tumor development and bone degradation. Therapeutic approaches include focusing on the VEGF/VEGFR, EGF/EGFR, FGF/FGFR, and TGFß/TGFßR pathways. These include a variety of compounds, such as small molecule inhibitors and monoclonal antibodies, which have shown potential to interfere with tumor-induced alterations in bone. The text discusses clinical trials and preclinical models, offering insights into the effectiveness and constraints of various treatments. Ultimately, this study provides a succinct but thorough summary of the present knowledge and treatment strategies focused on growth factor receptors in bone metastases. This highlights the significance of comprehending the signaling of growth factor receptors in the microenvironment where tumors spread to the bones, as well as the possibility of using targeted therapies to enhance the results for cancer patients with bone metastases. The advancement of treating bone metastases hinges on the development of treatments that specifically target the intricate relationships between malignancies and bone.

Efficacy of Combination Therapy With Radium-223 and Enzalutamide in Castration-resistant Prostate Cancer With Bone Metastases.

BACKGROUND/AIM: Radium-223 therapy has been reported to improve prognosis in patients with castration-resistant prostate cancer (CRPC) and bone metastases. Occasionally, radium-223 and androgen receptor signaling inhibitors (ARSIs) are used in combination for disease control, but the efficacy of this combination is unclear. This study assessed the efficacy of the addition of enzalutamide in patients treated with radium-223. PATIENTS AND METHODS: We included patients with CRPC and bone metastases who were treated with radium-223 at our institution. Patients were assigned to the enzalutamide combination group or non-combination group. We compared progression-free survival (PFS), overall survival (OS), and the completion rate of radium-223 between the two groups. RESULTS: In total, 39 patients with CRPC were included in this retrospective study. The median follow-up duration was 8.8 months. The enzalutamide combination and non-combination groups included 22 (56.4%) and 17 patients (43.6%), respectively. Median PFS was 11.3 months [95% confidence interval (CI)=3.9-19.9] in the combination group, versus 3.0 months (95%CI=1.9-5.5) in the non-combination group (p=0.004). Median OS did not significantly differ between the groups. The radium-223 completion rate was higher in the combination group than in the non-combination group (72.7% vs. 35.3%, p=0.026). CONCLUSION: The combined use of enzalutamide with radium-223 therapy improved PFS and treatment completion rates in patients with CRPC and bone metastases. This combination may be associated with a more favorable prognosis.

Interrogating Estrogen Signaling Pathways in Human ER-Positive Breast Cancer Cells Forming Bone Metastases in Mice.

Breast cancer bone metastases (BMET) are incurable, primarily osteolytic, and occur most commonly in estrogen receptor-α positive (ER+) breast cancer. ER+ human breast cancer BMET modeling in mice has demonstrated an estrogen (E2)-dependent increase in tumor-associated osteolysis and bone-resorbing osteoclasts, independent of estrogenic effects on tumor proliferation or bone turnover, suggesting a possible mechanistic link between tumoral ERα-driven osteolysis and ER+ bone progression. To explore this question, inducible secretion of the osteolytic factor, parathyroid hormone-related protein (PTHrP), was utilized as an in vitro screening bioassay to query the osteolytic potential of estrogen receptor- and signaling pathway-specific ligands in BMET-forming ER+ human breast cancer cells expressing ERα, ERß, and G protein-coupled ER. After identifying genomic ERα signaling, also responsibility for estrogen's proliferative effects, as necessary and sufficient for osteolytic PTHrP secretion, in vivo effects of a genomic-only ER agonist, estetrol (E4), on osteolytic ER+ BMET progression were examined. Surprisingly, while pharmacologic effects of E4 on estrogen-dependent tissues, including bone, were evident, E4 did not support osteolytic BMET progression (vs robust E2 effects), suggesting an important role for nongenomic ER signaling in ER+ metastatic progression at this site. Because bone effects of E4 did not completely recapitulate those of E2, the relative importance of nongenomic ER signaling in tumor vs bone cannot be ascertained here. Nonetheless, these intriguing findings suggest that targeted manipulation of estrogen signaling to mitigate ER+ metastatic progression in bone may require a nuanced approach, considering genomic and nongenomic effects of ER signaling on both sides of the tumor/bone interface.