Incidence, prevalence, and outcomes of systemic malignancy with bone metastases

Advancements in the development of radiopharmaceuticals for nuclear medicine applications in the treatment of bone metastases

Bone metastases are a painful and complex condition that overwhelmingly impacts the prognosis and quality of life of cancer patients. Over the years, nuclear medicine has made remarkable progress in the diagnosis and management of bone metastases. This review aims to provide a comprehensive overview of the recent advancements in nuclear medicine for the diagnosis and management of bone metastases. Furthermore, the review explores the role of targeted radiopharmaceuticals in nuclear medicine for bone metastases, focusing on radiolabeled molecules that are designed to selectively target biomarkers associated with bone metastases, including osteocytes, osteoblasts, and metastatic cells. The applications of radionuclide-based therapies, such as strontium-89 (Sr-89) and radium-223 (Ra-223), are also discussed. This review also highlights the potential of theranostic approaches for bone metastases, enabling personalized treatment strategies based on individual patient characteristics. Importantly, the clinical applications and outcomes of nuclear medicine in osseous metastatic disease are discussed. This includes the assessment of treatment response, predictive and prognostic value of imaging biomarkers, and the impact of nuclear medicine on patient management and outcomes. The review identifies current challenges and future perspectives on the role of nuclear medicine in treating bone metastases. It addresses limitations in imaging resolution, radiotracer availability, radiation safety, and the need for standardized protocols. The review concludes by emphasizing the need for further research and advancements in imaging technology, radiopharmaceutical development, and integration of nuclear medicine with other treatment modalities. In summary, advancements in nuclear medicine have significantly improved the diagnosis and management of osseous metastatic disease and future developements in the integration of innovative imaging modalities, targeted radiopharmaceuticals, radionuclide production, theranostic approaches, and advanced image analysis techniques hold great promise in improving patient outcomes and enhancing personalized care for individuals with bone metastases.

Evaluation of Different Regimens of Palliative Radiation Therapy for Symptomatic Bone Metastases: An Audit From a Tertiary Care Hospital in Jharkhand, India

Background This study aimed to assess the efficacy of different radiation therapy regimens in treating patients with symptomatic bone metastases. Methodology A retrospective study was conducted by assigning patients with symptomatic bone metastases from different primary cancers into three groups, namely, Arms A, B, and C. The radiation dose delivered in each arm was as follows: 8 Gray (Gy) in a single fraction for Arm A, 20 Gy in five fractions at the rate of 4 Gy per fraction for Arm B, and 30 Gy in 10 fractions at the rate of 3 Gy per fraction for Arm C. Each arm consisted of 15 patients. A comparison was conducted across all three arms to evaluate pain relief based on the Visual Analog Scale (VAS), performance score improvement based on the Eastern Cooperative Oncology Group (ECOG), and analgesic requirement based on the World Health Organization (WHO) step ladder at one week, one month, and three months. Results The pain relief was measured using the VAS in three different arms, i.e., Arm A, B, and C. After one week, the pain relief was 66.67%, 60%, and 60%, respectively. After one month, it was 73.33% in all three arms. At three months, it was 80%, 86.67%, and 86.67%, respectively. The study also measured the improvement in the ECOG performance score. The improvement in all three arms was 60% after one week and 66.67% in Arm A and 73.33% in Arms B and C after one month. After three months, the improvement was 73.33%, 80%, and 80% in Arms A, B, and C, respectively. The decrease in analgesic usage was also measured in all three arms. After one week, it was 60% in all three arms. After one month, it was 66.67%, 73.33%, and 73.33% in Arms A, B, and C, respectively. At three months, it was 73.33%, 80%, and 80% in Arms A, B, and C, respectively. No significant statistical difference was found between the three arms. Conclusions The efficacy of a single 8 Gy arm was almost equivalent to that of other arms of multifractionated regimens in terms of improvement in pain and performance score and decreased use of analgesics for a short duration of follow-up. For high-volume cancer centers and patients with economic constraints, a single-fraction regime provides effective palliation for painful bone metastases.

The Role of Osteocytes in Pre-metastatic Niche Formation

PURPOSE OF REVIEW

The formation of a pre-metastatic niche (PMN), in which primary cancer cells prime the distant site to be favorable to their engraftment and survival, may help explain the strong osteotropism observed in multiple cancers, such as breast and prostate. PMN formation, which includes extracellular matrix remodeling, increased angiogenesis and vascular permeability, enhanced bone marrow-derived cell recruitment and immune suppression, has mostly been described in soft tissues. In this review, we summarize current literature of PMN formation in bone. We also present evidence of a potential role for osteocytes to be the primary mediators of PMN development.

RECENT FINDINGS

Osteocytes regulate the bone microenvironment in myriad ways beyond canonical bone tissue remodeling, including changes that contribute to PMN formation. Perilacunar tissue remodeling, which has been observed in both bone and non-bone metastatic cancers, is a potential mechanism by which osteocyte-cancer cell signaling stimulates changes to the bone microenvironment. Osteocytes also protect against endothelial permeability, including that induced by cancer cells, in a loading-mediated process. Finally, osteocytes are potent regulators of cells within the bone marrow, including progenitors and immune cells, and might be involved in this aspect of PMN formation. Osteocytes should be examined for their role in PMN formation.

Hemibody Irradiation for Bone Metastases: A Systematic Review and Meta-Analysis

Hemibody irradiation (HBI) is a radiation therapy technique that involves treating one-half of the patient's skeletal system in a single radiation field. It is mostly given as upper hemibody irradiation (UHBI), lower hemibody irradiation (LHBI), or sequential UHBI and LHBI. It is used to treat extensive bone metastases from solid tumors. It was primarily utilized in the 1980s and 1990s and has since fallen out of favor. However, it is a potentially cost-effective treatment for widespread bone metastases. To determine its efficacy, we performed a meta-analysis of all available published articles on the efficacy of HBI to relieve pain from bone metastases. Twenty-seven articles involving 1318 patients were identified and analyzed. Our findings show that 80% of the patients had complete or partial pain relief and 29% had complete pain relief. The trials were of poor quality, but the results showed minimal heterogeneity in the response rates. These response rates are consistent with those seen with focal irradiation of bone metastases and for radionuclide treatment of bone metastases. The toxicity of the treatments decreased when delivered with modern treatment techniques. In light of this, we propose that this technique warrants re-evaluation with modern treatment methods.

An integrated analysis of bulk and single-cell sequencing data reveals that EMP1+/COL3A1+ fibroblasts contribute to the bone metastasis process in breast, prostate, and renal cancers

Introduction

Bone metastasis (BoM) occurs when cancer cells spread from their primary sites to a bone. Currently, the mechanism underlying this metastasis process remains unclear.

Methods

In this project, through an integrated analysis of bulk-sequencing and single-cell RNA transcriptomic data, we explored the BoM-related features in tumor microenvironments of different tumors.

Results

We first identified 34 up-regulated genes during the BoM process in breast cancer, and further explored their expression status among different components in the tumor microenvironment (TME) of BoM samples. Enriched EMP1+ fibroblasts were found in BoM samples, and a COL3A1-ADGRG1 communication between these fibroblasts and cancer cells was identified which might facilitate the BoM process. Moreover, a significant correlation between EMP1 and COL3A1 was identified in these fibroblasts, confirming the potential connection of these genes during the BoM process. Furthermore, the existence of these EMP1+/COL3A1+ fibroblasts was also verified in prostate cancer and renal cancer BoM samples, suggesting the importance of these fibroblasts from a pan-cancer perspective.

Discussion

This study is the first attempt to investigate the relationship between fibroblasts and BoM process across multi-tumor TMEs. Our findings contribute another perspective in the exploration of BoM mechanism while providing some potential targets for future treatments of tumor metastasis.

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Immune checkpoint inhibitors in bone metastasis: Clinical challenges, toxicities, and mechanisms

Immune checkpoint inhibitors (ICIs) have revolutionized the field of anti-cancer therapy over the last decade; they provide durable clinical responses against tumors by inhibiting immune checkpoint proteins that canonically regulate the T cell-mediated immune response. Despite their success in many primary tumors and soft tissue metastases, ICIs function poorly in patients with bone metastases, and these patients do not have the same survival benefit as patients with the same primary tumor type (e.g., non-small cell lung cancer [NSCLC], urothelial, renal cell carcinoma [RCC], etc.) that has not metastasized to the bone. Additionally, immune-related adverse events including rheumatologic and musculoskeletal toxicities, bone loss, and increased fracture risk develop after treatment with ICIs. There are few preclinical studies that investigate the interplay of the immune system in bone metastases; however, the current literature suggests a role for CD8+ T cells and myeloid cell subsets in bone homeostasis. As such, this review focuses on findings from the clinical and pre-clinical studies that have investigated immune checkpoint blockade in the bone metastatic setting and highlights the need for more comprehensive investigations into the relationship between immune cell subsets, ICIs, and the bone-tumor microenvironment.

Prevalence and factors associated with the occurrence of pathological fractures and their impact on the overall survival of patients with bone metastases under palliative care

OBJECTIVES

To assess the prevalence and factors associated with the occurrence of pathological fractures and their impact on the overall survival of patients with bone metastases under palliative care.

METHODS

An observational retrospective cohort assessment concerning both male and female patients with cancer presenting with bone metastases referred to a palliative care unit. Sociodemographic and clinical data were obtained before and after care unit referral. Patients were followed up until death or the last follow-up (4 years after referral). Logistic regression models and survival curves employing a log-rank test were applied.

RESULTS

A total of 348 patients were included in the study. Most were <65 years (65%) and female (62%), and the most frequent primary tumour site was the breast (40%). The prevalence of pathological fractures was 28%, more frequent in the axial skeleton (49%), with no association with overall patient survival (p=0.348). Patients with breast cancer exhibited a 2.96-fold higher chance (95% CI: 1.80 to 4.86) of developing a fracture compared with other tumours, and not receiving previous radiotherapy increased the chances of fracture occurrence by 5.60-fold (95% CI: 2.46 to 12.77).

CONCLUSION

A high prevalence of pathological fractures was observed. Presenting with breast cancer and not having undergone previous radiotherapy increase the chances of fracture occurrence, although this is not associated with overall survival in patients under palliative care.

A retrospective study on bone metastasis in dogs with advanced-stage solid cancer

OBJECTIVES

To review clinical characteristics, treatment, outcome and prognostic factors in dogs with solid cancer-bearing bone metastases.

MATERIALS AND METHODS

Records were reviewed from dogs with histologically-proven solid cancer and bone metastases. Clinicopathologic variables, bone metastases characteristics and skeletal-related events were recorded. Endpoints were time to bone metastases and survival.

RESULTS

Fifty dogs were included, 20 of them with synchronous and 30 of them with metachronous bone metastases. In the latter group, median time to diagnosis of bone metastases was 210 days (range, 30 to 1835). Most common primary cancer locations included mammary gland (n=6), spleen (n=5) and tonsil (n=5). Most common histotypes were carcinoma (n=32) and hemangiosarcoma (n=10). Nineteen dogs had multiple bones involvement, with humeri and vertebrae more commonly affected. Twenty-four dogs received antitumoural therapy, five symptomatic treatment and 21 were not treated. Overall median survival after bone metastases diagnosis was 30 days (range, 11 to 49); 83% of dogs died because of skeletal-related events. Lack of antitumoural therapy was significantly associated with shorter survival (hazard ratio: 2.7; 95% confidence interval: 1.3 to 5.6) and with increased risk of skeletal-related death (hazard ratio: 3.3; 95% confidence interval: 1.4 to 7.4). Dogs with endocrine/neuroendocrine tumours (odds ratio: 8.8; 95% confidence interval: 1.2 to 63.9), without appendicular metastases (odds ratio: 5.1; 95% confidence interval: 1.0 to 25.8), without extra-skeletal metastases (odds ratio: 5.2; 95% confidence interval: 1.1 to 24.5) and receiving antitumoural therapy (odds ratio: 14.8; 95% confidence interval: 1.7 to 131.4) had an increased chance of surviving more than 100 days.

CLINICAL SIGNIFICANCE

Bone metastases in dogs with solid cancers are associated with poor prognosis and a high risk of skeletal-related events. Treatment appears to have an impact on survival.

Enzalutamide Reduces Oxycodone Exposure in Men with Prostate Cancer

BACKGROUND AND OBJECTIVE

Up to 90% of patients with castration-resistant prostate cancer (CRPC) will develop symptomatic bone metastases requiring pain medication, with opioids being the mainstay of therapy in treating moderate and severe pain. Enzalutamide is an androgen receptor antagonist for the treatment of CRPC and a strong inducer of cytochrome P450 (CYP)3A4. Hereby, enzalutamide potentially reduces the exposure of oxycodone, an opioid metabolized by CYP3A4 and CYP2D6. Our objective was to evaluate the potential drug-drug interaction of enzalutamide and oxycodone.

METHODS

A prospective, nonrandomized, open-label, two-arm parallel study was performed. All patients received a single dose of 15 mg normal-release oxycodone. Patients in the enzalutamide arm (ENZ-arm) received enzalutamide 160 mg once daily. Plasma concentrations of oxycodone and its metabolites were quantified using a validated liquid chromatography with tandem mass spectrometry (LC-MS/MS) method.

RESULTS

Twenty-six patients (13 ENZ-arm; 13 control arm) were enrolled in the study. Enzalutamide decreased the mean AUC0-8 h and Cmax of oxycodone with, respectively, 44.7% (p < 0.001) and 35.5% (p = 0.004) compared with the control arm. The AUC0-8 h and Cmax of the active metabolite oxymorphone were 74.2% (p < 0.001) and 56.0% (p = 0.001) lower in the ENZ-arm compared with the control arm. In contrast, AUC0-8 h and Cmax of the inactive metabolites noroxycodone and noroxymorphone were significantly increased by enzalutamide.

CONCLUSION

Co-administration of enzalutamide significantly reduced exposure to oxycodone and its active metabolite oxymorphone in men with prostate cancer. This should be taken into account when prescribing enzalutamide combined with oxycodone.

Diagnostic value of whole -body diffusion weighted imaging added to bone scan in early diagnosis of bone metastases in breast cancer patients

Background

Metastases to the bones are a frequent location of metastasis in advanced breast cancer and are responsible for substantial morbidity and healthcare expenses. Imaging has been crucial in directing patient therapy for decades, contributing to the staging and response evaluation of the skeleton. This research aimed to assess the diagnostic value of whole-body magnetic resonance imaging with diffusion-weighted imaging added to radionuclide bone scans for early diagnosis of bone metastases in breast cancer patients.

Results

The study was a prospective observational cohort study performed on 20 patients with breast cancer and suspected bone metastases. The patients were evaluated first by obtaining a detailed personal history. Laboratory tests, including CBC, liver, and kidney function tests were assessed. All patients were examined by diffusion-weighted whole-body MRI (DWIBS; diffusion-weighted imaging with background body signal suppression) images and bone scintigraphy after intravenous injection of 20 mci of technetium-99m (99mTc) methylene diphosphonate using a dual head gamma camera. The total number of lesions detected by bone scan was 74, and 75 lesions were seen by DWIBS. Twenty-four lesions were missed by bone scan and detected by DWIBS. Fourteen lesions were detected by bone scan and found free by DWIBS examination in the spine and pelvic bones.

Conclusions

Whole body DWIBS seems to be a promising method of imaging in detecting bone metastases from breast cancer that could be used complementary to the traditional bone scan for more accurate diagnosis and staging of the tumor, helping to determine the most appropriate protocol of management.

Calcium phosphate bone cements as local drug delivery systems for bone cancer treatment

Bone cancer is usually a metastatic disease, affecting people of all ages. Its effective therapy requires a targeted drug administration locally at the cancer site so that the surrounding healthy organs and tissues stay unharmed. Upon a thorough literature search, a tremendous number of published articles are reporting on development of calcium phosphate cements (CPCs) for the treatment of a variety of diseases, such as osteoporosis, osteoarthritis, osteomyelitis, and other musculoskeletal disorders. However, just a limited number of research employs CPCs specifically for bone cancer treatment. In this review article, we study the factors influencing the local drug release from CPCs and particularly focus on bone cancer therapy. Finally, we locate the deficiencies in the literature regarding this specific topic and propose which other perspectives should be considered and discussed in future articles.

Musculoskeletal oncology and thermal ablation: the current and emerging role of interventional radiology

The role of interventional radiology (IR) is expanding. With new techniques being developed and tested, this radiology subspecialty is taking a step forward in different clinical scenarios, especially in oncology. Musculoskeletal tumoral diseases would definitely benefit from a low-invasive approach that could reduce mortality and morbidity in particular. Thermal ablation through IR has already become important in the palliation and consolidation of bone metastases, oligometastatic disease, local recurrences, and treating specific benign tumors, with a more tailored approach, considering the characteristics of every patient. As image-guided ablation techniques lower their invasiveness and increase their efficacy while the collateral effects and complications decrease, they become more relevant and need to be considered in patient care pathways and clinical management, to improve outcomes. We present a literature review of the different percutaneous and non-invasive image-guided thermal ablation methods that are currently available and that could in the future become relevant to manage musculoskeletal oncologic diseases.

Whole body imaging in musculoskeletal oncology: when, why, and how

The use of whole-body imaging has become increasingly popular in oncology due to the possibility of evaluating total tumor burden with a single imaging study. This is particularly helpful in cases of widespread disease where dedicated regional imaging would make the evaluation more expensive, time consuming, and prone to more risks. Different techniques can be used, including whole-body MRI, whole-body CT, and PET-CT. Common indications include surveillance of cancer predisposing syndromes, evaluation of osseous metastases and clonal plasma cell disorders such as multiple myeloma, and evaluation of soft tissue lesions, including peripheral nerve sheath tumors. This review focuses on advanced whole-body imaging techniques and their main uses in musculoskeletal oncology.

Predictive models for the risk and prognosis of bone metastasis in patients with newly-diagnosed esophageal cancer: A retrospective cohort study

Background

Esophageal cancer (EC) is a common malignant tumor worldwide, and patients with both EC and bone metastasis (BM) have a poor prognosis. We aimed to determine the risk and prognostic factors for BM in patients with newly diagnosed EC and to conduct two nomograms to predict the probability of BM and overall survival after BM.

Methods

Data from patients with EC from 2010 to 2015 were reviewed in the Surveillance, Epidemiology, and End Results (SEER) database. We divided participants into training and validation cohorts using univariate and multivariate logistic regression analyses and Cox regression models to explore the risk and prognostic factors of BM, respectively. Moreover, two nomograms were developed for predicting the risk and prognosis of BM in patients with EC. Then we used receiver operating characteristic curves, decision curve analysis, and calibration curves to evaluate the nomogram models. The overall survival of patients with EC and BM was analyzed using the Kaplan-Meier method.

Results

A total of 10,730 patients with EC were involved, 735 of whom had BM at the time of diagnosis. Histologic type, sex, age, N stage, primary site, liver, lung, and brain metastases, and tumor differentiation grade were identified as independent BM risk factors. Histological type, chemotherapy, brain, liver, and lung metastases were identified as prognostic risk factors for patients with EC and BM. We developed diagnostic and prognostic nomograms according to the results. Receiver operating characteristic curves, calibration, and Kaplan-Meier curves, and decision curve analysis all indicated that both nomograms had great clinical predictive ability and good clinical application potential.

Conclusions

Two novel nomograms were constructed to predict the risk and prognosis of BM in patients with EC. These prediction models can effectively assist clinicians in clinical decision-making based on their good accuracy and reliability.

Breast Cancer Exosomal microRNAs Facilitate Pre-Metastatic Niche Formation in the Bone: A Mathematical Model

Pre-metastatic niche is a location where cancer cells, separating from a primary tumor, find "fertile soil" for growth and proliferation, ensuring successful metastasis. Exosomal miRNAs of breast cancer are known to enter the bone and degrade it, which facilitates cancer cells invasion into the bone interior and ensures its successful colonization. In this paper, we use a mathematical model to first describe, in health, the continuous remodeling of the bone by bone-forming osteoblasts, bone-resorbing osteoclasts and the RANKL-OPG-RANK signaling system, which keeps the balance between bone formation and bone resorption. We next demonstrate how breast cancer exosomal miRNAs disrupt this balance, either by increasing or by decreasing the ratio of osteoclasts/osteoblasts, which results in abnormal high bone resorption or abnormal high bone forming, respectively, and in bone weakening in both cases. Finally we consider the case of abnormally high resorption and evaluate the effect of drugs, which may increase bone density to normal level, thus protecting the bone from invasion by cancer cells.

FLASH Radiotherapy for the Treatment of Symptomatic Bone Metastases (FAST-01): Protocol for the First Prospective Feasibility Study

BACKGROUND

In preclinical studies, FLASH therapy, in which radiation delivered at ultrahigh dose rates of ≥40 Gy per second, has been shown to cause less injury to normal tissues than radiotherapy delivered at conventional dose rates. This paper describes the protocol for the first-in-human clinical investigation of proton FLASH therapy.

OBJECTIVE

FAST-01 is a prospective, single-center trial designed to assess the workflow feasibility, toxicity, and efficacy of FLASH therapy for the treatment of painful bone metastases in the extremities.

METHODS

Following informed consent, 10 subjects aged ≥18 years with up to 3 painful bone metastases in the extremities (excluding the feet, hands, and wrists) will be enrolled. A treatment field selected from a predefined library of plans with fixed field sizes (from 7.5 cm × 7.5 cm up to 7.5 cm × 20 cm) will be used for treatment. Subjects will receive 8 Gy of radiation in a single fraction-a well-established palliative regimen evaluated in prior investigations using conventional dose rate photon radiotherapy. A FLASH-enabled Varian ProBeam proton therapy unit will be used to deliver treatment to the target volume at a dose rate of ≥40 Gy per second, using the plateau (transmission) portion of the proton beam. After treatment, subjects will be assessed for pain response as well as any adverse effects of FLASH radiation. The primary end points include assessing the workflow feasibility and toxicity of FLASH treatment. The secondary end point is pain response at the treated site(s), as measured by patient-reported pain scores, the use of pain medication, and any flare in bone pain after treatment. The results will be compared to those reported historically for conventional dose rate photon radiotherapy, using the same radiation dose and fractionation.

RESULTS

FAST-01 opened to enrollment on November 3, 2020. Initial results are expected to be published in 2022.

CONCLUSIONS

The results of this investigation will contribute to further developing and optimizing the FLASH-enabled ProBeam proton therapy system workflow. The pain response and toxicity data acquired in our study will provide a greater understanding of FLASH treatment effects on tumor responses and normal tissue toxicities, and they will inform future FLASH trial designs.

TRIAL REGISTRATION

: ClinicalTrials.gov NCT04592887; http://clinicaltrials.gov/ct2/show/NCT04592887.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/41812.

Team Approach: Management of Pathologic Fractures

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Optimal care for pathologic fractures centers on the use of a multidisciplinary team; thus, whenever there is a concern for pathologic fracture and proper workup is unable to be performed, prompt referral to a center equipped to manage these injuries should occur.

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Fixation strategies for pathologic fractures must take into account patient characteristics, cancer subtypes, and overall goals of treatment.

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As the treatments of cancers improve, patient life expectancy with disease will improve as well. This will lead to an increase in the incidence of impending or completed pathologic fractures. The broader subspecialties of orthopaedics must be aware of general principles in the diagnosis and management of these injuries.

Advanced 3D Magnetic Scaffolds for Tumor-Related Bone Defects

The need for bone substitutes is a major challenge as the incidence of serious bone disorders is massively increasing, mainly attributed to modern world problems, such as obesity, aging of the global population, and cancer incidence. Bone cancer represents one of the most significant causes of bone defects, with reserved prognosis regarding the effectiveness of treatments and survival rate. Modern therapies, such as hyperthermia, immunotherapy, targeted therapy, and magnetic therapy, seem to bring hope for cancer treatment in general, and bone cancer in particular. Mimicking the composition of bone to create advanced scaffolds, such as bone substitutes, proved to be insufficient for successful bone regeneration, and a special attention should be given to control the changes in the bone tissue micro-environment. The magnetic manipulation by an external field can be a promising technique to control this micro-environment, and to sustain the proliferation and differentiation of osteoblasts, promoting the expression of some growth factors, and, finally, accelerating new bone formation. By incorporating stimuli responsive nanocarriers in the scaffold's architecture, such as magnetic nanoparticles functionalized with bioactive molecules, their behavior can be rigorously controlled under external magnetic driving, and stimulates the bone tissue formation.

Radiographic imaging of carbon fiber implants in the appendicular skeleton in orthopedic oncology

Carbon fiber/poly-ether-ether-ketone implants are increasingly being used in orthopedic oncology. An understanding of how to evaluate the normal appearance of these implants is critical for detecting any failures or complications that may arise. The purpose of this manuscript is to provide primarily a radiographic review of the normal radiographic appearance of carbon fiber-reinforced poly-ether-ether-ketone implants in the appendicular skeleton with some cross-sectional imaging discussion. We additionally aim to highlight some of the unique clinical benefits compared to metal implants, review the unique appearance of failures of these implants, and propose a standardized radiologic method for their evaluation. Our review is based on a retrospective case review of 31 patients with carbon fiber-reinforced poly-ether-ether-ketone implants placed in a single center orthopedic oncology practice from 2017 to 2021.

Chemokines network in bone metastasis: Vital regulators of seeding and soiling

Chemokines are well equipped with chemo-attractive signals that can regulate cancer cell trafficking to specific organ sites. Currently, updated concepts have revealed the diverse role of chemokines in the biology of cancer initiation and progression. Genomic instabilities and alterations drive tumor heterogeneity, providing more options for the selection and metastatic progression to cancer cells. Tumor heterogeneity and acquired drug resistance are the main obstacles in managing cancer therapy and the primary root cause of metastasis. Studies emphasize that multiple chemokine/receptor axis are involved in cancer cell-mediated organ-specific distant metastasis. One of the persuasive mechanisms for heterogeneity and subsequent events is sturdily interlinked with the crosstalk between chemokines and their receptors on cancer cells and tissue-specific microenvironment. Among different metastatic niches, skeletal metastasis is frequently observed in the late stages of prostate, breast, and lung cancer and significantly reduces the survival of cancer patients. Therefore, it is crucial to elucidate the role of chemokines and their receptors in metastasis and bone remodeling. Here, we review the potential chemokine/receptor axis in tumorigenesis, tumor heterogeneity, metastasis, and vicious cycle in bone microenvironment.

The Burden of Metastatic Cancer-Induced Bone Pain: A Narrative Review

Bone pain is one of the most common forms of pain reported by cancer patients with metastatic disease. We conducted a review of oncology literature to further understand the epidemiology of and treatment approaches for metastatic cancer–induced bone pain and the effect of treatment of painful bone metastases on the patient’s quality of life. Two-thirds of patients with advanced, metastatic, or terminal cancer worldwide experience pain. Cancer pain due to bone metastases is the most common form of pain in patients with advanced disease and has been shown to significantly reduce patients’ quality of life. Treatment options for cancer pain due to bone metastases include nonsteroidal anti-inflammatory drugs, palliative radiation, bisphosphonates, denosumab, and opioids. Therapies including palliative radiation and opioids have strong evidence supporting their efficacy treating cancer pain due to bone metastases; other therapies, like bisphosphonates and denosumab, do not. There is sufficient evidence that patients who experience pain relief after radiation therapy have improved quality of life; however, a substantial proportion are nonresponders. For those still requiring pain management, even with available analgesics, many patients are undertreated for cancer pain due to bone metastases, indicating an unmet need. The studies in this review were not designed to determine why cancer pain due to bone metastases was undertreated. Studies specifically addressing cancer pain due to bone metastases, rather than general cancer pain, are limited. Additional research is needed to determine patient preferences and physician attitudes regarding choice of analgesic for moderate to severe cancer pain due to bone metastases.

Periprosthetic Metastatic Lung Carcinoma About a Total Knee Arthroplasty: A Case Report

CASE

A 64-year-old man presented with unrelenting left knee pain and an unremarkable radiograph 4 months after revision total knee arthroplasty (TKA). Pain persisted, despite conservative management, and repeat imaging demonstrated significant lysis of the left medial tibial condyle. A biopsy demonstrated metastatic squamous cell carcinoma of the lung. Management with excision and curettage of the tibial lesion was followed by palliative radiotherapy and chemotherapy until the patient died 7 months later.

CONCLUSION

This case highlights metastasis as an etiology for persistent TKA pain in a patient with significant risk factors.

Socioeconomic and insurance-related disparities in disease-specific survival among patients with metastatic bone disease

BACKGROUND

Approximately 5% of cancer patients in the United States presented with metastatic bone disease (MBD) at diagnosis. Current study explores the disparities in survival for patients with MBD.

METHODS

Patients with the diagnosis of MBD at presentation for the five most common primary anatomical sites were extracted from Surveillance, Epidemiology, and End Results Census tract-level dataset (2010-2016). Kaplan-Meier and Cox Proportional Hazard models were used to evaluate survival, and prognostic factors for each cohort. Prognostic significance of socioeconomic status (SES) and insurance status were ascertained.

RESULTS

The five most common anatomical-sites with MBD at presentation included "lung" (n = 59 739), "prostate" (n = 19 732), "breast" (n = 16 244), "renal and urothelium" (n = 7718) and "colon" (n= 3068). Lower SES was an independent risk factor for worse disease-specific survival (DSS) for patients with MBD originating from lung, prostate, breast and colon. Lack of insurance was an independent risk factor for worse DSS for MBD patients with primary tumors in lung and breast.

CONCLUSIONS

MBD patients from the five most common primary sites demonstrated SES and insurance-related disparities in disease-specific survival. This is the first and largest study to explore SES and insurance-related disparities among patients specifically afflicted with MBD. Our findings highlight vulnerability of patients with MBD across multiple primary sites to financial toxicity.

Improving providers' survival estimates and selection of prognosis- and guidelines-appropriate treatment for patients with symptomatic bone metastases: Development of the Bone Metastases Ensemble Trees for Survival Decision Support Platform

RATIONALE, AIMS AND OBJECTIVES

In the management of symptomatic bone metastases, current practice guidelines do not provide clear methodology for selecting palliative radiotherapy (RT) regimens based on specific patient and disease features. Decision support aids may offer an effective means for translating the complex data needed to render individualised treatment decisions, yet no such tools are available for use in this setting. Thus, we describe the development of the Bone Metastases Ensemble Trees for Survival-Decision Support Platform (BMETS-DSP), which aims to optimise selection of evidence-based, individualised palliative RT regimens.

METHOD

The Ottawa Decision Support Framework was used as the theoretical basis for development of BMETS-DSP. First, we utilised stakeholder input and review of the literature to assess determinants underlying the provider decision. Based on this assessment and iterative stakeholder feedback, we developed the web-based, provider-facing BMETS-DSP. Consistent with the underlying theoretical framework, our design also included assessment of decision quality using the International Patient Decision Aids Standards (IPDAS) certification checklist.

RESULTS

Stakeholder input and review of 54 evidence-based publications identified the following determinants of the provider decision: estimated prognosis, characteristics of the target symptomatic lesion and the primary cancer type, consideration of alternative interventions, access to patient-specific recommendations, and patient preferences. Based on these determinants, we developed the BMETS-DSP that (1) collects patient-specific data, (2) displays an individualised predicted survival curve, and (3) provides case-specific, evidence-based recommendations regarding RT, open surgery, systemic therapy, and hospice referral to aid in the decision-making process. The finalised tool met IPDAS quality requirements. Preliminary results of a pilot assessment suggest impact of clinical outcomes.

CONCLUSIONS

We describe the successful development of a provider-facing decision support platform to aid in the provision of palliative RT in better alignment with patient and disease features. Impact of the BMETS-DSP on decision outcomes will be further assessed in a randomised, controlled study.

Metastatic bone cancer: Consideration for optimal dose fractionation in radiation therapy

The bones are one of the most common sites for metastatic cancer spread. Unfortunately, there is no current known cure for many people affected by bone metastasis. Therefore, the treatment intent for radiotherapy remains a palliative objective, whereby treatments are meant to provide pain relief and alleviate symptoms. However, some debate has arisen in recent decades regarding the most appropriate dose prescription pertaining to dose protraction and fractionation. By delivering a larger dose in fewer fractions, patients can spend less time at the hospital and more time with loved ones. Additionally, many dose prescriptions were prioritized to be shortened during the COVID-19 pandemic, which may offer retrospective data on the treatment outcomes from providing shortened courses of radiotherapy.

Rehabilitation in Advanced Cancer Patients with Bone Metastases and Neural Compromise: Current Status and Future Directions

PURPOSE OF REVIEW

This review aimed to increase the understanding of oncologists and physiatrists about the necessity, efficacy, and safety of rehabilitation in advanced cancer patients with bone metastases and neural compromise.

RECENT FINDINGS

Recently, there are growing evidence supporting the safety and efficacy of rehabilitation in patients with bone metastases and neural compromise. Despite the potential benefits of rehabilitation, however, rehabilitative services are considerably underutilized in clinical practice. Many oncologists are not familiar with functional issues and have limited understanding of the available rehabilitative services. Moreover, medical professionals, even physiatrists, have uncertainties and concerns about skeletal complications and often regard rehabilitation as a contraindication in this patient group. This review aimed to raise awareness on the role of rehabilitation in the continuum of cancer treatment, to improve its use in clinical practice. A multidisciplinary team approach involving physiatrist may facilitate integration of relevant clinicians.

Sex, racial/ethnic and socioeconomic disparities in patients with metastatic bone disease

BACKGROUND

We have analyzed sex, race/ethnicity or socioeconomic disparities in the incidence of metastatic bone disease (MBD).

METHODS

Patients with the diagnosis of MBD at presentation for five most common primary anatomical sites was extracted from Surveillance, Epidemiology, and End Results Census tract-level dataset. Mean incidence of MBD for different sex, racial/ethnic and socioeconomic groups were compared.

RESULTS

The five most common anatomical sites with MBD at presentation include "lung: (n = 59 739), "prostate" (n = 19 732), "breast" (n = 16 244), "renal" (n = 7718) and "colon" (n = 3068). There was an increase in incidence of MBD among cancers originating from prostate (annual percentage change [APC] 4.94), renal (APC 2.55), and colon (APC 3.21) (p < 0.05 for all). Non-Hispanic Blacks had higher incidence of MBD for prostate and breast primary sites (p < 0.001). Non-Hispanic American Indian Alaskan Native had higher incidence of MBD for cancers originating from renal (p < 0.001) and colon (p = 0.049). A higher incidence of MBD was seen in lower socioeconomic status (SES) groups for the selected sites (p < 0.001).

CONCLUSIONS

These findings suggest that there are multiple sex-related, racial/ethnic and SES disparities in the incidence of MBD from the 5 most common primary sites. Higher incidence seen among lower SES suggests delay in diagnosis and limited access to screening modalities.

Therapy-induced bone changes in oncology imaging with 18F-sodium fluoride (NaF) PET-CT

¹⁸F-Sodium fluoride (¹⁸F-NaF) is a PET tracer that is mostly used in the evaluation of bone metastasis in oncology cases. Recently, ¹⁸F-NaF PET/CT is gaining wide popularity owing to its higher sensitivity over the other conventional bone tracer with higher and rapid single-pass extraction, negligible plasma protein binding, rapid blood, and renal clearance. In the era of constant evolution of cancer therapy regimens, considerable bone health impact is seen in the form of avascular necrosis, insufficiency fractures, among others. A significant number of these therapy-induced changes show high bone turnover and thereby ¹⁸F-NaF accumulation, mimicking metastatic lesions. This article summarizes and illustrates the pattern and morphological features of ¹⁸F-NaF PET/CT findings in these changes in the context of clinical and therapeutic history.

Finite Element Analysis of Osteoporotic and Osteoblastic Vertebrae and Its Association With the Proton Density Fat Fraction From Chemical Shift Encoding-Based Water-Fat MRI - A Preliminary Study

PURPOSE

Osteoporosis is prevalent and entails alterations of vertebral bone and marrow. Yet, the spine is also a common site of metastatic spread. Parameters that can be non-invasively measured and could capture these alterations are the volumetric bone mineral density (vBMD), proton density fat fraction (PDFF) as an estimate of relative fat content, and failure displacement and load from finite element analysis (FEA) for assessment of bone strength. This study's purpose was to investigate if osteoporotic and osteoblastic metastatic changes in lumbar vertebrae can be differentiated based on the abovementioned parameters (vBMD, PDFF, and measures from FEA), and how these parameters correlate with each other.

MATERIALS AND METHODS

Seven patients (3 females, median age: 77.5 years) who received 3-Tesla magnetic resonance imaging (MRI) and multi-detector computed tomography (CT) of the lumbar spine and were diagnosed with either osteoporosis (4 patients) or diffuse osteoblastic metastases (3 patients) were included. Chemical shift encoding-based water-fat MRI (CSE-MRI) was used to extract the PDFF, while vBMD was extracted after automated vertebral body segmentation using CT. Segmentation masks were used for FEA-based failure displacement and failure load calculations. Failure displacement, failure load, and PDFF were compared between patients with osteoporotic vertebrae versus patients with osteoblastic metastases, considering non-fractured vertebrae (L1-L4). Associations between those parameters were assessed using Spearman correlation.

RESULTS

Median vBMD was 59.3 mg/cm³ in osteoporotic patients. Median PDFF was lower in the metastatic compared to the osteoporotic patients (11.9% vs. 43.8%, p=0.032). Median failure displacement and failure load were significantly higher in metastatic compared to osteoporotic patients (0.874 mm vs. 0.348 mm, 29,589 N vs. 3,095 N, p=0.034 each). A strong correlation was noted between PDFF and failure displacement (rho -0.679, p=0.094). A very strong correlation was noted between PDFF and failure load (rho -0.893, p=0.007).

CONCLUSION

PDFF as well as failure displacement and load allowed to distinguish osteoporotic from diffuse osteoblastic vertebrae. Our findings further show strong associations between PDFF and failure displacement and load, thus may indicate complimentary pathophysiological associations derived from two non-invasive techniques (CSE-MRI and CT) that inherently measure different properties of vertebral bone and marrow.

Detection of Bone Metastases on Bone Scans through Image Classification with Contrastive Learning

Patients with bone metastases have poor prognoses. A bone scan is a commonly applied diagnostic tool for this condition. However, its accuracy is limited by the nonspecific character of radiopharmaceutical accumulation, which indicates all-cause bone remodeling. The current study evaluated deep learning techniques to improve the efficacy of bone metastasis detection on bone scans, retrospectively examining 19,041 patients aged 22 to 92 years who underwent bone scans between May 2011 and December 2019. We developed several functional imaging binary classification deep learning algorithms suitable for bone scans. The presence or absence of bone metastases as a reference standard was determined through a review of image reports by nuclear medicine physicians. Classification was conducted with convolutional neural network-based (CNN-based), residual neural network (ResNet), and densely connected convolutional networks (DenseNet) models, with and without contrastive learning. Each set of bone scans contained anterior and posterior images with resolutions of 1024 × 256 pixels. A total of 37,427 image sets were analyzed. The overall performance of all models improved with contrastive learning. The accuracy, precision, recall, F1 score, area under the receiver operating characteristic curve, and negative predictive value (NPV) for the optimal model were 0.961, 0.878, 0.599, 0.712, 0.92 and 0.965, respectively. In particular, the high NPV may help physicians safely exclude bone metastases, decreasing physician workload, and improving patient care.

Innovative Biomaterials for the Treatment of Bone Cancer

Bone cancer is a demanding challenge for contemporary medicine due to its high frequency of presentation and significant heterogeneity of malignant lesions developing within the bone. To date, available treatments are rarely curative and are primarily aimed at prolonging patients' survival and ameliorating their quality of life. Furthermore, both pharmacological and surgical therapies are aggravated by a consistent burden of adverse events and subsequent disability due to the loss of healthy bone structural and functional properties. Therefore, great research efforts are being made to develop innovative biomaterials able to selectively inhibit bone cancer progression while reducing the loss of bone structural properties secondary to local tissue invasion. In this review, we describe the state of the art of innovative biomaterials for the treatment of bone cancer. Along with physiological bone remodeling, the development of bone metastasis and osteosarcoma will be depicted. Subsequently, recent advances on nanocarrier-based drug delivery systems, as well as the application of novel, multifunctional biomaterials for the treatment of bone cancer will be discussed. Eventually, actual limitations and promising future perspectives regarding the employment of such approaches in the clinical scenario will be debated.

Dura promotes metastatic potential in prostate cancer through the CXCR2 pathway

PURPOSE

Spinal metastases are common in cancer. This preferential migration/growth in the spine is not fully understood. Dura has been shown to affect the surrounding microenvironment and promote cancer growth. Here, we investigate the role of dural cytokines in promoting the metastatic potential of prostate cancer (PCa) and the involvement of the CXCR2 signaling pathway.

METHODS

The role of dural conditioned media (DCM) in proliferation, migration and invasion of five PCa cell lines with various hormone sensitivities was assessed in the presence or absence of the CXCR2 inhibitor, SB225002. CXCR2 surface protein was examined by FACS. Cytokine levels were measured using a mouse cytokine array.

RESULTS

We observed high levels of cytokines produced by dura and within the vertebral body bone marrow, namely CXCL1 and CXCL2, that act on the CXCR2 receptor. All prostate cell lines treated with DCM demonstrated significant increase in growth, migration and invasion regardless of androgen sensitivity, except PC3, which did not significantly increase in invasiveness. When treated with SB225002, the growth response to DCM by cells expressing the highest levels of CXCR2 as measured by FACS (LNCaP and 22Rv1) was blunted. The increase in migration was significantly decreased in all lines in the presence of SB225002. Interestingly, the invasion increase seen with DCM was unchanged when these cells were treated with the CXCR2 inhibitor, except PC3 did demonstrate a significant decrease in invasion.

CONCLUSION

DCM enhances the metastatic potential of PCa with increased proliferation, migration and invasion. This phenomenon is partly mediated through the CXCR2 pathway.