Deep Learning for Delineation of the Spinal Canal in Whole-Body Diffusion-Weighted Imaging: Normalising Inter- and Intra-Patient Intensity Signal in Multi-Centre Datasets

BACKGROUND

Whole-Body Diffusion-Weighted Imaging (WBDWI) is an established technique for staging and evaluating treatment response in patients with multiple myeloma (MM) and advanced prostate cancer (APC). However, WBDWI scans show inter- and intra-patient intensity signal variability. This variability poses challenges in accurately quantifying bone disease, tracking changes over follow-up scans, and developing automated tools for bone lesion delineation. Here, we propose a novel automated pipeline for inter-station, inter-scan image signal standardisation on WBDWI that utilizes robust segmentation of the spinal canal through deep learning.

METHODS

We trained and validated a supervised 2D U-Net model to automatically delineate the spinal canal (both the spinal cord and surrounding cerebrospinal fluid, CSF) in an initial cohort of 40 patients who underwent WBDWI for treatment response evaluation (80 scans in total). Expert-validated contours were used as the target standard. The algorithm was further semi-quantitatively validated on four additional datasets (three internal, one external, 207 scans total) by comparing the distributions of average apparent diffusion coefficient (ADC) and volume of the spinal cord derived from a two-component Gaussian mixture model of segmented regions. Our pipeline subsequently standardises WBDWI signal intensity through two stages: (i) normalisation of signal between imaging stations within each patient through histogram equalisation of slices acquired on either side of the station gap, and (ii) inter-scan normalisation through histogram equalisation of the signal derived within segmented spinal canal regions. This approach was semi-quantitatively validated in all scans available to the study (N = 287).

RESULTS

The test dice score, precision, and recall of the spinal canal segmentation model were all above 0.87 when compared to manual delineation. The average ADC for the spinal cord (1.7 × 10-3 mm2/s) showed no significant difference from the manual contours. Furthermore, no significant differences were found between the average ADC values of the spinal cord across the additional four datasets. The signal-normalised, high-b-value images were visualised using a fixed contrast window level and demonstrated qualitatively better signal homogeneity across scans than scans that were not signal-normalised.

CONCLUSION

Our proposed intensity signal WBDWI normalisation pipeline successfully harmonises intensity values across multi-centre cohorts. The computational time required is less than 10 s, preserving contrast-to-noise and signal-to-noise ratios in axial diffusion-weighted images. Importantly, no changes to the clinical MRI protocol are expected, and there is no need for additional reference MRI data or follow-up scans.

Mechanical Gains Associated With Virtual Prophylactic Intramedullary Nail Fixation in Femurs With Metastatic Disease

Background

Many patients with metastatic bone disease (MBD) of the femur undergo prophylactic surgical fixation for impending pathologic fractures; intramedullary nailing (IMN) being the most common fixation type. However, surgeons often question if IMN fixation provides sufficient improvements in mechanical strength for particular metastatic lesions. Our goal was to use patient-specific finite element (FE) modeling to computationally evaluate the effects of simulated IMN fixation on the mechanics of femurs affected with MBD.

Methods

Computed tomography (CT) scans were available retrospectively from 48 patients (54 femurs) with proximal femoral metastases. The CT scans were used to create patient-specific, non-linear, voxel-based FE models of the femur, simulating the instant of peak hip joint contact force during normal walking. FE analyses were repeated after incorporating virtual IMN fixation (Smith and Nephew, TRIGEN INTERTAN) into the same femurs. Femur strength and load-to-strength ratio (LSR; lower LSR indicates lower fracture risk) were compared between untreated and IMN conditions using statistical analyses.

Results

IMN fixation resulted in a very modest average 10% increase in mechanical strength (p<0.001), which was associated with a slight 7% reduction in fracture risk (p<0.001). However, there was considerable variation in fracture risk reduction between individual femurs (0.13-50%). In femurs with the largest reduction in fracture risk (>10%), IMN hardware directly passed through a considerable section of that femur's metastatic lesion. Femurs with lytic (10%) and diffuse (9%) metastases tended to have greater reductions in fracture risk compared to femurs with blastic (5%) and mixed (4%) metastases (p=0.073).

Conclusion

Given the mechanically strong baseline condition of most femurs in this cohort, evident by the low fracture risk at the time of CT scanning, the relative increase in stiffness with the addition of the IMN hardware may not make a substantial contribution to overall mechanical strength. The mechanical gains of IMN fixation in femurs with MBD appear most beneficial when the hardware traverses an adequate section of the lesion. Level of Evidence: III.

Metastatic sarcomatoid carcinoma to bone

BACKGROUND AND OBJECTIVES

Distinguishing sarcomatoid carcinoma from primary sarcoma is clinically important. We sought to characterize metastatic sarcomatoid bone disease and its management.

METHODS

We analyzed the characteristics of all cases of sarcomatoid carcinoma to bone at a single institution from 2001 to 2021, excluding patients with nonosseous metastases. Survival was evaluated using the Kaplan-Meier method.

RESULTS

We identified 15 cases of metastatic sarcomatoid carcinoma to bone. In seven cases the primary cancer was unknown at presentation. Renal cell carcinoma was suspected or confirmed in nine cases. Nine patients presented with pathologic fracture and two with concomitant visceral metastases. All patients underwent image-guided core needle or open biopsy. Ten required surgery for discrete osseous metastases; in four cases definitive surgery was delayed (median delay, 19 days) due to inability to rule out sarcoma with frozen section. No patients required reoperation or had construct failure. Thirteen died of disease; median survival was 17.5 months (interquartile range, 6.2-25.1).

CONCLUSIONS

Metastatic sarcomatoid carcinoma is a clinically challenging entity. Multidisciplinary input and communication are key to identifying the primary carcinoma, locating osseous metastases, and defining an operative fixation that will survive the remainder of the patient's life.

Treatment of Epiphyseal Metastasis to the Proximal Humerus Secondary to Breast Carcinoma: A Case Report

Metastasis to the bone is a known risk of breast cancer, with the humerus being the most common upper extremity site of metastases, with most lesions located at the humeral diaphysis. We present a unique case of proximal humeral metastasis involving the epiphysis secondary to primary invasive ductal carcinoma in a middle-aged Caucasian female. It is important to have a high degree of suspicion for metastasis when musculoskeletal pain occurs in breast cancer patients, as it may be masked by common, degenerative conditions about the shoulder girdle. When humeral metastases involve the epiphysis, treatment options are complicated by its location, which jeopardizes the integrity of articular cartilage and the function of the shoulder girdle. External beam irradiation provides pain control in a non-invasive manner, sans surgical risks. Surgical intervention will vary depending on the characteristics of the bony lesion, but the use of endoprosthetics has emerged as the most effective option for restoring range of motion and pain control with acceptable rates of implant survival.

Quantitative vs. Qualitative SPECT-CT Diagnostic Accuracy in Bone Lesion Evaluation-A Review of the Literature

(1) Background: Considering the importance that quantitative molecular imaging has gained and the need for objective and reproducible image interpretation, the aim of the present review is to emphasize the benefits of performing a quantitative interpretation of single photon emission computed tomography-computed tomography (SPECT-CT) studies compared to qualitative interpretation methods in bone lesion evaluations while suggesting new directions for research on this topic. (2) Methods: By conducting comprehensive literature research, we performed an analysis of published data regarding the use of quantitative and qualitative SPECT-CT in the evaluation of bone metastases. (3) Results: Several studies have evaluated the diagnostic accuracy of quantitative and qualitative SPECT-CT in differentiating between benign and metastatic bone lesions. We collected the sensitivity and specificity for both quantitative and qualitative SPECT-CT; their values ranged between 74-92% and 81-93% for quantitative bone SPECT-CT and between 60-100% and 41-100% for qualitative bone SPECT-CT. (4) Conclusions: Both qualitative and quantitative SPECT-CT present an increased potential for better differentiating between benign and metastatic bone lesions, with the latter offering additional objective information, thus increasing diagnostic accuracy and enabling the possibility of performing treatment response evaluation through accurate measurements.

Thermal necrosis in orthopedic bone tumors: experimental research

Introduction

The extent of surgical resection in orthopedic oncology differs according to tumor biology. While malignant bone tumors are operatively managed with wide resection, benign bone tumors and metastatic carcinomas are often treated through intralesional excision and adjuvant modalities, including the elimination of residual neoplastic cells through thermal necrosis. This study investigates in vitro temperature thresholds for thermal necrosis in common orthopedic bone tumors.

Methodology

Eleven cell lines, including metastatic carcinomas to bone (A549, A498, FU-UR-1, PC3, MDA-MB-231, TT, MCF7, and K1), giant cell tumor of bone, osteosarcoma (HG-63), and control non-neoplastic cells (HEK293) were cultured. Cells were exposed to thermal stress at varying times and temperatures and evaluated for survival and viability with crystal violet and MTT assays.

Results

Both the MTT and crystal violet assay demonstrated statistically superior rates of viability and survival for A549 (lung carcinoma), FU-UR-1 (renal carcinoma), K1 (thyroid carcinoma), and MG-63 (osteosarcoma) cell lines compared to control (HEK293 cells) at 60°C. Additionally, the MTT assay demonstrated superior viability for PC3 (prostate carcinoma), MCF7 (breast carcinoma), and A498 (renal carcinoma) compared to control. All cell lines demonstrated significantly decreased survival and viability in temperatures more than 90°C.

Conclusion

This study demonstrated in vitro thresholds for thermal necrosis for cell lines of common orthopedic tumors of bone. The A549 (lung carcinoma), K1 (thyroid carcinoma), and FU-UR-1 (renal carcinoma) cell lines demonstrated greater resistance to heat stress compared to non-neoplastic control cells. Temperatures in excess of 90°C are necessary to reliably reduce cell survival and viability to less than 10%.

Minimally invasive stabilization of pelvic metastatic bone disease: A review of an emerging technique

Percutaneous pelvic stabilization is an emerging technique that provides mechanical stability to pathologic fractures of the pelvic ring and acetabulum. Variability exists in procedural technique among institutions; however, early case series consistently demonstrate an acceptable complication profile and significant improvement in patients' pain and function. This minimally invasive approach is less morbid than traditional, open acetabular and pelvic reconstructions. Therefore, this procedure is an encouraging palliative intervention for a growing patient population in need.

Intramedullary brachytherapy for the treatment of long bone metastatic disease: A case report

Case

A 56-year-old woman with metastatic melanoma and femoral lesions with impending pathologic fracture was indicated for intramedullary brachytherapy (IMBT) and intramedullary nail.

Conclusions

IMBT + intramedullary nail is a new technique for the treatment of long bone metastases. IMBT maximizes radiation to the tumor and minimizes radiation to surrounding tissues. It allows the patient to resume systemic treatment expediently. Our cadaver model and patient were both treated for femoral metastases; however, this technique allows for the treatment of any long bone. This is a safe technique that minimizes treatment time compared with other standard radiation regimens.

The dynamic microenvironment associated with metastatic bone disease: Current concepts

Patients with bone metastases may experience debilitating pain, neurological conditions, increased risk of pathological fractures, and death. A deeper understanding of the bone microenvironment, the molecular biology of cancer types prone to metastasis, and how bone physiology promotes cancer growth, may help to uncover targeted treatment options. The purpose of this paper is to outline the current concepts relevant to topics including bone remodeling, angiogenesis, and immunomodulation as it relates to metastatic bone disease.

External validation of the PATHFx decision-support tool on Turkish patients with skeletal metastasis

Objective

Accurate determination of life expectancy becomes very important when determining the treatment of patients with pathologic fractures. We aimed to investigate the predictive role of the PATHFx model in Turkish patients by estimating the area under curve (AUC) of the receiver operator characteristic (ROC) and externally validating the results of PATHFx on the Turkish population.

Methods

The data of 122 patients who presented to one of four orthopaedic oncology referral centres in Istanbul (2010-2017) and underwent surgical management of pathologic fractures were retrospectively collected. Patients were evaluated according to age, sex, type of pathologic fracture, presence of organ metastasis, presence of lymph node metastasis, haemoglobin concentration at presentation, primary oncologic diagnosis, number of bone metastases, and Eastern Cooperative Oncology Group (ECOG) status. Estimations of the PATHFx program by months were statistically evaluated using ROC analysis.

Results

In our study population (122 patients), all survived the first month, 102 survived the third month, 89 were alive at 6 months, and 58 patients survived at 12 months. At 18 and 24 months, 39 and 27 patients were alive, respectively. The AUC value was 0.677 at 3 months, 0.695 at 6 months, 0.69 at 12 months, 0.674 at 18 months, and 0.693 at 24 months. The 3-, 6-, 12-, 18-, and 24-month survival rates were statistically significant (P < 0.01 and P < 0.05). ECOG performance status was 0-2 points in 33 patients (Memorial Sloan-Kettering Cancer Center (MSKCC) data set: 93 cases, our data set: 33 cases). ECOG performance status was 3-4 points in 89 patients (MSKCC data set: 96 cases, our data set: 89 cases).

Conclusions

The objective data used by PATHFx for prediction provided statistically accurate estimates on Turkish patients, who are presumed to have mixed genomes through history from both Europe and Asia, and demonstrates its applicability to the Turkish population.

Wound complications in metastatic spine tumor patients with and without preoperative radiation

OBJECTIVE

Wound complications are a common adverse event following metastatic spine tumor surgery. Some patients with spinal metastases may first undergo radiation but eventually require spinal surgery because of either cord compression or instability. The authors compared wound complication rates in patients who had undergone surgery for metastatic disease and received preoperative radiation treatments, postoperative radiation, or no radiation.

METHODS

Records from patients treated at the University of California, San Francisco, for metastatic spine disease between 2005 and 2017 were retrospectively reviewed. Baseline characteristics were collected, including preoperative Karnofsky Performance Status (KPS), Spine Instability Neoplastic Score, total radiation dose, indication for surgery, diabetes status, time between radiation and surgery, use of perioperative chemotherapy or steroids, estimated blood loss, extent of fusion, and preoperative albumin level. Wound complication was defined as poor healing, dehiscence, or infection per the Centers for Disease Control and Prevention guidelines, within 6 months of surgery. One-way ANOVA was used to compare means across groups. Cumulative incidence analysis with competing risk methodology was used to adjust for risk of death during follow-up. Statistical analysis was performed using R software.

RESULTS

Two hundred five patients with adequate medical records were identified. Seventy patients had received preoperative radiation, 74 had received postoperative radiation within 6 months after surgery, and 61 had received no radiation at the surgical site. Wound complication rates were similar across the 3 cohorts: 14.3% (n = 10) in the group with preoperative radiation, 10.8% (n = 8) in the group that received postoperative radiation, and 11.5% (n = 7) in the group with no radiation (p = 0.773). Competing risk analysis showed a higher cumulative incidence of wound complications for the preoperative cohort, though this difference was not significant (p = 0.46). Overall, 89 patients were treated with external beam radiation therapy (EBRT), whereas 55 received stereotactic body radiation therapy (SBRT). There was no significant difference in wound complications for patients treated with EBRT (11.2%, n = 10) versus SBRT (14.5%, n = 8; p = 0.825). KPS was the only factor correlated with wound complications on univariate analysis (p = 0.03).

CONCLUSIONS

Wound complication rates did not differ across the 3 cohorts: patients treated with preoperative radiation, postoperative radiation within 6 months of surgery, or no radiation. The effect size was small for KPS and likely does not represent a clinically significant predictor of wound complications.

Quantitative Assessment of Treatment Response in Metastatic Breast Cancer Patients by SPECT-CT Bone Imaging-Getting Closer to PET-CT

BACKGROUND

Cancer represents the major cause of death mainly through its ability to spread to other organs, highlighting the importance of metastatic disease diagnosis and accurate follow up for treatment management purposes. Although until recently the main method for imaging interpretation was represented by qualitative methods, quantitative analysis of SPECT-CT data represents a viable, objective option.

METHODS

Seventy-five breast cancer patients presenting metastatic bone disease underwent at least two Bone SPECT-CT studies using [^99mTc]-HDP between November 2019 to October 2022.

RESULTS

Our findings show a good positive relationship between the qualitative methods of imaging interpretation and quantitative analysis, with a correlation coefficient of 0.608 between qualitative whole body scintigraphy and quantitative SPECT-CT, and a correlation coefficient of 0.711 between the qualitative and quantitative interpretation of SPECT-CT data; nevertheless, there is a need for accurate, objective and reproducible methods for imaging interpretation, especially for research purposes.

CONCLUSIONS

Quantitative evaluation of the SPECT-CT data has the potential to be the first choice of imaging interpretation for patient follow up and treatment response evaluation, especially for research purposes, because of its objectivity and expression of uptake changes in absolute units.

Increased Number of Medical Comorbidities Associated With Increased Risk of Presenting With Pathological Femur Fracture in Metastatic Bone Disease

Background

Many cancers metastasize to bone and may lead to pathologic fracture or impending pathologic fracture. Prophylactically stabilizing bones before fracture has been shown to be more cost-effective with improved outcomes. Many studies have examined risk factors for pathological fracture, with radiographic and functional pain data serving as predominant indicators for surgery. Conditions associated with poor bone health and increased risk of fracture in the non-oncologic population, including diabetes mellitus, chronic obstructive pulmonary disease (COPD), cardiovascular disease, renal disease, smoking, corticosteroid use, and osteoporosis, have not been studied in the context of metastatic disease. Characterization of these factors could help providers identify candidates for prophylactic stabilization thereby reducing the number of completed pathological fractures.

Methods

298 patients over the age of 40 with metastatic bone disease of the femur treated between 2010-2021 were retrospectively identified. Patients without complete medical documentation or with non-metastatic diagnoses were excluded. 186 patients met inclusion and exclusion criteria, including 74 patients who presented with pathological femur fracture and 112 patients who presented for prophylactic stabilization. Patient demographics and comorbidities including diabetes mellitus, COPD, cardiovascular disease, renal disease, osteoporosis, active tobacco or corticosteroid use, and use of anti-resorptive therapy were collected. Descriptive statistics were compiled, with univariable analysis by Mann-Whitney or chisquared testing. Multiple logistic regression was then performed to identify the most significant patient variables for presenting with completed fracture.

Results

On univariable analysis, patients with COPD were more likely to present with pathologic fracture (19/32 [59%] compared to 55/154 [36%], p = 0.02). A trend emerged for patients with an increasing number of comorbidities (28/55 [51%] for 2+ comorbidities compared to 18/61 [29%] with zero comorbidities, p = 0.06). On multivariable analysis, patients with two or more comorbidities (OR: 2.49; p=0.02) were more likely to present with a femur fracture.

Conclusion

This analysis suggests that those with an increasing number of comorbidities may be at increased risk for pathologic fracture. This study raises the possibility that patient factors and/ or comorbidities alter bone strength and/or pain experiences and may guide orthopaedic oncologists weighing prophylactic stabilization of femur lesions. Level of Evidence: III.

Heightened Procoagulation after Post-Operative Thromboprophylaxis Completion in Patients with Metastatic Bone Disease from Primary Colorectal Cancer

BACKGROUND

Platelets play a role in venous thromboembolism (VTE) and in mediating colorectal cancer (CRC) progression. Still, platelets' role in hypercoagulability after surgical intervention for metastatic bone disease (MBD) is ill-defined.

METHODS

In this quantitative observational study, we utilized a high-resolution imaging approach to temporally examine platelet procoagulant membrane dynamics (PMD) in four patients with MBD from primary CRC (CRC/MBD), before and after surgical intervention, over a 6-month period. We coupled this investigation with thrombelastography, quantitative plasma shotgun proteomics, and biochemical analysis.

RESULTS

The plasma of CRC/MBD patients was enriched in ADAM1a, ADAMTS7, and physiological ligands for platelet glycoprotein-VI/spleen tyrosine kinase (GPVI/Syk) activation. Thromboprophylaxis attenuated procoagulation upon its initial prescription (post-operative day one, POD1); however, all patients experienced rebound procoagulation between POD3 and POD14, which was associated with Syk activation (Y525/Y526) in all patients, and a VTE event in two patients. Plasma levels of DNA-histone complexes increased steadily after surgery and remained elevated throughout the study period. Additionally, we increasingly sighted both homotypic and heterotypic platelet microaggregates after surgery in CRC/MBD patients, but not in healthy control participants' plasma.

CONCLUSIONS

Our data elucidates the cell biology of a prothrombo-inflammatory state caused by disease and vascular injury, and recalcitrant to thromboprophylaxis. New mechanistic insights into hypercoagulability in CRC/MBD patients may identify novel drug targets for effective thromboprophylaxis type and duration after orthopaedic surgery.

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.

Prospective study of Na[18F]F PET/CT for cancer staging in morbidly obese patients compared with [99mTc]Tc-MDP whole-body planar, SPECT and SPECT/CT

PURPOSE

This prospective study aims to assess the diagnostic test characteristics of Na[¹⁸F]F PET/CT for the skeletal staging of cancer in morbidly obese patients compared with ^99mTc-methylene diphosphonate (MDP), whole-body planar (WBS), SPECT, and SPECT/CT acquisitions.

MATERIAL AND METHODS

One hundred seventeen obese patients (BMI 46.5 ± 6.1 kg/m² and mean age, 59.0 years; range 32-89 years) with BMI > 40 kg/m² were prospectively enrolled and underwent [^99mTc]Tc-MDP WBS, SPECT, SPECT/CT, and Na[¹⁸F]F PET/CT within two weeks for the osseous staging of a malignancy. Images were assessed qualitatively using a 3-point scale. Patient and lesion-based diagnostic test characteristics were estimated using an optimistic and pessimistic dichotomization method.

RESULTS

Bone metastases were confirmed in 44 patients. Patient-based optimistic diagnostic test characteristics were (sensitivity, specificity, overall accuracy): Na[¹⁸F]F PET/CT (95.5%, 95.9%, 95.7%), [^99mTc]Tc-MDP WBS (52.3%, 71.2%, 64.1%), SPECT (61.4%, 80.8%, 73.5%) and SPECT/CT (65.9%, 91.8%, 82.1%). Lesion-based optimistic diagnostic test characteristics were: Na[¹⁸F]F PET/CT (97.7%, 97.9%, 97.7%), [^99mTc]Tc-MDP WBS (39%, 67%, 48.9%), SPECT (52.9%, 93.6%, 67.3%) and SPECT/CT (65.9%, 91.8%, 82.1%). There was no significant difference in the specificity of Na[¹⁸F]F and SPECT/CT. All other pairwise comparisons were significant (p<.001). ROC curve analysis showed a high overall accuracy of Na[¹⁸F]F with significantly higher AUCs for Na[¹⁸F]F PET/CT compared to [^99mTc]Tc-MDP WBS, SPECT, and SPECT/CT on both patient and lesion-based analysis (p<.001). Moreover, Na[¹⁸F]F PET/CT changed patient management in 38% of patients.

CONCLUSIONS

Na[¹⁸F]F PET/CT may be the preferred imaging modality for skeletal staging in morbidly obese patients. The technique provides excellent diagnostic test characteristics superior to [^99mTc]Tc-MDP bone scan (including SPECT/CT), impacts patient management, has an acceptable radiation exposure profile, and is well-tolerated. Further cost-effectiveness evaluations are warranted.

Translational Strategies to Target Metastatic Bone Disease

Metastatic bone disease is a common and devastating complication to cancer, confounding treatments and recovery efforts and presenting a significant barrier to de-escalating the adverse outcomes associated with disease progression. Despite significant advances in the field, bone metastases remain presently incurable and contribute heavily to cancer-associated morbidity and mortality. Mechanisms associated with metastatic bone disease perpetuation and paralleled disruption of bone remodeling are highlighted to convey how they provide the foundation for therapeutic targets to stem disease escalation. The focus of this review aims to describe the preclinical modeling and diagnostic evaluation of metastatic bone disease as well as discuss the range of therapeutic modalities used clinically and how they may impact skeletal tissue.

Surgical Treatment of Metastatic Bone Disease in the Appendicular Skeleton: A Population-Based Study

Background: Population-based studies of patients with bone metastases in the appendicular skeleton (aBM) requiring surgery for complete or impending fracture are rare. In this epidemiologically-based observational study we created a large population-based cohort of patients treated for aBM, aiming to: (1) monitor possible time-related changes of the incidence of surgical treatment of aBM-lesions, (2) examine differences in the population and care of patients treated at different treatment centers and (3) examine if findings from a previous pilot study regarding absence of a suitable biopsy of the lesions representing debut of cancer or a relapse has improved the awareness of aBM and hereby increased the focus on regular tumor biopsies and follow-up imaging of cancer patients. Methods: We examined a population-based cohort consisting of all patients treated for aBM 2014−2019. Procedures were performed at five secondary surgical centers (SSC) or one tertiary referral Musculoskeletal Tumor Center (MTC). Patients were followed until end of study (30 September 2021) or death. No patients were lost to follow-up. Results: Four-hundred-fifty-seven patients (493 primary aBM-lesions, 482 procedures) were included. Annual incidence of aBM-surgery was 46 aBM-lesions/million. MTC-patients had a significant better preoperative status than SSC-patients considering factors known for survival. Patients with complete fracture experienced longer surgical delay when treated at MTC compared to SSC: 4 (1−9) and 1 (1−3) days (p < 0.001), respectively. Overall survival for the entire cohort was 37% and 11% at 1 and 5 years (MTC and SSC 1 and 5 year respectively: 44% and 15% vs. 29% and 5%, p < 0.001). In patients with debut or relapse of cancer, 8% and 9% had insufficient biopsies, and 21% and 12% had no biopsy, respectively. Comparison showed no change over time. Conclusions: The current study highlights the low awareness on treating aBM at SSC and emphasizes the importance of caution in interpretation of studies not representing an entire population, thus introducing selection bias.

ANALGESIC EFFECT OF VARIOUS RADIOPHARMACEUTICALS IN THE COMPLEX TREATMENT OF METASTATIC BONE DISEASE

OBJECTIVE

The study objective was to investigate and compare the effectiveness of different radiopharmaceuticalsin the treatment of metastatic bone disease.

MATERIALS AND METHODS

Cancer patients (n = 150, average age (55 ± 11.6) years, 95 females, 55 males) having gotvarious primary tumors and metastatic bone disease were given medical treatment at the Department of NuclearMedicine of the National Institute of Cancer. The 153Sm, 32Р, and 89Sr radiopharmaceutical agents produced by the«Radiopreparats» enterprise (Republic of Uzbekistan) and Radioisotope Centre Polatom (National Centre for NuclearResearch, Poland) were administered to the patients. There were cases of breast cancer (n = 75), prostate cancer(n = 45), lung cancer (n = 10), kidney cancer (n = 4), cervical cancer (n = 5), and rectosigmoid cancer (n = 11) amongthe treated subjects. In 135 patients (90 %) the bone metastases were detected by osteoscintigraphy with 99мTc- mo-nodiphosphonate. In 15 cases the diagnosis of metastatic bone disease was verified by other radiology methods.

RESULTS

The pain intensity rating scale (LACOMED) was used to assay the analgesic effect of various radiopharma-ceuticals in metastatic bone disease. Results of treatment with 32P, 89Sr, and 153Sm were included in a comparativeanalysis procedure. It was established that the level of pain syndrome ranged from 7-8 points on the LACOMED scalebefore treatment. Upon administration of radionuclide therapy the level of pain was reduced down to 3-5 points,namely with 32P therapy it has decreased by 30.7 %, with 89Sr by 33.2 %, and with 153Sm by 41.5 % respectively. Timepattern of 153Sm analgesic effectiveness was studied depending on the number of treatment sessions. The best valueof analgesic effect of 153Sm was registered after the first treatment session with a tendency to decrease after the sec-ond and significantly lower analgesic effects after the third session. Tolerance of 153Sm was rated on the CTCNCA (v)4.3 scale. The best tolerance was peculiar to 153Sm corresponding to the «good» level according to a point assess-ment. When using 89Sr the drug tolerance was lower, not requiring however the drug discontinuation. The 32P radio-pharmaceutical featured the lowest tolerance approaching the «satisfactory» rating. In 11 patients upon that theside effects were found significantly impairing the patient's status, accordingly some extra measures were required.No decision to cancel the drug administration was made.

CONCLUSIONS

Radionuclide therapy with 153Sm-oxabiphor agent can be used in the complex treatment of metastat-ic bone disease in cancer patients having got tumors of different localization. 153Sm-oxabiphor is the most effectiveand best tolerable radiopharmaceutical agent in the pain treatment in metastatic bone disease in comparison with32P and 89Sr preparations (р < 0.05).

The Surgical Management of Proximal Femoral Metastases: A Narrative Review

The proximal femur is a common location for the development of bony metastatic disease. Metastatic bone disease in this location can cause debilitating pain, pathologic fractures, reduced quality of life, anemia or hypercalcemia. A thorough history, physical examination and preoperative investigations are required to ensure accurate diagnosis and prognosis. The goals of surgical management is to provide pain relief and return to function with a construct that provides stability to allow for immediate weightbearing. Current surgical treatment options include intramedullary nailing, hemiarthroplasty or total hip arthroplasty and endoprosthetic reconstructions. Oligometastatic renal cell carcinoma must be given special consideration as tumor resection and reconstruction has survival benefit. Both tumor and patient characteristics must be taken into account before deciding on the appropriate surgical intervention.

Fracture Risk of Long Bone Metastases: A Review of Current and New Decision-Making Tools for Prophylactic Surgery

Simple Summary

Long bone metastases are frequently a pivotal point in the oncological history of patients. Weakening of the bone results in pathologic fractures that not only compromise patient function but also their survival. Therefore, the main issue for tumor boards remains timely assessment of the risk of fracture, as this is a key consideration in providing preventive surgery while also avoiding overtreatment. As the Mirels scoring system takes into account both the radiological and the clinical criteria, it has been used worldwide since the 1990s. However, due to increasing concern regarding the lack of accuracy, new thresholds have been defined for the identification of impending fractures that require prophylactic surgery, on the basis of axial cortical involvement and biomechanical models involving quantitative computed tomography. The aim of this review is to establish a state-of-the-art of the risk assessment of long bone metastases fractures, from simple radiologic scores to more complex multidimensional bone models, in order to define new decision-making tools.

Abstract

Long bone pathological fractures very much reflect bone metastases morbidity in many types of cancer. Bearing in mind that they not only compromise patient function but also survival, identifying impending fractures before the actual event is one of the main concerns for tumor boards. Indeed, timely prophylactic surgery has been demonstrated to increase patient quality of life as well as survival. However, early surgery for long bone metastases remains controversial as the current fracture risk assessment tools lack accuracy. This review first focuses on the gold standard Mirels rating system. It then explores other unique imaging thresholds such as axial or circumferential cortical involvement and the merits of nuclear imaging tools. To overcome the lack of specificity, other fracture prediction strategies have focused on biomechanical models based on quantitative computed tomography (CT): computed tomography rigidity analysis (CT-RA) and finite element analysis (CT-FEA). Despite their higher specificities in impending fracture assessment, their limited availability, along with a need for standardization, have limited their use in everyday practice. Currently, the prediction of long bone pathologic fractures is a multifactorial process. In this regard, machine learning could potentially be of value by taking into account clinical survival prediction as well as clinical and improved CT-RA/FEA data.

Thromboembolic complications after surgical fixation of bone metastases: A systematic review

BACKGROUND

Patients undergoing a major orthopedic surgery for metastatic bone disease (MBD) are at high risk of developing venous thromboembolic (VTE) complications. Despite concerns, there is no consensus on the most effective strategy to prevent VTE in these patients. The purpose of this systematic review was to determine the VTE rate following the surgical management of MBD.

METHODS

The databases MEDLINE, EMBASE, and CENTRAL were searched using keywords related to VTE and MBD requiring surgical management. Included studies reported VTE rates in patients with surgically managed MBD. Descriptive statistics and weighted mean totals were calculated.

RESULTS

In total, 2082 abstracts were screened, and 29 studies were included. The overall VTE rate was 4.7%. Patients receiving surgery for impending pathologic fracture had a higher rate of VTE (5.6%) compared to patients with acute pathologic fractures (4.2%). Low-molecular-weight heparin was the most used chemoprophylaxis.

CONCLUSIONS

Relative to other cancer and orthopedic patients, the VTE rate is extremely high in patients with MBD. The discordant recommendations of thromboprophylaxis, and absence of research in this distinct and more granular surgical oncology subgroup, underpins the challenges associated with developing guidelines to lessen the VTE risks in the MBD patient population.

What Is the Clinical Impact of Sending Tissue for Histopathology During Surgery for Known, Diffuse Metastatic Disease to Bone?

BACKGROUND/AIM

During surgery for patients with known, diffuse metastatic bone disease (MBD), lesional tissue is routinely sent for pathological evaluation. However, there are limited data to assess whether there is a role for histopathology for MBD despite time and cost of interpretation, as well as whether a positive sample changes the subsequent treatment course.

PATIENTS AND METHODS

Sixty-six cases from 2017 to 2020 were reviewed retrospectively. The median age at surgery was 63.5 years (range of 23 to 84 years), and the primary tumor was most frequently breast (24.2%, n=16), renal (21.2%, n=14) or lung (15.2%, n=10). The most common location of MBD was the femur (60.6%, n=40).

RESULTS

The overall yield of a positive tissue sample of MBD was 77.3% (n=51). The positive rate from sending intramedullary reamings was 65.4% (n=17 of 26). Among the 66 cases (63 patients), a change in the subsequent clinical management was recorded in 9.1% (n=6). The most common change was related to the medication regimen (n=5), with one change related to recognition of the carcinoma origin via histology, which was previously unknown.

CONCLUSION

Despite the routine practice of sending tissue for histology during surgery for known and diffuse MBD, a change in the subsequent clinical management is uncommon. Prior to sending tissue, surgeons should discuss this practice with the multidisciplinary care team on a per-patient basis.

Is There a Role for Intramedullary Tissue Sampling During Internal Fixation of Metastatic Disease in Long Bones? A Systematic Review and an Institutional Experience

BACKGROUND

The purpose of this investigation was to identify and summarize the current utility of intramedullary tissue sampling during long bone internal fixation (IF) for metastatic bone disease (MBD). The secondary aim was to provide the experience of a single institution using this technique.

METHODS

First, a systematic database query of the Cochrane Central Register of Controlled Trials (1976 to 2020), Cochrane Database of Systematic Reviews, Ovid MEDLINE (1946 to 2020), EMBASE, and PubMed (1964 to 2020) was performed. Following article identification, a description of the method of sampling and yield was recorded. Second, an institutional cohort was identified following Institutional Review Board approval. Cases of MBD treated with IF from 2018 to 2020 were reviewed. Data were collected and recorded from cases during which intramedullary reamings were sent for histopathology.

RESULTS

Ten studies met inclusion criteria. Four of the ten were techniques or technical notes. The remaining six were retrospective reviews in which tissue was sent for histopathology. Among those six, a total of 262 tissue samples were sent, and a negative result was recorded in 37.2% (n = 97) of cases. A total of 18.0% (n = 47) were noted as inadequate for interpretation. For reamings-only studies, the negative rate was higher at 50.5%. In our institutional cohort, a total of 16 tissue samples were sent in the setting of known MBD. The negative rate was 37.5% (n = 6), with zero instances of a change in clinical management after a positive result.

CONCLUSION

There are limited descriptions of intramedullary tissue sampling during IF of long bones for MBD. The existing literature, along with our institutional data, suggest this technique is less than optimal for tissue retrieval given the high rates of negative results from samples sent for histopathology. Furthermore, given the lack of clinical impact of a positive sample, we believe a multidisciplinary group should discuss preoperatively the utility of whether treatment might change based off a tissue diagnosis.Level of Evidence: V.

Venous thromboembolism in orthopaedic oncology

AIMS

Malignancy and surgery are risk factors for venous thromboembolism (VTE). We undertook a systematic review of the literature concerning the prophylactic management of VTE in orthopaedic oncology patients.

METHODS

MEDLINE (PubMed), EMBASE (Ovid), Cochrane, and CINAHL databases were searched focusing on VTE, deep vein thrombosis (DVT), pulmonary embolism (PE), bleeding, or wound complication rates.

RESULTS

In all, 17 studies published from 1998 to 2018 met the inclusion criteria for the systematic review. The mean incidence of all VTE events in orthopaedic oncology patients was 10.7% (1.1% to 27.7%). The rate of PE was 2.4% (0.1% to 10.6%) while the rate of lethal PE was 0.6% (0.0% to 4.3%). The overall rate of DVT was 8.8% (1.1% to 22.3%) and the rate of symptomatic DVT was 2.9% (0.0% to 6.2%). From the studies that screened all patients prior to hospital discharge, the rate of asymptomatic DVT was 10.9% (2.0% to 20.2%). The most common risk factors identified for VTE were endoprosthetic replacements, hip and pelvic resections, presence of metastases, surgical procedures taking longer than three hours, and patients having chemotherapy. Mean incidence of VTE with and without chemical prophylaxis was 7.9% (1.1% to 21.8%) and 8.7% (2.0% to 23.4%; p = 0.11), respectively. No difference in the incidence of bleeding or wound complications between prophylaxis groups was reported.

CONCLUSION

Current evidence is limited to guide clinicians. It is our consensus opinion, based upon logic and deduction, that all patients be considered for both mechanical and chemical VTE prophylaxis, particularly in high-risk patients (pelvic or hip resections, prosthetic reconstruction, malignant diagnosis, presence of metastases, or surgical procedures longer than three hours). Additionally, the surgeon must determine, in each patient, if the risk of haemorrhage outweighs the risk of VTE. No individual pharmacological agent has been identified as being superior in the prevention of VTE events. Cite this article: Bone Joint J 2020;102-B(12)1743:-1751.

Severe and prolonged hypocalcemia after a single dose of denosumab for metastatic breast cancer with diffuse bone involvement without prior calcium/vitamin D supplementations

INTRODUCTION

Denosumab is a human monoclonal antibody antiresorptive agent used for the treatment of bone metastasis in different cancer types, including breast cancer. Hypocalcemia is a known adverse effect of denosumab, and early supplementation plays an important role in the prevention and management of hypocalcemia.

CASE REPORT

A 63-year-old female with stage IV estrogen receptor-positive breast cancer with diffuse bone metastasis experienced severe, prolonged hypocalcemia following a single dose of denosumab. The patient also had several risk factors for denosumab-associated hypocalcemia. Despite not receiving additional doses of denosumab, the patient required multiple hospitalizations and outpatient infusions of calcium to resolve her symptomatic hypocalcemia.Management and outcome: Severe hypocalcemia associated with denosumab can be prevented or mitigated by recognizing the risk factors for hypocalcemia and supplementing with vitamin D/calcium. Proposed risk factors include poor renal function, hypoparathyroidism, insufficient calcium intake, and diffuse metastatic bone disease. Studies suggest that early supplementation before starting denosumab can lower this risk.

DISCUSSION

Several cases of severe hypocalcemia associated with denosumab have been reported. However, to the authors' knowledge, this is the first report that highlights the importance of early vitamin D/calcium supplementations for a patient with diffuse metastatic bone disease with pre-existing low levels of calcium.

Fracture risk assessment and clinical decision making for patients with metastatic bone disease

Metastatic breast, prostate, lung, and other cancers often affect bone, causing pain, increasing fracture risk, and decreasing function. Management of metastatic bone disease (MBD) is clinically challenging when there is potential but uncertain risk of pathological fracture. Management of MBD has become a major focus within orthopedic oncology with respect to fracture and impending fracture care. If impending skeletal-related events (SREs), particularly pathologic fracture, could be predicted, increasing evidence suggests that prophylactic surgical treatment improves patient outcomes. However, current fracture risk assessment and radiographic metrics do not have high accuracy and have not been combined with relevant patient survival tools. This review first explores the prevalence, incidence, and morbidity of MBD and associated SREs for different cancer types. Strengths and limitations of current fracture risk scoring systems for spinal stability and long bone fracture are highlighted. More recent computed tomography (CT)-based structural rigidity analysis (CTRA) and finite element (FE) analysis methods offer advantages of increased specificity (true negative rate), but are limited in availability. Other fracture prediction approaches including parametric response mapping and positron emission tomography/computed tomography measures show early promise. Substantial new information to inform clinical decision-making includes measures of survival, clinical benefits, and economic analysis of prophylactic treatment compared to after-fracture stabilization. Areas of future research include use of big data and machine learning to predict SREs, greater access and refinement of CTRA/FE approaches, combination of clinical survival prediction tools with radiographically based fracture risk assessment, and net benefit analysis for fracture risk assessment and prophylactic treatment.

Paget disease of bone in an elderly patient with chronic renal disease and weight loss: A case report

RATIONALE

Asymptomatic Paget disease of bone (PDB) is mostly diagnosed by accidental finding of osteolytic lesion on the plain film. However, in elderly patient with chronic renal insufficiency and weight loss, it is crucial to differentiate PDB from metabolic and metastatic bone diseases for further treatment and better outcome.

PATIENT CONCERNS

An 80-year-old man with chronic kidney disease presented to our emergency department due to fever with chillness for a day, while the abdominal fullness, anorexia, and weight loss had been noted for 3 months. Mixed osteoblastic and lytic changes in the pelvic bone were accidentally found on the abdominal plain film.

DIAGNOSIS

The patient was diagnosed as asymptomatic PDB and urinary tract infection of Pseudomonas aeruginosa.

INTERVENTIONS AND OUTCOME

The patient received 7 days intravenous and followed by 7 days oral antibiotic treatment, which lead to clinical improvement of his urinary tract infection. No pharmacological treatment was initiated for the asymptomatic and localized PDB. The patient was discharged under stable condition afterward.

LESSONS

In patients with mixed osteolytic and blastic lesions, the differential diagnoses include metabolic and metastatic bone disease. Thorough understanding of the morphology of the bone lesions in high risk patient, not only helps to make differential diagnosis, but it also leads to precise treatment and better outcome.

Long-term results of the Global Modular Replacement System tumor prosthesis for reconstruction after limb-sparing bone resections in orthopedic oncologic conditions: Results from a national cohort

BACKGROUND AND OBJECTIVES

We investigated implant revision, implant failure, and amputation risk after limb-sparing bone tumor surgery using the Global Modular Replacement System (GMRS) tumor prosthesis in patients suffering from bone sarcomas (BS), giant cell tumors (GCT), or metastatic bone disease (MBD).

MATERIAL AND METHODS

A retrospective study of a nationwide consecutive cohort (n = 119, 47 [12-81] years, M/F = 65/54) having limb-sparing surgery and reconstruction using the GMRS tumor prosthesis due to bone tumors (BS/GCT/MBD = 70/8/41) from 2005 to 2013. Anatomical locations were as followed: distal femur (n = 49), proximal femur (n = 41), proximal tibia (n = 26), or total femur (n = 3). Kaplan-Meier survival analysis and competing risk analysis with death as a competing risk were used for statistical analysis.

RESULTS

For BS and GCT patients, 5-year patient survival was 72% (95% confidence interval [CI]: 59-85%) and for MBD 33% (95% CI: 19-48%). Thirty-two patients underwent revision surgery (5-year revision incidence 14%; 95% CI: 8-21%). Twelve patients had revision of bone-anchored parts (implant failure) with a 5-year revision incidence 6% (95% CI: 2-10%). Ten amputations were performed due to local relapse (n = 9) or recurrent infections (n = 1) with a 5-year incidence of amputation: 8% (95% CI: 3-13%).

CONCLUSIONS

We identified a low risk of revision and amputation when using the GMRS tumor prosthesis for limb-sparing bone tumor.

Pain Management in Metastatic Bone Disease: A Literature Review

Cancer means an uncontrolled division of abnormal cells in the body. It is a leading cause of death today. Not only the disease itself but its complications are also adding to the increase in mortality rate. One of the major complications is the pain due to metastasis of cancer. Pain is a complex symptom which has physical, psychological, and emotional impacts that influence the daily activities as well as social life. Pain acts as an alarm sign, telling the body that something is wrong. Pain can manifest in a multitude fashion. Management of bone pain due to metastasis involves different modes with some specific treatments according to the type of primary cancer. Over the years various treatment modalities have been tried and tested to improve the pain management including the use of non-steroidal anti-inflammatory drugs (NSAIDs), opioids, bisphosphonates, tricyclic antidepressants, corticosteroids, growth factors and signaling molecules, ET-1 receptor antagonists, radiotherapy as well as surgical management. The topic of discussion will cover each one of these in detail.

Multimodal Treatment of Bone Metastasis-A Surgical Perspective

Over the past decades there has been an increase in the incidence of cancer worldwide. With the advancement in treatment, patient survival has improved in tandem with the increasing incidence. This, together with the availability of advanced modern diagnostic modalities, has resulted in more cases of metastatic bone disease being identified. Bone metastasis is an ongoing problem and has significant morbidity implications for patients affected. Multimodal treatment strategies are required in dealing with metastatic bone disease, which include both surgical and non-surgical treatment options. In the multidisciplinary team, orthopedic surgeons play an important role in improving the quality of life of cancer patients. Surgical intervention in this setting is aimed at pain relief, restoration of function and improvement in functional independence. In selected cases with resectable solitary metastasis, surgical treatment may be curative. With the advancement of surgical technique and improvement in implant design and manufacture, a vast array of surgical options are available in the modern orthopedic arena. In the majority of cases, limb salvage procedures have become the standard of care in the treatment of metastatic bone disease. Non-surgical adjuvant treatment also contributes significantly to the improvement of cancer patient care. A multidisciplinary approach in this setting is of paramount importance.

Drug-eluting implants for the suppression of metastatic bone disease: current insights

INTRODUCTION

The fixation of impending or pathologic fractures is challenging and their successful management can have a favourable impact on the quality of life of the patient. The progression of the metastatic bone disease can cause significant pain and disability but also could result in the loosening and subsequent failure of the implants. To prevent the additional local growth, postoperative radiotherapy is often recommended, and many patients receive endocrine or chemotherapy.

AREAS COVERED

Several reports support the antineoplastic drugs to bone cement as an adjuvant to improve implant stability as well as to prevent local cancer progression and failure of reconstructive devices used to treat patients with pathologic fractures. The aim of the present review is to present our current understanding on the effect of local delivery of antineoplastic drugs at the bone site.

EXPERT COMMENTARY

Encouraging evidence support the application of bone cement loaded with antineoplastic drugs to fill defects and strengthen the fixation of orthopaedic implants. This is an inexpensive and safe method that can improve implant stability, prevent local cancer progression and failure of reconstructive devices. To fully evaluate its clinical effectiveness randomized clinical studies are needed.

Magnetic resonance guided focused ultrasound for treatment of bone tumors

AIMS

Magnetic resonance guided focused ultrasound (MRgFUS) is a new modality in the management of primary and secondary bone tumors. We aimed to investigate the safety, efficacy, and feasibility of using MRgFUS for the treatment of (1) benign bone tumors with the intent of complete tumor ablation, (2) primary malignant bone tumors with the intent to assess its effectiveness in causing tumor necrosis, and (3) metastatic bone disease with the intent of pain relief.

METHOD

Twenty-four patients with benign bone tumors, primary malignant bone tumors, and metastatic bone disease were treated with one session of MRgFUS. Contrast-enhanced (CE) magnetic resonance imaging (MRI) was carried out post-procedure to assess and quantify the area of ablation. Those with malignant primary tumors had the tumors resected 2 weeks after the treatment and the ablated areas were examined histopathologically (HPE). The other patients were followed up for 3 months to assess for the side effects and pain scores.

RESULTS

Significant volume of ablation was noted on CE MRI after the treatment. Benign bone tumors were ablated with minimal adverse effects. Metastatic bone disease was successfully treated with significant decrease in pain scores. Ablated primary malignant tumors showed significant coagulative necrosis on MRI and the HPE showed 100% necrosis. Pain scores significantly decreased 3 months after the procedure. Only two patients had superficial skin blistering and three patients had increase in pain scores immediately after treatment.

CONCLUSION

MRgFUS is effective, safe, and noninvasive procedure that can be an adjunct in the management of primary and metastatic bone tumors.

Can We Estimate Short- and Intermediate-term Survival in Patients Undergoing Surgery for Metastatic Bone Disease?

BACKGROUND

Objective means of estimating survival can be used to guide surgical decision-making and to risk-stratify patients for clinical trials. Although a free, online tool ( www.pathfx.org ) can estimate 3- and 12-month survival, recent work, including a survey of the Musculoskeletal Tumor Society, indicated that estimates at 1 and 6 months after surgery also would be helpful. Longer estimates help justify the need for more durable and expensive reconstructive options, and very short estimates could help identify those who will not survive 1 month and should not undergo surgery. Thereby, an important use of this tool would be to help avoid unsuccessful and expensive surgery during the last month of life.

QUESTIONS/PURPOSES

We seek to provide a reliable, objective means of estimating survival in patients with metastatic bone disease. After generating models to derive 1- and 6-month survival estimates, we determined suitability for clinical use by applying receiver operator characteristic (ROC) (area under the curve [AUC] > 0.7) and decision curve analysis (DCA), which determines whether using PATHFx can improve outcomes, but also discerns in which kinds of patients PATHFx should not be used.

METHODS

We used two, existing, skeletal metastasis registries chosen for their quality and availability. Data from Memorial Sloan-Kettering Cancer Center (training set, n = 189) was used to develop two Bayesian Belief Networks trained to estimate the likelihood of survival at 1 and 6 months after surgery. Next, data from eight major referral centers across Scandinavia (n = 815) served as the external validation set-that is, as a means to test model performance in a different patient population. The diversity of the data between the training set from Memorial Sloan-Kettering Cancer Center and the Scandinavian external validation set is important to help ensure the models are applicable to patients in various settings with differing demographics and treatment philosophies. We considered disease-specific, laboratory, and demographic information, and the surgeon's estimate of survival. For each model, we calculated the area under the ROC curve (AUC) as a metric of discriminatory ability and the Net Benefit using DCA to determine whether the models were suitable for clinical use.

RESULTS

On external validation, the AUC for the 1- and 6-month models were 0.76 (95% CI, 0.72-0.80) and 0.76 (95% CI, 0.73-0.79), respectively. The models conferred a positive net benefit on DCA, indicating each could be used rather than assume all patients or no patients would survive greater than 1 or 6 months, respectively.

CONCLUSIONS

Decision analysis confirms that the 1- and 6-month Bayesian models are suitable for clinical use.

CLINICAL RELEVANCE

These data support upgrading www.pathfx.org with the algorithms described above, which is designed to guide surgical decision-making, and function as a risk stratification method in support of clinical trials. This updating has been done, so now surgeons may use any web browser to generate survival estimates at 1, 3, 6, and 12 months after surgery, at no cost. Just as short estimates of survival help justify palliative therapy or less-invasive approaches to stabilization, more favorable survival estimates at 6 or 12 months are used to justify more durable, complicated, and expensive reconstructive options.

Prognostic value of biochemical variables for survival after surgery for metastatic bone disease of the extremities

BACKGROUND AND OBJECTIVE

Prediction of survival in patients having surgery for metastatic bone disease in the extremities (MBDex) has been of interest in more than two decades. Hitherto no consensus on the value of biochemical variables has been achieved. Our purpose was (1) to investigate if standard biochemical variables have independent prognostic value for survival after surgery for MBDex and (2) to identify optimal prognostic cut off values for survival of biochemical variables.

METHODS

In a consecutive cohort of 270 patients having surgery for MBDex, we measured preoperative biochemical variables: hemoglobin, alkaline phosphatase, C-reactive protein and absolute, neutrophil and lymphocyte count. ROC curve analyses were performed to identify optimal cut off levels. Independent prognostic factors for variables were addressed with multiple Cox regression analyses.

RESULTS

Optimal cut off levels were identified as: hemoglobin 7.45 mmol/L, absolute lymphocyte count 8.5 × 10⁹ /L, neutrophil 5.68 × 10⁹ /L, lymphocyte 1.37 × 10⁹ /L, C-reactive protein 22.5 mg/L, and alkaline phosphatase 129 U/L. Regression analyses found alkaline phosphatase (HR 2.49) and neutrophil count (HR 2.49) to be independent prognostic factors.

CONCLUSIONS

We found neutrophil count and alkaline phosphatase to be independent prognostic variables in predicting survival in patients after surgery for MBDex.

Expression of Biomarkers CXCR4, IL11-RA, TFF1, MLF1P in Advanced Breast Cancer Patients with Bone Metastatic: a Diagnostic Study

AIM

to analyze expression of biomarkers CXCR4, IL11-RA, TFF1 and MLF1P, and clinicopathology in advanced breast cancer patients with bone metastatic.

METHODS

this is a cross-sectional study. Analysis was done against a total of 92 breast cancer patients, including 46 bone metastatic patients and 46 non-bone metastatic patients. Immunohistochemistry and microarray analysis was performed in 81 formalin fixed paraffin embedded (FFPE) samples from 81 patients were used. Data were collected through medical records, immunohistochemistry (IHC), and microarray with nanoString nCounterTM.

RESULTS

this article is part one of a two stage reporting research results. In part one we got the results of the IHC analysis, IL11-RA with cut-off ≥103.5 showed OR 3.803 (95 % confidence interval [CI], 1.375-10.581), p=0.010, MLF1P with cut-off ≥83.0 OR 2.784 (95% CI, 1.009-7.681), p=0.048, and ER+ OR 7.640 (95 % CI, 2.599-22.459), p<0.000, were associated with bone metastastic incidences in advanced breast cancer, and were statistically significantly different. A combination of IL-11RA, MLF1P and ER+, showed an accuracy of approaching 80% to discriminate between bone metastatic and non bone metastatic in advanced breast cancer patients.

CONCLUSION

IL11-RA, MLF1P, and ER+ were the determinants that were associated with increasing bone metastasis incidence.

Intravenous pamidronate versus oral and intravenous clodronate in bone metastatic breast cancer: a randomized, open-label, non-inferiority Phase III trial

Purpose

Patients with metastasized breast cancer often suffer from discomfort caused by metastatic bone disease. Thus, osteoprotection is an important part of therapy in breast cancer metastasized to bone, and bisphosphonates (BPs) are a major therapeutic option. In this study, our objectives were to compare the side effects of oral versus intravenous BP treatment and to assess their clinical effectiveness.

Patients and methods

In this prospective randomized, open-label, non-inferiority trial, we enrolled breast cancer patients with at least one bone metastasis and an Eastern Cooperative Oncology Group performance status of 0–2. Patients were randomly assigned to one of the three treatment groups: A, 60 mg pamidronate intravenously q3w; B-iv, 900 mg clodronate intravenously q3w; and B-o, 2,400 mg oral clodronate daily. Assessments were performed at baseline and every 3 months thereafter.

Results

Between 1995 and 1999, 321 patients with confirmed bone metastases from breast cancer were included in the study. At first follow-up, gastrointestinal (GI) tract side effects were most common, and adverse effects on the GI tract were more frequent in the oral treatment group (P=0.002 and P<0.001, respectively). There were no statistically significant differences among the treatment cohorts for other documented side effects (skin, serum electrolytes, urinary tract, immune system, and others). No significant differences in clinical effectiveness of BP treatment, as assessed by pain score, were detected among the groups; however, pathologic fractures were more effectively prevented by intravenous than oral BP administration (P=0.03). Noncompliance rates were similar among the study cohorts.

Conclusion

We conclude that oral BP treatment is significantly associated with higher rates of adverse GI side effects. Additionally, our data indicate that intravenous BP administration is more effective than oral treatment in prevention of pathologic fractures; hence, oral administration should be considered with caution.

New anti-resorptives and antibody mediated anti-resorptive therapy

The ageing population and an increase in both the incidence and prevalence of cancer pose a healthcare challenge, some of which is borne by the orthopaedic community in the form of osteoporotic fractures and metastatic bone disease. In recent years there has been an increasing understanding of the pathways involved in bone metabolism relevant to osteoporosis and metastases in bone. Newer therapies may aid the management of these problems. One group of drugs, the antibody mediated anti-resorptive therapies (AMARTs) use antibodies to block bone resorption pathways. This review seeks to present a synopsis of the guidelines, pharmacology and potential pathophysiology of AMARTs and other new anti-resorptive drugs. We evaluate the literature relating to AMARTs and new anti-resorptives with special attention on those approved for use in clinical practice. Denosumab, a monoclonal antibody against Receptor Activator for Nuclear Factor Kappa-B Ligand. It is the first AMART approved by the National Institute for Health and Clinical Excellence and the US Food and Drug Administration. Other novel anti-resorptives awaiting approval for clinical use include Odanacatib. Denosumab is indicated for the treatment of osteoporosis and prevention of the complications of bone metastases. Recent evidence suggests, however, that denosumab may have an adverse event profile similar to bisphosphonates, including atypical femoral fractures. It is, therefore, essential that orthopaedic surgeons are conversant with these medications and their safe usage.

TAKE HOME MESSAGE

Denosumab has important orthopaedic indications and has been shown to significantly reduce patient morbidity in osteoporosis and metastatic bone disease.

Denosumab-associated hypocalcaemia: incidence, severity and patient characteristics in a tertiary hospital setting

PURPOSE

Denosumab-associated hypocalcaemia (DAH) has been reported in patients with osteoporosis or metastatic bone disease and is associated with stages 4 and 5 chronic kidney disease (CKD, estimated glomerular filtration rate <30 mL/min/1.73m² ). Other risk factors for hypocalcaemia have not been fully elucidated. We aimed to investigate the incidence of hypocalcaemia amongst patients receiving denosumab and to identify clinical features associated with this adverse event.

METHODS

Retrospective cohort study between June 2013 and June 2014 of patients administered denosumab (60/120 mg) at a tertiary hospital in Melbourne, Australia, to identify the incidence of an albumin-adjusted serum calcium concentration <2.10 mmol/L or ionized calcium <1.13 mmol/L within 6 months of treatment. Univariable and multivariable logistic regression analyses were performed to identify clinical features associated with DAH.

RESULTS

One hundred and fifty-five patients were administered denosumab (100 osteoporosis, 55 bone metastases). Twenty-two patients (14% [95%CI 9.1-20.7]) developed hypocalcaemia: 55% were men, and 55% had osteoporosis. Eighty-six per cent had a 25-hydroxyvitamin D concentration >50 nmol/L, and 91% were on calcium/colecalciferol supplementation. Stages 4 and 5 CKD (adjusted odd ratio [aOR] 4.71, 95%CI 1.61-13.79, p = 0.005) and male sex (aOR 4.30, 95%CI 1.69-10.96, p = 0.002) were associated with DAH. No patients were documented as having hypocalcaemic symptoms. One patient received intravenous calcium gluconate treatment.

CONCLUSIONS

The incidence of denosumab-associated hypocalcaemia was 14% (95%CI 9.1-20.7) within 6 months of treatment despite widespread use of appropriate calcium/colecalciferol supplementation. Stages 4 and 5 CKD and male sex were associated with subsequent hypocalcaemia. Copyright © 2016 John Wiley & Sons, Ltd.

Use of Animal Models in Understanding Cancer-induced Bone Pain

Many common cancers have a propensity to metastasize to bone. Although malignancies often go undetected in their native tissues, bone metastases produce excruciating pain that severely compromises patient quality of life. Cancer-induced bone pain (CIBP) is poorly managed with existing medications, and its multifaceted etiology remains to be fully elucidated. Novel analgesic targets arise as more is learned about this complex and distinct pain state. Over the past two decades, multiple animal models have been developed to study CIBP’s unique pathology and identify therapeutic targets. Here, we review animal models of CIBP and the mechanistic insights gained as these models evolve. Findings from immunocompromised and immunocompetent host systems are discussed separately to highlight the effect of model choice on outcome. Gaining an understanding of the unique neuromolecular profile of cancer pain through the use of appropriate animal models will aid in the development of more effective therapeutics for CIBP.

Methotrexate-loaded glass ionomer cements for drug release in the skeleton: An examination of composition-property relationships

Chemotherapeutic-loaded bone cement may be an effective method of drug delivery for the management of cancer-related vertebral fractures that require cement injection for pain relief. Recent advancements in the development of aluminum-free glass ionomer cements (GICs) have rendered this class of biomaterials clinically viable for such applications. To expand the therapeutic benefits of these materials, this study examined, for the first time, their drug delivery potential. Through incrementally loading the GIC with methotrexate (MTX) by up to 10-wt%, composition-property relationships were established, correlating MTX loading with working time and setting time, as well as compressive strength, drug release, and cytotoxic effect over 31 days. The most significant finding of this study was that MTX was readily released from the GIC, while maintaining cytotoxic activity. Release correlated linearly with initial loading and appeared to be diffusion mediated, delivering a total of 1-2% of the incorporated drug. MTX loading in this range exerted minimal effects to handling and strength, indicating the clinical utility of the material was not compromised by MTX loading. The MTX-GIC systems examined herein are promising materials for combined structural delivery applications.

Runx2-Smad signaling impacts the progression of tumor-induced bone disease

Runx2, a master regulator of osteogenesis, is abnormally expressed in advanced prostate cancer. Here, we addressed Runx2 contribution to formation of prostate cancer-related osteolytic and osteoblastic bone lesions by mediating TGFβ/BMP signaling through direct interaction with Smads. Further, we examined involvement of the Runx2-Smad complex in mediating tumor growth and distal metastasis. To identify Runx2-Smad-specific mechanisms of prostate tumor activity in bone, we generated PC3 prostate cancer cell lines expressing Runx2-WT or one of two mutant proteins (Runx2-HTY and Runx2-ΔC) that each disrupt the Runx2-Smad interaction, either directly through a point mutation or by deletion of the functional C-terminus, respectively. Intratibial tumors generated from these cells revealed that Runx2-WT-expressing cells resulted in predominantly osteolytic disease, whereas cells expressing mutant proteins exhibited tumors with mixed osteolytic/osteoblastic lesions. Extent of bone loss and woven bone formation was assessed by radiography and micro-computed tomography. Bioluminescent imaging showed the presence of labeled prostate cancer cells in the lung at the latest time point examined, with Runx2-WT group exhibiting increased incidence of tumor cells in lung. Notably, disruption of the Runx2-Smad interaction significantly reduced incidence and size of lung tumors. Altered expression of Runx2 target genes involved in invasion, growth, adhesion and metastasis supported our findings. Thus, our studies demonstrate that Runx2 in prostate cancer cells plays a significant role in intratibial prostate cancer-related tumor growth and bone loss through mechanisms mediated by the Runx2-Smad signaling pathway. This work expands upon the potential importance of Runx2 as a therapeutic target in cancer.

Zoledronic acid in the management of metastatic bone disease

Many patients with advanced cancer experience decreased bone strength due to metastatic foci, underlying osteoporosis and/or cancer treatment induced bone loss. The clinical consequences of metastatic disease involving the skeleton are widespread. This review focuses on the efficacy, pharmacology, and safety when using intravenous biphosphonate such a zoledronic acid for cancer bone metastases. Zoledronic acid is the gold standard for the medical management of metastatic bone disease. The indications for treatment include prevention of skeletal relevant events (SRE), osteoporotic complications, and palliation of bone pain, among others. Zoledronic acid is the only bisphosphonate effective in decreasing SREs associated with bone metastases from advanced renal cell carcinoma and prostate cancer. Regarding prostate cancer, zoledronic acid effectively prevents both bone loss in patients with locally advanced disease receiving androgen deprivation therapy and SREs in men with hormone-refractory or hormone-sensitive metastatic disease. Zoledronic acid has an acceptable safety profile and tolerability, and has been effective at significantly decreasing the incidence, delaying the onset, and reducing the overall risk of experiencing an SRE compared to placebo. It is the only bisphosphonate currently approved for the prevention and treatment of skeletal complications in patients with bone metastases due to all solid tumors.

Overview of samarium sm 153 lexidronam in the treatment of painful metastatic bone disease

Bone pain associated with advanced prostate and other cancers is a frequent and significant complication, and the effective management of metastatic bone disease and accompanying symptoms continues to be one of the major problems facing patients and their physicians. Treatment is in part dependent on prior treatments; usually a combination of systemic and local modalities is used because no single treatment regimen is effective for an extended period of time. The 3 radionuclides currently approved for treatment of bone pain (phosphorus-32, strontium-89, and samarium-153) are discussed in this review as viable treatment options, with emphasis on the third-generation agent in this category, samarium Sm 153 lexidronam. Clinical trial data are described that support the use of this agent in patients with hormone-refractory prostate cancer with painful metastatic bone disease, and the efficacy of and role for combination therapies are also discussed.