The Impact of Isolated Versus Multiple Osteochondromas: Analysis of the CoULD Registry

PURPOSE

The burden of upper extremity (UE) osteochondromas on function and self-perception among pediatric patients is unclear. The purpose of our study was to study the impact of osteochondromas in comparison to population norms and to evaluate solitary versus multiple osteochondromas on subjective UE function as measured by patient rated outcomes.

METHODS

We utilized the CoULD (Congenital Upper Limb Differences) Registry to review all pediatric patients presenting with osteochondromas between January 2014 and February 2021. Demographic information was collected and patients were classified as having either single or multiple osteochondromas. Patient-Reported Outcome Measurement Information System (PROMIS) and Pediatric Outcomes Data Collection Instrument (PODCI) tools were utilized for assessment. Scores for PODCI subscales of UE function, Pain/comfort, and Happiness and PROMIS domains of UE Function, Pain, Depression, Anxiety, and Peer Relations were reviewed. Differences between groups were analyzed using the Student t test.

RESULTS

Ninety-nine patients met inclusion criteria for the study with an average age of presentation of 9.3 years and 61 patients (62%) were male. Overall, patients demonstrated worse UE Function as well as greater Anxiety and Depression in comparison to the population normals on PROMIS assessment. Patients also demonstrated worse patient and parent reported PODCI UE, Sports and Physical Functioning, Pain/Comfort and Global Functioning scores compared with population norms but demonstrated better than average happiness scores. Patients with multiple osteochondromas demonstrated greater PROMIS pain interference and more disability in PODCI Sports and Physical Functioning, Pain/Comfort and Global Functioning compared with those with solitary osteochondromas.

CONCLUSION

Patients with UE osteochondromas have worse overall function in comparison to population norms, exceeding established minimally clinically important difference values. In addition, patients with multiple osteochondromas reported more pain and poorer physical function than those with solitary osteochondromas. Physicians should be alert to the physical and psychosocial burden of this disease.

LEVEL OF EVIDENCE

Level II-prognostic.

Personalized endoprostheses for the proximal humerus and scapulohumeral joint in dogs: Biomechanical study of the muscles’ contributions during locomotion

Osteosarcoma represents one of the most common bone tumours in dogs. It commonly occurs in the proximal humerus, the most affected anatomic site. Until recently, amputation or limb-sparing surgery leading to an arthrodesis coupled with chemotherapy were the only available treatments, but they often lead to complications, reduced mobility and highly impact dog’s quality of life. Prototypes of both articulated and monobloc (no mobility) patient-specific endoprostheses have been designed to spare the limb afflicted with osteosarcoma of the proximal humerus. This study focuses on the biomechanical effects of endoprostheses and shoulder muscle kinematics. For each of the endoprosthesis designs, a minimal number of muscles needed to ensure stability and a certain degree of joint movement during walking is sought. A quasi-static study based on an optimization method, the minimization of the sum of maximal muscle stresses, was carried out to assess the contribution of each muscle to the shoulder function. The identification of the most important muscles and their impact on the kinematics of the prosthetic joint lead to an improvement of the endoprosthesis design relevance and implantation feasibility.

Clinical Impact of Nutritional Status and Sarcopenia in Pediatric Patients with Bone and Soft Tissue Sarcomas: A Pilot Retrospective Study (SarcoPed)

Background: We evaluated nutritional and sarcopenia status and their clinical impact in pediatric patients affected by bone and soft tissue sarcomas. Methods: Body mass index (BMI), prognostic nutritional index (PNI), and total psoas muscle area (tPMA) at diagnosis and after 12 months were analyzed. tPMA was measured from single cross-sectional computed tomography (CT) images at L4–L5. Age-specific and sex-specific tPMA Z-scores were retrieved from an online calculator. Results: A total of 21 patients were identified between February 2013 and December 2018. Twelve patients (57.1%) experienced sarcopenia at diagnosis, although not statistically associated with overall survival (OS) (p = 0.09). BMI Z-score, PNI, and tPMA Z-score significantly decreased between diagnosis and after 12 months of treatment (p < 0.05). Univariate analysis showed significant associations between poor OS and the presence of metastasis (p = 0.008), the absence of surgery (p = 0.005), PNI decrease (p = 0.027), and the reduction in tPMA > 25% (p = 0.042) over the 12 months. Conclusions: Sarcopenia affects more than half of the patients at diagnosis. Decreased PNI during 12 months of treatment has significant predictive value for OS. The role of tPMA derived from CT scan among pediatric patients with sarcoma should be investigated in further prospective and larger studies.

Lipid metabolism within the bone micro-environment is closely associated with bone metabolism in physiological and pathophysiological stages

Recent advances in society have resulted in the emergence of both hyperlipidemia and obesity as life-threatening conditions in people with implications for various types of diseases, such as cardiovascular diseases and cancer. This is further complicated by a global rise in the aging population, especially menopausal women, who mostly suffer from overweight and bone loss simultaneously. Interestingly, clinical observations in these women suggest that osteoarthritis may be linked to a higher body mass index (BMI), which has led many to believe that there may be some degree of bone dysfunction associated with conditions such as obesity. It is also common practice in many outpatient settings to encourage patients to control their BMI and lose weight in an attempt to mitigate mechanical stress and thus reduce bone pain and joint dysfunction. Together, studies show that bone is not only a mechanical organ but also a critical component of metabolism, and various endocrine functions, such as calcium metabolism. Numerous studies have demonstrated a relationship between metabolic dysfunction in bone and abnormal lipid metabolism. Previous studies have also regarded obesity as a metabolic disorder. However, the relationship between lipid metabolism and bone metabolism has not been fully elucidated. In this narrative review, the data describing the close relationship between bone and lipid metabolism was summarized and the impact on both the normal physiology and pathophysiology of these tissues was discussed at both the molecular and cellular levels.

Hypoxia inducible factor-3α promotes osteosarcoma progression by activating KDM3A-mediated demethylation of SOX9

Hypoxia/oxygen-sensing signally is closely associated with many tumor progressions, including osteosarcoma (OS). Previous research principally focused on the function of hypoxia-inducible factor (HIF)-1α and HIF-2α as the major hypoxia-associated transcription factors in OS, however, the role of HIF-3α has not been investigated. Our study found that HIF-3α was upregulated in OS tissues and cell lines. HIF-3α overexpression facilitated cell proliferation and invasion, and inhibited apoptosis, whereas HIF-3α knockdown showed the opposite results. Chromatin immunoprecipitation analysis revealed that lysine demethylase 3A (KDM3A) expression was transcriptionally activated by HIF-3α under hypoxia, and KDM3A occupied the SRY-box transcription factor 9 (SOX9) gene promoter region through H3 lysine 9 dimethylation (H3K9me2). Additionally, rescue results revealed that KDM3A or SOX9 overexpression reversed the effects of HIF-3α silence on cell functions. The Janus kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3) pathway inhibitor cucurbitacin I suppressed the promotive effects of HIF-3α overexpression on cell proliferation, invasion and TAK2/STAT3 pathway. Finally, OS cell line MG-63 transfected with HIF-3α short hairpin RNA (HIF-3α shRNA) were subcutaneously injected into nude mice, and the results found that HIF-3α knockdown significantly inhibited the xenograft tumor growth of OS in vivo. In conclusion, this study reveals that HIF-3α promotes OS progression in vitro and in vivo by activating KDM3A-mediated SOX9 promoter demethylation, which may provide a potential therapeutic mechanism for OS.

Mechanobiology of Bone Metastatic Cancer

PURPOSE OF REVIEW

In this review, we provide an overview of what is currently known about the impacts of mechanical stimuli on metastatic tumor-induced bone disease (TIBD). Further, we focus on the role of the osteocyte, the skeleton's primary mechanosensory cell, which is central to the skeleton's mechanoresponse, sensing and integrating local mechanical stimuli, and then controlling the downstream remodeling balance as appropriate.

RECENT FINDINGS

Exercise and controlled mechanical loading have anabolic effects on bone tissue in models of bone metastasis. They also have anti-tumorigenic properties, in part due to offsetting the vicious cycle of osteolytic bone loss as well as regulating inflammatory signals. The impacts of metastatic cancer on the mechanosensory function of osteocytes remains unclear. Increased mechanical stimuli are a potential method for mitigating TIBD.

Multimodal Imaging-Based Potential Visualization of the Tumor Microenvironment in Bone Metastasis

Bone metastasis (BM) is the most common malignant bone tumor and a significant cause of morbidity and mortality for patients with cancer. Compared to other metastatic organs, bone has unique characteristics in terms of the tumor microenvironment (TME). Precise assessments of the TME in BM could be an important step for developing an optimized management plan for patient care. Imaging approaches for BM have several advantages, such as biopsy not being required, multiple site evaluation, and serial assessment in the same sites. Owing to the developments of new imaging tracers or imaging modalities, bone TME could be visualized using multimodal imaging techniques. In this review, we describe the BM pathophysiology, diagnostic principles of major imaging modalities, and clinically available imaging modalities to visualize the TME in BM. We also discuss how the interactions between various factors affecting the TME could be visualized using multimodal imaging techniques.

Does a Modified Technique to Achieve Arthrodesis of the Wrist After Resection of the Distal Radius and Translocating the Ipsilateral Ulna as a Vascularized Graft to Reconstruct the Defect Improve Grip Strength and Outcomes Scores?

BACKGROUND

Ten years ago, we reported the results of a procedure in which we translocated the ipsilateral ulna as a vascularized autograft to reconstruct defects of the distal radius after tumor resection, with excellent functional results. At that time, wrist arthrodesis was achieved by aligning the translocated ulna with the scapholunate area of the carpus and usually the third metacarpal. This resulted in wrist narrowing. We then wondered if aligning the translocated ulna with the scaphoid and the second metacarpal would result in ulnar deviation and thereby improve grip strength. We believed lateralization would reduce the wrist narrowing that occurs with fusion to the third metacarpal and would make the cosmesis more acceptable. We also modified the incision to dororadial to make the scar less visible and thus improve the cosmesis.

QUESTIONS/PURPOSES

(1) Is there an objective improvement in grip strength and functional scores (Musculoskeletal Tumor Society [MSTS] and Mayo wrist) when the translocated ulna is lateralized and the wrist is fused with the translocated ulna and aligned with the second metacarpal versus when the translocated ulna is aligned with the third metacarpal? (2) Did lateralization caused by the wrist fusion aligned with the second metacarpal minimize wrist narrowing as measured by the circumference compared with the fusion aligned with the third metacarpal?

METHODS

From 2010 and 2018, we treated 40 patients with distal radius tumors at our institution, 30 of whom had a distal radius enbloc resection. Twenty-eight patients had an ipsilateral ulna translocation and wrist arthrodesis in which the radius and translocated ulna were aligned with either the second (n = 15) or the third (n = 13) metacarpals. Two patients in the second metacarpal group and three patients in the third metacarpal group were lost to follow-up before 24 months after surgery and were excluded. A retrospective analysis of 23 patients (20 with giant cell tumors and three with malignant bone tumors) included a review of radiographs and institutional tumor database for surgical and follow-up records to study oncologic (local disease recurrence), reconstruction (union of osteotomy junctions, implant breakage or graft fracture, and wrist circumference), and functional outcomes (MSTS and Mayo wrist scores and objective grip strength assessment compared with the contralateral side). The results were compared for each study group (second metacarpal versus third metacarpal). There was no difference in the incidence of local recurrence or the time to union between the two groups. There were no implant breakages or graft fractures noted in either group.

RESULTS

Patients in the second metacarpal group lost less grip strength compared with the unoperated side in the third metacarpal group (median 12% [range -30% to 35%] versus median 28% [15% to 42%], difference of medians 16%; p = 0.006). There were no between-group differences in terms of MSTS (median 30 [24 to 30] versus median 26.5 [22 to 30], difference of medians 3.5; p = 0.21) or Mayo wrist scores (median 83 [65 to 100] versus median 72 [50 to 90], difference of medians 11; p = 0.10). The second metacarpal group also had less wrist narrowing as seen from the median difference in circumference between the operated and unoperated wrists (median narrowing 10 mm [3 to 35 mm] in the second metacarpal group versus median 30 mm [15 to 35 mm] in the third metacarpal group, difference of medians 20 mm; p = 0.04).

CONCLUSION

Wrist arthrodesis after ulna translocation with alignment of the translocated ulna and the second metacarpal provides a functional position with ulnar deviation that offers some improvement in grip strength but no improvement in the MSTS or Mayo scores. Radialization/lateralization of the translocated ulna achieved from the alignment with the second metacarpal decreases the reduction in the wrist circumference and therefore reduces wrist narrowing.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Do Cohabitants Reliably Complete Questionnaires for Patients in a Terminal Cancer Stage when Assessing Quality of Life, Pain, Depression, and Anxiety?

BACKGROUND

Patients with bone metastases often are unable to complete quality of life (QoL) questionnaires, and cohabitants (such as spouses, domestic partners, offspring older than 18 years, or other people who live with the patient) could be a reliable alternative. However, the extent of reliability in this complicated patient population remains undefined, and the influence of the cohabitant's condition on their assessment of the patient's QoL is unknown.

QUESTIONS/PURPOSES

(1) Do QoL scores, measured by the 5-level EuroQol-5D (EQ-5D-5L) version and the Patient-reported Outcomes Measurement Information System (PROMIS) version 1.0 in three domains (anxiety, pain interference, and depression), reported by patients differ markedly from scores as assessed by their cohabitants? (2) Do cohabitants' PROMIS-Depression scores correlate with differences in measured QoL results?

METHODS

This cross-sectional study included patients and cohabitants older than 18 years of age. Patients included those with presence of histologically confirmed bone metastases (including lymphoma and multiple myeloma), and cohabitants must have been present at the clinic visit. Patients were eligible for inclusion in the study regardless of comorbidities, prognosis, prior surgery, or current treatment. Between June 1, 2016 and March 1, 2017 and between October 1, 2017 and February 26, 2018, all 96 eligible patients were approached, of whom 49% (47) met the selection criteria and were willing to participate. The included 47 patient-cohabitant pairs independently completed the EQ-5D-5L and the eight-item PROMIS for three domains (anxiety, pain, and depression) with respect to the patients' symptoms. The cohabitants also completed the four-item PROMIS-Depression survey with respect to their own symptoms.

RESULTS

There were no clinically important differences between the scores of patients and their cohabitants for all questionnaires, and the agreement between patient and cohabitant scores was moderate to strong (Spearman correlation coefficients ranging from 0.52 to 0.72 on the four questionnaires; all p values < 0.05). However, despite the good agreement in QoL scores, an increased cohabitant's depression score was correlated with an overestimation of the patient's symptom burden for the anxiety and depression domains (weak Spearman correlation coefficient of 0.33 [95% confidence interval 0.08 to 0.58]; p = 0.01 and moderate Spearman correlation coefficient of 0.52 [95% CI 0.29 to 0.74]; p < 0.01, respectively).

CONCLUSION

The present findings support that cohabitants might be reliable raters of the QoL of patients with bone metastases. However, if a patient's cohabitant has depression, the cohabitant may overestimate a patient's symptoms in emotional domains such as anxiety and depression, warranting further research that includes cohabitants with and without depression to elucidate the effect of depression on the level of agreement. For now, clinicians may want to reconsider using the cohabitant's judgement if depression is suspected.

CLINICAL RELEVANCE

These findings suggest that a cohabitant's impressions of a patient's quality of life are, in most instances, accurate; this is potentially helpful in situations where the patient cannot weigh in. Future studies should employ longitudinal designs to see how or whether our findings change over time and with disease progression, and how specific interventions-like different chemotherapeutic regimens or surgery-may factor in.

Molecular Mechanisms of Canine Osteosarcoma Metastasis

Osteosarcoma (OSA) represents the most common bone tumor in dogs. The malignancy is highly aggressive, and most of the dogs die due to metastasis, especially to the lungs. The metastatic process is complex and consists of several main steps. Assessment of the molecular mechanisms of metastasis requires in vitro and especially in vivo studies for a full evaluation of the process. The molecular and biological resemblance of canine OSA to its human counterpart enables the utilization of dogs as a spontaneous model of this disease in humans. The aim of the present review article is to summarize the knowledge of genes and proteins, including p63, signal transducer and activator of transcription 3 (STAT3), Snail2, ezrin, phosphorylated ezrin-radixin-moesin (p-ERM), hepatocyte growth factor-scatter factor (HGF-SF), epidermal growth factor receptor (EGFR), miR-9, and miR-34a, that are proven, by in vitro and/or in vivo studies, to be potentially involved in the metastatic cascade of canine OSA. The determination of molecular targets of metastatic disease may enhance the development of new therapeutic strategies.

Aggressive Bone Metastatic Prostate Cancer With Periosteal Reaction in 18F-Choline PET/CT

ABSTRACT

Prostate cancer bone metastases usually appear as osteosclerotic lesions. However, atypical lesions have also been described. We report herein the case of a 65-year-old man treated since 2013 for prostate cancer with early bone metastases. This asymptomatic patient was referred for 18F-choline PET/CT due to a major elevation of prostate-specific antigen to >1500 ng/mL. The results indicated multiple bone lesions, disseminated on the axial skeleton, girdles, and upper extremities of femurs. Interestingly, we described the development of an intensely hypermetabolic spiculated periosteal reaction, evidencing a rapidly progressive disease.

Biomechanical Properties of Metastatically Involved Osteolytic Bone

PURPOSE OF REVIEW

Skeletal metastasis involves the uncoupling of physiologic bone remodeling resulting in abnormal bone turnover and radical changes in bony architecture, density, and quality. Bone strength assessment and fracture risk prediction are critical in clinical treatment decision-making. This review focuses on bone tissue and structural mechanisms altered by osteolytic metastasis and the resulting changes to its material and mechanical behavior.

RECENT FINDINGS

Both organic and mineral phases of bone tissue are altered by osteolytic metastatic disease, with diminished bone quality evident at multiple length-scales. The mechanical performance of bone with osteolytic lesions is influenced by a combination of tissue-level and structural changes. This review considers the effects of osteolytic metastasis on bone biomechanics demonstrating its negative impact at tissue and structural levels. Future studies need to assess the cumulative impact of cancer treatments on metastatically involved bone quality, and its utility in directing multimodal treatment planning.

Assessing the effects of body weight on subchondral bone formation with quantitative 18F-sodium fluoride PET

OBJECTIVES

The aim of this study was to quantify subchondral bone remodeling in the elbows, hands, knees, and feet using volumetric and metabolic parameters derived from ¹⁸F-sodium fluoride positron emission tomography (NaF-PET) and to assess the convergent validity of these parameters as an index of joint degeneration and preclinical osteoarthritis.

METHODS

A retrospective analysis was conducted in 34 subjects (32 males, 2 females) with metastatic bone disease who underwent full-body NaF-PET/CT scans. An adaptive contrast-oriented thresholding algorithm was applied to segment NaF-avid regions in the bilateral elbows, hands, knees, and feet of each subject, and metabolically active volume (MAV), maximum standardized uptake value (SUVmax), mean metabolic volumetric product (MVPmean), and partial volume-corrected MVPmean (cMVPmean) of the segmented regions were calculated. Global parameters for MAV, SUVmax, MVPmean, and cMVPmean were defined as the sum of the corresponding values in all the joints of a subject. Inter-rater reliability was determined with Lin's concordance correlation, and associations of global values with subject body weight and age were assessed with Pearson correlation and Spearman correlation analyses.

RESULTS

Inter-rater reliability was observed to be the highest in SUVmax (ρc = 0.99), followed by MVPmean (ρc = 0.96), cMVPmean (ρc = 0.93), and MAV (ρc = 0.93). MAV, MVPmean, and cMVPmean were observed to significantly increase with weight (all p < 0.0001) determined by Pearson correlation. In addition, Spearman rank-order analysis demonstrated a significant correlation between SUVmax and weight in addition to MAV, MVPmean, and cMVPmean and weight (all p < 0.01). No significant association between age and any PET parameter was observed.

CONCLUSIONS

These preliminary data demonstrate the feasibility and reliability of assessing bone turnover at the joints using quantitative NaF-PET. Our findings corroborate the fact that biomechanical factors including mechanical loading and weight-bearing are contributors to osteoarthritis disease progression.

The Pediatric Toronto Extremity Salvage Score (pTESS): Validation of a Self-reported Functional Outcomes Tool for Children with Extremity Tumors

BACKGROUND

The physical function of children with sarcoma after surgery has not been studied explicitly. This paucity of research is partly because of the lack of a sufficiently sensitive pediatric functional measure. The goal of this study was to establish and validate a standardized measure of physical function in pediatric patients with extremity tumors.

QUESTIONS/PURPOSES

(1) What is the best format and content for new upper- and lower-extremity measures of physical function in the pediatric population? (2) Do the new measures exhibit floor and/or ceiling effects, internal consistency, and test-retest reliability? (3) Are the new measures valid?

METHODS

In Phase 1, interviews with 17 consecutive children and adolescents with bone tumors were conducted to modify the format and content of draft versions of the pediatric Toronto Extremity Salvage Score (pTESS). In Phase 2, the pTESS was formally translated into French. In Phase 3, 122 participants between 7 and 17.9 years old with malignant or benign-aggressive bone tumors completed the limb-specific measure on two occasions. Older adolescents also completed the adult TESS. Floor and ceiling effects, internal consistency, test-retest reliability, and validity were evaluated.

RESULTS

Feedback from interviews resulted in the removal, addition, and modification of draft items, and the pTESS-Leg and pTESS-Arm questionnaires were finalized. Both versions exhibited no floor or ceiling effects and high internal consistency (α > 0.92). The test-retest reliability was excellent for the pTESS-Leg (intraclass correlation coefficient [ICC] = 0.94; 95% CI, 0.90-0.97) and good for the pTESS-Arm (ICC = 0.86; 95% CI, 0.61-0.96). Known-group validity (ability to discriminate between groups) was demonstrated by lower mean pTESS-Leg scores for participants using gait aids or braces (mean = 68; SD = 21) than for those who did not (mean = 87; SD = 11; p < 0.001). There was no significant difference between pTESS arm scores among respondents using a brace (n = 5; mean = 73; SD = 11) and those without (n = 22; mean = 83; SD = 19; p = 0.13). To evaluate construct validity, we tested a priori hypotheses. The duration since chemotherapy correlated moderately with higher pTESS-Leg scores (r = 0.4; p < 0.001) but not with pTESS-Arm scores (r = 0.1; p = 0.80), and the duration since tumor resection correlated moderately with higher pTESS-Leg scores (r = 0.4; p < 0.001) but not pTESS-Arm scores (r = 0.2; p = 0.4). Higher VAS scores (that is, it was harder to do things) antecorrelated with both pTESS versions (pTESS-Leg: r = -0.7; p < 0.001; pTESS-Arm: r = -0.8; p < 0.001). To assess criterion validity, we compared the pTESS with the current "gold standard" (adult TESS). Among adolescents, strong correlations were observed between the TESS and pTESS-Leg (r = 0.97, p < 0.001) and pTESS-Arm (r = 0.9, p = 0.007).

CONCLUSIONS

Both pTESS versions exhibited no floor or ceiling effects and had high internal consistency. The pTESS-Leg demonstrated excellent reliability and validity, and the pTESS-Arm demonstrated good reliability and reasonable validity. The pTESS is recommended for cross-sectional evaluation of self-reported physical function in pediatric patients with bone tumors.

LEVEL OF EVIDENCE

Level II, outcome measurement development.

Integrins in Osteocyte Biology and Mechanotransduction

PURPOSE OF REVIEW

Osteocytes are the main mechanosensitive cells in bone. Integrin-based adhesions have been shown to facilitate mechanotransduction, and therefore play an important role in load-induced bone formation. This review outlines the role of integrins in osteocyte function (cell adhesion, signalling, and mechanotransduction) and possible role in disease.

RECENT FINDINGS

Both β₁ and β₃ integrins subunits have been shown to be required for osteocyte mechanotransduction. Antagonism of these integrin subunits in osteocytes resulted in impaired responses to fluid shear stress. Various disease states (osteoporosis, osteoarthritis, bone metastases) have been shown to result in altered integrin expression and function. Osteocyte integrins are required for normal cell function, with dysregulation of integrins seen in disease. Understanding the mechanism of faulty integrins in disease may aid in the creation of novel therapeutic approaches.

Imbalanced spinal infiltration of Th17/Treg cells contributes to bone cancer pain via promoting microglial activation

Increasing evidence suggests that T cells participate in the pathology of neuropathic pain, as well as the activation of microglia. However, whether T cells infiltrate into the spinal cord and contribute to the development of bone cancer pain (BCP) remains unknown. Here, we used a mouse model of BCP to show that numbers of T cells infiltrated into the spinal cord after sarcoma cell implantation with increased BCP, and most infiltrating T cells in the spinal cord were CD3⁺CD4⁺ T cells. Both Th17 and Treg subpopulations were analyzed by immunofluorescence. Treg cells in the spinal cord were transiently up-regulated, followed by an imbalance towards Th17 afterwards, and elevated IL-17/IL-17A levels were observed in both blood and spinal cord. Meanwhile, TGF-β, IL-6, and IL-23, the factors which regulate Th17/Treg differentiation, increased their expressions during the development of BCP. Additionally, IL-17A receptor (IL-17AR) was found to be expressed on microglia, and the level of IL-17AR increased with activated microglia during BCP development. Furthermore, BCP was ameliorated when IL-17/IL-17A neutralizing antibodies were intrathecally injected, accompanied with inhibited Th17/Treg infiltration and suppressed microglial activation. In conclusion, T cells infiltrated into the spinal cord with the imbalance of Th17/Treg towards Th17 during the development of BCP, which could promote the microglial activation and further increased BCP, while neutralizing IL-17/IL-17A in the spinal cord could ameliorate BCP. Our results suggest that targeting the imbalanced Th17/Treg infiltration in the spinal cord could be a novel strategy for BCP therapy.

Clinical and translational pharmacology of drugs for the prevention and treatment of bone metastases and cancer-induced bone loss

Bone disease is a frequent event in cancer patients, both due to cancer spread to bone and to cancer therapies. Bone is the organ most frequently affected by metastatic disease when considering the two most frequent cancers in the Western world (breast and prostate cancers). Bone metastases can have a substantial detrimental effect on patients' quality of life, as well as significant morbidity due to complications collectively known as skeletal-related events (SREs), which include hypercalcaemia, pathological fractures, spinal cord compression, and need of radiotherapy or surgery to the bone. These have been successfully mitigated with the development of bone-targeted agents (BTAs; bisphosphonates and denosumab), focused on inhibiting osteoclast activity. The potential direct antitumour effect of bisphosphonates, as well as the impact of osteoclast inhibition with subsequent decrease in bone metabolism, have also propelled investigation on the role of BTAs in preventing cancer relapse in bone. In this review, the authors aimed to discuss the role of BTAs in the treatment and prevention of bone metastases, as well as their potential value in preventing cancer treatment-induced bone loss (CTIBL). The review will focus on breast and prostate cancers, with the aim of providing the most relevant clinical data emerging from bench to bedside translational research in the field of cancer-induced bone disease.

Up-regulation of microRNA-496 suppresses proliferation, invasion, migration and in vivo tumorigenicity of human osteosarcoma cells by targeting eIF4E

Osteosarcoma is an aggressive bone tumor characterized by a high level of genetic instability and recurring DNA deletions and amplifications. This study aims to investigate how microRNA-496 (miR-496) affects proliferation, invasion, and migration of human osteosarcoma (OS) cells and in vivo tumorigenicity by targeting eukaryotic translation initiation factor 4E (eIF4E). Microarray-based gene expression profiling involving OS was used in order to identify differentially expressed genes. After that, the interaction between miR-496 expression and OS patients' survival rate was determined. The expression pattern of miR-496 and eIF4E was determined in OS tissues and cells, and their potential relationship was further analyzed by using the dual luciferase reporter gene assay. With the purpose of identifying the functional role miR-496 in OS, cell proliferation, migration, and invasion were measured in cells treated with miR-496 mimic or inhibitor. A nude mouse model was constructed in order to investigate the regulatory effects of miR-496 on tumor growth in vivo by regulating eIF4E. OS cells exhibited a down-regulated expression of miR-496 and an up-regulated expression of eIF4E. miR-496 expression was positively correlated to OS patients' survival rate. Bioinformatics analysis suggested eIF4E would be a direct target of miR-496, and the expression of eIF4E was inhibited by overexpression of miR-496. miR-496 elevation was found to exert suppressive effects on OS cell proliferation, migration and invasion in vitro and tumor growth in vivo, with the effects being reversed using miR-496 depletion. Altogether, the above findings support a conclusion that miR-496 could work as a tumor suppressor in OS through down-regulation of eIF4E. This study may provide a novel target for treatment of OS.

Management of elbow dysfunction associated with giant cell tumor of the distal humerus: achieving oncologic safety and good function by a combined reconstruction

BACKGROUND

The purpose of our study was to evaluate the functional outcomes and oncologic results of elbow salvage surgery using arthrolysis combined with ligament repair and external fixation for reconstruction of the elbow after tumor excision and autografting.

METHODS

We retrospectively reviewed 6 patients with elbow dysfunction associated with giant cell tumor of the distal humerus. All patients were treated with our combined protocol. We assessed the Musculoskeletal Tumor Society system score, range of motion, Mayo Elbow Performance Score, recurrence, and complications for each patient.

RESULTS

The mean follow-up period was 48 months (range, 36-60 months). There were no cases of postoperative fracture, infection, elbow dislocation, elbow stiffness, or local recurrence. The average Musculoskeletal Tumor Society score was 28 of 30 points (93%; range, 87%-100%). The Mayo Elbow Performance Score improved from a mean of 61 points to 93 points, with mean flexion of 135° and mean extension of 3°.

CONCLUSIONS

Local tumor resection, autografting, and elbow reconstruction by arthrolysis combined with ligament repair and external fixation can be performed with oncologic safety and provide satisfactory functional outcomes with low complication rates.

Microsurgical reconstruction with vascularized fibula and massive bone allograft for bone tumors

INTRODUCTION

Combining massive bone allograft and vascularized fibula in intercalary reconstruction following resection of bone tumors represents a complex reconstructive procedure that requires specialists in microvascular surgery as well as orthopedic surgery. The purpose of our study was to examine the outcomes using this surgical technique in patients with bone tumors in terms of oncologic results, complications related to surgery, Musculoskeletal Tumor Society (MSTS) scores and duration of surgery.

MATERIALS AND METHODS

We analyzed 81 patients with femoral or tibial sarcomas who underwent intercalary resection and microsurgical reconstruction with massive bone allograft and vascularized fibula. There were 56 boys and 25 girls with a mean age of 13.4 years at the time of surgery. The patients' medical records were reviewed for clinical and functional outcomes as well as postoperative complications. The study group was comprised of 33 patients who underwent reconstruction of the femur with massive bone allograft and free vascularized fibula and 48 patients who underwent reconstruction of the tibia with massive bone allograft and free or pedicle vascularized fibula. The mean length of resection was 15.9 cm (8-31 cm). The functional evaluation of the patients was done at the end of the follow-up using MSTS score for the lower limb. All patients had at least a 2-year follow-up.

RESULTS

The overall limb salvage rate was 94%, although many patients required re-operation after the procedure. Complications occurred in 24 patients, 18 of which underwent additional surgical procedures. They included fractures of the massive bone allograft-vascularized fibula construct with or without implant failure (19) and deep infection (5). After surgical or conservative treatment, all the fractures successfully healed. The overall MSTS functional score was good to excellent in 91% of patients.

CONCLUSIONS

The combination of massive bone allograft and vascularized fibula seems to be a reasonable option for reconstruction of diaphyseal defects following intercalary resection of bone tumors. Although there was a high rate of complications and therefore re-operations, the biology of vascularized fibula was able to save the reconstruction in most of the cases that had complications.

Notch in skeletal physiology and disease

Notch (Notch1 through 4) are transmembrane receptors that play a fundamental role in cell differentiation and function. Notch receptors are activated following interactions with their ligands in neighboring cells. There are five classic ligands termed Jagged (Jag)1 and Jag2 and Delta-like (Dll)1, Dll3, and Dll4. Recent work has established Notch as a signaling pathway that plays a critical role in the differentiation and function of cells of the osteoblast and osteoclast lineages and in skeletal development and bone remodeling. The effects of Notch are cell-context dependent, and the four Notch receptors carry out specific functions in the skeleton. Gain- and loss-of-function mutations of components of the Notch signaling pathway result in a variety of congenital disorders with significant craniofacial and skeletal manifestations. The Notch ligand Jag1 is a determinant of bone mineral density, and Notch plays a role in the early phases of fracture healing. Alterations in Notch signaling are associated with osteosarcoma and with the metastatic potential of carcinoma of the breast and of the prostate. Controlling Notch signaling could prove useful in diseases of Notch gain-of-function and in selected skeletal disorders. However, clinical data on agents that modify Notch signaling are not available. In conclusion, Notch signaling is a novel pathway that regulates skeletal homeostasis in health and disease.

Hypoxic Microenvironment and Metastatic Bone Disease

Hypoxia is a common feature of solid tumors and is associated with an increased risk of metastasis and a poor prognosis. Recent imaging techniques revealed that bone marrow contains a quite hypoxic microenvironment. Low oxygen levels activate hypoxia signaling pathways such as hypoxia-inducible factors, which play critical roles in the key stages of metastatic dissemination including angiogenesis, epithelial-mesenchymal transition, invasion, maintenance of cancer stem cells, tumor cell dormancy, release of extracellular vesicles, and generation of pre-metastatic niches. Hypoxia also affects bone cells, such as osteoblasts and osteoclasts, and immune cells, which also act to support the development and progression of bone metastases. Paradoxically, hypoxia and related signaling molecules are recognized as high-priority therapeutic targets and many candidate drugs are currently under preclinical and clinical investigation. The present review focuses on our current knowledge of the potential roles of hypoxia in cancer metastasis to bone by considering the interaction between metastatic cancer cells and the bone microenvironment. Current therapeutic approaches targeting hypoxia are also described.

Natural Course of Local Bone Mineralization After Treatment of Benign or Borderline Bone Tumors and Cysts With a Composite Ceramic Bone Graft Substitute

After surgical bone tumor removal, filling of the bone defect is frequently performed using a bone graft or bone graft substitute. During follow-up, precise quantification of changes in bone mineral density, within the treated bone defect, is very difficult using conventional X-ray examinations. The objectives of this study were to characterize the pattern of resorption/biodegradation of a composite calcium sulfate/hydroxyapatite bone graft substitute and to quantify the bone defect healing with repeated dual-energy X-ray absorptiometry (DXA) measurements. Seventeen patients treated for 18 benign bone lesions, with subsequent defect filling using 2 variants of a composite ceramic bone graft substitute (CERAMENT™|BONE VOID FILLER or CERMAMENT™|G, BONESUPPORT AB, Lund, Sweden), were scanned postoperatively and after 2, 6, 12, 26, and 52 wk using DXA. After an initial increase in bone mineral density after implantation of the bone graft substitute, bone mineral density decreased in the bone defect region throughout the 52 wk: rapidly in the first 12 wk and slower in the remaining weeks. Despite this continuous decrease, bone mineral density remained, on average, 25% higher in the operated extremity, compared with the nonoperated extremity, after 52 wk. The observed pattern of reduction in bone mineral density is consistent with the anticipated resorption of calcium sulfate within the bone graft substitute during the first 12 wk after surgery. We believe the DXA technique provides a precise method for quantification of bone graft resorption, but for evaluation of new bone formation, 3-dimensional imaging is needed.

The Palliative Radiotherapy and Inflammation Study (PRAIS) - protocol for a longitudinal observational multicenter study on patients with cancer induced bone pain

BACKGROUND

Radiation therapy (RT) results in pain relief for about 6 of 10 patients with cancer induced bone pain (CIBP) caused by bone metastases. The high number of non-responders, the long median time from RT to pain response and the risk of adverse effects, makes it important to determine predictors of treatment response. Clinical features such as cancer type, performance status and pain intensity, and biomarkers for osteoclast activity are proposed as predictors of response to RT. However, results are inconsistent and there is a need for better predictors of RT response. A similar argument can be stated for the development of cachexia; there are currently no predictors that can identify patients who will develop cachexia later in the cancer disease trajectory. Experimental and preclinical studies show that pain, depression and cachexia are related to inflammation. However, it is not known if inflammatory biomarkers can predict CIBP, depression or development of cachexia.

METHODS

This multicenter, multinational longitudinal observational study will include 600 adult patients receiving RT for CIBP. Demographic data, clinical variables, osteoclast and inflammatory biomarkers will be assessed before start of RT, and 3, 8, 16, 24 and 52 weeks after last course of RT. The primary aim of the study is to identify potential predictors for pain relief from RT. Secondary aims are to explore potential predictors for development of cachexia, the longitudinal relationship between pain intensity and depression, and if inflammatory biomarkers are associated with changes in pain intensity, cachexia and depression during one-year follow up.

DISCUSSION

The immediate clinical implication of the PRAIS study is to identify potential predictive factors for a RT response on CIBP, and thereby reduce non-efficacious RT. Patient benefits are fewer hospital visits, reduced risk of adverse effects and more individualized pain treatment. The long-term clinical implication of the PRAIS study is to improve the knowledge about inflammation in relation to CIBP, cachexia and depression and potentially identify associations and mechanisms that can be targeted for treatment.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02107664 , date of registration April 8, 2014 (retrospectively registered).

TRIAL SPONSOR

The European Palliative Care Research Centre (PRC), Department of Clinical and Molecular Medicine, NTNU, Faculty of medicine and Health Sciences, Trondheim, N-7491, Norway.

A rare presentation of osseous metastasis in Hepatocellular Carcinoma (HCC) on bone scintigraphy

Bone metastases in HCC are uncommon with an incidence of 3% to 20%. Screening for bone metastasis is not a routine practice. Diagnosis is often delayed, and usually made once symptoms develop.

Bone transport for reconstruction of large bone defects after tibial tumor resection: a report of five cases

This study was performed to explore the clinical efficacy of bone transport using external fixation for treatment of large bone defects after tibial tumor resection in five patients. Bone transport started 14 days postoperatively at 1 mm/day and was adjusted according to the callus-to-diameter ratio. The bone transport time, bone graft fusion, relapse, and metastasis were recorded. Clinical efficacy was evaluated using the Musculoskeletal Tumor Society (MSTS) scoring system. The tumors included osteosarcoma (n=2), Ewing sarcoma (n=1), malignant schwannoma (n=1), and hemangioma (n=1). The average bone defect length after resection was 11.6 cm. The five patients were followed up for an average of 50.8 months, and the average bone transport time was 15.5 months. Three patients who underwent postoperative chemotherapy were followed for 22.7 months, and two who did not undergo chemotherapy were followed for 4.75 months. Four patients underwent iliac bone grafting, and one underwent vascular pedicle fibular transplantation. The average MSTS score was 21.2 (19.3 for patients who underwent chemotherapy and 24.0 for patients who did not). No relapse or metastasis was observed. Bone transport is effective for reconstruction of large bone defects after tibial tumor resection as well as tibial malignancies with high doses of chemotherapy.

Pitfalls in bone density monitoring in prostate cancer during anti-resorptive treatment

A 74-year-old man presented to the Andrology Clinic for management of potential complications of androgen deprivation therapy for prostate cancer. He had a rising prostate-specific antigen with a concurrent rise in alkaline phosphatase and bone remodeling markers. This was despite treatment with a radical prostatectomy, androgen deprivation, and anti-resorptive therapy. A follow-up dual-energy X-ray absorptiometry scan revealed a marked increase in his bone mineral density at both the lumbar spine and femoral neck. This increase, especially in the context of rising bone remodeling markers, was unlikely due to the effect of anti-resorptive therapy alone. Subsequent whole-body bone scintigraphy demonstrated a "superscan" phenomenon which is characterized by uniform and avid tracer retention throughout the skeleton, in this case due to widespread skeletal metastasis, so that the usual physiological uptake in the kidneys is no longer observed and can be misinterpreted as a "normal" scan if the absence of the kidneys is not recognized. This case highlights the importance of considering diffuse metastatic disease when there is a rapid increase in bone mineral density, even in individuals treated with anti-resorptive therapy.

Functional and Hybrid Imaging of Bone Metastases

Bone metastases are common, cause significant morbidity, and impact on healthcare resources. Although radiography, computed tomography (CT), magnetic resonance imaging (MRI), and bone scintigraphy have frequently been used for staging the skeleton, these methods are insensitive and nonspecific for monitoring treatment response in a clinically relevant time frame. We summarize several recent reports on new functional and hybrid imaging methods including single photon emission CT/CT, positron emission tomography/CT, and whole-body MRI with diffusion-weighted imaging. These modalities generally show improvements in diagnostic accuracy for staging and response assessment over standard imaging methods, with the ability to quantify biological processes related to the bone microenvironment as well as tumor cells. As some of these methods are now being adopted into routine clinical practice and clinical trials, further evaluation with comparative studies is required to guide optimal and cost-effective clinical management of patients with skeletal metastases. © 2018 American Society for Bone and Mineral Research.

Bisphosphonates in Oncology: Physiopathologic Bases and Clinical Activity

Osteoclastic activation is the ultimate way of bone resorption in neoplasia, induced by the combined effects of tumor-secreted humoral factors (especially parathyroid hormone-related peptides) and osteoclastic-osteoblastic interaction. Bisphosphonates inhibit the osteoclast activity and reduce bone resorption and are a valuable supportive measure for bone disease of neoplasms. Experimental models also suggest an activity of bisphosphonates against cancer cells. Controlled studies, especially in advanced breast cancer and multiple myeloma, indicate different effectiveness against the distinct skeletal-related events. Intravenous clodronate and, especially, pamidronate and zoledronate are the first-choice drugs for hypercalcemia, and they play a significant role in reducing metastatic bone pain. Their prolonged use delays, without hampering, the progression of bone disease, including the appearance of osteolysis and the occurrence of pathologic fractures. This effect is probably more valuable when bisphosphonates are administered early in the course of the disease. The evidence that adjuvant bisphosphonates improve survival needs to be confirmed in ongoing studies. Although poorly absorbed by the gastrointestinal tract, oral bisphosphonates are effective in preventing and treating cancer-induced osteoporosis in long-living patients with operable breast cancer. At present, there is little hope that newer bisphosphonates are more effective than those currently used.

CA 15-3 and Bone Scintigraphy in the follow-up of Breast Cancer

By means of the retrospective study of the clinical records of 158 women followed for breast cancer, we aimed to evaluate the consequences of a non-systematic indication for bone scan (BS) based either on CA 15-3 levels alone or a combination of tumor marker levels and clinical criteria. With the first option, the negative predictive value was 95% and 82% of the BS would have been avoided. With the second option, the negative predictive value was 97% and 59% of the BS would have been avoided. Furthermore, the preliminary results of a longitudinal study showed that those patients with normal CA 15-3 levels and positive bone scans showed a subsequent rise in CA 15-3 levels which frequently became elevated with an average delay of 15 months. Omission of systematic bone scans in the follow-up of breast cancer patients is likely to lead to a delay in the diagnosis of bone metastasis in 3% to 5%, the consequences of which have to be examined carefully.

Role of Pamidronate Disodium in the Treatment of Metastatic Bone Disease

Aims and Background

Bone metastases are a common feature of advanced neoplastic disease and are considered to be among the most frequent causes of pain and complications in oncologic patients. The main objective of the treatment of such patients is to control their symptoms and improve their quality of life. Pamidronate disodium is a second-generation bisphosphonate capable of inhibiting bone resorption (particularly osteoclast activity) without affecting bone reminerali-zation. After a brief introduction concerning the pathophysiology of bone metastases and neoplastic bone pain, we herein present data on the clinical pharmacology and toxicity of bisphosphonates in general, and pamidronate in particular. We conclude by reviewing the literature on the use of pamidronate in phase II and III trials involving patients with metastatic bone disease.

Methods

The paper is based on a review of articles published between 1984 and 1997 selected from the Cancerline and Medline databases.

Results

In the considered phase II and III studies involving patients with bone metastases (breast cancer and multiple myeloma in particular), pamidronate proved to be efficacious in reducing the incidence of pain and skeletal complications, decreasing the excretion of metabolic markers of bone resorption and improving the quality of life. Intravenous infusions of 60-90 mg over a period of 2 hr every 3-4 weeks did not cause any significant toxic effects and was easily managed.

Conclusions

Pamidronate is a bisphosphonate that is efficacious in the treatment of symptomatic bone metastases and can be considered an important therapeutic option in association with systemic treatments, radiotherapy and normal supportive care, especially in patients with breast cancer and multiple myeloma. Further randomized studies are necessary to confirm the positive preliminary results in other neoplasms, analyze the cost/benefit ratio of the treatment, and verify the possibility that, in addition to being used for palliative purposes, pamidronate may also prevent or delay the appearance of bone metastases.

Hallmarks of Bone Metastasis

Breast cancer bone metastasis develops as the result of a series of complex interactions between tumor cells, bone marrow cells, and resident bone cells. The net effect of these interactions are the disruption of normal bone homeostasis, often with significantly increased osteoclast and osteoblast activity, which has provided a rational target for controlling tumor progression, with little or no emphasis on tumor eradication. Indeed, the clinical course of metastatic breast cancer is relatively long, with patients likely to experience sequential skeletal-related events (SREs), often over lengthy periods of time, even up to decades. These SREs include bone pain, fractures, and spinal cord compression, all of which may profoundly impair a patient's quality-of-life. Our understanding of the contributions of the host bone and bone marrow cells to the control of tumor progression has grown over the years, yet the focus of virtually all available treatments remains on the control of resident bone cells, primarily osteoclasts. In this perspective, our focus is to move away from the current emphasis on the control of bone cells and focus our attention on the hallmarks of bone metastatic tumor cells and how these differ from primary tumor cells and normal host cells. In our opinion, there remains a largely unmet medical need to develop and utilize therapies that impede metastatic tumor cells while sparing normal host bone and bone marrow cells. This perspective examines the impact of metastatic tumor cells on the bone microenvironment and proposes potential new directions for uncovering the important mechanisms driving metastatic progression in bone based on the hallmarks of bone metastasis.

Osteomimicry: How the Seed Grows in the Soil

Metastasis is defined as a very inefficient process, since less than 0.01% of cancer cells injected into the circulation will engraft in a distant organ, where they must acquire the ability to survive and proliferate inside a "foreign" environment. In bone metastases, the interaction with the host organ is much more favoured if tumour cells gain "osteomimicry", that is the ability to resemble a resident bone cell (i.e. the osteoblast), thus intruding in the physiology of the bone. This is accomplished by the expression of osteoblast markers (e.g. alkaline phosphatase) and the production of bone matrix proteins and paracrine factors which deregulate the physiology of bone, fuelling the so-called "vicious cycle". The main challenge of researchers is therefore to identify the genetic profile determining the osteotropism of tumour cells, which would eventually lead to bone colonisation. This could likely provide the answer to a quite intriguing question, that is why some cancers, such as prostate and breast, have a specific predilection to metastasise to the bone. Therefore, it is important to completely address the molecular mechanisms underlying this aspect of bone oncology, identifying relevant pathways, the targeting of which could make any type of bone metastasis curable or avoidable.

Bone Marrow Microenvironment as a Regulator and Therapeutic Target for Prostate Cancer Bone Metastasis

Bone is the most common site of prostate cancer metastasis. Once prostate cancer cells metastasize to bone, the mortality rate of prostate cancer patients increases significantly. Furthermore, bone metastases produce multiple skeletal complications, including bone pain that impairs the patients' quality of life. Effective therapies for bone metastatic disease are underdeveloped with most current therapies being primarily palliative with modest survival benefit. Although the exact mechanisms through which prostate cancer metastasizes to bone are unclear, growing evidence suggests that the bone marrow microenvironment, particularly its hematopoietic activity, is a significant mediator of prostate cancer bone tropism. Moreover, the bone microenvironment may regulate metastatic prostate cancer cells between dormant and proliferative states. In this review, we discuss (1) how prostate cancer cells interact with the bone microenvironment to establish bone metastases and (2) current and future potential treatments for prostate cancer patients with bone metastases.

Activation of ventral tegmental area dopaminergic neurons reverses pathological allodynia resulting from nerve injury or bone cancer

Chronic pain induced by nerve damage due to trauma or invasion of cancer to the bone elicits severe ongoing pain as well as hyperalgesia and allodynia likely reflecting adaptive changes within central circuits that amplify nociceptive signals. The present study explored the possible contribution of the mesolimbic dopaminergic circuit in promoting allodynia related to neuropathic and cancer pain. Mice with ligation of the sciatic nerve or treated with intrafemoral osteosarcoma cells showed allodynia to a thermal stimulus applied to the paw on the injured side. Patch clamp electrophysiology revealed that the intrinsic neuronal excitability of ventral tegmental area (VTA) dopamine neurons projecting to the nucleus accumbens (N.Acc.) was significantly reduced in those mice. We used tyrosine hydroxylase (TH)-cre mice that were microinjected with adeno-associated virus (AAV) to express channelrhodopsin-2 (ChR2) to allow optogenetic stimulation of VTA dopaminergic neurons in the VTA or in their N.Acc. terminals. Optogenetic activation of these cells produced a significant but transient anti-allodynic effect in nerve injured or tumor-bearing mice without increasing response thresholds to thermal stimulation in sham-operated animals. Suppressed activity of mesolimbic dopaminergic neurons is likely to contribute to decreased inhibition of N.Acc. output neurons and to neuropathic or cancer pain-induced allodynia suggesting strategies for modulation of pathological pain states.

The unusual osteochondroma: A case of snapping scapula syndrome and review of the literature

Snapping scapula syndrome is a rare condition characterized by crepitus of the scapula on motion of the ipsilateral upper extremity. It may be quite painful and disabling. The majority of cases are due to bursal and muscular disorders. Snapping scapula syndrome secondary to an underlying osteochondroma is an even more infrequent phenomenon. The case presented highlights the unusual post pubertal growth of an osteochondroma of the scapula that progressed to develop a snapping scapular syndrome. Review of the literature revealed less than fifty reported cases of this phenomenon secondary to an underlying osteochondroma.

Resveratrol attenuates bone cancer pain through regulating the expression levels of ASIC3 and activating cell autophagy

Bone cancer pain (BCP) is one of the most common pains in patients with malignant cancers. The mechanism underlying BCP is largely unknown. Our previous studies and the increasing evidence both have shown that acid-sensing ion channels 3 (ASIC3) is an important protein in the pathological pain state in some pain models. We hypothesized that the expression change of ASIC3 might be one of the factors related to BCP. In this study, we established the BCP model through intrathecally injecting rat mammary gland carcinoma cells (MRMT-1) into the left tibia of Sprague-Dawley female rats, and found that the BCP rats showed bone destruction, increased mechanical pain sensitivities and up-regulated ASIC3 protein expression levels in L4-L6 dorsal root ganglion. Then, resveratrol, which was intraperitoneally injected into the BCP rats on post-operative Day 21, dose-dependently increased the paw withdrawal threshold of BCP rats, reversed the pain behavior, and had an antinociceptive effect on BCP rats. In ASIC3-transfected SH-SY5Y cells, the ASIC3 protein expression levels were regulated by resveratrol in a dose- and time-dependent manner. Meanwhile, resveratrol also had an antinociceptive effect in ASIC3-mediated pain rat model. Furthermore, resveratrol also enhanced the phosphorylation of AMPK, SIRT1, and LC3-II levels in ASIC3-transfected SH-SY5Y cells, indicating that resveratrol could activate the AMPK-SIRT1-autophagy signal pathway in ASIC3-transfected SH-SY5Y cells. In BCP rats, SIRT1 and LC3-II were also down-regulated. These findings provide new evidence for the use of resveratrol as a therapeutic treatment during BCP states.

SHP2 Regulates the Osteogenic Fate of Growth Plate Hypertrophic Chondrocytes

Transdifferentiation of hypertrophic chondrocytes into bone-forming osteoblasts has been reported, yet the underlying molecular mechanism remains incompletely understood. SHP2 is an ubiquitously expressed cytoplasmic protein tyrosine phosphatase. SHP2 loss-of-function mutations in chondroid cells are linked to metachondromatosis in humans and mice, suggesting a crucial role for SHP2 in the skeleton. However, the specific role of SHP2 in skeletal cells has not been elucidated. To approach this question, we ablated SHP2 in collagen 2α1(Col2α1)-Cre- and collagen 10α1(Col10α1)-Cre-expressing cells, predominantly proliferating and hypertrophic chondrocytes, using "Cre-loxP"-mediated gene excision. Mice lacking SHP2 in Col2α1-Cre-expressing cells die at mid-gestation. Postnatal SHP2 ablation in the same cell population caused dwarfism, chondrodysplasia and exostoses. In contrast, mice in which SHP2 was ablated in the Col10α1-Cre-expressing cells appeared normal but were osteopenic. Further mechanistic studies revealed that SHP2 exerted its influence partly by regulating the abundance of SOX9 in chondrocytes. Elevated and sustained SOX9 in SHP2-deficient hypertrophic chondrocytes impaired their differentiation to osteoblasts and impaired endochondral ossification. Our study uncovered an important role of SHP2 in bone development and cartilage homeostasis by influencing the osteogenic differentiation of hypertrophic chondrocytes and provided insight into the pathogenesis and potential treatment of skeletal diseases, such as osteopenia and osteoporosis.

Can exercise suppress tumour growth in advanced prostate cancer patients with sclerotic bone metastases? A randomised, controlled study protocol examining feasibility, safety and efficacy

INTRODUCTION

Exercise may positively alter tumour biology through numerous modulatory and regulatory mechanisms in response to a variety of modes and dosages, evidenced in preclinical models to date. Specifically, localised and systemic biochemical alterations produced during and following exercise may suppress tumour formation, growth and distribution by virtue of altered epigenetics and endocrine-paracrine activity. Given the impressive ability of targeted mechanical loading to interfere with metastasis-driven tumour formation in human osteolytic tumour cells, it is of equal interest to determine whether a similar effect is observed in sclerotic tumour cells. The study aims to (1) establish the feasibility and safety of a combined modular multimodal exercise programme with spinal isometric training in advanced prostate cancer patients with sclerotic bone metastases and (2) examine whether targeted and supervised exercise can suppress sclerotic tumour growth and activity in spinal metastases in humans.

METHODS AND ANALYSIS

A single-blinded, two-armed, randomised, controlled and explorative phase I clinical trial combining spinal isometric training with a modular multimodal exercise programme in 40 men with advanced prostate cancer and stable sclerotic spinal metastases. Participants will be randomly assigned to (1) the exercise intervention or (2) usual medical care. The intervention arm will receive a 3-month, supervised and individually tailored modular multimodal exercise programme with spinal isometric training. Primary endpoints (feasibility and safety) and secondary endpoints (tumour morphology; biomarker activity; anthropometry; musculoskeletal health; adiposity; physical function; quality of life; anxiety; distress; fatigue; insomnia; physical activity levels) will be measured at baseline and following the intervention. Statistical analyses will include descriptive characteristics, t-tests, effect sizes and two-way (group × time) repeated-measures analysis of variance (or analysis of covariance) to examine differences between groups over time. The data-set will be primarily examined using an intention-to-treat approach with multiple imputations, followed by a secondary sensitivity analysis to ensure data robustness using a complete cases approach.

ETHICS AND DISSEMINATION

Ethics approval was obtained from the Human Research Ethics Committee (HREC) of Edith Cowan University and the Sir Charles Gairdner and Osborne Park Health Care Group. If proven to be feasible and safe, this study will form the basis of future phase II and III trials in human patients with advanced cancer. To reach a maximum number of clinicians, practitioners, patients and scientists, outcomes will be disseminated through national and international clinical, conference and patient presentations, as well as publication in high-impact, peer-reviewed academic journals.

TRIAL REGISTRATION NUMBER

ACTRN 12616000179437.

Methyl Protodioscin Induces Apoptosis in Human Osteosarcoma Cells by Caspase-Dependent and MAPK Signaling Pathways

Methyl protodioscin (MPD), a furostanol saponin derived from the rhizomes of Dioscorea collettii var. hypoglauca (Dioscoreaceae), has been shown to exhibit broad bioactivities such as anti-inflammation and antitumor activities. Here, we explored the molecular mechanisms by which MPD induced apoptosis in MG-63 cells. The data showed that MPD significantly suppressed cell growth (cell viabilities: 22.5 ± 1.9% for 8 μM MPD versus 100 ± 1.4% for control, P < 0.01) and enhanced cell apoptosis. The exposure to MPD resulted in a significant induction of reactive oxygen species, loss of mitochondrial membrane potential, and activation of caspase-9 and caspase-3 (P < 0.01, all cases). Furthermore, treatment with MPD increased the levels of phosphorylated JNK and p38 MAPK and markedly decreased the levels of phosphorylated ERK in MG-63 cells. Co-administration of the JNK-specific antagonist, the p38-specific antagonist, or the caspase antagonist (P < 0.05, all cases) has reversed the apoptotic effects in MPD treatment. We also found that exposure to MPD resulted in a significant reduction in the protein level of anti-apoptotic proteins Bcl-2, survivin, and XIAP (P < 0.05, all cases). In conclusion, our results indicate that MPD induces apoptosis of human osteosarcoma MG-63 cells, at least in part, by caspase-dependent and MAPK signaling pathways.

Disruption of collagen/apatite alignment impairs bone mechanical function in osteoblastic metastasis induced by prostate cancer

Prostate cancer (PCa) frequently metastasizes to the bone, generally inducing osteoblastic alterations that increase bone brittleness. Although there is growing interest in the management of the physical capability of patients with bone metastasis, the mechanism underlying the impairment of bone mechanical function remains unclear. The alignment of both collagen fibrils and biological apatite (BAp) c-axis, together with bone mineral density, is one of the strongest contributors to bone mechanical function. In this study, we analyzed the bone microstructure of the mouse femurs with and without PCa cell inoculation. Histological assessment revealed that the bone-forming pattern in the PCa-bearing bone was non-directional, resulting in a spongious structure, whereas that in the control bone was unidirectional and layer-by-layer, resulting in a compact lamellar structure. The degree of preferential alignment of collagen fibrils and BAp, which was evaluated by quantitative polarized microscopy and microbeam X-ray diffraction, respectively, were significantly lower in the PCa-bearing bone than in the control bone. Material parameters including Young's modulus and toughness, measured by the three-point bending test, were simultaneously decreased in the PCa-bearing bone. Specifically, there was a significant positive correlation between the degree of BAp c-axis orientation and Young's modulus. In conclusion, the impairment of mechanical function in the PCa-bearing bone is attributable to disruption of the anisotropic microstructure of bone in multiple phases. This is the first report demonstrating that cancer bone metastasis induces disruption of the collagen/BAp alignment in long bones, thereby impairing their mechanical function.

Engineered Multifunctional Nanomedicine for Simultaneous Stereotactic Chemotherapy and Inhibited Osteolysis in an Orthotopic Model of Bone Metastasis

A novel multifunctional Ag₂ S quantum dot (QD)-based nanomedicine of alendronate (Ald)/doxorubicin (DOX)@Ag₂ S is developed for highly effective bone tumor therapy in an orthotopic model. The bone-targeting and osteolysis inhibition of Ald and the chemotherapeutic effect of DOX on the bone tumor are in situ visualized by Ag₂ S QDs with emission in the second near-infrared window.

Radial Shaft Reconstruction With an Intercalary Endoprosthesis Following Resection of Metastatic Tumor

Improvements in imaging and treatment of musculoskeletal tumors have increased the variety of options for reconstruction following joint-sparing diaphyseal resection. The purpose of this case series was to show that reconstruction of malignant tumors of the radial shaft with an intercalary prosthesis may be an option for patients with segmental bone loss. Three consecutive patients underwent wide resection of the radial diaphysis followed by reconstruction with a custom intercalary prosthesis. A custom intercalary prosthesis with lap joint design was used in all 3 cases. Mean follow-up was 18 months (range, 9-25 months). All patients were weight bearing as tolerated 1 week postoperatively. At the most recent follow-up, patients' mean elbow flexion and extension arc was 137° (range, 130°-140°). At the forearm, mean supination was 60° (range, 30°-90°) and mean pronation was 70° (range, 60°-90°). At the wrist, mean palmar flexion was 80° (range, 70°-90°) and mean dorsiflexion was 80° (range, 70°-90°). All patients reported minimal to no pain and no significant functional limitations. Mean Musculoskeletal Tumor Society score was 26/30 (87%). Reconstruction with an intercalary prosthesis is a viable option for patients with metastatic disease of the radial shaft. All patients had satisfactory results and early return to function; none required return to the operating room. Possible advantages of reconstruction with an intercalary prosthesis compared with reconstruction with a bone graft or polymethylmethacrylate osteosynthesis include early return to function and minimal weight-bearing restrictions postoperatively. [Orthopedics. 2017; 40(2):e242-e247.].

Unusual Location of Osteoid Osteoma in the Acromion

We present the clinical case of a 14-year-old female patient complaining of omalgia. A focus of osteoid osteoma located in the acromion was diagnosed. The lesion was removed using the arthroscopic technique, and the symptoms subsided completely. We also present a review of published papers regarding unusual locations of osteoid osteoma.

What are the Functional Results, Complications, and Outcomes of Using a Custom Unipolar Wrist Hemiarthroplasty for Treatment of Grade III Giant Cell Tumors of the Distal Radius?

PURPOSE

A giant cell tumor (GCT) of bone presenting in the distal radius is rare, however, when they occur, Campanacci Grade III tumors can present formidable reconstructive challenges. They are associated with a high local recurrence rate with intralesional treatment, therefore approaches to reconstruct the wrist after en bloc resection warrant study.

QUESTIONS

We asked: (1) What are the functional outcomes after en bloc resection and reconstruction of the wrist with a unipolar prosthesis in patients with Grade III GCT of the distal radius? (2) What complications occur with use of a unipolar prosthesis in these patients? (3) What are the oncologic outcomes with using en bloc resection and reconstruction with a custom unipolar wrist hemiarthroplasty for Grade III GCTs of the distal radius?

METHODS

We retrospectively analyzed 10 patients with Campanacci Grade III GCTs of the distal radius treated by a unipolar prosthesis after wide resection of the tumor between January 2008 and October 2013. During that period, all patients at our medical group who presented with a Grade III GCT of the distal radius were treated with wide resection and reconstruction using a custom unipolar implant. Pre- and postoperative pain at rest were assessed according to a 10-cm VAS score. The functional outcomes of the wrist were assessed using the modified Mayo wrist score, and the degenerative changes were evaluated radiographically by a new rating system based on the Knirk and Jupiter scale. We also analyzed tumor recurrence, metastases, and complications associated with the reconstruction procedure. All patients were available for followup at a mean of 52 months (range, 24-90 months).

RESULTS

Although the complication rate associated with prosthetic arthroplasty was relatively high (six of 10), none of our patients experienced severe complications. Two patients reported having occasional pain of the involved wrist at the time of final followup (VAS, preoperative versus postoperative: 0 versus 3; 5 versus 2, respectively). The mean modified Mayo wrist score was 68 (range, 45-90). Degenerative changes were found in three wrists (Grade 1, two patients; Grade 2, one patient). Aseptic loosening occurred in one patient and wrist subluxation occurred in two patients. Lung metastases or local tumor recurrence were not observed.

CONCLUSIONS

Because of the proportion of patients who had complications and progressive degeneration with this approach, we recommend first exploring alternatives to reconstruction with custom unipolar wrist hemiarthroplasty after resection of Grade III GCTs of the distal radius, such as fibular autografting. However, this technique provides an alternative for patients with concerns regarding possible morbidity associated with autografting, and for situations when allograft is not available.

LEVEL OF EVIDENCE

Level IV, therapeutic study.

Efficacy and Safety of Radium-223 Dichloride in Symptomatic Castration-resistant Prostate Cancer Patients With or Without Baseline Opioid Use From the Phase 3 ALSYMPCA Trial

BACKGROUND

The phase 3 ALSYMPCA trial enrolled metastatic castration-resistant prostate cancer patients with or without baseline opioid use.

OBJECTIVE

To assess the efficacy and safety of radium-223 dichloride (radium-223) versus placebo in ALSYMPCA patients by baseline opioid use.

DESIGN, SETTING, AND PARTICIPANTS

Nine hundred and twenty one patients enrolled at 136 centers globally.

INTERVENTION

Radium-223 (50 kBq/kg, intravenous injection) every 4 wk for six cycles or matching placebo, each plus best standard of care.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Primary endpoint (overall survival [OS]), main secondary efficacy endpoints, and safety were evaluated by baseline opioid use. Additional analyses included time to first opioid use, time to first external beam radiation therapy for bone pain, and safety of concomitant external beam radiation therapy.

RESULTS AND LIMITATIONS

At baseline, 408 (44%) patients had no pain and no analgesic use or mild pain with nonopioid therapy (World Health Organization ladder pain score 0-1 [nonopioid subgroup]), and 513 (56%) had moderate pain with occasional opioids or severe pain with regular daily opioids (World Health Organization ladder pain score 2-3 [opioid subgroup]). Radium-223 significantly prolonged OS versus placebo in nonopioid (hazard ratio [HR]=0.70; 95% confidence interval [CI]: 0.52-0.93; p=0.013) and opioid (HR=0.68; 95% CI: 0.54-0.86; p=0.001) subgroups, and significantly reduced risk of symptomatic skeletal events versus placebo, regardless of baseline opioid use (nonopioid subgroup: HR=0.56, 95% CI: 0.39-0.82, p=0.002; opioid subgroup: HR=0.72, 95% CI: 0.53-0.98, p=0.038). Time to first opioid use for bone pain was significantly delayed with radium-223 versus placebo (HR=0.62, 95% CI: 0.46-0.85, p=0.002). Adverse event incidences were similar between opioid subgroups.

CONCLUSIONS

Radium-223 versus placebo significantly prolonged OS and reduced symptomatic skeletal event risk with a favorable safety profile in castration-resistant prostate cancer patients with symptomatic bone metastases, regardless of baseline opioid use.

PATIENT SUMMARY

In this ALSYMPCA opioid subgroup analysis, baseline symptom levels did not appear to impact radium-223 dichloride efficacy or safety.

[Denosumab may be a supplement to the surgical treatment of giant cell tumours of bone]

Giant cell tumour of bone (GCTB) is an aggressive bone tumour causing bone destruction. GCTB requires surgical treatment, and severe cases have a high risk of functional morbidity. GCTB consists of receptor activator of nuclear factor kappa-B (RANK)-positive osteoclast-like giant cells. The formation and activity of these cells are mediated by the interaction with RANK ligand (RANKL) released from neoplastic stromal cells. Denosumab is a human monoclonal antibody which inhibits RANKL and impairs the growth of the GCTB. Several studies have described the ability of denosumab to downgrade the extent of surgical treatment and improve the functional outcome.

Thymidine phosphorylase exerts complex effects on bone resorption and formation in myeloma

Myelomatous bone disease is characterized by the development of lytic bone lesions and a concomitant reduction in bone formation, leading to chronic bone pain and fractures. To understand the underlying mechanism, we investigated the contribution of myeloma-expressed thymidine phosphorylase (TP) to bone lesions. In osteoblast progenitors, TP up-regulated the methylation of RUNX2 and osterix, leading to decreased bone formation. In osteoclast progenitors, TP up-regulated the methylation of IRF8 and thereby enhanced expression of NFATc1 (nuclear factor of activated T cells, cytoplasmic 1 protein), leading to increased bone resorption. TP reversibly catalyzes thymidine into thymine and 2-deoxy-d-ribose (2DDR). Myeloma-secreted 2DDR bound to integrin αVβ3/α5β1 in the progenitors, activated PI3K (phosphoinositide 3-kinase)/Akt signaling, and increased DNMT3A (DNA methyltransferase 3A) expression, resulting in hypermethylation of RUNX2, osterix, and IRF8 This study elucidates an important mechanism for myeloma-induced bone lesions, suggesting that targeting TP may be a viable approach to healing resorbed bone in patients. Because TP overexpression is common in bone-metastatic tumors, our findings could have additional mechanistic implications.