Bone sarcomas: ESMO-EURACAN-GENTURIS-ERN PaedCan Clinical Practice Guideline for diagnosis, treatment and follow-up

Prognostic factors for disease progression of central high-grade conventional osteosarcoma of the appendicular skeleton: Single-centre experience within South Africa with minimum 3-year follow-up

Background

Disease progression (DP) of osteosarcomas, albeit with aggressive treatments, hinders improving survival. The DP patterns are unique in low- and middle-income countries like South Africa. We determine the prognostic factors associated with disease progression (DP) of the appendicular skeleton's central high-grade conventional osteosarcoma (COS).

Methods

This is a retrospective study of 77 patients, with a minimum 3-year follow-up period diagnosed with histological biopsy-confirmed COS. Descriptive statistics, Cox proportional regression modelling, and the Kaplan-Meier method were employed for the analysis.

Results

DP occurred in 75 % of patients (58/77), either as a local progression - LP 32 % (25/77), systemic progression - SP 61 % (47/77) or both 32 % (24/77). In the univariate analysis, the factors associated with DP were proximal humerus tumor site (hazard ratio [HR] 2.48; 95 % confidence interval [CI], 1.02 to 6.04; p < 0.046), metastasis at diagnosis (HR 1.91; 95 % CI, 1.10 to 3.32; p < 0.022), multiple metastatic lesions (HR 2.58; 95 % CI, 1.13 to 5.88; p < 0.024), curative treatment (HR 0.33; 95 % CI 0.17 to 0.62; p < 0.001), palliative treatment (HR 2.17; 95 % CI 1.24 to 3.78; p < 0.007), and wide surgical resection (HR 0.48, 95 % CI 0.27 to 0.86; p < 0.013). On multivariate analysis, only age >19 years was an independent risk factor (HR 1.04; 95 % CI 1.00 to 1.08; p < 0.034). The median survival time was 24 months, with an overall survival (OS) of 57.1 % at 3 years. The projected Kaplan- Meier 5-year OS rate was 29.78 %, with a progression-free survival (PFS) rate of 10.28 % (HR 0.76; 95 % CI 0.52 to 1.112; p < 0.128).

Conclusion

In this series of central high-grade conventional osteosarcoma of the appendicular skeleton from South Africa, we observed a uniquely high proportion of disease progression (DP). Age >19, metastatic disease, and no chemotherapy response yielded poor outcomes; in contrast, wide surgical resection is beneficial. Further elucidation is needed at a larger scale in this region.

Study evidence level

IV.

Arterial perfusion chemoembolization combined with iodine-125 seeds for stage IIB osteosarcoma: A case report

Osteosarcoma is a highly malignant bone tumor that predominantly affects adolescents. Its aggressive nature, complex treatment options and poor prognosis render it a notable concern in oncology. With advancements in therapy for osteosarcoma, neoadjuvant chemotherapy in conjunction with limb-salvage surgery has emerged as the preferred surgical strategy. However, the physical and emotional trauma associated with surgery, along with the adverse side effects of chemotherapy, can be unacceptable to some patients. In recent years, alternative local treatment modalities such as transarterial chemoembolization (TACE) and iodine-125 seed implantation have garnered considerable attention. These techniques show potential in enhancing local tumor control while minimizing systemic toxicity. TACE involves obstructing the blood supply to the tumor while administering localized chemotherapy, resulting in tumor ischemia and necrosis, which is particularly effective for hypervascular tumors. Meanwhile, iodine-125 seeds act as low-energy radiation sources that can effectively target tumor cells while sparing the surrounding healthy tissue. The present study describes a case of osteosarcoma treated with a combination of TACE and iodine-125 seed implantation. The patient, diagnosed with osteosarcoma of the left knee joint, declined surgical intervention. Consequently, a treatment plan involving TACE paired with iodine-125 seed implantation was established. Post-treatment follow-up demonstrated marked pain relief, improved limb function and a notable reduction in tumor volume with decreased bone destruction visible on imaging. Over a follow-up period of 6 years, there were no signs of disease recurrence or distant metastasis, and no notable chemotherapy-related side effects were reported. The quality of life of the patient was markedly improved. The current case illustrates the antitumor efficacy and reduced toxicity of combining TACE with iodine-125 seed implantation in the management of osteosarcoma.

Conventional radiography for the assessment of focal bone lesions of the appendicular skeleton: fundamental concepts in the modern imaging era

Bone lesions of the appendicular skeleton can be caused by primary benign or malignant tumors, metastases, osteomyelitis, or pseudotumors. Conventional radiography plays a crucial role in the initial assessment of osseous lesions and should not be underestimated even in this era of modern complex and advanced imaging technologies. Combined with patient age, clinical symptoms and biology, and lesion features including location, solitary versus multiplicity, density, margin (transitional zone evaluated with Lodwick-Madewell grading score), and, if present, the type of periosteal reaction and matrix mineralization can narrow the differential diagnosis or offer a likely diagnosis. These radiographic features help guide further follow-up or management.

Evaluation of primary physicians' awareness regarding the radiological findings of osteosarcoma: A retrospective study

A referral from a primary physician is a crucial initial diagnostic intervention for the management of osteosarcoma. We reviewed the awareness of primary physicians regarding the radiological findings of osteosarcoma through their referral documents. Referral documents of 40 patients (27 male and 13 female; median age, 19 [8-81] years) with osteosarcoma were retrospectively investigated. The documents were examined for suggested supplementary radiological procedures, presence or absence of a descriptive keyword for the radiological findings of osteosarcoma, periosteal reaction, matrix, soft tissue mass, type of border of the lesion, and type of bone destruction, followed by an assessment of the diagnostic radiologists' findings. The keywords "periosteal reaction," "matrix," "soft tissue extension," "border of the lesion," and "type of bone destruction" were described in 5 (7.5%), 5 (15%), 4 (10%), 0 (0%), and 7 (17.5%) cases by the primary physicians, respectively. Records with "periosteal reaction," "matrix," "soft tissue mass," "type of border of the lesion," and "type of bone destruction" were described in 5 (31.25%), 5 (31.25%), 10 (62.5%), 3 (18.8%), and 3 (18.8%) radiologic findings of the diagnostic radiologists, respectively. The descriptions of keywords for radiological findings suggesting osteosarcoma in referral documents from primary physicians seemed generally insufficient. More enhanced and comprehensive awareness of the typical radiological findings of osteosarcoma is necessary to prevent diagnostic delays.

Ewing sarcoma of the rib with a rare PTEN mutation

BACKGROUND

Rib involvement in Ewing sarcoma (ES) is very rare (3-5 %) and may often lead to unique presentations due to mass effect within the thorax. Molecular studies may sometimes offer insights into disease prognosis and possible targeted treatment approaches.

CASE PRESENTATION

Here we present the case of a 39-year-old female who presented with shortness of breath from a massive primary tumor in the right rib and lung. She was diagnosed with ES, which was confirmed by the presence of EWSR1/FLI-1 rearrangement and received multimodal therapy with neoadjuvant VDC-IE (vincristine-doxorubicin-cyclophosphamide, and ifosfamide-etoposide) followed by surgical excision after partial response, and adjuvant chemoradiation. Unfortunately, the patient experienced histologically confirmed local and distant recurrence after several months. NGS of the recurrent tumor revealed a pathogenic PTEN c.640C>T(p.Q214*) nonsense variant with a very high variant allele frequency (VAF) of 82.6 % but negative germline assessment. She received several lines of chemotherapy but only demonstrated a short response to the oral multi-tyrosine kinase inhibitor cabozantinib before eventually passing away.

CONCLUSIONS

PTEN mutations in ES, although rare, may result in a higher likelihood of chemotherapy resistance and poor prognosis. Clinical studies targeting specific molecular traits of these tumors, such as PTEN inactivation, could help improve outcomes in selected cases.

[Update of the recommendations for the management and treatment of giant cell bone tumors, on behalf of GroupOS]

INTRODUCTION

Giant cell tumours (GCTs) are benign primary bone tumours that frequently present with local recurrence and occasionally malignant transformation to high-grade sarcoma. Surgery is the mainstay of treatment and generally consists of intralesional curettage. Denosumab was approved by the European Medicines Agency (EMA) in 2014 for the treatment of skeletally mature adults and adolescents with unresectable GCTs or where resection is likely to result in severe morbidity.

METHODS

On the basis of national recommendations established in 2016 and a summary of the current state of knowledge, a GroupOS working group was set up to update and develop recommendations on the management and treatment of GCTs in adults, as well as on the place of denosumab.

RESULTS

Seven recommendations are proposed here: (1) diagnostic approach and imaging work-up; (2) principles of treatment for GCTs of the limbs; (3) indications for denosumab in GCTs of the limbs; (4) specific features of GCTs of axial location and multifocal GCTs; (5) therapeutic strategy following progression after treatment with denosumab; (6) progression under treatment with denosumab and suspicion of malignant form of GCT under denosumab; (7) monitoring procedures.

CONCLUSION

There are still unresolved issues, such as the optimal duration of treatment or the precise interval between maintenance doses of denosumab. Rarely, GCTs undergo malignant transformation. No clinical, histological or radiographic criteria can accurately predict subsequent aggressive behaviour.

Post-treatment late and long-term effects in bone sarcoma: A scoping review

Despite the fact that chemotherapy for bone sarcomas (e.g. Ewing sarcoma, osteosarcoma) has well-reported toxicities and that surgical intervention is frequently life altering, follow-up care to monitor for late and long-term effects beyond that of oncological surveillance in former patients is variable. Anecdotal evidence suggests that inconsistent follow-up means some former bone sarcoma patients are left to cope with post-treatment late and long-term effects with limited support. Here, we performed a scoping review to provide a more empirical identification of the knowledge gaps and to provide an overview of the peer reviewed academic literature reporting the late and long-term effects of treatment for bone sarcoma. JBI Scoping Review Network guidelines for charting, analysis and data extraction were followed. Literature searches were conducted in Medline (Ovid), Cochrane CENTRAL, EMBASE (Ovid), CINAHL, PsycINFO, Proquest and Web of Science (Clarivate Analytics) from March 2024 to September 2024. Paper titles and abstracts were screened by two independent reviewers followed by full text analysis by the lead researcher. Seventy-four peer reviewed articles were included in the analysis. Most studies were of a retrospective study design, some up to 20 years of follow-up and included chemotherapy, surgery and sometimes radiotherapy as the treatment modality. Our analysis identified secondary malignancies, cardio- and nephrotoxicity, lower bone mineral density and microarchitectural deterioration, cancer related fatigue and motor neuropathies as the major physical late and long-term effects requiring dedicated follow-up. In some cases, follow-up may need to span decades, especially given the increasing population of former patients. Our results form the evidence-based foundations for future work that might include late and long-term effect follow-up service mapping exercises and expanded clinical recommendations.

Targeting metastasis in paediatric bone sarcomas

Paediatric bone sarcomas (e.g. Ewing sarcoma, osteosarcoma) comprise significant biological and clinical heterogeneity. This extreme heterogeneity affects response to systemic therapy, facilitates inherent and acquired drug resistance and possibly underpins the origins of metastatic disease, a key component implicit in cancer related death. Across all cancers, metastatic models have offered competing accounts on when dissemination occurs, either early or late during tumorigenesis, whether metastases at different foci arise independently and directly from the primary tumour or give rise to each other, i.e. metastases-to-metastases dissemination, and whether cell exchange occurs between synchronously growing lesions. Although it is probable that all the above mechanisms can lead to metastatic disease, clinical observations indicate that distinct modes of metastasis might predominate in different cancers. Around 70% of patients with bone sarcoma experience metastasis during their disease course but the fundamental molecular and cell mechanisms underlying spread are equivocal. Newer therapies such as tyrosine kinase inhibitors have shown promise in reducing metastatic relapse in trials, nonetheless, not all patients respond and 5-year overall survival remains at ~ 50%. Better understanding of potential bone sarcoma biological subgroups, the role of the tumour immune microenvironment, factors that promote metastasis and clinical biomarkers of prognosis and drug response are required to make progress. In this review, we provide a comprehensive overview of the approaches to manage paediatric patients with metastatic Ewing sarcoma and osteosarcoma. We describe the molecular basis of the tumour immune microenvironment, cell plasticity, circulating tumour cells and the development of the pre-metastatic niche, all required for successful distant colonisation. Finally, we discuss ongoing and upcoming patient clinical trials, biomarkers and gene regulatory networks amenable to the development of anti-metastasis medicines.

Integrating Radiogenomics and Machine Learning in Musculoskeletal Oncology Care

Musculoskeletal tumors present a diagnostic challenge due to their rarity, histological diversity, and overlapping imaging features. Accurate characterization is essential for effective treatment planning and prognosis, yet current diagnostic workflows rely heavily on invasive biopsy and subjective radiologic interpretation. This review explores the evolving role of radiogenomics and machine learning in improving diagnostic accuracy for bone and soft tissue tumors. We examine integrating quantitative imaging features from MRI, CT, and PET with genomic and transcriptomic data to enable non-invasive tumor profiling. AI-powered platforms employing convolutional neural networks (CNNs) and radiomic texture analysis show promising results in tumor grading, subtype differentiation (e.g., Osteosarcoma vs. Ewing sarcoma), and predicting mutation signatures (e.g., TP53, RB1). Moreover, we highlight the use of liquid biopsy and circulating tumor DNA (ctDNA) as emerging diagnostic biomarkers, coupled with point-of-care molecular assays, to enable early and accurate detection in low-resource settings. The review concludes by discussing translational barriers, including data harmonization, regulatory challenges, and the need for multi-institutional datasets to validate AI-based diagnostic frameworks. This article synthesizes current advancements and provides a forward-looking view of precision diagnostics in musculoskeletal oncology.

Exploring perspectives on skull base chordoma management: a modified Delphi approach to consensus

OBJECTIVE

Current treatment for skull base chordomas utilizes both surgical resection and adjuvant radiation, but recent studies have demonstrated evidence that has brought the use of adjuvant radiotherapy into question. Chordomas differ greatly in molecular makeup and proliferation. These factors have led to significant variation in management across providers. We used a modified Delphi approach to work towards consensus on standardized operative definitions and evidence-based management of chordomas.

METHODS

Our multidisciplinary panel included participants representing the AANS/CNS Tumor Section and North American Skull Base Society (NASBS) with a track record of publishing on chordoma management. Our approach involved a four-step process: one statement-generation round, two voting rounds to establish consensus and refine statements, and a final external validation round by NASBS members. Anonymous voting was completed via Qualtrics surveys.

RESULTS

The statement-generation process produced 65 statements. Through the Delphi process, 36 statements reached consensus during the first round and an additional 17 were refined for further consensus in the second round. Moderate (67-80%) or strong (> 80%) consensus was achieved for 43 final statements. Forty-one items were externally validated. There was consensus that an endoscopic endonasal approach should be utilized whenever possible. They defined the tumor characteristics (molecular and cytogenic) to consider before offering adjuvant radiotherapy.

CONCLUSIONS

This modified Delphi study generated consensus on 41 statements regarding skull base chordoma management. These statements aim to shed light on the consensus among providers regarding the use of surgery, neoadjuvant radiation, adjuvant radiation, adjuvant systemic therapies, and treatment of recurrence for chordoma.

Canadian Association of Radiologists Spine Imaging Referral Guideline

The Canadian Association of Radiologists (CAR) Spine Expert Panel is made up of physicians from the disciplines of radiology, emergency medicine, neurology, neurosurgery, physiatry, a patient advisor, and an epidemiologist/guideline methodologist. After developing a list of 10 clinical/diagnostic scenarios, a rapid scoping review was undertaken to identify systematically produced referral guidelines that provide recommendations for one or more of these clinical/diagnostic scenarios. Recommendations from 23 guidelines and contextualization criteria in the Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) for guidelines framework were used to develop 22 recommendation statements across the 8 scenarios (one scenario points to the CAR Trauma Referral Guideline and one scenario points to the CAR Musculoskeletal Guideline). This guideline presents the methods of development and the referral recommendations for myelopathy, suspected spinal infection, possible atlanto-axial instability (non-traumatic), axial pain (non-traumatic), radicular pain (non-traumatic), cauda equina syndrome, suspected spinal tumour, and suspected compression fracture. Spondyloarthropathies and spine trauma point to other CAR Diagnostic Imaging Referral Guidelines, Musculoskeletal and Trauma, respectively.

Ensemble learning guided survival prediction and chemotherapy benefit analysis in high-grade chondrosarcoma: A study based on the surveillance, epidemiology, and end results (SEER) database

Purpose: The chemotherapy benefit for high-grade chondrosarcoma remains controversial. Ensemble learning has better overall performance than single computational approaches for clinical decision. The primary objective was to select prognostic variables and develop optimal ensemble learning algorithms for survival prediction and analyzing chemotherapy benefit in high-grade chondrosarcoma. The secondary objective included identifying specific patient groups with estimated survival benefit for guidance in chemotherapy strategies. Methods: The data of 1931 patients with chondrosarcoma from 2000 to 2019 were obtained from the Surveillance, Epidemiology, and End Results database to conduct the retrospective analysis. Among 468 patients with high-grade chondrosarcoma, cox proportional hazards models and random survival forests were used for feature selection. Ensemble learning and survival support vector machine with different kernel methods were developed and compared for their prognostic performance. Results: Ensemble learning outperformed the single models, with the concordance index reaching 0.764 (based on inverse probability of censoring weights) and the mean area under time-dependent receiver operating characteristic curve of 0.851. According to the ensemble model, overall survival generally improved in younger patients after chemotherapy. Age-stratified analysis revealed differential chemotherapy benefits across various clinical subgroups. Survival benefits were observed in: Age ≤ 10 with dedifferentiated chondrosarcoma, amputation, local surgical treatment, absence of distant metastasis, or grade III tumor; Age ≤ 20 who were male with clear cell chondrosarcoma, non-axial primary sites, or no radiotherapy; Age ≤ 30 who were female with primary site at pelvis/limb, received radiotherapy, extension beyond periosteum, further extension, or distant metastasis; Age≤40 with chondrosarcoma NOS (including mesenchymal, juxtacortical and classical chondrosarcoma); Age ≤ 50 with grade IV tumor or no surgery received. Conclusion: Ensemble learning algorithms demonstrate outstanding overall performance in prognostic assessment of high-grade chondrosarcoma and identification of age-specific factors associated with chemotherapy benefit for tailored chemotherapy strategy.

Genetic predisposition in sarcomas: clinical implications and management

Recent studies indicate up to 20% of sarcomas may be associated with predisposition genes, and this number will probably increase as genetic testing becomes more available. Evidence on the management of patients with sarcoma and genetic predisposition remains, however, scarce. This review compiles available research on genetic predisposition syndromes associated with sarcoma and sarcoma treatment within such syndromes, addressing key gaps in knowledge. We explore the current evidence on how genetic predisposition may influence treatment decisions and clinical management, focusing on surgery, radiotherapy, systemic treatment, and surveillance. Evidence-based recommendations are currently not available for most syndromes, and we have therefore included pragmatic advice for clinicians. Unanswered questions and unmet needs are also identified, underscoring the importance of multidisciplinary input from specialists such as geneticists, radiologists, surgeons and oncologists. The review stresses the need for future research to improve clinical outcomes for patients with sarcoma and genetic predisposition.

Funding

No funding has been provided for this work.

Global and regional disparities in access to specialist sarcoma services

Aims

Cancer care guidelines have been developed in many subspecialities, usually in advanced health systems. However, there are notable global disparities in healthcare access, which can impact sarcoma care. Unfortunately, there is a lack of global data on this subject. Our aim was to describe access to sarcoma care based on a comprehensive global survey among orthopaedic oncologists, and assess for global as well as regional differences.

Methods

A 25-question survey was emailed to the attendees of the 2024 Birmingham Orthopaedic Oncology Meeting and included questions about the respondents' training and practice, access to sarcoma centres, and specific items for sarcoma diagnosis and treatment. For data analysis and comparison, countries were grouped geographically and per the World Bank's income classification.

Results

A total of 192 specialists from 47 countries completed the survey (67%). Overall, 40% declared that most patients in their country were treated in a specialized sarcoma centre. Declared access to specific diagnostic technology ranged from 69% (translocation studies) to 86% (various immunohistochemistry). Only 31% stated having access to proton therapy and 82% to all possible reconstruction methods. Compromise of ideal surgical management because of prior treatments and financial constraints was declared to have happened regularly in 40% and 17% of practices, respectively. Regions with better-developed healthcare systems had improved access to all aspects surveyed. Similar results were observed when comparing high-income countries against low- to middle-income countries.

Conclusion

Our study highlights substantial global and regional disparities in access to sarcoma services, which could potentially impact clinical outcomes. Further studies are needed to clarify this reality.

Sonographic characteristics of local soft tissue recurrence in primary bone tumor and diagnostic efficacy versus MRI

BACKGROUND

The accurate diagnosis of local soft tissue recurrence (LR) in primary bone tumors is crucial for guiding clinical management and predicting patient outcomes. However, standardized postoperative surveillance protocols remain undefined. This study aims to compare the diagnostic efficacy of ultrasound (US) versus magnetic resonance imaging (MRI) in detecting LR following primary bone tumor surgery and to characterize the sonographic features of osteosarcoma recurrence.

METHODS

We conducted a retrospective review of medical records from patients who underwent postoperative surveillance for primary bone tumors at our institution between 01/06/2016 to 01/09/2023. Diagnostic performance was compared using McNemar's test for paired variables. Sonographic characteristics were analyzed using logistic regression analysis, with statistical significance set at p < 0.05.

RESULTS

Comparative analysis revealed no statistically significant differences (p > 0.05) in sensitivity, specificity, or accuracy between MRI and US, and the exact values for these parameters are provided in Table 1. Key sonographic features predictive of osteosarcoma recurrence included tumor size and anatomical location. The diagnostic model demonstrated excellent discriminative ability, with an area under the receiver operating characteristic (ROC) curve of 0.973. The diagnostic parameters were as follows: sensitivity (96.6%), specificity (90.9%), accuracy (94.6%), positive predictive value (95.0%), and negative predictive value (93.8%).

CONCLUSION

The findings from this study support the role of ultrasonography as a valuable tool in tumor surveillance paradigms, providing a scientific rationale for optimizing integrated management strategies in bone oncology.

Establishment and characterization of NCC-OS2-C1: a novel patient-derived cell line of osteosarcoma

Osteosarcoma is the most common primary bone sarcoma with a bimodal age distribution. Complete surgical resection with neoadjuvant chemotherapy is the standard curative treatment, and no effective therapeutic strategy has been established for metastatic cases, resulting in poor prognosis. Osteosarcoma presents complex and heterogeneous clinical and molecular features, and no molecular-targeted drugs are available. Therefore, effective multidisciplinary treatment strategies are urgently required. Patient-derived cell lines are essential tools in basic and translational oncology. Considering the heterogeneity of the disease, we established a novel cell line, NCC-OS2-C1, using surgically resected tumor tissues from a patient with osteosarcoma. NCC-OS2-C1 cells demonstrated constant proliferation, spheroid formation, and invasion. In addition, we demonstrated that NCC-OS2-C1 is applicable for the high-throughput screening of drugs. Thus, NCC-OS2-C1 is a valuable tool for basic and translational research on osteosarcoma.

[Practical Guidance on the Detection of NTRK Fusions in Sarcomas: Current Status and Diagnostic Challenges]

Sarcomas are a rare and heterogeneous group of mesenchymal malignant tumors and account for approximately 1% of all adult cancers and around 20% of all pediatric solid tumors in Europe. Technology advances have enabled a more accurate and efficient characterization of the molecular mechanisms underlying the pathogenesis of sarcoma subtypes and revealed novel and unexpected therapeutic targets with prognostic/predictive biomarkers, namely the neurotrophic tyrosine receptor kinase (NTRK) gene fusion. The NTRK fusion assessment has recently become a standard part of management for patients with unresectable locally advanced or metastatic cancers and has been identified in various tumor types. In the more prevalent adult and pediatric sarcomas, NTRK fusions are present in 1% and 20%, respectively, and in more than 90% of very rare subsets of tumors. The inhibition of TRK activity with first-generation TRK inhibitors has been found to be effective and well tolerated in adult and pediatric patients, independently of the tumor type. Overall, the therapeutic benefit to those patients compensates for the difficulties of identifying NTRK gene fusions. However, the rarity and diagnostic complexity of NTRK gene fusions raise several questions and challenges for clinicians. To address these issues, an expert panel of medical and pediatric oncologists, radiologists, surgeons, orthopedists, and pathologists reviewed the recent literature and discussed the current status and challenges, proposing a diagnostic algorithm for identifying NTRK fusion sarcomas. The aim of this article is to review the updated information on this issue and to provide the experts' recommendations and practical guidance on the optimal management of patients with soft tissue sarcomas, infantile fibrosarcoma, gastrointestinal stromal tumors, and osteosarcoma.

Molecular pathological insights into tumorigenesis and progression of giant cell tumor of bone

Giant cell tumor of bone (GCTB) is a primary bone tumor that typically exhibits benign histological appearance and clinical behavior in most cases, with local aggressiveness and rare metastasis. It predominantly affects individuals in the young adult age group. It is characterized by the presence of multinucleated osteoclastic giant cells and a stromal population of neoplastic cells. A key hallmark for GCTB pathogenesis is the G34W genetic mutation in the histone H3.3 gene, which is restricted to the population of cancerous stromal cells and is absent in osteoclasts and their progenitor cells. This review presents a comprehensive overview of the pathology of GCTB, including its histopathological characteristics, cytological features, histopathological variants, and their clinical relevance. We also discuss recent insights into genetic alterations in relation to the molecular pathways implicated in GCTB. A summary of the current understanding of GCTB pathology will update the knowledge base to guide the diagnosis and management of this unique bone tumor.

Intensified Induction Therapy for Newly Diagnosed, Localized Skeletal Ewing Sarcoma (ISG/AIEOP EW-1): A Randomized, Open-Label, Phase 3, Non-Inferiority Trial

BACKGROUND

Several studies have shown that the intensity of treatment in Ewing sarcoma has an impact on outcome. The present trial tested the non-inferiority of intensive, shorter, induction chemotherapy (25 weeks total treatment time) compared to the standard treatment (37 weeks) in non-metastatic Ewing sarcoma (ES) at onset.

PROCEDURE

This national, multicenter, parallel, randomized, controlled, open-label, non-inferiority, phase III trial was conducted in 14 specialized hospitals in Italy. Patients aged 2-40 years with newly diagnosed localized ES were randomized to receive four courses of induction therapy (one every 21 days) either with a standard arm (Arm A) or with an intensive arm (Arm B). For consolidation therapy, good responders (GRs) in Arm A received nine courses (37 weeks), while Arm B patients received five courses (25 weeks). Poor responders for both arms received four courses followed by high-dose busulfan/melphalan + autologous stem cell rescue. Follow-up was 5 years.

RESULTS

In the study period 2009-2018, 274 patients with ES at onset were screened, 248 were eligible, 15 refused randomization, and 233 were randomized (Arm A: 113; Arm B: 120). Median age was 14 years. Arm B was not inferior to Arm A: 5-year EFS was 77.5% and 71.6%, respectively (HR vs. Arm A: 0.74, 90% CI: 0.49-1.14). GRs were 54.9% in Arm A and 62.5% in Arm B. Hematological, gastrointestinal, and cardiovascular Grade ≥3 toxicities had higher frequencies in Arm B.

CONCLUSIONS

Intensive induction therapy showed non-inferiority in 5-year EFS when compared with the standard induction therapy. Higher toxicity was reported in Arm B with similar outcome, counterbalanced in GRs with a shorter treatment plan.

CLINICALTRIALS

gov Identifier: NCT02063022.

Do patient-specific cutting guides for pelvic and sacral tumour resection provide tumour-free bone margins?

BACKGROUND

Achieving R0 margin, i.e., tumour-free margin, during conservative surgery for pelvic or sacral tumours is demanding. Small cohort studies suggest that patient-specific instrumentation (PSI) may hold promise, notably for bone margin accuracy. Objectives of this study were to determine whether PSI allowed R0 bone margins; R0 soft-tissue margins; and increased disease-free survival, without local recurrence or distant metastases, comparatively to previous studies of patients treated by free-hand or navigated surgery; and whether PSI positioning for the bone cuts was readily achieved.

HYPOTHESIS

Using PSI provides R0 bone margins in 100% patients and improves disease-free survival).

MATERIAL AND METHODS

Retrospective study including consecutively patients who underwent PSI-assisted surgical resection of a pelvic or sacral tumour between October 2011 and February 2020. Bone and soft-tissue margins were assessed according to the Union for International Cancer Control classification. Overall survival and disease-free survival were evaluated using the Kaplan-Meier method. PSI positioning was assessed by surgeons for each patient on a scale from 5 (excellent) to 1 (failed).

RESULTS

Of the 42 included patients (26 males and 16 females), 34 had primary bone malignancies, 3 had soft-tissue malignancies extended to the bone, 3 had locally aggressive benign bone tumours, and 2 had solitary bone metastases. Mean follow-up was 49 (range 4-112) mo. Bone margins were as follow: R0 in 40 (95%) patients; R1 in 1 (2.5%) and R2 in 1 (2.5%). Soft-tissue margins were as follow: R0 in 76% of patients; R1 in 21.5% of patients. At 5 years, overall disease-free survival was 63.4% (95% CI, 49.3-81.4), survival without local recurrence was 65.5% (95% CI, 47.7-90.0], and survival without distant metastases was 70.1% (95% CI, 55.4-88.5). Positioning of the 60 PSIs used was rated excellent or good in 93.3% of cases and fair or poor in 6.7% of cases; no cases of positioning failure were recorded.

DISCUSSION

PSIs provided excellent accuracy for achieving R0 bone margin. Nonetheless, local recurrence remained high similarly to free-hand surgery. This finding may be related to surgeons relying on PSI's accuracy for maximal preservation.

CONCLUSION

PSIs are technically reliable and safe for obtaining R0 margins during conservative resection surgery to treat pelvic and sacral tumours. However, PSIs do not substantially decrease the local recurrence rate.

LEVEL OF EVIDENCE

IV; retrospective observational cohort study.

Exploring the Potential of Optical Genome Mapping in the Diagnosis and Prognosis of Soft Tissue and Bone Tumors

Sarcomas are rare malignant tumors of mesenchymal origin with a high misdiagnosis rate due to their heterogeneity and low incidence. Conventional diagnostic techniques, such as Fluorescence In Situ Hybridization (FISH) and Next-Generation Sequencing (NGS), have limitations in detecting structural variations (SVs), copy number variations (CNVs), and predicting clinical behavior. Optical genome mapping (OGM) provides high-resolution genome-wide analysis, improving sarcoma diagnosis and prognosis assessment. This study analyzed 53 sarcoma samples using OGM. Ultra-high molecular weight (UHMW) DNA was extracted from core and resection biopsies, and data acquisition was performed with the Bionano Saphyr platform. Bioinformatic pipelines identified structural variations, comparing them with known alterations for each sarcoma subtype. OGM successfully analyzed 62.3% of samples. Diagnostic-defining alterations were found in 95.2% of cases, refining diagnoses and revealing novel oncogenic and tumor suppressor gene alterations. The challenges included DNA extraction and quality issues from some tissue samples. Despite these limitations, OGM proved to be a powerful diagnostic and predictive tool for bone and soft tissue sarcomas, surpassing conventional methods in resolution and scope, enhancing the understanding of sarcoma genetics, and enabling better patient stratification and personalized therapies.

Predicting survival outcomes in dedifferentiated chondrosarcoma: a prognostic factor analysis from a National Registry

INTRODUCTION

Dedifferentiated chondrosarcoma (DDCS) is a high-grade subtype of chondrosarcoma with a poor prognosis. Treatment for localized DDCS generally involves wide resection; the effectiveness of adjuvant radiotherapy and chemotherapy is questionable. This research was designed to find prognostic factors for DDCS and evaluate the impact of adjuvant therapies on localized cases.

METHODS

One hundred thirty-two patients with DDCS diagnosed by pathology in the period 2006 to 2022 were identified in the Japanese National Bone and Soft Tissue Tumor Registry database and were retrospectively analyzed.

RESULTS

Patients with distant metastases at diagnosis (n = 34) had significantly poorer survival than those without metastases (n = 98), with a 5-year disease-specific survival (DSS) of 9.7% vs. 37.1% (P < 0.0001). For patients without distant metastasis at diagnosis, uni- and multivariate analysis showed that R1 or R2 surgical margin was an independent risk factor linked with unfavorable local recurrence (hazard ratio [HR] 3.39 [95% CI: 1.35-8.52]; P = 0.010). Adjuvant radiotherapy was not associated with local recurrence (HR 2.41 [95% CI: 0.87-6.64]; P = 0.090). Larger size (HR 1.13 [95% CI: 1.06-1.19]; P < 0.001) and no surgery (HR 3.87 [95% CI: 1.61-9.28]; P = 0.002) were independent risk factors for unfavorable DSS. Previous surgery (HR 0.19 [95% CI: 0.04-0.84]; P = 0.028) and adjuvant chemotherapy (HR 0.36 [95% CI: 0.16-0.77]; P = 0.009) were independent risk factors for favorable DSS.

DISCUSSION

Survival may have been improved by chemotherapy, but the effect of adjuvant radiotherapy in controlling the local spread of the tumor appears to have been limited in DDCS cases that were localized.

How to Preserve Fertility in Reproductive-Age Women with Cancer

Chemotherapy and radiotherapy, among other gonadotoxic treatments, can significantly affect ovarian reserve and function, potentially leading to premature ovarian insufficiency (POI) and sterility. With the increasing survival rates among young female cancer patients, fertility preservation (FP) has become an essential aspect of cancer care. The decision to pursue FP depends on various factors, including patient age, ovarian reserve, the type of treatment, and its gonadotoxic potential. Several FP strategies are available, including oocyte, embryo, and ovarian tissue cryopreservation. While oocyte and embryo cryopreservation are the gold standard techniques, ovarian tissue cryopreservation and in vitro maturation (IVM) present viable alternatives for patients who cannot undergo ovarian stimulation or for whom stimulation is contraindicated. Despite significant advances within the FP practice, challenges remain in ensuring timely FP counseling, equitable access to services, and optimizing long-term reproductive outcomes. Continued research is needed to refine existing FP techniques, explore innovative approaches, and address ethical considerations in FP decision-making. This review explores current FP options, their clinical applications, and future directions to improve reproductive outcomes in young women undergoing gonadotoxic treatments.

Primary cutaneous/subcutaneous Ewings sarcoma

Amongst Ewing sarcoma family of tumours, (EFST), cutaneous/subcutaneous Ewing sarcoma are defined as tumours arising from cutaneous or subcutaneous tissue, not invading the underlying aponeurosis. They are rare tumours, with less than 200 patients published. They are typically small tumours (less than 5cm), and can arise at any anatomical location, with a particular tropism for distal, truncal and head/neck locations, compared to classical Ewing sarcoma. Like other conjunctive tumours, they have to be treated in specialized centers, with a diagnostic procedure following ESMO guidelines about soft-tissue tumours, favoring a core needle biopsy in most cases. They share classical pathological and molecular features of EFST (including EWSR1 rearrangement). Metastatic presentation is rare (less than 5% at diagnosis), but must be carefully searched using appropriated imaging considered the bad prognosis of these patients. Treatment strategy relies on neoadjuvant and adjuvant chemotherapy, surrounding the local treatment. Patients with localized disease have good prognosis and have to be treated with the dual objective of curability, and of minimizing acute and late toxicity. That is why in case of small tumours (<200mL), patients can be treated with less intensive protocols, as Saint Jude's (low-dose semi-continuous cyclophosphamide/doxorubicin regimen as induction chemotherapy and vincristine/actinomycin courses as maintenance therapy), setting aside the option of classical VDC/IE protocol for larger tumors. Local treatment must rely on carcinologic surgery, with the aim to avoid radiotherapy when possible. Patients with metastatic disease have bad prognosis resemble classical Ewing sarcoma, and have to be treated accordingly.

Ziyuglycoside II suppressed the progression of osteosarcoma by coordinating estrogen-related receptor gamma and p53 signaling pathway

Osteosarcoma (OS) is the most prevalent primary malignant bone tumor affecting children and adolescents. Despite ongoing research efforts, the 5-year survival rate has remained stagnant for many years, highlighting the critical need for novel drug development to enhance current treatment protocols. Ziyuglycoside II (ZYG II), a triterpenoid saponin extracted from S. officinalis, has recently demonstrated antitumor properties. This study evaluates the antitumor effect of ZYG II on osteosarcoma and elucidates its mechanism of action through the co-regulation of p53 and estrogen-related receptor gamma (ESRRG), which inhibits disease progression. The research employs in vitro experiments using multiple established osteosarcoma cell lines, as well as in vivo studies utilizing a nude mouse model of orthotopic xenograft osteosarcoma. Additionally, ESRRG shRNA was used to construct stable ESRRG-reducing OS cell lines to investigate the molecular mechanism by which ZYG II exerts its anti-osteosarcoma effects through the co-regulation of ESRRG and p53. Results indicate that ZYG II administration led to decreased OS cell viability and reduced tumor volumes. Furthermore, cell cycles were arrested at the G0/G1 phase, while the proportion of apoptotic cells increased. Expression of p53, ESRRG, p21, Bax, Cleaved Caspase-9, and Cleaved Caspase-3 proteins increased, while expression of CDK4, Cyclin D1, and Bcl-2 proteins decreased. Multiple ZYG II and ESRRG docking patterns were simulated through molecular docking. Comparing the pharmacodynamic response of ZYG II to OS cell lines with reduced ESRRG and normal expression demonstrated that ZYG II inhibits osteosarcoma progression, induces cell cycle arrest, and promotes cell apoptosis through the coordination of p53 and ESRRG. In conclusion, ZYG II inhibits osteosarcoma progression, leads to cell cycle arrest, and promotes cell apoptosis through synergistic regulation of p53 and ESRRG.

Nab-Paclitaxel Based Chemotherapy in the Treatment of Advanced Epithelioid Hemangioendothelioma: A Single-Institution Experience

Objective

To evaluate the clinical efficacy of nab-paclitaxel based chemotherapy in the treatment of advanced epithelioid hemangioendothelioma (EHE).

Methods

Since March 2022, chemotherapy has been recommended for patients with advanced EHE characterized by large tumors (liver tumors > 10 cm or tumors in other organs > 3 cm), rapid tumor progression, severe symptoms, serosal effusion, and treatment failure. Two chemotherapy regimens were administered: nab-paclitaxel plus bevacizumab and nab-paclitaxel plus sirolimus. Clinical data and outcomes were retrospectively analyzed.

Results

From March 2022 to August 2024, 21 patients with histologically confirmed EHE who received nab-paclitaxel based chemotherapy were included. At baseline, 18 patients (85.7%) presented with tumor-related symptoms, and serosal effusion was detected in 12 patients (57.1%). Among patients with hepatic EHE, six (28.6%) had tumors > 10 cm, while six (28.6%) with EHE at other sites had tumors > 3 cm. Partial response and stable disease were achieved in 5 (23.8%) and 12 (57.1%) patients, respectively, resulting in a disease control rate of 80.9%. Symptom relief was observed in 15 of 18 patients (83.3%), and decreased serosal effusion was noted in 6 of 12 patients (50.0%). The 1- and 2-year progression-free survival rates were 50.7% and 13.5%, respectively, while the 1- and 2-year overall survival rates were 70.6% and 51.5%, respectively.

Conclusion

Nab-paclitaxel based chemotherapy may offer an effective treatment option for patients with advanced EHE exhibiting adverse prognostic factors. However, further clinical trials are required to confirm its efficacy.

Anti-osteosarcoma activity of Corynoline via Src/JNK signaling-mediated cell cycle arrest and mitochondrial apoptosis

Corynoline (COR) is an isoquinoline alkaloid derived from the traditional Chinese medicine Corydalis bungeana Turcz, known for its analgesic, antibacterial, neuroprotective, and osteoporosis-alleviating properties. However, its potential molecular effects against osteosarcoma (OS) remain unclear, warranting further investigation. This study demonstrated that COR inhibits OS cell proliferation and promotes apoptosis in a dose-dependent manner. Additionally, COR induced G2/M phase cell cycle arrest. Using an integrative computational and experimental approach, we found the Src/JNK pathway was identified as a significant target. Western blot analysis revealed that OS cells treated with COR showedan increase in levels was evident of p-Src, p-JNK, and p-c-JUN. Moreover, the JNK inhibitor SP600125 counteracted COR's anti-proliferative effects and reversed mitochondrial apoptosis and cell cycle arrest. In vivo, COR significantly reduced tumor size in OS xenograft nude mice without causing toxicity. Following COR treatment, elevated levels of p-JNK and cyclin B1 were observed, while Ki-67 decreased and JNK levels remained unchanged. We finally elucidated the COR inhibits OS via Src/JNK pathway. Given its multifaceted roles in regulating cell behavior in the context of OS, the Src/JNK pathway is being explored for therapeutic interventions. Targeting this pathway could potentially improve treatment outcomes by modulating the balance between cell survival and death in OS. Thus, understanding the Src/JNK pathway is essential for unraveling the intricate mechanisms underlying OS progression and for developing effective therapeutic strategies.

Efficacy and safety of regorafenib in the treatment of bone sarcomas: systematic review and meta-analysis

BACKGROUND

Metastatic or recurrent bone sarcomas are often associated with an unfavorable prognosis, posing a formidable challenge in extending patients' survival. Currently, regorafenib has shown promise in treating metastatic and recurrent bone sarcomas. However, there is a lack of consensus on its efficacy and safety. This systematic review and meta-analysis aims to consolidate existing data to assess the efficacy and safety of regorafenib in bone sarcomas.

METHODS

A comprehensive search strategy utilizing MeSH terms and free-text keywords was employed to systematically search the Embase, PubMed, Web of Science, and Cochrane databases up to May 26, 2024. Randomized controlled trials investigating regorafenib monotherapy for metastatic or recurrent bone sarcomas were included. The primary outcomes of interest were progression-free survival (PFS), overall survival(OS) and adverse events (AEs).

RESULTS

We retrieved 335 articles and included 5 of them. Regorafenib significantly extended PFS-3 months and PFS-6 months in patients with metastatic or recurrent bone sarcomas compared to the control group, exhibiting a favorable odds ratio (OR) of 2.04 (95% CI: 1.21-2.86, P < 0.01) and 1.03 (95% CI: 0.08-1.99, P < 0.05), respectively. However, regorafenib did not improve OS at any observation point compared with the control group(P > 0.05), and the frequency of AEs was higher, with an odds ratio of 1.35 (95% CI: 0.63-2.07, P < 0.01).

CONCLUSION

Regorafenib emerges as a promising therapeutic option for metastatic or recurrent bone sarcomas, demonstrating certain clinical benefits alongside manageable adverse reactions. Nevertheless, further research is warranted to refine the efficacy and safety profile of regorafenib, particularly in exploring safe dosage ranges or alternative treatment modalities.

REGISTRATION NUMBER

CRD42024551705.

Multimodal Imaging of Osteosarcoma: From First Diagnosis to Radiomics

Osteosarcoma is a primary malignant bone tumor characterized by the production of an osteoid matrix. Although histology remains the definitive diagnostic standard, imaging plays a crucial role in diagnosis, therapeutic planning, and follow-up. Conventional radiography serves as the initial checkpoint for detecting this pathology, which often presents diagnostic challenges due to vague and nonspecific symptoms, especially in its early stages. Today, the integration of different imaging techniques enables an increasingly personalized diagnosis and management, with each contributing unique and complementary information. Conventional radiography typically initiates the imaging assessment, and the Bone Reporting and Data System (Bone-RADS) of the Society of Skeletal Radiology (SSR) is a valuable tool for stratifying the risk of suspicious bone lesions. CT is the preferred modality for evaluating the bone matrix, while bone scans and PET/CT are effective for detecting distant metastases. MRI reveals the extent of the lesion in adjacent soft tissues, the medullary canal, and joints, as well as its relationship to neurovascular structures and the presence of skip lesions. Advanced techniques such as dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI), diffusion-weighted imaging (DWI), and perfusion MRI help characterize the tumor environment and assess treatment response. Osteosarcoma comprises a range of subtypes with differing clinical and imaging characteristics, some of which are particularly distinctive, such as in the case of telangiectatic osteosarcoma. Knowledge of these variants can guide radiologists in the differential diagnosis, which includes both central and surface forms, ranging from highly aggressive to more indolent types. In this review, we present a wide range of representative cases from our hospital case series to illustrate both typical and atypical imaging presentations. Finally, we discuss recent advancements and challenges in applying artificial intelligence approaches to the imaging of osteosarcoma.

Osteosarcoma and Ewing Sarcoma of Bone: An Italian Mono-Institutional Epidemiological Study

Background/Objectives: Musculoskeletal neoplasms are rare and challenging diseases. Their geographic pattern varies worldwide, and no studies analyze their distribution in Italy. The aim of this study was to investigate a possible association between clinical variables to a period of diagnosis and geographic origin in Italy. Moreover, we wanted to describe the survival rate of bone osteosarcoma (OS) and Ewing sarcoma (EwS) from the Rizzoli Orthopaedic Institute (IOR) experience. Methods: We retrospectively reviewed 3098 diagnoses of high-grade bone OS and EwS made at the IOR in the past 40 years (1982-2021). Incidence, measures of associations, and survival rates have been analyzed. Results: The time of diagnosis and geographic origin were associated either with each other or with age and stage of tumor. Overall, the 10-year survival rate was 54% (95% CI 52-56) and 53% (95% CI 50-56) for bone OS and EwS, respectively. Multivariate analyses showed that adverse factors at diagnosis are age, location, stage, and time of diagnosis, in both cohorts. Conclusions: We confirmed known prognostic factors, and owing to the large cohort, we highlight their importance in clinical practice. No differences were observed in patient survival associated with different areas of Italy, although geographic origin was associated with most clinical variables analyzed, suggesting a further factor to investigate. Given the above-mentioned results, a Sarcoma Specialist Network with a recognized expertise is determinably in charge of the management of sarcomas.

UK guidelines for the management of bone sarcomas

This document is an update of the British Sarcoma Group guidelines (2016) and provides a reference standard for the clinical care of UK patients with primary malignant bone tumours (PMBT) and giant cell tumours (GCTB) of bone. The guidelines recommend treatments that are effective and should be available in the UK, and support decisions about management and service delivery. The document represents a consensus amongst British Sarcoma Group members in 2024. Key recommendations are that bone pain, or a palpable mass should always lead to further investigation and that patients with clinical or radiological findings suggestive of a primary bone tumour at any anatomic site should be referred to a specialist centre and managed by an accredited bone sarcoma multidisciplinary team. Treatment recommendations are provided for the major tumour types and for localised, metastatic and recurrent disease. Follow-up schedules are suggested.

Chimeric protein EWS::FLI1 drives cell proliferation in Ewing Sarcoma via aberrant expression of KCNN1/SK1 and dysregulation of calcium signaling

Ewing sarcoma (ES) is characterized by EWS::FLI1 or EWS::ERG fusion proteins. Knowing that ion channels are involved in tumorigenesis, this work aimed to study the involvement of the KCNN1 gene, which encodes the SK1 potassium channel, in ES development. Bioinformatics analyses from databases were used to study KCNN1 expression in patients and cell lines. Molecular approaches and in vitro assays were used to study the transcriptional regulation of KCNN1 and its involvement in the regulation of ES cell proliferation. KCNN1 is overexpressed in ES patient biopsies, and its expression is inversely correlated with patient survival. EWS::FLI1, like EWS::ERG, promotes KCNN1 and SK1 expression, binding to GGAA microsatellites near the promoter of KCNN1 isoforms. KCNN1 is involved in the regulation of ES cell proliferation, with its silencing being associated with a slowing of the cell cycle, and its expression modulates membrane potential and therefore calcium flux. These results highlight that KCNN1 is a direct target of EWS::FLI1 and EWS::ERG and demonstrate that KCNN1 is involved in the regulation of intracellular calcium activity and ES cell proliferation, making it a promising therapeutic target in ES.

A unique pediatric thoracic tumor: A case report of mediastinal Ewing sarcoma

INTRODUCTION AND SIGNIFICANCE

Ewing's sarcoma is a rare tumor occurring in the mediastinum. It is a malignant, aggressive, and rapidly growing tumor that often lacks distinctive clinical or radiological features. Diagnosis is primarily made through histological and immunocytochemical examination. Complete surgical excision followed by chemotherapy is the preferred treatment.

CASE PRESENTATION

We present a case of a child who initially presented with mild respiratory distress. The condition rapidly progressed, leading to an external misdiagnosis and the placement of a chest defibrillator due to misinterpreted findings. The child was referred to our institution, where a large mediastinal mass was diagnosed and surgical intervention was undertaken to completely resect the mass and confirm the diagnosis of Ewing's sarcoma.

CLINICAL DISCUSSION

It is crucial for medical practitioners, especially surgeons, to include Ewing's sarcoma in the differential diagnosis of mediastinal lesions. This consideration is essential for developing an appropriate surgical intervention plan and subsequent follow-up.

CONCLUSION

Our case highlights several important points in clinical practice. It emphasizes the need to avoid relying solely on non-contrast CT scans when a mass is suspected. Additionally, fine-needle aspiration (FNA) should be considered for mass lesions to establish a diagnosis before surgical intervention, as some conditions, such as lymphoma, may not require surgery. Our case also demonstrates the successful removal of a large chest mass through a posterior lateral thoracic approach.

Prediction of tumor response to neoadjuvant chemotherapy in high-grade osteosarcoma using clustering-based analysis of magnetic resonance imaging: an exploratory study

PURPOSE

To evaluate the ability of magnetic resonance imaging (MRI)-based clustering analysis to predict the pathological response to neoadjuvant chemotherapy (NACT) in patients with primary high-grade osteosarcoma.

MATERIALS AND METHODS

Twenty-two patients were included in this retrospective study. All patients underwent MRIs before and after NACT. The entire tumor volume was manually delineated on post-contrast T1-weighted images and subsegmented into three clusters using the K-means algorithm. Histogram-based parameters were calculated for each lesion. The response to NACT was obtained from the histopathological assessment of the tumor necrosis rate following resection. The Mann-Whitney test was used to compare poor and fair-to-good responders. The receiver operating characteristic curve was used to evaluate the diagnostic performance of the optimal parameters.

RESULTS

At baseline, poor responders showed a significantly larger volume of cluster1 (Vol1) than fair-to-good responders (p = 0.038). After NACT, they exhibited a lower 10th percentile (P10) and kurtosis (p = 0.038 and 0.002, respectively). Vol1 at baseline and P10 after NACT had an AUC of 77% (95% CI 56-98%). The kurtosis after NACT had the best discriminative power, with an AUC of 89.7% (95% CI 75-100%).

CONCLUSION

The MRI-based histogram and clustering analysis provided a good ability to differentiate between poor and fair-to-good responders before and after NACT. Further investigations using larger datasets are required to corroborate our findings.

Curative-intent surgery for solitary bone metastasis from extremity and trunk wall sarcoma: What are the outcomes and complications?

INTRODUCTION

Approximately 40-50 % of sarcoma patients will develop lung metastasis, but only 10 % will develop bone metastasis. The survival benefit of surgery for solitary bone metastasis remains unclear.

METHODS

From 1987 to 2019, 47 patients who underwent curative-intent treatment for localized bone or soft tissue sarcoma in the extremities or trunk wall developed solitary bone metastases as the first distant recurrence. Of them, 51 % (24/47) received curative-intent metastasectomy. We compared the clinicopathologic characteristics of the metastasectomy versus non-metastasectomy patients and evaluated the prognostic impact of solitary bone metastasectomy. The primary outcome measure was disease-specific survival (DSS) after developing solitary bone metastasis.

RESULTS

The post-metastasis DSS was worse with larger primary tumour size (HR 1.09; 95 % CI 1.02-1.16; p = 0.01) and bone metastasis in the pelvis or spine versus other bones (HR 3.79, 95 % CI 1.46-9.87; p = 0.01), and better with curative-intent surgery for the solitary bone metastasis (HR 0.14; 95 % CI 0.06-0.34; p < 0.001). The median DSS was 43 (95 % CI, 24-69) months for the metastasectomy group vs. 13 (95 % CI, 7-19) months for the non-metastasectomy group (p < 0.001). The metastasectomy group had fewer patients with metastasis in the spine or pelvis and longer metastasis-free interval. In the multivariate analysis, curative-intent surgery for solitary bone metastasis was associated with better survival (HR 0.21; 95 % CI 0.08-0.53; p = 0.001).

CONCLUSIONS

Curative-intent surgery for solitary bone metastasis from sarcoma is associated with a better prognosis and is a reasonable treatment strategy whenever feasible.

Postoperative Imaging of Bone and Soft Tissue Tumors in the Extremity: A Comprehensive Review

Postoperative imaging of musculoskeletal tumors poses a significant diagnostic challenge for radiologists. The complexity arises from the need to differentiate between expected postoperative changes, potential complications, and local recurrence. The choice of imaging modality depends on the type of primary tumor. Standard radiological modalities such as radiography, computed tomography (CT), and magnetic resonance imaging (MRI) are widely utilized. Radiography and CT are especially valuable for assessing primary bone tumors, as they provide detailed views of bone structures and alignment, as well as revealing postoperative complications. MRIs are particularly effective for evaluating soft tissue tumors and identifying local recurrences due to its superior soft tissue contrast. The advanced imaging techniques, such as diffusion-weighted imaging and dynamic contrast-enhanced MRI, have significantly improved diagnostic accuracy in detecting tumor recurrence. An in-depth understanding of surgery-specific imaging findings, as well as the ability to detect recurrent disease, is crucial for early diagnosis of complications and improved patient outcomes. Familiarity with normal postoperative changes helps radiologists distinguish them from abnormal findings indicative of complications or tumor recurrence. This review article aims to outline the surgical options for musculoskeletal tumors, detail the various imaging techniques used in postoperative surveillance, and discuss the potential complications. By understanding the role of different imaging modalities and their applications associated with various surgical procedures, clinicians and radiologists can provide accurate and timely diagnoses.

18 F-FDG PET Metabolic Parameters for the Prediction of Histological Response to Induction Chemotherapy in Osteosarcoma and Ewing Sarcoma : A Systematic Review and Network Meta-analysis

PURPOSE

This study aimed to evaluate the ability of 18 F-FDG PET/CT metabolic parameters to predict the histological response to neoadjuvant chemotherapy in patients with osteosarcoma and Ewing sarcoma.

PATIENTS AND METHODS

This systematic review and network meta-analysis adhered to the PRISMA-NMA and Cochrane guidelines. Electronic databases were searched from January 2008 to January 2024; this search was supplemented by snowballing methods. The risk of bias was evaluated with QUADAS-2, and evidence certainty was assessed using the GRADE approach. The prognostic value of 18 F-FDG PET/CT parameters, including pretreatment and posttreatment SUVs (SUV1, SUV2 and the SUV2/SUV1 ratio), metabolic tumor volume (MTV1, MTV2, ΔMTV), and total lesion glycolysis (TLG1, TLG2, ΔTLG), was examined.

RESULTS

The meta-analysis of 18 studies (714 patients) identified the ΔTLG, ΔMTV, and SUV ratio as superior predictors of histological response. The changes in metabolic activity, as indicated by these parameters, provided a robust indication of treatment effectiveness. Baseline parameters showed limited predictive value compared with posttreatment assessments. The study's robustness was confirmed through meta-regression, which revealed that the predictive value of the SUV2 and SUV ratio was consistent across various cutoff thresholds.

CONCLUSIONS

18 F-FDG PET/CT metabolic parameters, particularly those measuring changes posttherapy, are effective in predicting the histological response in patients with osteosarcoma and Ewing sarcoma. These findings underscore the potential of 18 F-FDG PET/CT in guiding early treatment decisions, thereby enhancing personalized therapeutic approaches.

Beyond the sarcoma center: establishing the Sarcoma HASM network-a Hub and Spoke Model network for global integrated and precision care

The landscape of sarcoma treatment has evolved significantly, transitioning from amputations to limb-sparing surgeries, underpinned by advancements in multidisciplinary strategies. The establishment of specialized sarcoma centers has been pivotal, though challenges in accessibility and expertise persist. This manuscript proposes the Sarcoma Hub and Spoke Model (HASM) network to address these issues, enhancing coordination and expanding access to specialized care. The HASM network centralizes complex case management at hubs while peripheral spokes manage routine diagnostics and treatments, optimizing resource use and ensuring patient-centered care. Integration with digital interoperable platforms facilitates real-time/real-world data exchange, supports multidisciplinary team meetings, and enables advanced predictive analytics such as Sarcoma Digital Twins and causal machine learning for personalized treatment. The Sarcoma Care Data Warehouse further enhances this model by aggregating comprehensive patient data, supporting quality assessment and continuous improvement. This innovative approach aims to set a new standard for sarcoma care, leveraging technology and collaborative expertise to improve outcomes globally.

Twenty-five years of experience with patient-reported outcome measures in soft-tissue sarcoma patients: a systematic review

PURPOSE

As the importance of the patient's perspective on treatment outcome is becoming increasingly clear, the availability of patient-reported outcome measures (PROMs) has grown accordingly. There remains insufficient information regarding the quality of PROMs in patients with soft-tissue sarcomas (STSs). The objectives of this systematic review were (1) to identify all PROMs used in STS patients and (2) to critically appraise the methodological quality of these PROMs.

METHODS

Literature searches were performed in MEDLINE and Embase on April 22, 2024. PROMs were identified by including all studies that evaluate (an aspect of) health-related quality of life in STS patients by using a PROM. Second, studies that assessed measurement properties of the PROMs utilized in STS patients were included. Quality of PROMs was evaluated by performing a COSMIN analysis.

RESULTS

In 59 studies, 39 PROMs were identified, with the Toronto Extremity Salvage Score (TESS) being the most frequently utilized. Three studies evaluated methodological quality of PROMs in the STS population. Measurement properties of the TESS, Quick Disability of the Arm, Shoulder and Hand (QuickDASH) and European Organization for Research and Treatment for Cancer Quality of Life Questionnaire (EORTC-QLQ-C30) were reported. None of the PROMs utilized in the STS population can be recommended for use based on the current evidence and COSMIN analysis.

CONCLUSION

To ensure collection of reliable outcomes, PROMs require methodological evaluation prior to utilization in the STS population. Research should prioritize on determining relevant content and subsequently selecting the most suitable PROM for assessment.

Implementation of a new classification and stratification system for solitary bone tumour: osseous tumour radiological and interpretation and management system

OBJECTIVES

To propose a histological-grades-based Osseous Tumor Radiological and Interpretation and Management System (OT-RIMS) that would simplify the radiological evaluation of bone tumours, categorize key radiological features into severity levels, and inform corresponding patient management actions.

METHODS

This retrospective study between January 2015 and August 2022 evaluated patients with solitary bone tumours confirmed by pathology and imaging follow-up received 2 or 3 imaging modalities of radiographs, CT, or MRI. Three radiologists independently assessed radiological features, categorized bone lesions based on OT-RIMS criteria, and reached a consensus. Kappa statistics and observed agreement were calculated.

RESULTS

A total of 341 patients (mean age, 26.0 years; 159 women) were included, with 102 malignant, 177 benign, and 62 intermediate or low-grade malignant bone lesions. Sensitivity and specificity of readers 1, 2, and 3, respectively, in the identification of malignant tumours into OT-RIMS 4 were 93.1% (95 of 102) and 93.3% (223 of 239), 96.1% (98 of 102) and 91.6% (219 of 239), 92.2% (94 of 102) and 89.5% (214 of 239). Inter-reader agreement of OT-RIMS category for 3 readers was considered excellent (Kendall's W = 0.924, P < .001) with a kappa value of reproducibility in categories 1&2, 3, and 4 of 0.764, 0.528, and 0.930, respectively.

CONCLUSIONS

The OT-RIMS category demonstrated excellent reproducibility despite the reader's expertise level in categorizing the risk stratification of bone tumours and informing patient management, with histological grades used as the reference standard.

ADVANCES IN KNOWLEDGE

The OT-RIMS category reliably stratifies bone tumours into 4 categories corresponding to histological grades and standardized patient management.

[Pathological fractures of the extremities]

The diagnostics and treatment of pathological fractures of the extremities differ from the approach for conventional fractures. Metastases from breast, bronchial, renal cell and prostate cancer are the predominant cause. Typically, patients present at over 50 years old present after an inadequate trauma. They often report symptoms or swelling in the affected region that already existed before the fracture. An underlying malignant disease is sometimes already known; however, occasionally this is manifested in the form of a fracture. The femur is affected in 74% of cases, followed by the humerus and the tibia. Important indications for the presence of a pathological fracture can even be obtained from conventional radiographs. The diagnostics are supplemented with further modalities depending on the treatment goal. Surgical treatment is the first choice as the fractures do not heal using conservative measures. In this context, a prognosis-stratified approach is recommended.

Analysis of foot-originating malignant bone tumors: Epidemiology, characteristics, and survival outcomes

BACKGROUND

The study examines the characteristics and outcomes of foot-originating malignant bone tumors via Surveillance Epidemiology and End Results (SEER) database analysis.

METHODS

A retrospective review of 14,695 malignant bone tumor cases from 2000 to 2019 was conducted.

RESULTS

Of the eligible cases, 147 (2.3 %) were foot-origin tumors, typically smaller and more commonly treated with surgery than those in other locations. These tumors were more frequently treated with surgical resection, with a higher proportion undergoing amputation. In contrast, foot-origin tumors were less often managed with chemotherapy and radiation. Foot-origin tumors exhibited higher survival rates compared to non-foot-origin tumors as shown in univariate analysis, although multivariate analysis did not reflect significant differences.

CONCLUSION

Foot-originating malignant bone tumors tend to be smaller and are frequently surgically treated, correlating with favorable survival outcomes. These findings point to early detection as a potential factor in the improved survival rates, not necessarily the tumor's origin.

Automated detection of bone lesions using CT and MRI: a systematic review

PURPOSE

The aim of this study was to systematically review the use of automated detection systems for identifying bone lesions based on CT and MRI, focusing on advancements in artificial intelligence (AI) applications.

MATERIALS AND METHODS

A literature search was conducted on PubMed and MEDLINE. Data were extracted and grouped into three main categories, namely baseline study characteristics, model validation strategies, and the type of AI algorithms.

RESULTS

A total of 10 studies were selected and analyzed, including 2,768 patients overall with a median of 187 per study. These studies utilized various AI algorithms, predominantly deep learning models (6 studies) such as Convolutional Neural Networks. Among machine learning validation strategies, K-fold cross-validation was the mostly used (5 studies). Clinical validation was performed using data from the same institution (internal testing) in 8 studies and from both the same and different (external testing) institutions in 1 study, respectively.

CONCLUSION

AI, particularly deep learning, holds significant promise in enhancing diagnostic accuracy and efficiency. However, the review highlights several limitations, such as the lack of standardized validation methods and the limited use of external datasets for testing. Future research should address these gaps to ensure the reliability and applicability of AI-based detection systems in clinical settings.

Long-Circulating and Targeted Liposomes Co-loading Cisplatin and Mifamurtide: Formulation and Delivery in Osteosarcoma Cells

Osteosarcoma (OS) is one of the most common primary bone sarcoma with high malignant degree and poor prognosis, for which there is an urgent need to develop novel therapeutic approaches. Recent research has revealed that mifamurtide significantly improved the outcome of OS patients when combined with adjuvant chemotherapy drugs including cisplatin (DDP). The present study aimed to construct a drug delivery system co-loading DDP and mifamurtide. Long-circulating targeted liposomes co-loading DDP and mifamurtide were constructed with Soy lecithin (SPC), cholesterol (Chol) and 1,2-distearoylglycero-3-phosphoethanolamine-n-[poly(ethyleneglycol)] (DSPE-PEG), modified with MMP14 targeting peptide BCY-B in the surface of liposomes. In addition to characterization, the cellular uptake, endocytosis pathway and inhibition on cell viability, migration, invasion and cell apoptosis of MG-63 cells were explored. The constructed liposomal delivery possessed the basic characteristics of liposomes and showed high affinity to MG-63 cells, resulting in high uptake efficiency in MG-63 cells. The endocytosis might be involved in multiple pathways including caveolae-mediated endocytosis, clathrin-mediated endocytosis and macropinocytosis, dependently on energy. The constructed long-circulating targeted liposomes co-loading DDP and mifamurtide significantly inhibited the cell viability, migration, invasion and cell apoptosis of MG-63 cells, improving the antitumor effect of DDP and mifamurtide in vitro. The constructed liposomal delivery system is suitable for co-loading DDP and mifamurtide to achieve active tumor targeting, supplying a new strategy for the treatment of OS.

Bayesian unsupervised clustering identifies clinically relevant osteosarcoma subtypes

Identification of cancer subtypes is a critical step for developing precision medicine. Most cancer subtyping is based on the analysis of RNA sequencing (RNA-seq) data from patient cohorts using unsupervised machine learning methods such as hierarchical cluster analysis, but these computational approaches disregard the heterogeneous composition of individual cancer samples. Here, we used a more sophisticated unsupervised Bayesian model termed latent process decomposition (LPD), which handles individual cancer sample heterogeneity and deconvolutes the structure of transcriptome data to provide clinically relevant information. The work was performed on the pediatric tumor osteosarcoma, which is a prototypical model for a rare and heterogeneous cancer. The LPD model detected three osteosarcoma subtypes. The subtype with the poorest prognosis was validated using independent patient datasets. This new stratification framework will be important for more accurate diagnostic labeling, expediting precision medicine, and improving clinical trial success. Our results emphasize the importance of using more sophisticated machine learning approaches (and for teaching deep learning and artificial intelligence) for RNA-seq data analysis, which may assist drug targeting and clinical management.

Real world data of Ewing sarcoma from a resource-limited setting with poor compliance to treatment leading to poor outcomes

Background

There is limited data from India on Ewing sarcoma (ES) patients. We analysed the demographic and clinical profile of ES patients, the systemic chemotherapy, local treatment and outcomes in patients with localised, metastatic and recurrent disease.

Methods

Data of ES patients reporting from 2010 to 2019 to a tertiary care referral centre in north India was evaluated. A total of 81 patients were retrieved of whom 76 were assessed for treatment and outcomes. Patients were stratified as per localised (LD) or metastatic disease (MD). Outcomes were evaluated in terms of 3-year and 5-year disease-free survival (DFS) and overall survival (OS). Prognostic factors influencing OS for patients with LD were assessed.

Results

The majority (68%, n = 55) of patients presented from rural areas with 30% (n = 24) presenting 6 months after the onset of symptoms, 63% (n = 51) had primary tumours more than 8 cm and 7% (n = 6) had a pathological fracture at presentation, 78% (n = 63) patients had LD while 22% (n = 18) patients had MD. Local treatment consisted of surgery in 56% (n = 28) patients and definitive radiotherapy in 44% (n = 22) patients. Compliance with chemotherapy was poor with patients receiving a median of five and seven cycles of chemotherapy as neoadjuvant and consolidation chemotherapy, respectively. Three-year OS for LD, MD and overall cohort was 41%, 6% and 32%, respectively. Size of the primary tumour > 8 cm, completion of less than 15 cycles of chemotherapy and presence of MD was associated with inferior survival on multivariate analysis.

Conclusion

Poor outcomes were reported in this cohort of ES patients from a resource-limited setting where patients have a delayed diagnosis, advanced disease and poor compliance to adjuvant consolidation chemotherapy secondary to geographical, social and financial barriers. There is an urgent need to address these barriers for low middle-income countries to improve outcomes.

Prognostic factors for mesenchymal chondrosarcoma

INTRODUCTION

Mesenchymal chondrosarcoma (MCS) is a malignant, biphasic, high-grade, primitive mesenchymal tumor that has a well-differentiated, organized hyaline component. MCS has a poor prognosis, and treatment recommended for localized MCS is based on wide resection while controversy remains regarding the efficacy of adjuvant chemotherapy and radiotherapy. In this study, we aimed to investigate the prognostic factors of MCS, especially the efficacy of adjuvant chemotherapy and radiotherapy for localized MCS.

METHODS

Eighty patients with MCS pathologically diagnosed between 2006 and 2022 from the Japanese National Bone and Soft Tissue Tumor Registry database were analyzed retrospectively.

RESULTS

Patients with distant metastases at presentation (n = 23) had significantly shorter survival than those without (n = 57) (5-year disease-specific survival 19.9% [95% confidence interval (CI): 5.6-50.7] vs. 79.8% [95% CI: 62.4-90.4]; p < 0.0001). In the group without distant metastasis at presentation (n = 57), R1 or R2 surgical margin was a risk factor for unfavorable local recurrence (hazard ratio (HR): 17.44 [95% CI: 2.17-139.98]; p = 0.007). There was no correlation between adjuvant radiotherapy and local recurrence rate (HR 5.18 [95% CI: 0.99-27.12]; p = 0.051). R1 or R2 surgical margin was a risk factor for unfavorable disease-specific survival (HR 17.42 [95% CI: 2.18-138.90]; p = 0.007). There was no correlation between adjuvant chemotherapy and disease-specific survival (HR 0.99 [95% CI: 0.28-3.47]; p = 0.990).

DISCUSSION

Patients with MCS and distant metastases at presentation have a poor prognosis, and wide resection is important for the treatment of localized MCS. The efficacy of adjuvant radiotherapy and chemotherapy could not be determined because of the small number of patients.

Case report: Pulmonary Ewing sarcoma disguised as non-small cell lung cancer

Ewing sarcoma is the second most common primary malignant bone cancer in children and adolescents. This rare type of cancer is characterized by its high malignancy and therefore high risk of metastases. Typically, Ewing sarcomas originate from bones. However, extraosseous Ewing sarcoma such as pulmonary Ewing sarcoma can also be found. In this case report, we present a 55-year old male patient who was initially diagnosed with non-small cell lung cancer at his local district hospital. However, the diagnosis was changed to one of pulmonary Ewing sarcoma after subsequent histopathological and molecular pathological analysis performed in a reference pathology laboratory. After patient referral to a certified (according to the German Cancer Society) high-volume sarcoma center, multimodal chemotherapy was initiated based on recently published clinical data as opposed to the more commonly used treatment regimen in Europe. The patient responded well to treatment and underwent a complete surgical tumor resection followed by radiotherapy. In summary, this case report highlights the importance of a rigorous and timely histopathological examination of biopsy samples by a specialized cancer center to enable a correct diagnosis of the cancer type. Additionally, molecular pathology plays a crucial part in this analysis and allows the necessary differentiation between cancer types. Up to now, there is no international treatment guideline available for the treatment of Ewing sarcoma. Patients should be referred to specialist centers to allow the best possible treatment of the cancer type in view of current published clinical data. In the case of Ewing sarcoma, and in accordance with the most recent research, patients should be treated with vincristine, doxorubicin and cyclophosphamide plus ifosfamide and etoposide in combination with local treatment such as surgery and/or radiotherapy because this has been demonstrated to be the more effective therapy.

Tumor Microenvironment Reprogramming Improves Nanomedicine-Based Chemo-Immunotherapy in Sarcomas

Sarcomas are a heterogeneous group of rare cancers that originate in soft tissues or bones. Their complexity and tendency for metastases make treatment challenging, highlighting the need for new therapeutic approaches to improve patient survival. The difficulties in treating these cancers primarily stem from abnormalities within the tumor microenvironment (TME), which leads to reduced blood flow and oxygen levels in tumors. Consequently, this hampers the effective delivery of drugs to tumors and diminishes treatment efficacy despite higher toxic doses of chemotherapy. In this study, we tested the mechanotherapeutic ketotifen combined with either pegylated liposomal doxorubicin (PLD) or pegylated liposomal coencapsulated alendronate-doxorubicin (PLAD) plus anti-programmed cell death protein 1 antibody in mouse models of fibrosarcoma and osteosarcoma. We found that ketotifen successfully reprogrammed the TME by reducing tumor stiffness and increasing perfusion, proven by changes measured by shear-wave elastography and contrast-enhanced ultrasound, respectively, and enhanced the therapeutic efficacy of our nanomedicine-based chemo-immunotherapy protocols. Furthermore, we observed a trend toward improved antitumor responses when nano-chemotherapy is given alongside anti-programmed cell death protein 1 and when the immunomodulator alendronate was present in the treatment. We next investigated the mechanisms of action of this combination. Ketotifen combined with nanomedicine-based chemo-immunotherapy increased T-cell infiltration, specifically cytotoxic CD8+ T cells and CD4+ T helper cells, and decreased the number of regulatory T cells. In addition, the combination also altered the polarization of tumor-associated macrophages, favoring the M1 immune-supportive phenotype over the M2 immunosuppressive phenotype. Collectively, our findings provide evidence that ketotifen-induced TME reprogramming can improve the efficacy of nanomedicine-based chemo-immunotherapy in sarcomas.

Role of 18F-FDG-PET/CT in the initial staging of very high-risk Ewing Sarcoma in a prospective multicentric Phase II Study: Is there still a place for bone marrow sampling?

BACKGROUND

The Ewing Sarcoma Family of Tumors (ESFT) constitutes a group of rare malignancies, wherein approximately one-third of cases exhibit metastatic spread, particularly impacting prognosis when bone and/or bone marrow (BM) are involved. Primary extra-pulmonary metastatic ESFT often necessitates intensified therapeutic approaches. Accurate staging plays a pivotal role in clinical decision-making, with fluorine-18-fluorodeoxyglucose-positron emission tomography/computed tomography (PET/CT) currently serving as a non-invasive modality for assessing ESFT's BM extent.

METHODS

In the French phase II COMBINAIR3 (NCT03011528) study, a comprehensive approach for patients with extra-pulmonary ESFT metastasis was evaluated. We prospectively compared the efficacy of PET/CT to BM aspiration and biopsy (BMAB) analysis in patients undergoing initial staging.

RESULTS

Among the 42 patients analyzed (median age 14 y, 2:1 male/female ratio), 45% presented with pelvic primary tumors and 83% had bone/BM involvement at diagnosis. Our findings showed PET/CT had 100% specificity and 83.3% sensitivity in detecting initial BM involvement. Overall, PET/CT correctly classified 92.8% of patients, reaching 100% accuracy in patients identified with bone involvement, thus surpassing the standard BMAB.

DISCUSSION

These results suggest that the conventional use of BMAB in the initial staging of high-risk ESFT patients can be omitted, promoting PET/CT as a non-invasive alternative, thus improving staging accuracy and treatment decisions in ESFT management.