Denosumab in patients with giant-cell tumour of bone: a multicentre, open-label, phase 2 study

Rebound hypercalcaemia timing is associated with cumulative weight-based denosumab dose for central giant cell granuloma treatment in children despite a dose weaning regimen

Central giant cell granulomas (CGCG) are locally destructive, non-neoplastic lesions that express receptor activator of nuclear factor-κB (RANK) and RANK ligand. Denosumab, a monoclonal antibody against RANK ligand, is licensed in skeletally mature patients, with less experience in children who are at risk of rebound hypercalcaemia. We describe the response to denosumab in five skeletally immature children with CGCG. Denosumab was started aged 2.1 to 11.6 years, for 8 to 22 months, with a cumulative dose of 9.6 to 58.8 mg/kg. Three patients followed a weaning protocol (using reducing dose frequency and zoledronic acid). Denosumab ossified all lesions. Three patients had subsequent surgery, and one had recurrence. All had rebound hypercalcaemia, 8.9-47 weeks (median 23.3 weeks) after the last treatment dose. Four presented with symptomatic hypercalcaemia and acute kidney injury. Cumulative denosumab treatment dose/kg positively correlated with (1) time to rebound after the last treatment dose (r2 = 0.94, p = 0.006); and (2) length of admission for hypercalcaemia treatment (r2 = 0.87, p = 0.02). All patients had increased bone mineral density and metaphyseal sclerosis that improved after stopping denosumab. One had a clavicular fracture at the intersection of normal and high-density bone. We propose that rebound hypercalcaemia should be an anticipated consequence of stopping denosumab in skeletally immature patients and exists on a spectrum. A higher cumulative denosumab dose/kg increases the time to rebound hypercalcaemia and its severity. Further work is needed to establish the lowest dose and the shortest treatment duration to balance effective treatment with minimising side effects.

Malignant Giant Cell Tumor of Bone: A Clinicopathologic Series of 28 Cases Highlighting Genetic Differences Compared With Conventional, Atypical, and Metastasizing Conventional Tumors

Giant cell tumors of bone are locally aggressive, frequently harbor H3F3A p.G34W mutations, and rarely undergo malignant transformation. The pathogenesis of malignant transformation remains incompletely characterized. Herein, we present 28 malignant giant cell tumors of bone from 14 males and 14 females, aged 16 to 65 (median 39) years. Primary sites included long bones (n=20), pelvis (n=3), vertebrae (n=2), and rarely rib, phalanx, and cuneiform (n=1 each). Sixteen (62%) of 26 tumors with available history represented malignant transformation or recurrence of conventional giant cell tumors of bone, at intervals of 1.3 to 35 (median 7.3) years before malignant transformation. Eight of 15 patients with available treatment history received denosumab before a diagnosis of malignancy. Ten (38%) of 26 tumors with available history likely arose de novo, including 7 with conventional areas and 3 H3F3A -mutant sarcomas lacking conventional giant cell tumor of bone. Of 28 malignant giant cell tumors of bone, 18 (64%) and 10 (36%) harbored osteoblastic and chondroblastic elements, respectively. Among 23 tumors with available genetic testing or surrogate immunohistochemistry, 17 (74%) were p.G34W-mutant, whereas other tumors carried H3F3A p.G34L (n=2), p.G34V (n=2), and p.G34R (n=1) alterations; 1 tumor harbored H3F3B p.K116E and p.R117S in cis. Seven (70%) of 10 malignant giant cell tumors of bone showed complex copy number alterations by single nucleotide polymorphism (SNP) array, DNA next-generation sequencing (NGS), and/or karyotype analysis. In contrast, complex chromosomal alterations were lacking in 32 conventional giant cell tumors of bone tested (24 by karyotype, 7 by SNP array, 1 by DNA NGS), 3 atypical giant cell tumors of bone with isolated marked nuclear atypia (2 by karyotype, 1 by SNP array) and 3 metastasizing conventional giant cell tumors of bone (2 by DNA NGS, 1 by karyotype). Clinical follow-up was available for 20 patients (71%), and one additional patient had metastases at presentation. Overall, 14 of 21 patients (67%) developed metastases, and 10 of 20 patients with follow-up (50%) died of disease at 2 months to 9.6 years (median 7 mo). Most patients were treated with chemotherapy; 1 patient (PD-L1 TPS >95%) was treated with pembrolizumab, with complete clinical response of metastatic disease at 2.5 years. In conclusion, malignant giant cell tumors of bone typically arise from long bones, harbor osteosarcomatous and/or chondrosarcomatous differentiation, and show significant risk for distant metastasis and demise. Our data suggest that copy number analysis may be useful in distinguishing malignant giant cell tumors of bone from their conventional, atypical, and metastasizing conventional counterparts.

Denosumab as an immune modulator in HER2-negative early breast cancer: results of the window-of-opportunity D-BIOMARK clinical trial

BACKGROUND

The RANK pathway has been extensively investigated for its role in bone resorption; however, its significance extends beyond bone metabolism. Preclinical models suggest that inhibition of RANK signaling can prevent mammary tumor development by reducing proliferation and tumor cell survival. Additionally, both preclinical and clinical data support the ability of RANK pathway inhibitors to enhance the anti-tumor immune response.

METHODS

D-BIOMARK is a prospective, randomized window-of-opportunity clinical trial assessing the biological effects of denosumab, a monoclonal antibody against RANKL, in patients with HER2-negative early breast cancer. The study aims to assess denosumab's impact on breast tumor cell proliferation, apoptosis, and its potential to influence the tumor immune microenvironment. A total of 60 patients were enrolled and randomized 2:1 to receive two doses of single agent denosumab (120 mg one week apart) before surgery or to the control arm (no treatment). Fifty-eight patients were evaluated, 27 pre-menopausal and 31 post-menopausal women, 48 with luminal tumors and 10 with triple negative breast cancer. Paired tumor samples were collected to compare baseline (core biopsy) and surgical (surgical specimen) time points, as well as serum samples at both time points.

RESULTS

Denosumab demonstrated its ability to reduce serum free RANKL levels (experimental p < 0.001, control p = 0.270). However, a reduction in tumor cell proliferation or cell survival was not observed. A denosumab-driven increase in tumor infiltrating lymphocytes (TILs) was observed (experimental p = 0.001, control p = 0.060), particularly in the luminal B-like population (experimental p = 0.012, control p = 0.070) and a similar trend in the TNBC group (experimental p = 0.079, control p = 0.237). Denosumab led to increased TILs in both pre-menopausal (experimental p = 0.048, control p = 0.639) and post-menopausal (experimental p = 0.041, control p = 0.062) women with luminal tumors. RANK protein expression in tumor and stroma was associated with markers of tumor aggressiveness but an increase in TILs was observed in the experimental arm, irrespectively of RANK and RANKL expression in tumor or stromal cells.

CONCLUSIONS

The D-BIOMARK trial suggests a potential role for denosumab as an immune-enhancing agent in early HER2-negative breast cancer. Although preoperative denosumab did not reduce tumor proliferation or increased apoptosis, it led to an increase in TILs, particularly in luminal B-like tumors. These findings underscore the importance of further investigation into the multifaceted aspects of the RANK pathway. Trial registration EudraCT number: 2016-002678-11 registered on June 15, 2018.

CLINICALTRIALS

gov identifier: NCT03691311, retrospectively registered on September 04, 2018.

DENO Research Group, de la Calva C, Angulo M, González-Rojo P, Peiró A, Machado P, Cebrián JL, García-Maroto R, Valcárcel A, Puertas P, Valero-Cifuentes G, Pablos Ó, Maireles M, Fontalva ML, Chaves I, Orce A, Coll-Mesa L, Pérez I, González F, Sanz MDC, Gracia I. A Multicenter Study by the DENO Research Group on the Use of Denosumab in Giant-Cell Tumors of the Bone

Background/Objectives: Despite the therapeutic potential of denosumab for the treatment of giant-cell tumors of the bone (GCTBs), there is a lack of standardization in treatment protocols. Methods: We present a multicenter, retrospective, descriptive study conducted across the seven hospitals in Spain affiliated with the DENO Research Group. Seventy-three patients diagnosed with GCTB and treated with denosumab were included and stratified according to treatment strategy-neoadjuvant (n = 38), adjuvant (n = 8), and single treatment (n = 27). Results: Patients in the neoadjuvant group received denosumab for a median of 6.1 months, with reintroduction after surgery in 25.8% of all cases. Among the neoadjuvant patients treated with curettage, recurrence was 35.5%, with no association with denosumab treatment duration (p = 0.274) nor with denosumab reintroduction after surgery (p = 0.405). In the adjuvant group, those who completed treatment received denosumab for 15.3 months, while those still undergoing therapy received it for a median of 12.8 months; only one case (12.5%) recurred. Recurrence rates in neoadjuvant and adjuvant treatment strategies were not different (p = 0.394). Patients treated only with denosumab and no longer on treatment had received it for 34.2 months, with 31.3% recurrence; those still on treatment had received it for 51.8 months, with 25.0% recurrence. Across all strategies, more than 85% of patients reported favorable clinical outcomes, and only 43.8% presented adverse events. No deaths occurred during this study. Conclusions: Although patients who experienced recurrence during neoadjuvant treatment had longer durations of denosumab administration, the difference was not statistically significant. Similarly, recurrence rates did not differ significantly, whether denosumab was reintroduced after surgery or not. Among the patients treated with curettage, recurrence rates were comparable between neoadjuvant and adjuvant strategies. Discontinuation of the single treatment did not necessarily result in disease progression.

Surgical and radiological outcomes of giant cell tumor of the bone: prognostic value of Campanacci grading and selective use of denosumab

BACKGROUND

Advancements in diagnostic and therapeutic modalities for giant cell tumors of bone (GCTB) have introduced molecular and radiological tools that refine clinical decision-making. H3.3 G34W immunohistochemical staining has become a routine diagnostic marker, while H3F3A mutational analysis enhances prognostic insights. Treatment primarily involves surgical methods such as curettage or en bloc resection, with denosumab serving as an adjunct in high-risk or inoperable cases.

METHODS

We retrospectively analyzed 55 patients with GCTB, focusing on clinicopathologic and radiological findings. Tumors were evaluated using the Campanacci grading system. Immunohistochemical analysis with H3.3 G34W antibody and next-generation sequencing (NGS) were performed to detect H3F3A mutations. A subgroup of nine patients treated with denosumab was further analyzed for clinical outcomes and histological changes.

RESULTS

The cohort had a mean age of 37.7 years, with tumors most commonly affecting the knee joint (55%). All tested tumors demonstrated positive H3.3 G34W staining, with eight exhibiting H3F3A G34W mutations. Recurrence rates were 32% following curettage and 18% after en bloc resection. Denosumab treatment, administered for an average of 14.6 months, facilitated tumor downsizing and new bone formation without major side effects. Histologically, treated tumors showed a depletion of giant cells and increased bone matrix deposition.

CONCLUSIONS

Surgery remains the cornerstone of GCTB treatment, with curettage or resection tailored to tumor characteristics. Denosumab offers a valuable adjunct in high-risk cases, enhancing surgical feasibility and promoting joint preservation. The Campanacci grading system continues to be a crucial tool for prognostication and treatment planning, particularly when complemented by molecular and radiological diagnostics. Future research should focus on integrating advanced imaging and artificial intelligence for personalized GCTB management.

LEVEL OF EVIDENCE

Level 4.

[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.

RANKL promotes MT2 degradation and ROS production in osteoclast precursors through Beclin1-dependent autophagy

ROS produced under oxidative stress are crucial for osteoclast differentiation. Metallothionein (MT) is a ROS-scavenging molecule. As a member of MT family, MT2 can clear ROS in osteoclast precursors (OCPs) and contributes to osteoclast differentiation. RANKL can promote OCP autophagy. Given the molecular-degrading effect of autophagy, the relationship between RANKL-dependent autophagy, MT2 and ROS during osteoclast differentiation is worth exploring. We depended in vitro RANKL administration and RANKL-overexpressing (Tg-RANKL) mice to observe the effects of RANKL on ROS production, MT2 protein expression, Beclin1 expression and autophagic activity in OCPs. Spautin1 was used to investigate the relationship between Beclin1-dependent autophagy and RANKL-regulated MT2 expression. Osteoclast-targeting MT2-cDNA-AAVs were applied to assess the therapeutic effect of MT2 on Tg-RANKL-related bone loss. The results showed that RANKL promoted ROS production but reduced MT2 protein expression in OCPs. RANKL also enhanced Beclin1 expression and LC3-puncta abundance. Decreased Beclin1 expression with spautin1 blocked RANKL-increased ROS production and osteoclast differentiation and recovered RANKL-decreased MT2 expression. MT2 selective overexpression with CD11b-promoter-MT2-cDNA-AAVs attenuated ROS production and osteoclastogenesis in Tg-RANKL mice and improved bone loss. Overall, RANKL can reduce MT2 protein expression through Beclin1-dependent autophagy, thereby promoting ROS production and osteoclast differentiation; this suggests that MT2-overexpressing small molecule drugs have the potential to treat RANKL-related bone loss.

Treatment of Extraosseous Giant Cell Tumor of Bone and Calcitriol-Mediated Hypercalcemia With Denosumab in Paget Disease

Extraosseous giant cell tumor of bone (GCTB) associated with Paget disease of bone (PDB) is rare. We report a patient aged in their 70s with polyostotic PDB involving the skull, spine, and pelvis, previously treated with bisphosphonates, who presented with symptomatic hypercalcemia (calcium 14.8 mg/dL [3.7 mmol/L]; reference range [RR], 8.6-10.5 mg/dL [2.1-2.6 mmol/L]), kidney injury (creatinine 2.6 mg/dL [230 μmol/L]; RR, 0.4-1.1 mg/dL [35-97 μmol/L]), and a 17.5 cm pelvic mass. Testing showed elevated calcitriol or 1,25-dihydroxyvitamin D (1,25(OH)2D) (57-108 pg/mL [137-259 pmol/L]; RR, 18-72 pg/mL [43-173 pmol/L]), but normal parathyroid hormone and bone-specific alkaline phosphatase (BSAP), arguing against parathyroid autonomy and active osseous PDB. Histopathology showed osteoclast-like giant cells and stromal mononuclear cells without atypia, necrosis, or mitoses. A one-time dose of denosumab 120 mg resulted in normalized calcium (9.0 mg/dL [2.2 mmol/L]) and 1,25(OH)2D (24 pg/mL [57 pmol/L]) and reduced tumor size. Denosumab was continued at a dose of 60 mg every 6 months. After 20 months, calcium and 1,25(OH)2D remained normal, with no tumor regrowth, and BSAP stayed low. This is the first report of 1,25(OH)2D-mediated hypercalcemia in extraosseous GCTB. It responded well to denosumab. Long-term management options are discussed in the context of existing literature.

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.

Denosumab regimens in the treatment of giant cell tumor of bone: A systematic review with meta-analysis

BACKGROUND

Giant cell tumor of bone (GCTB) is a rare, locally aggressive neoplasm that should be treated surgically, whenever possible. This treatment approach may be linked with greater morbidity besides functional impairment. Denosumab is a human monoclonal antibody. Its administration inhibits bone resorption and has become part of the therapeutic armamentarium against GCTB, as it allows local control with a view to downstaging for a more conservative surgical procedure. However, there is no consensus in the literature regarding the optimal denosumab regimen for GCTB. Therefore, a wide discussion of denosumab regimen is necessary.

AIM

To assess the effectiveness of various therapy protocols employing denosumab in individuals with GCTB.

METHODS

A broad and systematic literature search was carried out using the PRISMA guidelines. We analyzed studies that reported skeletally mature patients with GCTB regardless of sex or ethnicity treated with denosumab. Articles with fewer than five patients and in languages except Spanish, Portuguese and English were excluded. Statistical analysis with proportion meta-analysis was performed due to the dichotomous nature of the data.

RESULTS

1005 articles were screened, of which 26 articles met the inclusion criteria and were selected, totaling 1742 patients, 51.8% women and 48.2% men, with an average of 35 years of age. Treatment with denosumab was associated with high rates of clinical benefit (CB) and imaging response (IR), without changing local recurrence rates when compared to patients treated without denosumab, regardless of the therapeutic regimen adopted and the number of doses applied. The adverse events (AE) presented were mostly mild, with the exception of a malignant transformation to osteosarcoma.

CONCLUSION

Treatment of GCTB with denosumab is effective, showing high rates of CB and IR. The AE that occurred were mostly mild. We found no differences between the articles considering the researched outcomes regardless of the therapeutic regimen adopted.

Management and surveillance of metastatic giant cell tumour of bone

Giant cell tumour of bone (GCTB) is viewed as a benign, locally aggressive primary bone tumour with metastatic potential. Current management is surgery with bone curettage or resection and systemic therapy with denosumab. Diagnosis is confirmed histologically prior to surgery, with staging for pulmonary disease, as pulmonary metastases (PM) reportedly occur in <8%. This study aimed to assess incidence, surveillance and management of PM in patients with GCTB, with histopathological review. A retrospective audit of the Oxford bone tumour registry was performed from January 2014 - October 2023. Inclusion criterion was histological confirmation of GCTB. Exclusion criteria were incomplete medical, imaging or histology records, or referral for secondary MDT opinion for diagnosis. From an initial group of 126 GCTB patients, 83 patients met the full selection criteria. Pulmonary metastases were identified in 11 patients. Three with PM were excluded on histopathological review as being giant cell rich osteosarcoma rather than metastatic GCTB. This left 8 (9.6%) patients, one had PM at presentation and seven at follow-up between 2 and 42 months. Two were histologically confirmed after cardiothoracic surgery and biopsy, six radiologically diagnosed. Three (37.5%) patients with PM have died (between 1 and 12 months after confirmed PM), five are alive with stable disease. Seven (87.5%) of patients with pulmonary disease were treated with denosumab/chemotherapy (three before, four after pulmonary diagnosis). Five (62.5%) with pulmonary disease had recurrence of local disease requiring further surgery. Local recurrence was an independent risk factor for PM on statistical analysis. GCTB may present with PM, but more commonly, metastasis occurs after surgery, presenting on surveillance and can progress. There were no distinct differences in histopathological appearance between patients with GCTB that developed PM and those that did not, therefore morphological features of the tumour cannot be currently used to predict tumour behaviour. PM can behave aggressively, necessitating identifying histological markers to recognise patients at risk of metastatic GCTB, for example, through mRNA single cell analysis. We propose GCTB patients with PM receive regular chest surveillance with PET scan and/or CT to monitor disease progression, and a multi-centre audit of GCTB outcome undertaken to further define optimal clinical management.

Preoperative denosumab combined with microwave ablation for joint preservation in advanced giant cell tumor of bone: a retrospective study

BACKGROUND

Preoperative denosumab has been an essential part of the management of giant cell tumor of bone (GCTB) which enhanced subchondral bone integrity and facilitated joint preservation surgery. However, evidence suggests that denosumab-induced sclerotic changes may potentially increase the risk of postoperative recurrence. This study evaluates the efficacy of microwave ablation (MWA) as an adjuvant to intralesional curettage following denosumab treatment in advanced GCTB.

METHODS

A retrospective review was conducted on 54 patients with extremity GCTB treated with preoperative denosumab between 2019 and 2024. 33 patients underwent curettage, while 21 patients underwent combined microwave ablation with curettage. The recurrence rates and joint preservation rates were analyzed. Functional outcomes were assessed by the Musculoskeletal Tumor Society (MSTS) score.

RESULTS

Local recurrence occurred in 14 patients, including 3 in the MWA group and 11 in the curettage-only group. In the MWA group, all recurrences were managed with repeat curettage, whereas 6 patients in the curettage-only group required extensive resection. The joint preservation rate was significantly higher in the MWA group (100%) compared to the curettage-only group (81.8%). The local recurrence rate was lower in the MWA group (14.3%) than in the curettage-only group (33.3%), with two-year local recurrence-free survival rates of 95.2% and 68.2%, respectively; however, the difference was not statistically significant (P = 0.12). Functional outcomes were comparable, with a mean MSTS score of 24.9 ± 1.33.

CONCLUSION

The preoperative denosumab combined with adjuvant MWA offers an alternative approach to enhance joint preservation in advanced GCTB, emphasizing its potential as an effective adjuvant strategy. Further large-scale studies are warranted to validate these findings and refine treatment strategies.

GIANT CELL TUMOR OF THE DISTAL RADIUS: FACTORS ASSOCIATED WITH LOCAL RECURRENCE

Objectives

To assess patient and tumor characteristics and treatment outcomes, focusing on local recurrence rates based on treatment type.

Methods

This is a retrospective review of cases of GCTB of the distal radius, identified from the databases of 74 patients in Brazilian institutions specializing in musculoskeletal tumor treatment. Data were collected from electronic and paper medical records by 18 centers between 1989 and 2021. Variables included demographic data, clinical presentation, treatment-related factors, and primary outcome (local recurrence rate).

Results

Among the 74 patients in the study, the mean age at diagnosis was 32.6 years, with a slight female predominance. Pathological fractures on presentation were observed in 15.7% of patients, and pulmonary metastasis in 1.4%. Treatment approaches were divided equally between intralesional curettage and en bloc resection. The overall local recurrence rate was 25.7% and was higher in patients treated with intralesional curettage (35.1%) compared to resection (16.2%).

Conclusions

The study confirms high recurrence risk with intralesional curettage, emphasizing the need for standardized protocols and improved surgical techniques to reduce recurrence rates and enhance outcomes for distal radius GCTB patients. Level of Evidence III; Retrospective Cohort Study.

Successful treatment of adult cherubism with a 60 mg denosumab 6-monthly regimen

Cherubism is a rare autosomal dominant skeletal dysplasia, affecting the maxilla and/or mandible. The condition typically has childhood onset, followed by progression until puberty, with subsequent regression. Cherubism lesions share histological features with giant cell tumor of bone, where high-dose monthly denosumab is an effective medical treatment. Therefore, high-dose denosumab has also been trialed in children with cherubism with positive outcomes. However, the role of denosumab in adult cherubism, particularly a lower dose and frequency, has not been established. We present the case of a 60-year-old man with cherubism, reviewed for a new 39 × 21 mm left mandibular lesion. The patient had multiple surgeries up to the age of 30 for tumors in the right maxilla and mandible. Given the impact of further surgery on his appearance and quality of life, the patient was referred to Endocrinology for consideration of medical therapy. His bone turnover markers were slightly elevated with normal calcium, phosphate, 25-OH vitamin D, and parathyroid hormone levels. A bone density scan showed lumbar spine osteopenia. He was commenced on 60 mg denosumab 6-monthly with excellent clinical and radiological responses over the next 30 months. The most recent CT mandible showed a sustained reduction in the lesion size, measuring 36 × 18 mm, with osteoid formation and improvement in cortical thinning. Surgery is no longer indicated. No adverse effects from denosumab were reported in the patient. This is the first study to report the efficacy and safety of a low-dose denosumab regimen in the management of cherubism. This treatment approach was able to prevent major surgery and minimize denosumab-related adverse effects. While the optimal treatment duration remains unclear, the patient will continue with 60 mg denosumab 6-monthly in the short-term given the favorable response. In summary, a low-dose denosumab regimen should be considered for patients with cherubism, particularly those with contraindications or preferences to avoid surgery.

Denosumab usage in atypical cemento-osseous dysplasia involving the entire mandible: a case report

BACKGROUND

Cemento-osseous dysplasia (COD) is the most common apical radiopaque lesion that develops in the tooth-bearing area. However, large, destructive lesions are rare. Herein, we report a case in which COD extended to bilateral condyles, affecting the entire mandible, and was managed with denosumab rather than surgical resection.

CASE PRESENTATION

A 45-year-old woman presented to our hospital with progressive, large, destructive COD involving the entire mandible, including bilateral condyles, and associated bony expansion, which led to facial deformity and malocclusion. The patient declined total mandible resection and opted for off-label denosumab use instead. Although rapid ossification of the osteolytic lesion was observed after 9 months of treatment, the lesion volume remained unchanged. Single-photon emission computed tomography performed at follow-up revealed stable disease without progression.

CONCLUSION

Denosumab may help prevent the progression of severe, destructive COD in patients averse to surgical intervention.

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.

Clinical Outcome of Extended Curettage with Postoperative Denosumab Administration for the Treatment of Campanacci Grade III Giant Cell Tumors of the Extremities

Purpose

To investigate the local recurrence rate, joint preservation status, and functional outcomes after extended curettage and postoperative denosumab treatment for Campanacci Grade III giant cell tumors of the extremities.

Methods

We retrospectively reviewed 23 patients with Campanacci Grade III GCTB of the extremities in our hospital between January 2017 and June 2023 who underwent extended curettage and postoperative denosumab administration alone, without preoperative denosumab treatment. Patients were followed-up for adverse events of denosumab, surgical outcomes, limb function of lesions, and local recurrence following extended curettage with postoperative denosumab.

Results

All incisions healed without deep infections or internal fixation failure. The mean age of the patients at surgery was 36.6 years, and the mean follow-up was 35.8 months (range, 6-72 months). There of the 3 patients experienced a postoperative local recurrence. The recurrence rate was found to be 13.0%. Two patients were treated with repeat intralesional surgery with no additional recurrence two years later, and the other was treated with en bloc resection and reconstruction with a vascularized fibular graft. One patient experienced knee osteoarthritis without oral analgesics. No patient developed pulmonary metastases or malignant transformation of the GCTB. The mean Musculoskeletal Tumor Society functional score at the last follow up was 27.3 30 (range, 25-29). No serious adverse events were observed after the denosumab treatment.

Conclusion

Our observations suggest that extended curettage with postoperative denosumab administration is a reasonable option for treating Campanacci Grade III giant cell tumors of the extremities. Extended curettage with adjuvant denosumab therapy results in beneficial surgical downstaging, including a less morbid surgical procedure or delayed en bloc resection. Resection should be considered when the structural integrity cannot be regained after bone grafting or bone cement filling combined with internal fixation.

Giant cell tumor of proximal femur managed by extended curettage with fibular strut allograft using long intramedullary interlocking nail: A case report and literature review

RATIONALE

We first report a unique case of proximal femoral Giant cell tumor of bone, a subtrochanteric lesion associated with femoral neck and intertrochanteric involvement. We chose a completely new surgical approach to treat the primary tumor and preserve the hip joint. No cases of this type have ever been reported.

PATIENT CONCERNS

The patient, a 26-year-old man, came to our hospital for treatment of right hip pain more than 4 months ago, had no family history of similar diseases.

DIAGNOSES

Based on the imaging results and pathology, a diagnosis of Giant cell tumor of bone was confirmed.

INTERVENTIONS

Based on the imaging grade and patients' wishes, the tumor managed by extended curettage and reconstructed with a fibular strut allograft and long intramedullary interlocking nail was used for prophylactic fixation of fractures. The patient did not undergo disuzumab.

OUTCOMES

After 40 months of follow-up, although the bone defect finally reached bone healing, the hip function was good, and the tumor did not recur, there were signs of internal fixation loosening at 12 months of the surgery.

LESSONS

For young patients with imaging grade <3 who need limb salvage, fibular strut allograft and intramedullary nail-fixation are also an alternative treatment option for hip reconstruction after tumor surgery when the lesion involves the entire proximal femur.

A Short Course of Preoperative Denosumab Injection Followed by Surgery in High-Risk Giant Cell Tumors of the Extremities: A Retrospective Study

Despite early promising results with denosumab treatment in giant cell tumor of bone (GCTB), recent studies have raised concerns about a high local recurrence rate following preoperative denosumab administration and joint preservation surgery. This retrospective study evaluated data from 25 high-risk GCT patients (Campanacci grade II or III with features like soft tissue extension, pathological fracture, minimal periarticular or subarticular bone) treated with five doses of neoadjuvant denosumab injection followed by either curettage and cementing (n = 13) or joint reconstruction with fibular graft/endoprosthesis (n = 12) between 2014 and 2019. With an average follow-up of 40 months, the study found only one patient of local recurrence. All patients were independently ambulant, with a mean MSTS score of 26.32. Subgroup analysis revealed an MSTS score of 27.76 in the joint preservation group, and 24.75 in the excision with reconstruction/prosthetic replacement group (unpaired t-test, p-value < 0.001). Five patients experienced postoperative complications, including two infections, one recurrence, one mediolateral instability in the prosthetic component, and one restriction of wrist movement. A short course of neoadjuvant denosumab, followed by curettage and cementing or wide excision with joint reconstruction/prosthetic replacement, appears to be an effective strategy for high-risk GCTB patients. This approach not only minimizes surgical morbidity but also does not increase the local recurrence rate. The short course regimen may present a cost-effective and practical option in clinical practice.

Establishment and characterization of NCC-GCTB14-C1 and NCC-GCTB15-C1: two novel patient-derived cell lines of giant cell tumor of bone

Giant cell tumor of bone (GCTB) is a rare bone tumor that is genetically characterized by a unique mutation in the H3-3A gene. Curative surgical resection is the standard treatment. Unfortunately, a considerable proportion of patients with GCTB have local recurrence and pulmonary metastasis after surgical treatment, and current chemotherapy treatments have shown non-effective. Considering the heterogeneity of the disease, patient-derived cancer models established from multiple cases are required. Therefore, we aimed to establish novel GCTB cell lines for use in preclinical studies. In this study, we successfully established two GCTB cell lines, NCC-GCTB14-C1 and NCC-GCTB15-C1. Both cell lines retained the genetic characteristics of the original tumors, constantly proliferated, and exhibited migratory activity. These cells formed spheroids with morphologically variable phenotypes. We found that they were compatible with chemosensitivity assays, and drug screening using these cell lines led to the identification of potential therapeutic candidates for GCTB. Therefore, NCC-GCTB14-C1 and NCC-GCTB15-C1 may be useful for elucidating the pathogenesis of and developing novel treatments for GCTB.

Exploring Denosumab in the Treatment of Giant Cell Tumors: Clinical Evidence and Controversies

Giant cell tumors (GCTs) are benign but locally aggressive bone neoplasms that primarily affect skeletally mature individuals. They are characterized by a tendency for recurrence and being associated with significant morbidity. Traditional treatment has focused on surgical resection; however, the role of medical therapies, such as Denosumab, a bone anti-resorptive drug, which has been Food and Drug Administration (FDA)-approved for unresectable GCTs since 2013, recently has gained prominence. Denosumab is a human monoclonal antibody that inhibits receptor activator of nuclear factor kappa B ligand (RANKL). This article aims to consolidate the current literature on Denosumab's efficacy in treating GCTs, highlighting its mechanism of action, clinical evidence, and potential complications. Clinical studies have demonstrated that Denosumab effectively reduces tumor size improving patient outcomes. Yet, some clinicians maintain concerns and reservations regarding local recurrence and malignant transformation. This review discusses the biochemical background of GCTs, current treatment guidelines, challenges, and future directions for research. Ultimately, Denosumab represents a potentially viable advancement in the management of GCTs, particularly in cases where surgical options are limited.

Efficacy and safety of JMT103 in patients with unresectable or surgically-challenging giant cell tumor of bone: a multicenter, phase Ib/II study

This was a multicenter, single-arm, open-label, phase Ib/II study (NCT04255576), aimed to evaluate the efficacy and safety of JMT103 in patients with unresectable or surgically-challenging giant cell tumor of bone (GCTB). JMT103 (2 mg/kg) was administered subcutaneously every four weeks, with loading doses on days 8 and 15. The primary endpoint was the objective tumor response rate (OTR) based on best response, defined as the proportion of patients who achieved elimination of at least 90% of the giant cells or radiologic complete or partial response per the modified Inverse Choi density/size (mICDS) or modified European Organization for Research and Treatment of Cancer (mEORTC) within 12 weeks. Secondary endpoints included objective response rate (ORR) per mICDS and mEORTC, and safety. A total of 139 patients were enrolled, and 135 were analyzed for efficacy. OTR, determined by the independent review committee (IRC) was 93.3% (95% CI 87.7-96.9). Treatment-related adverse events occurred in 90 (64.7%) patients, with hypophosphatemia and hypocalcemia being the most common. No serious treatment-related adverse events were observed. Thus, JMT103 demonstrates potential as a therapeutic option for GCTB.

Recurrent benign fibrous histiocytoma of the bone benefits from denosumab followed by malignant transformation: a case report

Benign fibrous histiocytoma of the bone (BFHB) is a rare mesenchymal tumor, representing less than 1% of all benign bone tumors. This controversial entity is characterized by a mixture of fibroblasts arranged in a storiform pattern, varying amounts of osteoclast-type giant cells and foamy macrophages. Curettage or simple resection is usually curative. However, it was reported that up to 11% of the patients suffer from relapse. Here, we report a case of malignant transformation of BFHB after long-lasting disease stabilization under denosumab therapy.

The Risk of Medication-Related Osteonecrosis of the Jaw in Children: Guidance for Antiresorptive Use in Pediatric Patients

BACKGROUND

Antiresorptive targeted cancer therapies, such as denosumab and bisphosphonates, are used in adults, but their application in pediatric cancer is more recent. Side effects such as osteonecrosis of the jaw (ONJ) observed in adults have curtailed use of these medications in the pediatric population.

PURPOSE

This study assesses the frequency of ONJ, other side effects, and the indications for use of denosumab versus bisphosphonates in pediatric subjects.

STUDY DESIGN, SETTING, SAMPLE

A retrospective cohort study of pediatric subjects who underwent bisphosphonate or denosumab therapy at our institution from 2007-2023 was conducted. Subjects aged ≥ 18 years at therapy initiation were excluded.

INDEPENDENT VARIABLE

The independent variable was antiresorptive therapy divided into 2 groups, treatment with intravenous bisphosphonates or denosumab.

MAIN OUTCOME VARIABLE(S)

Primary outcomes were development of bisphosphonate-related and denosumab-related ONJ. Secondary outcomes included additional side effects.

COVARIATES

ONJ risk factors, subject demographics, indications for use, timing, duration, and cumulative dose of antiresorptive therapy were abstracted.

ANALYSES

Univariate and bivariate statistics were computed to describe the sample and measure associations between antiresorptive therapy and outcomes. P values < .05 conferred statistical significance.

RESULTS

The sample was composed of 178 subjects with a mean age of 11.7 ± 6.1 years. There were 14 (7.9%) and 164 (92.1%) subjects treated with denosumab and bisphosphonate therapies, respectively. There were 0 cases of ONJ across all subjects. The most common indication for treatment was adjuvant targeted therapy for aggressive tumors and malignancy (39.3%) followed by osteoporosis (14.6%). Subjects treated with denosumab had higher frequencies of hypercalcemia and severe bone pain than subjects treated with bisphosphonates, 28.6% versus 1.2% (P < .001) and 14.3% versus 0.00% (P < .001), respectively.

CONCLUSION AND RELEVANCE

While invasive dental procedures are ideally performed before antiresorptive treatment, our data suggest that bisphosphonates may be used safely in the pediatric population with low concern for ONJ. Our data also demonstrated bisphosphonates may have a more tolerable side effect profile than denosumab. If the perceived benefits are similar, we recommend using bisphosphonates as first-line therapy in children while reserving denosumab for refractory cases. Future studies will help determine long-term side effects and differences in efficacies of these medications.

Denosumab combined with en bloc resection and arthrodesis for recurrent grade 3 giant cell tumor of bone in distal radius

PURPOSE

This study aimed to analyse the clinical outcomes of preoperative adjuvant denosumab therapy (PADT) combined with resection and arthrodesis for recurrent grade 3 giant cell tumor of bone (GCTB) in the distal radius.

METHODS

A retrospective study was conducted on twenty-three patients (8 males, 15 females) who were treated with the adjuvant denosumab combined with en bloc resection (EBR) and arthrodesis for biopsy confirmed recurrent Campanacci III giant cell tumor of bone in the distal radius between January 2015 and December 2022. All 23 patients were treated with wrist arthrodesis reconstruction using autogenous free iliac crest bone graft (ICBG), bridging plate and screws. The local control, metastasis and overall survival were evaluated during the follow-up period. Functional outcomes were evaluated using the Disabilities of the Arm, Shoulder and Hand (DASH) score, Musculoskeletal Tumor Society Score (MSTS-87 and MSTS-93), and grip strength in the follow-up period. Additionally, all surgical or denosumab-related complications that occurred were recorded in this study.

RESULTS

Twenty-three patients were included in this retrospective study and no patients were lost in the follow-up period. The average patient age was 32.5 ± 10.2 years (range, 19-53 years) and the mean follow-up time was 35.5 ± 18.4 months (range, 13-72 months). The average tumor length was 71.7 ± 8.7 mm (range, 50 to 85 mm) and bone reconstruction length was 78.5 ± 8.5 mm (range, 60 to 90 mm). Four patients (17.4%) had secondary local recurrence after reoperation and two patients had (8.7%) multiple recurrences. One patient (4.3%) was deceased in the last follow-up due to multiple metastases. The estimated 5-year recurrence-free survival rate was 81.3% and 5-year metastasis-free survival rate was 95.7%. The mean union time was 8.5 ± 1.9 (6-12) months and the overall survivorship of the allograft was 82.7% (21/23) at an average 35 month follow-up. The average MSTS-87 and MSTS-93 scores were 27.8 ± 1.6 (range, from 23 to 30) and 91.5 ± 5.0 (range, from 76 to 100), and the average DASH score was 8.9 ± 3.2 (range, from 3 to 15), respectively. The average grip strength was 64.6 ± 15.7% (range, from 30 to 95%) of the uninvolved side. Eight patients (34.7%) had at least one complication in the follow-up time. Two autografts (8.7%) were removed due to local recurrence and bone nonunion, and the average autograft survival time was 32.8 ± 18.5 months (range, 12 to 72 months).

CONCLUSIONS

Preoperative adjuvant denosumab therapy (PADT) combined with en bloc resection and arthrodesis is a promising method for the treatment of recurrent Campanacci III GCTB in distal radius with acceptable short-term local control and functional satisfaction.

LEVEL OF EVIDENCE

level IV Therapeutic.

Combined preoperative denosumab and adjuvant microwave ablation for high-risk giant cell tumor of bone: a retrospective study in a single center

BACKGROUND

Giant cell tumor of bone (GCTB) is a locally aggressive neoplasm with a high propensity for recurrence following intralesional curettage. The introduction of denosumab, a RANKL inhibitor, has shown potential in facilitating joint-sparing surgery. However, concerns exist regarding its impact on local recurrence rates. This study aimed to evaluate the efficacy and safety of combined preoperative denosumab with adjuvant microwave ablation (MWA) for the treatment of high-risk GCTB.

METHODS

We conducted a retrospective review of 19 patients with high-risk GCTB who underwent preoperative denosumab treatment followed by curettage and adjuvant MWA. The primary outcome measure was the local recurrence rate, with secondary outcomes including functional status assessed by the Musculoskeletal Tumor Society (MSTS) score and safety profile of the treatment.

RESULTS

In this retrospective analysis, we evaluated the outcomes of 19 patients with high-risk GCTB treated with preoperative denosumab and adjuvant MWA. The median follow-up duration was 33.1 months, 3 patients (15.8%) experienced local recurrence at a median of 21.6 months postoperatively and the local recurrence-free survival was 81.2% at two years. Notably, no patient developed lung metastasis, and all recurrences were successfully managed with repeat curettage and MWA, with a mean MSTS score of 27.3. No patient required joint replacement due to tumor recurrence, resulting in a 100% joint preservation rate.

CONCLUSION

The combination of preoperative denosumab and adjuvant MWA is a feasible and effective strategy for the management of high-risk GCTB, providing effective local control with preserved joint function. This approach may offer a surgical alternative for young patients where joint preservation is paramount.

Denosumab Re-Challenge and Long-Term Efficacy for Aneurysmal Bone Cyst of the Spine: Enhanced Treatment Algorithm

Background/Objective: Surgical treatment of aneurysmal bone cysts (ABCs) can be challenging, especially in the spine. Non-surgical treatments such as with denosumab have shown promising results in different osteolytic pathologies. This retrospective observational study aimed to evaluate the long-term clinical and radiologic response of patients with ABCs of the mobile spine treated with denosumab and propose an updated treatment algorithm. Methods: Six patients with relapsed and symptomatic ABCs of the mobile spine were treated with denosumab (120 mg subcutaneously on days 1, 8, 15, 29, and every 4 weeks thereafter) between 2012 and 2023. Disease assessments were conducted using CT and MRI at 3, 6, 9, and 12 months post-treatment. Clinical data, including pain levels, symptoms, and adverse events, were documented from patients' charts. Results: Patients underwent an initial phase of treatment with denosumab, receiving a mean of 22 administrations (range 13-42) over a median follow-up period of 41 months (range 15-98 months). Clinical improvement was observed in all patients after 4 weeks of treatment, and all patients demonstrated a radiological response after 12-24 weeks on denosumab. Three patients were progression-free after discontinuing denosumab following 13, 15, and 42 administrations, respectively. At the last follow-up, after 38, 43, and 98 months, these patients remained stable without relapse of the disease. Three patients had a relapse of disease after denosumab; two of them underwent denosumab re-challenge, while one patient received one mesenchymal stem cells (MSCs) injection. All patients showed clinical and radiological improvement and were resulted to be disease-free at the last follow-up. Conclusions: This study demonstrates the long-term efficacy and safety of denosumab in treating ABCs of the mobile spine, as well as the potential of re-challenge in managing recurrence. A treatment algorithm is proposed, positioning denosumab as a viable therapeutic option after other local treatments. Careful patient selection, monitoring, and further research are necessary to optimize denosumab use for ABCs.

Interferons as Neoadjuvant Chemotherapy for Giant Cell Tumor: A Hospital-Based Prospective Pilot Study

Introduction Neoadjuvant chemotherapy is now considered an effective way to treat Campanacci grade 2 and 3 giant cell tumors (GCTs). Assessment of these drugs is essential clinically, radiologically, and pathologically. This study analyzes the early results of angiogenesis inhibitors (interferons) in the aggressive GCT of bone.

Methodology A prospective pilot study was conducted from January 2021 to July 2022 including eight biopsy-proven GCT patients subjected to interferon therapy. Radiological assessment was done with changes on plain radiograph, computerized tomography scan, and magnetic resonance imaging. Histopathological examination was done by changes in the biopsy and resected segment.

Results Out of the eight patients included in the study, 26% (n = 3) were males and 62% (n = 5) were females, with mean age of the patients being 24.6 ± 8.48 years (range: 22–38). There was significant reduction of the size of swelling (p-value: 0.049), significant reduction in Visual Analog Scale score (p-value: 0.011), significant decrease in swelling size on radiograph (p-value: 0.012), significant marginal sclerosis (p-value: 0.001), significant neocortex formation on radiographs (p-value: 0.001), significant result in and osteoid formation (p-value: 0.001) on histology. Whereas Campanacci grade on plain radiographs, number of viable cells, and number of viable stromal cell were not statistically different in comparison with pretherapy and posttherapy status.

Conclusion Interferon therapy in a GCT has potential beneficiary effect in terms of clinical, radiological, and pathological outcomes. It might prove to be an effective alternative to standard neoadjuvant chemotherapy in the management of aggressive GCT of bones.

Level of Evidence III.

Multifocal Giant Cell Tumor of the Nasal Fossa: Case Report and Literature Review

Giant cell tumors of bone (GCT) are rare soft tissue tumors, that account for 3%-5% of primary bone tumors with <2% occurring in the head and neck. The nasal cavity is a highly unusual site of presentation. We reviewed 15 cases of GCT of nasal cavity and paranasal sinuses. We add 1 case to the literature. The case herein reported, appears to be the second nasal fossa GCT described in the literature and the first documented case with multifocal localization. A case of multifocal GCT of the nasal cavity is described. Although rare in the general population, GCT should be included among the possibilities in the differential diagnosis when evaluating tumors of the head and neck. Management of this particular tumor remains challenging; surgical removal is still the gold standard treatment, preferring a minimally invasive trans-nasal approach to reduce intra and post-operative morbidity. Laryngoscope, 134:2774-2778, 2024.

Keratin-Positive Giant Cell-Rich Tumor: A Review and Update

Keratin-positive giant cell-rich tumor (KPGCT) is an extremely rare and recently described mesenchymal neoplasm that occurs in both soft tissue and bone, frequently found in young women. It has locally recurrent potential if incompletely excised but low risk for metastasis. KPGCT is histologically similar to conventional giant cell tumors of soft tissue but shows the presence of keratin-positive mononuclear cells. Interestingly, KPGCT also shares some morphological features with xanthogranulomatous epithelial tumors. These two tumors have recently been shown to harbor an HMGA2-NCOR2 fusion, arguing in favor of a single entity. Surgery is the treatment of choice for localized KPGCT. Therapeutic options for advanced or metastatic disease are unknown. This review provides an overview of the current knowledge on the clinical presentation, pathogenesis, histopathology, and treatment of KPGCT. In addition, we will discuss the differential diagnosis of this emerging entity.

Giant Cell Tumor of Soft Tissue: An Updated Review

Giant cell tumor of soft tissue (GCTST) is a locally aggressive mesenchymal neoplasm of intermediate malignancy that predominantly occurs in the superficial soft tissue of the extremities. It is histologically similar to a giant cell tumor of bone (GCTB) and shows a mixture of round to oval mononuclear cells and osteoclast-like multinucleated giant cells. Currently, immunohistochemistry plays a very limited role in the diagnosis of GCTST. Primary or secondary malignant GCTST has recently been described and tumors exhibiting high-grade histological features demonstrate higher rates of distant metastasis. GCTST lacks the H3-3A gene mutations that are identified in the vast majority of GCTBs, suggesting a different pathogenesis. Surgery is the standard treatment for localized GCTST. Incomplete surgical resection is usually followed by local recurrence. Radiation therapy may be considered when the close proximity of critical structures prevents microscopically negative surgical margins. The systemic treatment options for advanced or metastatic disease are very limited. This review provides an updated overview of the clinicoradiological features, pathogenesis, histopathology, and treatment for GCTST. In addition, we will discuss the differential diagnosis of this peculiar neoplasm.

Management of RANKL-mediated Disorders With Denosumab in Children and Adolescents: A Global Expert Guidance Document

CONTEXT

Denosumab is an effective treatment for many receptor activator of nuclear factor kappa-B ligand (RANKL)-mediated disorders but there are potential safety considerations and limited data to guide its use in children and adolescents.

OBJECTIVE

This document seeks to summarize the evidence and provide expert opinion on safe and appropriate use of denosumab in pediatric RANKL-mediated disorders.

PARTICIPANTS

Ten experts in pediatric bone and mineral medicine from 6 countries with experience in the use of denosumab participated in the creation of this document.

EVIDENCE

Data were sourced from the published literature, primarily consisting of case reports/series and review articles because of the lack of higher level evidence. Expert opinion of the authors was used substantially when no published data were available.

CONCLUSION

Denosumab is an effective treatment for RANKL-mediated disorders in children and adolescents but is often not curative and, in some cases, is best used in conjunction with surgical or other medical treatments. Careful multidisciplinary planning is required to define the goals of treatment and expert oversight needed to manage the risk of mineral abnormalities. Substantive, collaborative research efforts are needed to determine optimal treatment regimens and minimize risks.

The Evaluation and Management of Lung Metastases in Patients with Giant Cell Tumors of Bone in the Denosumab Era

Giant cell tumor of bone (GCTB) is characterized by uncertain biological behavior due to its local aggressiveness and metastasizing potential. In this study, we conducted a meta-analysis of the contemporary literature to evaluate all management strategies for GCTB metastases. A combination of the terms "lung metastases", "giant cell tumor", "bone", "treatment", and "oncologic outcomes" returned 133 patients meeting our inclusion criteria: 64 males and 69 females, with a median age of 28 years (7-63), at the onset of primary GCTB. Lung metastases typically occur at a mean interval of 26 months (range: 0-143 months) after treatment of the primary site, commonly presenting as multiple and bilateral lesions. Various treatment approaches, including surgery, chemotherapy, radiotherapy, and drug administration, were employed, while 35 patients underwent routine monitoring only. Upon a mean follow-up of about 7 years (range: 1-32 years), 90% of patients were found to be alive, while 10% had died. Death occurred in 25% of patients who had chemotherapy, whereas 96% of those not treated or treated with Denosumab alone were alive at a mean follow-up of 6 years (range: 1-19 years). Given the typically favorable prognosis of lung metastases in patients with GCTB, additional interventions beyond a histological diagnosis confirmation may not be needed. Denosumab, by reducing the progression of the disease, can play a pivotal role in averting or delaying lung failure.

Current Concepts in the Treatment of Giant Cell Tumor of Bone: An Update

Curettage is recommended for the treatment of Campanacci stages 1-2 giant cell tumor of bone (GCTB) in the extremities, pelvis, sacrum, and spine, without preoperative denosumab treatment. In the distal femur, bone chips and plate fixation are utilized to reduce damage to the subchondral bone and prevent pathological fracture, respectively. For local recurrence, re-curettage may be utilized when feasible. En bloc resection is an option for very aggressive Campanacci stage 3 GCTB in the extremities, pelvis, sacrum, and spine, combined with 1-3 doses of preoperative denosumab treatment. Denosumab monotherapy once every 3 months is currently the standard strategy for inoperable patients and those with metastatic GCTB. However, in case of tumor growth, a possible malignant transformation should be considered. Zoledronic acid appears to be as effective as denosumab; nevertheless, it is a more cost-effective option. Therefore, zoledronic acid may be an alternative treatment option, particularly in developing countries. Surgery is the mainstay treatment for malignant GCTB.

The Effectiveness of Denosumab in Middle Eastern Patients With Giant Cell Tumor of the Bone: A Single-Center, Retrospective Study

BACKGROUND

Giant cell tumor of the bone (GCTB) is an aggressive benign tumor, which constitutes 5% of all primary bone tumors. Denosumab, a receptor activator of nuclear factor κB ligand monoclonal antibody, inhibits osteoclast-induced bone destruction and has demonstrated promising results in patients with GCTB. However, the long-term efficacy of the drug has not been extensively studied, especially in the Middle East.

METHODOLOGY

In this study, we retrospectively analyzed the five-year progression-free survival (PFS) in patients with GCTB at a single Saudi center. PFS was defined as the time from diagnosis until disease progression, relapse, or death. Events were censored after five years from diagnosis.

RESULTS

Sixty-two patients with GCTB were included in the study. The median age at diagnosis was 31.16 years, and 38 (61.3%) patients were female. Twenty-nine patients (46.8%) received denosumab during the study period. The median duration of denosumab treatment was 5.06 months, and the median number of cycles was 6. The median PFS was not reached, and the five-year PFS rate was 60.3%. Age, gender, body mass index, performance status at presentation, and tumor location had no impact on five-year PFS. Denosumab treatment prolonged PFS; however, this was not statistically significant compared to non-denosumab patients (P = 0.603).

CONCLUSIONS

Denosumab does not seem to provide superior long-term outcomes compared to surgery alone. Although our findings are generally consistent with other studies in the literature, larger long-term studies are needed to confirm our findings.

Precision Oncology in Soft Tissue Sarcomas and Gastrointestinal Stromal Tumors

Soft tissue sarcomas (STSs), including gastrointestinal stromal tumors (GISTs), are mesenchymal neoplasms with heterogeneous clinical behavior and represent broad categories comprising multiple distinct biologic entities. Multidisciplinary management of these rare tumors is critical. To date, multiple studies have outlined the importance of biological characterization of mesenchymal tumors and have identified key molecular alterations which drive tumor biology. GIST has represented a flagship for targeted therapy in solid tumors with the advent of imatinib which has revolutionized the way we treat this malignancy. Herein, the authors discuss the importance of biological and molecular diagnostics in managing STS and GIST patients.

GIANT CELL TUMOR OF BONE: A MULTICENTER EPIDEMIOLOGICAL STUDY IN BRAZIL

Introduction

Giant cell tumor of bone (GCTB) mainly affects young adults' long bone epiphyses, threatening bone strength and joint function. Surgery is the primary treatment, although post-surgery recurrence is significant. This study analyzes patient profiles, treatments, and outcomes for GCTB in Brazil.

Methods

We retrospectively assessed local recurrence, metastasis, and treatment approaches in 643 GCTB patients across 16 Brazilian centers (1989-2021), considering regional differences.

Results

5.1% (n=33) developed pulmonary metastases, 14.3% (n=92) had pathological fractures, and the local recurrence rate was 18.2% (n=114). Higher rates of pulmonary metastases (12.1%) and advanced tumors (Campanacci III, 88.9%) were noted in lower-income North and Northeast regions. The North also had more pathological fractures (33.3%), extensive resections (61.1%), and amputations (27.8%). These regions faced longer surgical delays (36-39 days) than the South and Southeast (27-33 days).

Conclusions

Our findings corroborate international data, underscoring regional disparities in Brazil that may lead to worse outcomes in disadvantaged areas. This highlights the need for improved orthopedic oncology care in Brazil's economically and structurally challenged regions. Level of Evidence III; Retrospective Cohort.

Could MRONJ Be Related to Osimertinib Monotherapy in Lung Cancer Patients after Denosumab Suspension?

BACKGROUND

Medication-related osteonecrosis of the jaws is the most frequent complication in patients treated or in therapy with antiresorptive/antiangiogenetic drugs. The list of medications possibly related to MRONJ onset is constantly growing; we aimed to report on a third-generation epidermal growth factor receptor tyrosine kinase inhibitor (Osimertinib) as possibly responsible for bilateral maxillary necrosis onset in the herein-described case.

METHODS

In June 2023, an oncologic patient with two different maxillary bone exposures was referred to our attention. His medical history revealed a two-year Denosumab regimen along with Osimertinib, the latter not suspended before teeth extractions. The clinicians performed a sequestrum removal and bone debridement after three cycles of antibiotic therapy.

RESULTS

Histologic examinations confirmed the clinical diagnosis of MRONJ excluding a metastatic occurrence, while complete mucosal healing was achieved after 15 days.

CONCLUSIONS

The patient suspended Denosumab for more than six months before teeth extraction for MRONJ prevention; hence, failure to discontinue Osimertinib led us to consider it a possible etiological factor. From a literature analysis, only one case has already been published reporting a possible Osimertinib-related occurrence of MRONJ in lung cancer patients. Our case is a further report that could be intended as an alert both for oncologists and dentists to share decisions about the oral management of such patients together, also informing them about this possible risk. Also, this report could trigger in the scientific community the necessity to evaluate further guidelines for similar doubtful cases in which the drug interaction, the mono-suspension, and the possible removable prosthesis-related additional trauma should be considered causes or con-causes.

Diagnosis and monitoring denosumab therapy of giant cell tumors of bone: radiologic-pathologic correlation

OBJECTIVE

To determine the value of CT and dynamic contrast-enhanced (DCE-)MRI for monitoring denosumab therapy of giant cell tumors of bone (GCTB) by correlating it to histopathology.

MATERIALS AND METHODS

Patients with GCTB under denosumab treatment and monitored with CT and (DCE-)MRI (2012-2021) were retrospectively included. Imaging and (semi-)quantitative measurements were used to assess response/relapse. Tissue samples were analyzed using computerized segmentation for vascularization and number of neoplastic and giant cells. Pearson's correlation/Spearman's rank coefficient and Kruskal-Wallis tests were used to assess correlations between histopathology and radiology.

RESULTS

Six patients (28 ± 8years; five men) were evaluated. On CT, good responders showed progressive re-ossification (+7.8HU/month) and cortical remodeling (woven bone). MRI showed an SI decrease relative to muscle on T1-weighted (-0.01 A.U./month) and on fat-saturated T2-weighted sequences (-0.03 A.U./month). Time-intensity-curves evolved from a type IV with high first pass, high amplitude, and steep wash-out to a slow type II. An increase in time-to-peak (+100%) and a decrease in Ktrans (-71%) were observed. This is consistent with microscopic examination, showing a decrease of giant cells (-76%), neoplastic cells (-63%), and blood vessels (-28%). There was a strong statistical significant inverse correlation between time-to-peak and microvessel density (ρ = -0.9, p = 0.01). Significantly less neoplastic (p = 0.03) and giant cells (p = 0.04) were found with a time-intensity curve type II, compared to a type IV. Two patients showed relapse after initial good response when stopping denosumab. Inverse imaging and pathological findings were observed.

CONCLUSION

CT and (DCE-)MRI show a good correlation with pathology and allow adequate evaluation of response to denosumab and detection of therapy failure.

Denosumab combined with precision radiotherapy for recurrent giant cell tumor of the thoracic spine: a case report and literature review

Giant cell tumors of the spine have a high recurrence rate owing to their special anatomical site; hence, further treatment after recurrence is very challenging. Achieving effective tumor control and improving the long-term quality of life of the patients are the main treatment purposes to consider for recurrent giant cell tumors of the spine. A patient showing giant cell tumor recurrence of the thoracic spine after curettage received denosumab combined with precision radiotherapy, through which the tumor gained good control and the patient could regain normal functioning. A review of the relevant literature suggested that denosumab combined with radiotherapy is an effective new approach for the treatment of recurrent giant cell tumors of the spine.

Human Chorionic Gonadotropin Regulates the Smad Signaling Pathway by Antagonizing TGF-β in Giant Cell Tumor of Bone

BACKGROUND

Giant cell tumor of bone (GCTB) is a locally aggressive bone tumour aggravated by stromal cell proliferation and metastasis.

OBJECTIVE

We investigated the mechanism of action of human chorionic gonadotropin (HCG) in mediating GCTB proliferation and invasion.

METHODS

The expression of HCG was quantified using quantitative real-time PCR. After the primary stromal cells were isolated and identified, the function of HCG in GCTB was estimated using the cell counting kit-8, flow cytometry, scratch experiment, transwell assay, Western blot, and immunofluorescence. Moreover, the mechanism of HCG was assessed through western blotting.

RESULTS

HCG expression was decreased in clinical tissue samples from patients with GCTB. We validated that HCG repressed stromal cell proliferation, migration, invasion, autophagy, and epithelial- mesenchymal transition (EMT) and promoted cell apoptosis in GCTB. We also verified that HCG repressed the autophagy and EMT of stromal cells through the Smad signaling axis in GCTB. HCG inhibited the transduction of the Smad signaling pathway by restraining the binding of the TGF-β II receptor to ligand Activin A.

CONCLUSION

HCG restrained the Smad signaling pathway by antagonizing TGF-β signaling in GCTB. HCG may serve as a useful patent to treat GCTB.

Denosumab Induces Neoplastic Stromal Cell Apoptosis Via p62 Downregulation Dependent on Autophagy Pathway in Giant Cell Tumour of Bone

BACKGROUND

As the only humanized monoclonal antibody against receptor activator of nuclear factor-κB ligand (RANKL) for giant cell tumour of bone (GCTB) therapy, denosumab has limited antitumour effect on neoplastic stromal cells. Nevertheless, its mechanism of action has not yet been clarified. A previous study has revealed that p62 may play an important role in the antitumour activity of denosumab.

OBJECTIVE

The study aimed to investigate if the mechanism by which denosumab inhibits GCTB neoplastic stromal cells growth is via p62 modulation and other related mechanisms.

METHODS

p62 expression before and after denosumab therapy was analysed by RT‒qPCR, western blot, ELISA, and immunohistochemical assays. Two primary neoplastic stromal cells were isolated from fresh GCTB tumour tissue (L cell) and metastatic tissue (M cell). Cell proliferation, migration, apoptosis, and autophagy were investigated in p62 knockdown neoplastic stromal cells transfected by short hairpin RNA lentivirus in vitro. Tumor growth was evaluated in the chick chorioallantoic membrane model in vivo.

RESULTS

p62 expression was found to be downregulated following denosumab therapy. The patients with a decrease in p62 expression had lower recurrence-free survival rates. The proliferation of M cells was not inhibited by denosumab therapy, but it was restored by p62 knockdown. Moreover, p62 knockdown inhibited tumour growth in vivo. Denosumab induced M cell apoptosis and arrested the cell cycle at the G1/G0 transition and these effects were also enhanced by p62 knockdown. Autophagic flux assays revealed p62 modulation to be dependent on autophagy following denosumab incubation.

CONCLUSION

Denosumab induced neoplastic stromal cells apoptosis via p62 downregulation dependent on autophagy pathway. The combination of p62 and RANKL knockdown might be a better strategy than RANKL knockdown alone for GCTB targeted therapy.

Surgical Strategy for Recurrent Giant Cell Tumor in the Thoracolumbar Spine

OBJECTIVE

Recurrent giant cell tumor (RGCT) of the spine represents a clinical challenge for surgeons, and the treatment strategy remains controversial. This study aims to describe the long-term follow-up outcomes and compare the efficacy of en bloc spondylectomy versus piecemeal spondylectomy in treating RGCT of the thoracolumbar spine.

METHODS

A total of 32 patients with RGCT of the thoracolumbar spine treated from June 2012 to June 2019 were retrospectively reviewed. A total of 15 patients received total en bloc spondylectomy (TES) with wide or marginal margin while 17 patients received total piecemeal spondylectomy (TPS) with intralesional margin. Postoperative Eastern Cooperative Oncology Group Performance Score (ECOG-PS), Frankel classification and recurrence-free survival (RFS) were evaluated after surgery. Survival curves were estimated by the Kaplan-Meier method and differences were analyzed with the log-rank test. Multivariate analysis was performed with Cox regression to identify the independent prognostic factors affecting RFS.

RESULTS

During a median follow-up of 41.9 ± 17.5 months, all patients with compromised neurologic functions exhibit significant improvement, with the mean ECOG-PS decreasing from 1.5 ± 1.3 to 0.13 ± 0.3 (p < 0.05). Among the 17 patients treated with TPS, eight patients developed local recurrence after a median time of 15.9 ± 6.4 months and four patients died from progressive disease. On the other hand, local recurrence were well managed with TES, since only one out of 15 patients experienced local relapse and all patients are alive with satisfied function at the latest follow-up. The median RFS for patients receiving TES and TPS are 75.0 months (95% CI: 67.5-82.5 m) and 38.3 months (95% CI: 27.3-49.3 m) respectively (p = 0.008). Multivariate analysis shows that the Ki67 index (p = 0.016), resection mode (p = 0.022), and denosumab (p = 0.039) are independent risk factors affecting RFS.

CONCLUSIONS

TES with wide/marginal margin should be offered to patients with RGCT whenever feasible, given its long-term benefits in local control and symptom alleviation. Additionally, patients with lower Ki67 index and application of denosumab tend to have a better prognosis.

Denosumab for an inoperable giant cell tumour of the ischial bone

Giant cell tumour of bone is a benign, locally aggressive osteolytic tumour that typically affects skeletally mature young individuals. It predominantly emerges within the metaphysis, extending towards the epiphysis of long bones, while occurrences in flat bones are exceptionally rare. We present a case of a woman in her late 20s who presented with a large right ischial mass. A biopsy confirmed the mass as a giant cell tumour. The tumour extended to the acetabulum, and due to the potential risk of significant bleeding and contamination during en bloc excision, a prudent approach involved initiating denosumab therapy, a monoclonal antibody targeting receptor activator of nuclear factor-κB ligand therapy, before proceeding with radical surgery. Denosumab therapy successfully rendered a previously inoperable tumour favourable for surgical intervention. We went on to perform a type 2 and 3 internal hemipelvectomy, followed by a reconstruction with a hip endoprosthesis replacement.

Denosumab for giant cell tumors of bone from 2010 to 2022: a bibliometric analysis

Giant cell tumors of the bone (GCTB) are considered moderately malignant bone tumors. Denosumab, as a neoadjuvant therapy, provides new possibilities for treating GCTB. However, even after multiple studies and long-term clinical trials, there are limitations in the treatment process. Research data and Medical Subject Headings terms related to denosumab and GCTB were collected from January 2010 to October 2022 using the Web of Science and MeSH ( https://meshb.nlm.nih.gov ) browsers. These data were imported into CiteSpace and VOSviewer softwares for bibliometric analysis. Overall, 445 publications on denosumab and GCTB were identified. Over the last 12 years, the growth rate of the total number of publications has remained relatively stable. The USA published the highest number of articles (83) and had the highest centrality (0.42). Amgen Inc. and Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) First Ortoped Rizzoli were identified as the most influential institutions. Many authors have made outstanding contributions to this field. Lancet Oncology had the highest journal impact factor (54.433). Local recurrence and drug dosage are current research hotspots, and future development trends will mainly focus on prognostic markers of GCTB and the development of new therapies. Further research is required to analyze denosumab's safety and efficacy and understand its local recurrence of GCTB, to identify the optimal dose. Future progress in this field will likely focus on exploring new diagnostic and recurrence markers to monitor disease progression and examine new therapeutic targets and treatment strategies.

Management of a rare mandibular giant cell tumor of bone by neoadjuvant denosumab therapy and surgery: A 4-year follow-up case report

INTRODUCTION

Giant cell tumor of bone (GCTB) is a very rare tumor encountered in the jaws and its histology is quite similar to the more common giant cell granuloma of the jaws (GCGJ). These two entities can be easily confused in maxillofacial region. They are classically managed surgically, but in some localizations and in specific medical-surgical contexts, neoadjuvant therapy with denosumab may be indicated. This report tends to reinforce existing evidence in favor of the use of a neoadjuvant approach, particularly for localization of GCTB in the orofacial region.

PRESENTATION OF CASE

This is a 57-year-old female patient, an alcoholic smoker, in whom a voluminous mandibular radiolucent lesion was discovered during a routine X-ray by her dentist. After medical imaging assessment and incisional biopsy, diagnosis of GCTB was established. A neoadjuvant denosumab therapy was proposed first followed by a secondary surgical curettage. After 4 years' follow-up, complete healing was observed with no recurrence of the lesion.

DISCUSSION

Surgical management of aggressive GCTB is risky particularly in localizations involving the sacrum, spine or craniofacial skeleton with a high residual recurrence rate. The use of denosumab to stop tumor progression and facilitate secondary excision surgery is a recent approach that is now well documented in the literature showing promising results with a low rate of side effects.

CONCLUSION

This case of mandibular GCTB is to our knowledge the unique case described in this localization and treated by denosumab neoadjuvant therapy followed by surgery with a 4-year follow-up showing a complete healing.

Revisiting En Bloc Resection Versus Piecemeal Resection for the Treatment of Giant Cell Tumor of the Spine

OBJECTIVE

Surgery for spinal giant cell tumors (GCTs) is challenging because these tumors often exhibit a poor clinical course owing to their locally aggressive features. This study aimed to investigate the prognostic factors of GCT recurrence in the spine by focusing on surgical factors.

METHODS

We retrospectively reviewed patients who underwent surgery for spinal GCTs between January 2005 and December 2016. Using the Kaplan-Meier method, surgical variables were evaluated for disease-free survival (DFS). Since tumor violation may occur at the pedicle during en bloc resection of the spine, it was further analyzed as a separate variable. Multivariate Cox proportional hazard regression analysis was performed for other clinical and radiographic variables. A total of 28 patients (male:female = 8:20) were included. The mean follow-up period was 90.5 months (range, 15-184 months).

RESULTS

Among the 28 patients, gross total resection (GTR) was the most important factor for DFS (P = 0.001). Any form of tumor violation was also correlated with DFS (P = 0.049); however, use of en bloc resection technique did not show a significant DFS gain compared to piecemeal resection (P = 0.218). In the patient group that achieved GTR, the mode of resection was not a significant factor for DFS (P = 0.959). In the multivariate analysis, the extent of resection was the only significant variable that affected DFS (P = 0.016).

CONCLUSIONS

Conflicting results on tumor violation from univariate and multivariate analyses suggest that GTR without tumor violation should be the treatment goal for spinal GCTs. However, when tumor violation is unavoidable, it would be important to prioritize GTR over adhering to en bloc resection.

Proximal Tibia Tumour Location and Curettage Are Major Risk Factors of Local Recurrence in Giant Cell Tumour of Bone

Giant cell tumour of bone (GCTB) is one of the most common local aggressive tumourous lesions with a wide variety of biological behaviour. However, there are no clear indicative criteria when choosing the type of procedure and the complication rates remain high, especially in terms of local recurrence. The purpose of the study was to (1) identify the main risk factors for local recurrence, (2) evaluate the recurrence-free survival in dependence on neoadjuvant denosumab use and the type of procedure, and (3) compare the functional outcomes after curettage and en bloc resection. The group included 102 patients with GCTB treated between 2006 and 2020. The mean age of patients was 34.4 years (15-79). The follow-up period was 8.32 years (2-16) on average. Local recurrence occurred in 14 patients (29.8%) who underwent curettage and in 5 patients (10.6%) after en bloc resection. Curettage was shown to be a factor in increasing recurrence rates (OR = 3.64 [95% CI: 1.19-11.15]; p = 0.023). Tibial location was an independent risk factor for local recurrence regardless of the type of surgery (OR = 3.22 [95% CI: 1.09-9.48]; p = 0.026). The recurrence-free survival rate of patients treated with resection and denosumab was higher compared to other treatments at five years postoperatively (p = 0.0307). Functional ability and pain as reported by patients at the latest follow-up were superior after curettage compared to resection for upper and lower extremity (mean difference: -4.00 [95% CI: -6.81 to -1.18]; p < 0.001 and mean difference: -5.36 [95% CI: -3.74 to -6.97]; p < 0.001, respectively). Proximal tibia tumour location and curettage were shown to be major risk factors for local recurrence in GCTB regardless of neoadjuvant denosumab treatment. The recurrence-free survival rate of patients treated with resection and denosumab was higher compared to other treatments. The functional outcome of patients after curettage was better compared to en bloc resection.

Maxillary Sinusitis Induced by Medication-Related Osteonecrosis of the Jaw

The involvement of maxillary sinuses in patients taking bone-related medications has not been comprehensively considered in the literature, mostly dental. Considering the fact that paranasal sinuses are often captured in dental radiographs, it is incumbent upon dental practitioners to recognize abnormal presentations in the paranasal sinuses to ensure the appropriate management of medication-related osteonecrosis of the jaw (MRONJ). We present a case of a giant cell tumor (GCT) with atypical chronic sinusitis manifestation leading to MRONJ.