RANKL, denosumab, and giant cell tumor of bone

Denosumab combined with microwave ablation excisional scraping for giant cell tumor of the thoracic spine: a case report and literature review

Denosumab has recently become an important part of the treatment regime for spinal giant cell tumors of the bone (GCTB). Its use has significantly reduced the risk of surgery and postoperative complications in patients with spinal GCTB. However, the use of denosumab has not yet been optimized to reap the maximum benefits. Here, we have reported the case of a patient who was treated with denosumab in combination with excision and scraping for GCTB of the T10 vertebrae, which achieved good tumor control and no recurrence at the 2-year postoperative follow-up. We have also reviewed the case in the light of relevant literature as well as presented our ideas and recommendations for the optimal use of denosumab.

The successful control of multiple pulmonary metastasis from giant cell tumor of bone by monthly denosumab administration: A case report

Giant cell tumor of bone (GCTB) is a locally aggressive benign neoplasm that is associated with a large biological spectrum ranging from latent benign to highly recurrent and occasionally metastatic tumor. In this article, we present a case of a 37-year-old woman who presented with fracture at the distal femur due to GCTB. Bone segment resection and reconstruction were done, and histopathology showed tumor features for GCTB. Later, multiple lung metastasis was found 22 months post-operation, which was verified by biopsy. Then systemic denosumab therapy with different intervals (1-month and 2-month) was tried as the treatment. It was clarified that monthly denosumab administration, instead of 2-month interval, was required to control the progression of the unresectable multiple lung metastasis from GCTB, which could be a choice for the future treatment of these patients.

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.

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.

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.

The Role of Denosumab in the Treatment of Primary Tumors of Bone

Many hand surgeons treat benign bone tumors without referral to orthopedic oncologists. However, there have been considerable advances in medical therapy for some of these tumors, with which hand surgeons may not be as familiar. This review focuses on the mechanism and uses of denosumab in the treatment of benign tumors of bone. Although the hand surgeon may not be directly prescribing this therapy, they are often the only physician treating the patient for these conditions. As such, awareness regarding the use of this therapy in reducing pain, decreasing tumor volume, and treatment of potential lung metastases is critical to those taking on these cases without the support of an orthopedic oncologist. This article aims to familiarize hand surgeons with denosumab to help promote knowledge of this therapeutic option and the potential role of this medication in the treatment of primary bone tumors in the hand.

Current therapies and future prospective for locally aggressive mesenchymal tumors

Locally aggressive mesenchymal tumors comprise a heterogeneous group of soft tissue and bone tumors with intermediate histology, incompletely understood biology, and highly variable natural history. Despite having a limited to absent ability to metastasize and excellent survival prognosis, locally aggressive mesenchymal tumors can be symptomatic, require prolonged and repeat treatments including surgery and chemotherapy, and can severely impact patients' quality of life. The management of locally aggressive tumors has evolved over the years with a focus on minimizing morbid treatments. Extensive oncologic surgeries and radiation are pillars of care for high grade sarcomas, however, play a more limited role in management of locally aggressive mesenchymal tumors, due to propensity for local recurrence despite resection, and the risk of transformation to a higher-grade entity following radiation. Patients should ideally be evaluated in specialized sarcoma centers that can coordinate complex multimodal decision-making, taking into consideration the individual patient's clinical presentation and history, as well as any available prognostic factors into customizing therapy. In this review, we aim to discuss the biology, clinical management, and future treatment frontiers for three representative locally aggressive mesenchymal tumors: desmoid-type fibromatosis (DF), tenosynovial giant cell tumor (TSGCT) and giant cell tumor of bone (GCTB). These entities challenge clinicians with their unpredictable behavior and responses to treatment, and still lack a well-defined standard of care despite recent progress with newly approved or promising experimental drugs.

The Efficacy of Denosumab in Treating Spinal Aneurysmal Bone Cyst: A Case Report

The optimal treatment for aneurysmal bone cysts (ABCs) of the spine remains controversial. No treatment guidelines exist for the use of denosumab in aneurysmal bone cysts. In this report, we describe the results from a representative case and compare our experience with those of previously published reports. A 38-year-old male was referred for pain in the lower back and left leg. Radiographs and a needle biopsy specimen revealed a lumbar aneurysmal bone cyst, which was treated with denosumab chemotherapy. The pain in the lower back and left leg gradually improved, and at 16 weeks, the symptoms had resolved. Once a satisfactory local effect was achieved, denosumab therapy was discontinued. However, the erosive lesion subsequently expanded. After re-initiation of treatment, there was no subsequent evidence of recurrence. Single-therapy denosumab is an option for aneurysmal bone cysts. However, recurrences have been documented after denosumab termination, and the timing for cessation of denosumab is controversial.

Unique presentation of occipital condyle giant cell tumor as occipital condyle syndrome - A review

Giant cell tumors (GCTs) of the skull are rare and only a few case series with limited number of cases have been reported till date. In the cranium, GCT usually occurs in the sphenoid and temporal bone, occipital condyle GCTs are very rare. We report a rare presentation of GCT of the occipital condyle manifested as occipital condyle syndrome. Despite gross total resection, they can recur aggressively; the presence of cortical breach might be an indicator of aggressiveness prompting early post-operative imaging and adjuvant therapy.

Endoscopic Endonasal Surgery for Uncommon Pathologies of the Sellar and Parasellar Regions

Endoscopic skull base surgery has become an integral part of the present neurosurgical armamentarium. The pioneering efforts in which the purely endoscopic transsphenoidal approach was introduced have triggered a growing tide of using the endoscopic endonasal procedures for a large variety of skull base lesions. Because of their anatomical peculiarities, lesions of the sellar and parasellar regions lend themselves very well to the endoscopic endonasal approaches. Apart from the common pathological entities, many other less frequent pathologies are encountered in the sellar and parasellar area. In this chapter, we review the surgical technique of the endoscopic endonasal transsphenoidal approach and its extensions applied to a variety of rare and uncommon pathological entities involving the sella turcica and clivus. An overview of these pathological entities is also presented and exemplified.

The role of neoadjuvant denosumab in the treatment of aneurysmal bone cysts: a case series and review of the literature

OBJECTIVE

Aneurysmal bone cysts (ABCs) are benign cystic lesions most commonly occurring in the long bones of pediatric patients. Spinal ABCs may be difficult to resect given their invasive, locally destructive nature, proximity to critical structures such as the spinal cord, and their intrinsic hypervascularity, for which complete embolization is often constrained by radiculomedullary segmental feeders. Denosumab, a monoclonal antibody that binds the receptor activator of nuclear factor kappa B (NF-κB) ligand, has been utilized in the treatment of ABCs most often as a rescue therapy for recurrent disease. Here, the authors present 3 cases of neoadjuvant denosumab use in surgically unresectable tumors to calcify and devascularize the lesions, allowing for safer, more complete resection.

METHODS

This is a single-center, retrospective case series treated at a tertiary care cancer center. The authors present 3 cases of spinal ABC treated with neoadjuvant denosumab.

RESULTS

All 3 patients experienced calcification, size reduction, and a significant decrease in the vascularity of their ABCs on denosumab therapy. None of the patients developed new neurological deficits while on denosumab. Subsequently, all underwent resection. One patient continued denosumab during the immediate postoperative period because a subtotal resection had been performed, with stabilization of the residual disease. No complications were associated with denosumab administration.

CONCLUSIONS

The use of denosumab in unresectable ABCs can cause calcification and devascularization, making safe resection more likely.

Comprehensive treatment outcomes of giant cell tumor of the spine: A retrospective study

There is no consensus on a treatment strategy for spinal giant cell tumor of bone (GCTB) because of the difficulty in their treatment. Treatment options often include the use of the controversial denosumab, an antibody therapy aimed at tumor shrinkage, different curettage techniques, resection, or a combination of these therapies. The current study aimed to identify treatment methods associated with favorable outcomes in patients with spinal GCTB. We retrospectively reviewed 5 patients with spinal GCTB, including patients with tumors of the sacrum, treated at our hospital between September 2011 and November 2020. Two men and 3 women were included in the study. The median follow-up period was 74 months (range: 14-108 months). We surveyed the tumor site, treatment method, denosumab use, and outcomes. The median age was 17 years (range: 17-42 years). There were 2 cases of sacral GCTB and 1 case each of lumbar, cervical, and thoracic vertebral GCTB. The comorbidities observed included hepatitis, malignant lymphoma, atopic dermatitis, and asthma. The treatment method included zoledronic acid after embolization and denosumab, denosumab only, curettage and posterior fusion, and curettage resection after embolization and anterior and posterior fusion. Denosumab was used in all cases. Three patients were continuously disease-free, 1 patient with no evidence of disease, and 1 patient alive with disease. Aggressive treatment, especially surgical treatment, may lead to good results in spinal GCTB.

K. Unique Presentation of Occipital Condyle Giant Cell Tumor as Occipital Condyle Syndrome—A Review

Giant cell tumors (GCT) of the skull are rare and only a few case series with limited number of cases have been reported till date. In the cranium, GCT usually occurs in the sphenoid and temporal bone, and occipital condyle GCTs are very rare. We report a rare presentation of GCT of the occipital condyle manifested as occipital condyle syndrome. Despite gross total resection, they can recur aggressively; presence of cortical breach might be an indicator of aggressiveness prompting early postoperative imaging and adjuvant therapy.

Rechallenge of denosumab in advanced giant cell tumor of the bone after atypical femur fracture: A case report and review of literature

Giant cell tumor of the bone (GCTB) is a locally aggressive neoplasm where surgery is often curative. However, it can rarely give rise to distant metastases. Currently, the only available active therapeutic option for unresectable GCTB is denosumab, an anti-RANKL monoclonal antibody that dampens the aggressive osteolysis typically seen in this disease. For advanced/metastatic GCTB, denosumab should be continued lifelong, and although it is usually well tolerated, important questions may arise about the long-term safety of this drug. In fact, uncommon but severe toxicities can occur and eventually lead to denosumab discontinuation, such as atypical fracture of the femur (AFF). The optimal management of treatment-related AFF is a matter of debate, and to date, it is unknown whether reintroduction of denosumab at disease progression is a clinically feasible option, as no reports have been provided so far. Hereinafter, we present a case of a patient with metastatic GCTB who suffered from AFF after several years of denosumab; we describe the clinical features, orthopedic treatment, and oncological outcomes, finally providing the first evidence that denosumab rechallenge after AFF occurrence may be a safe and viable option at GCTB progression.

A Large Cavernous Sinus Giant Cell Tumor Invading Clivus and Sphenoid Sinus Masquerading as Meningioma: A Case Report and Literature Review

Giant cell tumor (GCT) of the bone is a rare benign, locally aggressive tumor that occurs in the epiphysis of long bones, especially the lower femur and the upper tibia. GCT of the bone of cranial origin is very rare, accounting for 1% of all GCT of the bone. We report the diagnosis, treatment, and immunohistochemistry of a rare case of intracranial GCT of the bone. We also review and summarize the imaging features, diagnostic markers, and current major treatment options for GCT of the bone. Our case and literature review emphasizes the importance of considering the full picture when making a diagnosis, rather than relying on imaging alone to make the diagnosis.

New Target for Precision Medicine Treatment of Giant-Cell Tumor of Bone: Sunitinib Is Effective in the Treatment of Neoplastic Stromal Cells with Activated PDGFRβ Signaling

Simple Summary

The purpose of this study was to analyze differential cell signaling in response to denosumab treatment to identify and subsequently inhibit molecular targets in the neoplastic stromal cell population, which poses a risk for tumor recurrence. Using phosphoprotein arrays, a distinct signaling profile was detected in GCTB tissues treated with denosumab, a specific RANKL antibody, which coincided with the RTK profile in derived cell lines. PDGFRβ was selected as a promising receptor target, and its inhibition by the small-molecule inhibitor sunitinib resulted in potent inhibition of cell proliferation in vitro. The addition of sunitinib to denosumab resulted in the disappearance of both multinuclear giant cells and neoplastic stromal cells, as reported here. Thus, sunitinib could become an effective addition to denosumab in the treatment of GCTB with activated PDGFRβ.

Abstract

Giant-cell tumor of bone (GCTB) is an intermediate type of primary bone tumor characterized by locally aggressive growth with metastatic potential. The aim of this study was to identify new druggable targets among the cell signaling molecules involved in GCTB tumorigenesis. Profiles of activated signaling proteins in fresh-frozen tumor samples and tumor-derived cell lines were determined using phosphoprotein arrays. Analysis of the obtained data revealed epidermal growth factor receptor (EGFR) and platelet-derived growth factor receptor beta (PDGFRβ) as potential targets, but only the PDGFR inhibitor sunitinib caused a considerable decrease in stromal cell viability in vitro. Furthermore, in the case of a 17-year-old patient suffering from GCTB, we showed that the addition of sunitinib to the standard treatment of GCTB with the monoclonal antibody denosumab resulted in the complete depletion of multinucleated giant cells and mononuclear stromal cells in the tumor tissue. To summarize, the obtained data showed that a specific receptor tyrosine kinase (RTK) signaling pattern is activated in GCTB cells and plays an important role in the regulation of cell proliferation. Thus, activated RTKs and their downstream signaling pathways represent useful targets for precision treatment with low-molecular-weight inhibitors or with other types of modern biological therapy.

The current standing on the use of denosumab in giant cell tumour of the bone

Giant cell tumour of the bone (GCTB) has been classically treated surgically. With the advent of denosumab, there is potential to use it as a targeted therapy to downstage the tumour and control its progression. Like all new therapies, the dosage, duration, and long-term effects of treatment can only be determined over the time through numerous trials and errors. The current recommendation of use of the monoclonal antibody is 3-4 months of neoadjuvant denosumab in patients with advanced GCTB for cases who were not candidates for primary curettage initially, and prolonged use for surgically unsalvageable GCTB. The use of Denosumab in the adjuvant setting to prevent recurrence is not established.

Profiling of three H3F3A-mutated and denosumab-treated giant cell tumors of bone points to diverging pathways during progression and malignant transformation

Giant cell tumor of bone (GCTB) is a locally aggressive lesion of intermediate malignancy. Malignant transformation of GCTB is a rare event. In 2013, the humanized monoclonal antibody against receptor activator of nuclear factor-κb-Ligand (RANKL) denosumab was approved for treatment of advanced GCTB. Since then, several reports have questioned the role of denosumab during occasional malignant transformation of GCTB. We report on three patients with H3F3A-mutated GCTBs, treated with denosumab. The tissue samples were analysed by histomorphology, immunohistochemistry, and in two instances by next generation panel sequencing of samples before and after treatment. One patient had a mutation of ARID2 in the recurrence of the GCTB under treatment with denosumab. One patient developed a pleomorphic sarcoma and one an osteoblastic osteosarcoma during treatment. Sequencing revealed a persisting H3F3A mutation in the osteosarcoma while the pleomorphic sarcoma lost the H3F3A mutation; however, a FGFR1 mutation, both in the recurrence and in the pleomorphic sarcoma persisted. In addition, the pleomorphic sarcoma showed an AKT2 and a NRAS mutation. These data are inconclusive concerning the role denosumab plays in the event of malignant progression/transformation of GCTB and point to diverging pathways of tumor progression of GCTB associated with this treatment.

Giant Cell Tumor: Changing Behavior from Intraorbital to Intraosseous Mass

Purpose

To present a patient with giant cell tumor (GCT) of the orbit by changing behavior from an intraorbital mass to an intraosseous tumor.

Methods

A 16-year-old boy presented with pain, swelling, erythematous of the left upper and lower eyelids, proptosis, and diplopia. Ophthalmic examination revealed chemosis, conjunctival injection, limited elevation, depression as well as abduction in the left eye.

Results

Multislice computed tomography scan (CT scan) of the orbit and paranasal sinuses showed a hyperdense, oval, extraconal mass with bone erosion. Magnetic resonance imaging of the orbit showed an inferior lateral isointense, oval, extraconal mass that had indented the globe. The patient underwent superior lateral orbitotomy, and the orbital mass was excised. Two months later, the patient developed proptosis, severe chemosis, and eyelid erythema in the same eye. CT scan showed an intraosseous mass in the lateral wall of the orbit that had pushed the globe anteromedially. Intraosseous tumor was resected, and the lateral orbital wall was drilled during the second surgery. GCT was diagnosed based on pathological survey.

Conclusion

Following the resection of the orbital GCT, the tumor behavior may change to an intraosseous lesion.

Integration of denosumab therapy in the management of giant cell tumors of bone

A review of the literature indicated denosumab is gaining favorability in the oncology community, particularly with increasing frequency in GCTB. Will denosumab be the breakthrough GCTB treatment? Here, we provide a pertinent case example, a review of the literature regarding the history and basic science behind the use of denosumab for GCTB, highlight the newest insights into the dosing and duration of treatment, and note advancements in the field.

Clinical, radiological and pathological outcomes following treatment of primary giant cell tumour of bone with Denosumab

BACKGROUND

Giant cell tumour of bone (GCTOB) is a relatively uncommon, benign, but locally aggressive neoplasm. Denosumab is a fully human monoclonal antibody with inhibitory effects on receptor activator of nuclear factor kappa-B ligand that has shown early promise as a possible treatment adjuvant for GCTB. However, much is still unknown about its current indications, long-term effects, the potential risk for rapid relapse and its involvement in sarcomatous transformation.

METHODS

We analysed the outcomes of 154 patients with GCTOB. We assessed clinical outcomes via local recurrence free-survival, metastatic free-survival and sarcomatous transformation between those treated without Denosumab and those with neo-adjuvant Denosumab. Our radiological and pathological outcomes were assessed through independent specialist reviews.

RESULTS

Four (19.0%) patients of the neo-adjuvant group had local recurrence of disease versus 16 (12.0%) patients in the surgery alone group; this results in a 3.62 times increased likelihood of developing local recurrence (P = 0.030). The median time to local recurrence was shorter for the neo-adjuvant group (421.5 days versus 788.5 days) (P = 0.01). There was no difference between Denosumab and the surgery groups in terms of metastatic disease (P = 0.45). Two patients in our cohort with GCTOB developed sarcomatous transformation, both were treated with Denosumab.

CONCLUSION

Our use of Denosumab tended to be for those patients who had surgically difficult tumours to halt the progression and allow easier resections. Of concern we noted a trend towards increasing recurrence rates with the potential risk for rapid relapse. Furthermore, two cases experienced sarcomatous transformation, which is a growing area of concern within the literature.

Role of (Neo)adjuvant Denosumab for Giant Cell Tumor of Bone

OPINION STATEMENT

Denosumab is a RANK ligand inhibitor approved for the treatment of giant cell tumor of bone. While the role of denosumab in the setting of advanced and unresectable disease is well established, its role in surgically resectable disease is currently under discussion. Several prospective and retrospective series on neoadjuvant therapy in potentially resectable tumor with high morbidity surgery reported a relapse rate of 10-20% after resection and 30-40% after curettage. At the same time, less morbid surgery has obvious clinical advantages for the patient, and several studies have shown the efficacy of denosumab in downgrading of the surgical procedure. Currently, the role of neoadjuvant denosumab in operable GCTB is limited to selected cases in which a diffuse reactive bone formation and peripheral ossification can make an easier surgical procedure, for example, in tumors with a large soft tissue component. A planned resection may become less morbid when preoperative denosumab is administered. Whenever a segmental resection is thought to be indicated at diagnosis, denosumab may be considered in the neoadjuvant setting. A preoperative course of 6 months is considered safe and effective. Two case scenarios are presented and critically discussed. Because of the high recurrence rates after denosumab treatment followed by curettage, we discourage the use of denosumab when curettage is considered feasible. In this setting, a short course of preoperative denosumab (2-6 months) may be considered for highly selected cases, for example in pathological fractures. The role of adjuvant denosumab needs further investigation. Long-term disease control has been reported in case of non-surgical lesions, even after treatment interruption, but there is no consensus on ideal treatment duration and dosage for these scenarios. In all cases, multidisciplinary discussion with oncology, pathologist, radiologist, and surgeons is mandatory. Patient's comorbidities, dental conditions, and preferences, including family planning, should always be taken into account.

The two faces of giant cell tumor of bone

Giant cell tumor (GCT) is a bone-destructive benign neoplasm characterized by distinctive multinucleated osteoclast-like giant cells with osteolytic properties distributed among neoplastic stromal cells. GCT is locally aggressive with progressive invasion of adjacent tissues and occasionally displays malignant characteristics including lung metastasis. GCT is characterized genetically by highly recurrent somatic mutations at the G34 position of the H3F3A gene, encoding the histone variant H3.3, in stromal cells. This leads to deregulated gene expression and increased proliferation of mutation-bearing cells. However, when GCT complicates Paget disease of bone (GCT/PDB) it behaves differently, showing a more malignant phenotype with 5-year survival less than 50%. GCT/PDB is caused by a germline mutation in the ZNF687 gene, which encodes a transcription factor involved in the repression of genes surrounding DNA double-strand breaks to promote repair by homologous recombination. Identification of these driver mutations led to novel diagnostic tools for distinguishing between these two tumors and other osteoclast-rich neoplasms. Herein, we review the clinical, histological, and molecular features of GCT in different contexts focusing also on pharmacological treatments.

Soft Tissue Special Issue: Giant Cell-Rich Lesions of the Head and Neck Region

Giant cell-rich lesions represent a heterogeneous group of tumors and non-neoplastic lesions, usually arising in bone, which harbor varying number of reactive osteoclastic-type multinucleate giant cells as a common feature. Among these entities, some are confined to the head and neck region (e.g., central giant cell granuloma and mimicking lesions, i.e., peripheral giant cell granuloma and cherubism) or show a relative predilection for this region (e.g., aneurysmal bone cyst and brown tumor of hyperparathyroidism), while others are rare but associated with distinct underlying disease (e.g., giant cell tumor of bone) or histology (e.g., tenosynovial giant cell tumor of the temporomandibular joint and phosphaturic mesenchymal tumor of the jaws) when occurring in the head and neck. Collectively, these lesions pose great challenge in the pathologic diagnosis, which often requires combinatory assessment from the clinical, histopathologic, and/or molecular aspects. This review provides a summary of pertinent clinical and pathologic features and an update of recent molecular and genetic findings of these entities. The considerations in differential diagnosis as well as the effects of the emerging therapeutic RANKL-antagonizing antibody denosumab will also be addressed.

Aneurysmal bone cyst: results of an off label treatment with Denosumab

Background

The treatment of aneurysmal bone cysts (ABCs) has evolved and less invasive methods have been tried. Denosumab is a monoclonal antibody which inhibits osteoclasts. It has been shown to be effective in giant cell tumour of bone (GCT) of bone and hence promises some effect also in ABC. We report on 6 patients treated with Denosumab and compare our results to the cases already published.

Methods

Data of 6 patients with ABCs and patients whose treatment included Denosumab were retrospectively analyzed. Denosumab was used at a dose of 120 mg on days 1, 8, 15 and 29, and every 4 weeks thereafter. In some of these patients the dose was reduced at the end of the treatment. Clinical and radiological responses were evaluated.

Results

In 4 female and 2 male patients with a mean age of 17 years (range: 6–30 years) the lesions were located in the sacrum (2), in distal radius, distal femur, talus and pelvis. One of the sacral lesions healed after 12 months and has stayed stable for 3 years since. The second patient received 2 years of therapy with recalcification, but recurred 1 year later and is under renewed therapy. The pelvic lesion improved but recurred. This patient has a 13-years history of intermittent therapy including surgery, two pregnancies and remains in a stable situation. The lesion of the talus did not improve with Denosumab after surgery and was complicated by destruction of the ankle joint with osteoarthritis. Recurrent lesions of the distal femur and the distal radius, previously treated by curettage and bone grafting healed under Denosumab and have remained stable for 2 and 3 years, respectively. One case of severe hypercalcemia was observed in a 7-year old child 6 months after discontinuation of Denosumab.

Conclusion

Denosumab provides a treatment option for ABCs in anatomically critical locations. Adjuvant application might reduce the rate of local recurrence. In young patients, severe rebound hypercalcemia months after discontinuation of Denosumab may occur.

Denosumab treatment for giant-cell tumor of bone: a systematic review of the literature

BACKGROUND

Denosumab is a human monoclonal antibody (mAb) that specifically inhibits tumor-associated bone lysis through the RANKL pathway and has been used as neoadjuvant therapy for giant-cell tumor of bone (GCTB) in surgical as well as non-surgical cases. The purpose of this systematic review of the literature, therefore, is to investigate: (1) demographic characteristics of patients affected by GCTBs treated with denosumab and the clinical impact, as well as, possible complications associated with its use (2) oncological outcomes in terms of local recurrence rate (LRR) and development of lung metastasis, and (3) characteristics of its treatment effect in terms of clinical, radiological, and histological response.

METHODS

A systematic review of the literature was conducted using PubMed, EMBASE, and COCHRANE search including the following terms and Boolean operators: "Denosumab" AND "primary bone tumor", "denosumab" AND "giant cell tumor", "denosumab" AND "treatment", and finally, "denosumab" AND "giant cell tumor" AND "treatment" since 2000. After applying inclusion and exclusion criteria, a total of 19 articles were included. The quality of the included studies was assessed using STROBE for the assessment of observational studies.

RESULTS

A total of 1095 patients were included across all 19 studies. Across all the studies included, there were 615 females and 480 males. The mean patient age was 33.7 ± 8.3 years when starting the denosumab treatment. The pooled weighted local recurrence rate was 9% (95% CI 6-12%) and the pooled weighted metastases rate was 3% (95% CI 1-7%). The most common adverse event was fatigue and muscular pain. Radiologic response was estimated to occur in 66-100% of the patients. A significant reduction in pain under denosumab treatment was reported in seven studies and additional improvement in function and mobility was reported by several authors. Only two studies reported musculoskeletal tumor society (MSTS) scores which were better after denosumab treatment.

CONCLUSIONS

The use of denosumab as an adjuvant treatment of GCTB has shown a positive but variable histological response with consistent radiological changes and several types of adverse effects. There is a positive clinical response in terms of pain relief with decrease on the morbidity of surgical procedures to be performed. Finally, oncological outcomes are disparate with neither effect on metastatic disease nor local recurrence rates.

LEVEL OF EVIDENCE

IV.

Surgical Management of Giant Cell Tumor Involving the Lateral Skull Base

The aim of the study is to discuss the current management options for intra- and extra-cranial communication giant cell tumor of the lateral skull base and perform a review of the literature. A total of 6 patients with giant cell tumor of the lateral skull base were retrospectively enrolled in the study. The principal complaints, imaging manifestations, surgical resection and reconstruction of intra- and extra-cranial communication defects for the diseases were discussed. There were 2 males and 4 females. The most of principal complaints were discomfort or pain in the temporomandibular joint in 5 cases (83.3%). Imaging examination showed invasion of the temporal bone alone in 3 cases (50.0%) and both temporal bone and sphenoid bone involvement in 3 cases (50.0%). C-shaped preauricular infratemporal fossa approach was used for tumour removal and gross total resection was done in all 6 cases. The pedicled temporal muscle fascial flap was used to reconstruct the intra- and extra-cranial communication defect of the lateral skull base. The conclusion is that giant cell tumor is a benign tumor but is also locally aggressive. Gross total resection is the most commonly recommended treatment choice for giant cell tumor of the skull and can achieve good treatment outcomes. The temporalis muscle flap is a good alternative choice for reconstruction of the defect.

Malignant Sarcomatous Transformation of Benign Giant Cell Tumor of Bone after Treatment with Denosumab Therapy: A Literature Review of Reported Cases

Giant cell tumor of bone (GCTB) is a biologically benign and locally aggressive tumor that most often affects the epiphyseal and metaphyseal sites of long bones in the young adult population. Overexpression of receptor activator of nuclear factor kappa B ligand (RANKL) by cancerous mesenchymal stromal cells stimulates a signal transduction cascade that recruits and activates multinucleated osteoclast-like giant cells, resulting in pathologic bone resorption. Denosumab, an RANKL inhibitor that blocks the RANKL-mediated osteoclast activation, has been recently approved by the United States Food and Drug Administration (FDA) for the treatment of aggressive GCTB. Although uncommon, several studies reported drug-related malignant morphological transformation of benign GCTB following treatment with denosumab therapy. The aim of the article was to review the clinicopathological characteristics of all the reported cases of malignant sarcomatous transformation of GCTB after treatment with denosumab therapy in patients without any history of prior exposure to radiotherapy.

Giant-cell granuloma: 2 case reports

Introduction: Giant-cell granuloma (GCG) is a benign tumor occurring almost exclusively in the jaws. These lesions remain rare but can sometime have an aggressive behavior. In this article, we will describe and follow two cases of GCG. Observations: The first case is a referred female patient, who presents a mandibular swelling. Its clinical and radiological aspects lead us to do a biopsy, with a histological result of GCG. The second case is a patient with a terminal kidney failure, referred for a buccal swelling in the upper left jaw. The cone-beam computed tomography X-ray shows a compartmentalized lesion with blurry limits. An excisional biopsy is performed and the histological diagnosis is a GCG. Discussion: Although the first patient suffers from no systemic disease, the second one presents a terminal kidney failure resulting in a chronic hyperparathyroidism. Hyperparathyroidism can activate osteoclastic resorption and create bone lesions such as brown tumors. Conclusion: The slow and asymptomatic growth of these lesions often result in a late diagnosis. It should be kept in mind as a differential diagnosis when dealing with an osteolytic lesion of the jaws with no clear etiology, especially if hyperparathyroidism or kidney failure is associated.

Giant Cell Tumor of the Lateral Skull Base: Diagnostic and Management Options

Giant cell tumor of bone (GCTB) is a rare, benign, osteolytic neoplasm that most commonly occurs in early adulthood and often involves the long bones of the body. Although GCTB largely affects the epiphyses of long bones, several reports of GCTB involvement of the cranial and facial bones exist in the literature. In addition to reviewing other reported cases of GCTBs of the lateral skull base in the literature, the authors report here on the clinical presentation, radiographic findings, and neurosurgical management of a patient found to have a GCTB of the middle and infratemporal fossae, which was treated by aggressive en bloc resection of the lateral skull base.

Denosumab treatment of inoperable or locally advanced giant cell tumor of bone - Multicenter analysis outside clinical trial

BACKGROUND

Giant cell tumor of bone (GCTB) is an osteolytic, locally aggressive, rarely metastazing bone tumor. This is a retrospective study evaluating a large series of GCTB patients treated with denosumab in routine practice in 6 European reference centers.

METHODS

Patients with locally advanced, unresectable or metastatic GCTB, treated with denosumab outside clinical trials were eligible. Primary end-point was progression-free survival (PFS) for all patients; secondary end-points were: type of surgery, relapse rate and event-free survival for patients after preoperative denosumab + surgery.

RESULTS

We identified 138 patients treated in the period 2011-2016. In 40/43 cases the diagnosis was confirmed by H3F3A gene mutation. Median follow-up time was 23 months (range 6-48). Primary tumor was located in lower limb (38%) - mostly in femur and tibia, in upper limb (34%), and in pelvis/axial skeleton/ribs (28%). 110 (80%) patients had primary tumors, 28 (22%) recurrent tumors after previous surgical procedures (+/- radiotherapy). 89/138 patients had locally advanced GCTB and underwent neoadjuvant denosumab. The median denosumab treatment duration was 8 months (median number of cycles 11), 98% had clinical benefit from therapy. 39 (44%) had wide en-bloc resection - WE (+implantation of the prosthesis in 17 cases), the other 50 (56%) cases had intralesional curettage - C. Progression after surgical treatment was observed in 19 patients, 16 of them after C (32%); 13 patients underwent denosumab re-challenge, and all responded. Two-year progression-free survival (PFS; from denosumab start) rate was 81%; 2-year EventFS (from surgery) was significantly better in WE group (93%) vs 55% in C group (p = 0.006). Treatment was well tolerated with only 2 cases of grade 3 toxicity and one osteonecrosis of the jaw.

CONCLUSION

Our retrospective study confirms that denosumab is extremely efficient in unresectable/metastatic disease as well as in a neoadjuvant setting. Our data confirm excellent efficacy and short-term tolerability of this drug. Our data suggest that neoadjuvant therapy with denosumab is the option for treatment of initially locally advanced tumors to facilitate complete surgical resection or avoid mutilating surgery. The risk of recurrences after curettage of GCTB following denosumab raises questions about the optimal management of such cases.

Giant cell tumours of bone treated with denosumab: histological, immunohistochemical and H3F3A mutation analyses

AIMS

Denosumab, a human monoclonal antibody directed against the receptor activator of nuclear factor-κB ligand (RANKL), is a therapeutic agent for giant cell tumour of bone (GCTB). Although some studies have reported that denosumab shrinks tumours and induces bone formation, the actual effects of RANKL suppression on GCTB remain unclear. A mutation in the H3 histone family member 3A gene (H3F3A) was recently identified as a genetic signature for GCTB. The aim of this study was to investigate the histopathological features and H3F3A mutation status of GCTBs treated with denosumab.

METHODS AND RESULTS

Nine biopsy-diagnosed patients with GCTB, who underwent curettage after neoadjuvant denosumab therapy, were reviewed. Immunohistochemistry for NFATc1 (an osteoclast marker), RUNX2 (an osteoblast marker) and histone H3.3 G34W (G34W, a GCTB marker) was performed; furthermore, H3F3A mutation status was examined with direct sequencing. Before therapy, GCTBs comprised NFATc1+ and RUNX2+ cells. All cases were G34W+ and contained H3F3A mutations. After therapy, the osteoclast-like giant cells disappeared. Areas of slender spindle cell proliferation and reticular woven bone that were NFATc1- and RUNX2+ replaced the lesions in various proportions. However, all post-therapy lesions still contained many G34W+ cells and harboured H3F3A mutations. Immunofluorescence double staining revealed that RUNX2+ mononuclear cells coexpressed G34W in pre-therapy and post-therapy lesions. Two patients experienced radiologically detected local recurrence within 2 years.

CONCLUSIONS

Denosumab therapy effectively decreases the number of osteoclastic cells in GCTBs. However, the neoplastic cells with H3F3A mutation survive denosumab treatment and undergo dramatic histological changes in response to this agent.

Locally Aggressive Connective Tissue Tumors

In this review, we highlight the complexities of the natural history, biology, and clinical management of three intermediate connective tissue tumors: desmoid tumor (DT) or aggressive fibromatosis, tenosynovial giant cell tumor (TGCT) or diffuse-type pigmented villonodular synovitis (dtPVNS), and giant cell tumor of bone (GCTB). Intermediate histologies include tumors of both soft tissue and bone origin and are locally aggressive and rarely metastatic. Some common aspects to these tumors are that they can be locally infiltrative and/or impinge on critical organs, which leads to disfigurement, pain, loss of function and mobility, neurovascular compromise, and occasionally life-threatening consequences, such as mesenteric, bowel, ureteral, and/or bladder obstruction. DT, PVNS, and GCTB have few and recurrent molecular aberrations but, paradoxically, can have variable natural histories. A multidisciplinary approach is recommended for optimal management. In DT and PVNS, a course of observation may be appropriate, and any intervention should be guided by symptoms and/or disease progression. A surgical approach should take into consideration the infiltrative nature, difficulty in obtaining wide margins, high recurrence rates, acute and chronic surgical morbidities, and impact on quality of life. There are similar concerns with radiation, which especially relate to optimal field and transformation to high-grade radiation-associated sarcomas. Systemic therapies must be considered carefully in light of acute and chronic toxicities. Although standard and novel therapies are promising, many unanswered questions, such as duration of therapy and optimal end points to evaluate efficacy of drugs in clinical practice and trials, exist. Predictive biomarkers and novel clinical trial end points, such as volumetric measurement, magnetic resonance imaging T2 weighted mapping, nuclear imaging, and patient-reported outcomes, are in development and will require validation in prospective trials.

Salleh MS, Yahaya S, Syahrul Fitri ZM. The Values of Receptor Activator Nuclear Kappa-B Ligand Expression in Stage III Giant Cell Tumor of the Bone

BACKGROUND

Giant cell tumor (GCT) of bone is a benign locally aggressive primary bone tumor which is risky for local recurrences and pulmonary metastasis. Till date, there are still many uncertainties in predicting the aggressiveness of GCT. We aim to investigate whether receptor activator nuclear kappa-B ligand (RANKL) expression may determine the prognosis of the lesion.

MATERIALS AND METHODS

We examined RANKL expression in 39 patients (21 males, 18 females) by immunohistochemistry. Four patients (10%) were presented with tumor recurrence, eight patients (20%) were complicated with lung metastasis, and two patients (5%) were presented with both recurrence and lung metastasis. Positive RANKL expression was assessed according to a scoring system evaluating the percentage of the immunostained epithelial area and the staining intensity. The cumulative score was calculated to determine the final score value. Data were analyzed using PASW version 18.0 and independent t-test between nonrecurrence/recurrence groups, and nonlung metastasis/lung metastasis groups. Significance was set at P < 0.05.

RESULTS

Thirty-two patients (82%) scored 3 in RANKL-staining percentage from whole stromal cell population (>75%), 6 patients scored 2, and 1 patient scored 1. Nine patients (23%) scored 3 in RANKL-staining intensity (most intense), 19 patients (48%) scored 2, and 11 patients (29%) scored 1. Twenty six patients (67%) had strong RANKL expression (total score of 5-6), 12 patients (31%) showed moderate score (3-4) whereas only 1 patient (2%) showed weak RANKL expression. Together, the mean value of RANKL-staining percentage was 2.79, intensity 1.95 and the total score 4.77. The mean RANKL-staining percentage between recurrence and nonrecurrence groups was statistically significant (P = 0.009). There was no significant difference in the mean staining intensity and total score between nonrecurrence and recurrence groups, and staining percentage staining intensity and a total cumulative score of RANKL expression between lung metastasis and nonlung metastasis groups.

CONCLUSION

RANKL expression is generally high in Stage III GCT and is a reliable prognostic marker in predicting the risk of local recurrence however not in lung metastasis.

Giant cell tumour of the distal radius/ulna: response to pre-operative treatment with short-term denosumab

Background

Treatment of giant cell tumour of bone (GCTB) of the distal radius/ulna poses a surgical challenge, as complex reconstructive surgery may be required. This study evaluates the clinical, radiological and pathological findings in five cases of GCTB of the distal forearm where a 3 month course of denosumab was given prior to surgery.

Methods

Patients with biopsy proven distal forearm GCTB, treated for 3 months with denosumab, followed by salvage surgery (curettage and cementation) were included. Wrist pain and function were assessed using the modified Mayo Wrist Score (MMWS). Plain radiographs, MRI and PET/CT were performed pre-treatment and 2 months after initiation of denosumab therapy. Histological comparison was made between the original biopsy and surgical curettage specimens.

Results

Five patients with an average age of 25 years were included in the study. Improvement in wrist pain and function was seen in all patients with the average MMWS increasing from 30 pre-treatment to 85 at 3 months. Plain radiographs demonstrated marginal sclerosis in all cases with reconstitution of cortical and subarticular bone by 2 months; internal matrix sclerosis and osseous consolidation was more variable. Increased tumour heterogeneity and low signal were observed on T2-weighted MR images. PET/CT revealed a decrease in average SUV from 14.8 pre-treatment to 4.7 at 2 months. Histology showed disappearance of osteoclasts and increased fibro-osseous tissue. Denosumab treatment has the potential to facilitate salvage surgery, thus avoiding bone resection and graft reconstruction. A good outcome was achieved apart from local recurrence in one case. Follow up ranged from 17 to 54 months.

Conclusion

Distal forearm GCTB responds clinically, radiologically and histologically to a short course of pre-operative denosumab therapy, which has the potential to facilitate salvage surgery.

In Vitro Study of the Effects of Denosumab on Giant Cell Tumor of Bone: Comparison with Zoledronic Acid

Giant cell tumor of bone (GCTB) is a locally aggressive primary bone tumor that contains numerous osteoclasts formed from marrow-derived precursors through receptor activator of nuclear factor κ-B ligand (RANKL), an osteoclast differentiation factor expressed in neoplastic cells of GCTB. Denosumab, a fully human monoclonal antibody targeting RANKL, has recently been used for the treatment of GCTB, and superior treatment effects have been reported. The aim of this work was to elucidate the mechanism of action of denosumab, and the differences between denosumab and zoledronic acid at the level of GCTB cells. We isolated GCTB cells from 3 patients and separated them into osteoclasts, osteoclast precursors and proliferating spindle-shaped stromal cells (the true neoplastic component), and examined the action of denosumab on differentiation, survival and bone resorption activity of osteoclasts. Denosumab and zoledronic acid inhibited osteoclast differentiation from mononuclear cells containing osteoclast precursors. Zoledronic acid inhibited osteoclast survival, whereas an inhibitory effect of denosumab on osteoclast survival was not observed. The inhibitory effect on bone resorption by both agents was confirmed in culture on dentin slices. Furthermore, zoledronic acid showed dose-dependent inhibition of cell growth of neoplastic cells whereas denosumab had no inhibitory effect on these cells. Denosumab has an inhibitory effect on osteoclast differentiation, but no inhibitory effects on survival of osteoclasts or growth of neoplastic cells in GCTBs.

Giant cell tumor of bone revisited

Giant cell tumor (GCT) of bone is a locally aggressive benign neoplasm that is associated with a large biological spectrum ranging from latent benign to highly recurrent and occasionally metastatic malignant bone tumor. It accounts for 4–10% of all bone tumors and typically affects the meta-epiphyseal region of long bones of young adults. The most common site involved is the distal femur, followed by the distal radius, sacrum, and proximal humerus. Clinical symptoms are nonspecific and may include local pain, swelling, and limited range of motion of the adjacent joint. Radiographs and contrast-enhanced magnetic resonance imaging (MRI) are the imaging modalities of choice for diagnosis. Surgical treatment with curettage is the optimal treatment for local tumor control. A favorable clinical outcome is expected when the tumor is excised to tumor-free margins, however, for periarticular lesions this is usually accompanied with a suboptimal functional outcome. Local adjuvants have been used for improved curettage, in addition to systematic agents such as denosumab, bisphosphonates, or interferon alpha. This article aims to discuss the clinicopathological features, diagnosis, and treatments for GCT of bone.

Denosumab in patients with giant-cell tumor of bone in Norway: results from a nationwide cohort

BACKGROUND

Denosumab is a relatively new treatment option for patients with giant-cell tumor of bone (GCTB). The purpose of this study was to report the results for patients treated in Norway.

MATERIALS AND METHODS

Patients treated with denosumab for GCTB were identified from the clinical databases at the Norwegian sarcoma reference centers. Data were retrieved from the clinical databases and supplemented by retrospective review of patient records. Denosumab was given as a subcutaneous injection every 4 weeks with loading doses on day 8 and 15 in cycle 1.

RESULTS

Eighteen patients treated with denosumab for GCTB were identified. Denosumab was given for recurrent disease in seven cases and as first-line treatment in 11 patients, of which 6 received therapy as part of a neoadjuvant/adjuvant strategy and 5 for surgically unsalvageable primary tumor. Ten of 12 patients with unresectable disease are still on denosumab without progression with median treatment duration of 41 months (range 18-60). Two patients discontinued treatment due to osteonecrosis of the jaw and reduced compliance, respectively. In the adjuvant group, four patients experienced disease recurrence after stopping denosumab. In three of six patients, the extent of surgery was reduced due to neoadjuvant therapy. Seventeen of 18 patients underwent response evaluation with 18F-FDG PET/CT at median 4.7 weeks from starting denosumab. Median baseline SUV_max was 11.0 and median SUV_max at evaluation was 4.9 (p < 0.001).

CONCLUSIONS

In a nationwide GCTB patient cohort, denosumab was an effective agent and durable responses were observed. Our results do not support the use of adjuvant therapy in routine clinical practice. 18F-FDG PET/CT could be a valuable tool for early response evaluation.

Clinical and pathological results of denosumab treatment for giant cell tumors of bone: Prospective study of 14 cases

Objective

Giant cell tumor of bone (GCT) is a primary, osteolytic, benign tumor of the bone. Surgery is the commonly used treatment; however, recurrence remains a problem. Receptor activator of nuclear factor kappa B (RANKL) is responsible for the formation of osteoclastic cells. Discovery of RANKL and its human monoclonal antibody, denosumab, led to use of denosumab for treatment of GCT. The aim of this study was to evaluate clinical and pathological results of treatment of GCT with denosumab and to assess adverse effect profile and recurrence rate.

Methods

Thirteen patients with 14 lesions were enrolled in the study. Mean age was 38.3 years. Patients were given subcutaneous injections of denosumab (120 mg) every 4 weeks (with additional doses on days 0, 8 and 15 in cycle 1 only) and were radiologically evaluated for tumor response. Pain and functional status were measured using Visual Analog Score (VAS) and Musculoskeletal Tumor Society Score (MSTS). Adverse effects were analyzed after each cycle.

Results

Participants were 5 men and 8 women. Mean follow-up was 17 months. One lesion was Campanacci grade I, 8 were grade II, and 5 were grade III. Eight lesions were recurrent, and remaining were primary lesions. After average of 9 cycles (range: 4–17 cycles), all tumors underwent radiological regression. Ten lesions were removed surgically. More than 90% of giant cells were found to have regressed in all pathological specimens. On last follow-up, average VAS was 1 and MSTS was 87%. Fatigue and joint and muscle pain after injections was reported by 46% of patients, and mild hypocalcaemia was seen in 1 patient.

Conclusion

Denosumab has been shown to be a successful drug in treatment of GCT. Denosumab can be used as neoadjuvant for all recurrent lesions, grade II lesions with high surgical risk, grade III lesions, and metastatic cases of GCT.

Level of evidence

Level IV, Therapeutic study

Denosumab treatment of inoperable or locally advanced giant cell tumor of bone

Giant cell tumor of bone (GCTB) is an osteolytic, locally aggressive tumor that rarely metastasizes and typically occurs in the bones. At present, the primary treatment for GCTB is curettage with local adjuvants. Giant cells express receptor activator of nuclear factor-κB ligand (RANKL). Denosumab, a RANKL inhibitor appears to present an effective therapeutic option in advanced cases of GCTB. The aim of the present study was to confirm the efficacy of denosumab in large group of patients with locally advanced GCTB. A total of 35 patients with histologically confirmed GCTB that were treated with denosumab with no participation in clinical trials between May 2013 and September 2015 were included in the present study. Denosumab treatment was administered until complete tumor resection was feasible or tumor progression or unacceptable toxicity had occurred. The mean denosumab treatment duration was 7.4 months. A total of 17 patients received surgery following denosumab treatment: 11 patients underwent wide en bloc resection with prosthesis implantation in 10 cases and 6 patients were treated with intralesional curettage. Tumor progression was observed in 2 patients that underwent intralesional curettage without prosthesis implantation. In addition, tumor progression was observed during denosumab treatment in 2 patients that had previously undergone radiotherapy. The overall 1-year progression-free survival rate was 92.8%. Thus, for patients with advanced, unresectable, progressive or symptomatic pretreated GCTB, denosumab provides a therapeutic option not previously available, which has become the standard therapy in multidisciplinary management of GCTB.

Thallium-201 Uptake of Giant Cell Tumor: One Step Toward the Differential Diagnosis to Atypically Presenting Osteosarcoma

OBJECTIVE

The radiologic differential diagnosis of giant cell tumors (GCTs) is challenging because there is a risk of misdiagnosis of GCTs as malignant lesions such as atypically presenting osteosarcomas (OSs). This study aims to assess the feasibility of ²⁰¹Tl scintigraphy for the differential diagnosis of GCT and atypical OS.

MATERIALS AND METHODS

Thallium-201 scintigraphy scans obtained between January 2006 and October 2015 of patients with histologically proven GCT (23 patients [male-to-female ratio, 15:8]; median age, 33.0 years; age range, 20-61 years) and patients with atypically presenting OS (20 patients [male-to-female ratio, 11:9]; median age, 30.0 years; age range, 12-69 years) were retrospectively reviewed. Morphologic classification of osseous lesions was performed on radiographs and CT scans. The ²⁰¹Tl scintigraphy-based tumor-to-background contrast (TBC) and washout rate (WR) were calculated on early phase and delayed phase scans. The laboratory parameters lactate dehydrogenase (LDH), C-reactive protein (CRP), and alkaline phosphatase were obtained. Statistical significance was estimated using the Mann-Whitney U test. Cutoff values were calculated for early phase TBC and delayed phase TBC.

RESULTS

Twenty-two of 23 GCTs were detected on the initial radiographs, whereas only six of 20 atypical OSs were detected on the initial radiographs. The early phase TBC was increased in GCT (median, 2.59; range, 0.51-12.26) compared with atypical OS (median, 1.68; range, 0.90-6.45) (p = 0.07). The delayed phase TBC was increased in GCT (median, 1.65; range, 0.22-5.26) compared with atypical OS (median, 0.96; range, 0.39-3.76) (p = 0.02). The median WR was not significantly decreased in GCT. The cutoff value for the early phase TBC was 3.90, and the cutoff value for the delayed phase TBC was 1.64; these cutoff values for early and delayed phase TBC yielded a sensitivity of 80.0% and a specificity of 47.8% and 52.2% respectively. Serum LDH (mean: atypical OS vs GCT, 215.5 vs 170.5 U/L, respectively; p = 0.01), alkaline phosphatase (median: 355.0 vs 252.0 U/L; p = 0.03), and CRP (median: 0.21 vs 0.09 mg/dL; p = 0.04) values were significantly increased in atypical OS compared with GCT.

CONCLUSION

The intense ²⁰¹Tl uptake of GCT in combination with laboratory OS biomarkers facilitate the differential diagnosis of GCT and atypically presenting OS.

Current status and unanswered questions on the use of Denosumab in giant cell tumor of bone

Denosumab is a monoclonal antibody to RANK ligand approved for use in giant cell tumour (GCT) of bone. Due to its efficacy, Denosumab is recommended as the first option in inoperable or metastatic GCT. Denosumab has also been used pre-operatively to downstage tumours with large soft tissue extension to allow for less morbid surgery. The role of Denosumab for conventional limb GCT of bone is yet to be defined. Further studies are required to determine whether local recurrence rates will be decreased with the adjuvant use of Denosumab along with surgery. The long term use and toxicity of this agent is unknown as is the proportion of patients with primary or secondary resistance. It is advised that complicated cases of GCT requiring Denosumab treatment should be referred and followed up at expert centres. Collaborative studies involving further clinical trials and rigorous data collection are strongly recommended to identify the optimum use of this drug.

Denosumab for the treatment of giant cell tumor of the bone

Giant cell tumor of bone is typically composed of neoplastic stromal cells and non-neoplastic osteoclastic giant cells. RANK-expressing osteoclastic giant cells are recruited by RANK ligand excreted by the stromal cells, and used by these neoplastic cells to create expansion space. Denosumab specifically binds to and inhibits RANK ligand, thereby eradicating osteoclastic giant cells from the tumor and thus reducing osteolytic activity. Clinical studies reported disease stabilization and clinical benefit in terms of reduced pain and analgesics use, avoided surgeries or surgeries with less morbid procedures. Adverse events observed in patients with giant cell tumor of bone were consistent with the known safety profile of denosumab with a very low incidence of hypocalcemia and osteonecrosis. Overall, denosumab was shown to suppress osteolytic activity and slow disease progression and is thus a treatment option for patients with giant cell tumor of bone.

Chemotherapy for bone sarcomas in adults: the MD anderson experience

Increasing age is an adverse prognostic factor in the treatment of primary bone tumors. There are few published data on treatment of primary bone tumors in adults. This paper presents data from the Department of Sarcoma Medical Oncology at The University of Texas MD Anderson Cancer Center, summarizing our treatment results. To treat primary osteosarcoma, we used 90 mg/m2 of doxorubicin as a continuous intravenous infusion over 48 to 96 hours and 120 to 160 mg/m2 of cisplatin intravenously or intra-arterially. Initially, we found a marked difference in postoperative continuous disease-free survival (CDFS) between those with 90% or greater (i.e., good response) tumor necrosis and those with less than 90% (i.e., poor response) tumor necrosis. The sequential addition of high-dose methotrexate and ifosfamide to patients with poorly responding disease improved their CDFS to that of patients with good response. Older patients and those who have tumors with variant histology have inferior outcomes. Evaluation of subsequent patients revealed similar outcomes for those with good or poor response to induction therapy, supporting our practice of adaptation of postoperative chemotherapy to the results of preoperative chemotherapy. PET-CT is the best imaging modality to screen for a response with tumors inside bone. To treat Ewing sarcoma, we have employed 2 mg of vincristine, 75 to 90 mg/m2 of doxorubicin as a 72-hour infusion, and 2.5 g/m2 of ifosfamide over 3 hours daily for 4 doses (i.e., vincristine, doxorubicin, and ifosfamide [VAI]). Preliminary analysis indicates a higher CDFS when adjusted for patient age than seen with the standard alternating regimen used in pediatrics. A screening MRI of the pelvis and spine can detect subtle metastatic disease in bone or bone marrow that is missed by other imaging modalities or blind biopsy. Chondrosarcoma is treated surgically or on investigational protocols. Giant cell tumor of bone is usually managed surgically, but multiple options exist for medical treatment, and therapy is individualized with embolization, denosumab, and interferon.

Two Cases of Sarcoma Arising in Giant Cell Tumor of Bone Treated with Denosumab

Giant cell tumor (GCT) of bone is a generally benign, but often locally aggressive, neoplasm of bone, with a propensity for recurrence. Sarcomatous transformation is rare and typically occurs with a history of recurrences and radiation treatment. Denosumab, an inhibitor of the RANK ligand involved in bone resorption in GCT, is increasingly used in treatment of recurrent or unresectable giant cell tumor of bone. We report two cases of sarcomatous transformation of GCT to osteosarcoma in patients receiving denosumab. One was a 59-year-old male with a 12-year history of GCT and multiple recurrences taking denosumab for 2.5 years. The second case was in a 56-year-old male with a seven-year history of GCT taking denosumab for six months. Review of the literature shows one case report of malignant transformation of GCT in a patient being treated with denosumab. As the use of denosumab for treatment of GCT will likely increase, larger, controlled studies are needed to ascertain whether denosumab may play a role in malignant transformation of giant cell tumor of bone.

Giant cell tumor of the humeral head treated by denosumab: Implication to shoulder surgeons

Giant cell tumor is a benign bone tumor that is commonly encountered. The optimal treatment of a giant cell tumor which causes extensive bony destruction is controversial. Recent studies on the receptor activator of nuclear factor κB ligand antagonist denosumab may offer a new treatment option for these patients. We presented a patient with giant cell tumor of the humeral head. He was initially treated with denosumab and subsequently with the operation. The shoulder joint was successfully salvaged. But there are potential difficulties that surgeons may face in patients treated with denosumab.