Giant cell tumor: rapid recurrence after cessation of long-term denosumab therapy

Significance of Biogenetic Markers in Giant Cell Tumor Differentiation and Prognosis: A Narrative Review

Background: Giant cell tumor of bone (GCTB) is a locally aggressive tumor. It accounts for only 5% of all bony tumors. Early diagnosis, and follow-up for recurrence is often difficult due to a lack of biogenetic markers. Giant cells are multinucleated epithelioid cells derived from macrophages. Histologically, giant cells are also present in other pathologies of bone, e.g., aneurysmal bone cyst, chondroblastoma, giant cell granuloma, and malignant giant cell tumor, etc. Similarly, radiographic findings overlap with other osteolytic lesions, making the diagnosis and prognosis of giant cell tumor very challenging. Aims and Objectives: The purpose of this study was to explore biological and genetic markers which can be used for detection, differentiation, recurrence, and prognosis of GCTB. This will help to better understand the clinical outcome of GCTB and minimize the need for interventions. Methods: We conducted a literature search using Google, Google Scholar, PubMed, Wiley Library, Medline, Clinical trials.org, and Web of Science. Our search strategy included MeSH terms and key words for giant cell tumor and biogenetic markers from date of inception to September 2020. After excluding review articles, 246 duplicates, and non-relevant articles, we included 24 articles out of 1568 articles, summarizing the role of biogenetic markers in the prognosis of GCT. Results: P63 is 98.6% sensitive and relatively specific for GCT as compared to other multinucleated giant cells containing neoplasms. MDM2 (mouse double minute 2 homolog), IGF1 (insulin-like growth factor 1), STAT1 (signal transducer and activator of transcription 1), and RAC1 (Ras-related C3 botulinum toxin substrate 1) are associated with GCTB recurrence, and might serve as biomarkers for it. Increased expression of the proteins STAT5B, GRB2, and OXSR1 was related to a higher probability of metastasis. H3F3A and H3F3B mutation analysis appears to be a highly specific, although less sensitive, diagnostic tool for the distinction of giant cell tumor of bone (GCTB) and chondroblastoma from other giant cell-containing tumors. A neutrophil to lymphocyte ratio (NLR) > 2.70, platelet to lymphocyte ratio (PLR) > 215.80, lymphocyte to monocyte ratio (LMR) ≤ 2.80, and albumin to globulin ratio (AGR) < 1.50 were significantly associated with decreased disease-free survival (DFS) (p < 0.05). Large amounts of osteoclast-related mRNA (cathepsin K, tartrate-resistant acid phosphatase, and matrix metalloproteinase9) in GCTs (p < 0.05) are associated with the grade of bone resorption. We propose that subarticular primary malignant bone sarcomas with H3.3 mutations represent true malignant GCTB, even in the absence of a benign GCTB component. IMP3 and IGF2 might be potential biomarkers for GCT of the spine in regulating the angiogenesis of giant cell tumor of bone and predicting patients' prognosis. Conclusions: This review study shows serological markers, genetic factors, cell membrane receptor markers, predictive markers for malignancy, and prognostic protein markers which are highly sensitive for GCT and relatively specific for giant cell tumor. MDM2, IGF1, STAT1, RAC1 are important makers in determining recurrence, while P63 and H3F3A differentiate GCT from other giant cell-containing tumors. STAT5B, GRB2, and OXSR1 are significant in determining the prognosis of GCT. Apart from using radiological and histological parameters, we can add them to tumor work-up for definitive diagnosis and prognosis.

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.

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.

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.

Metastasis in Sinonasal Region Revealing a Silent Primary: A Series of 2 Cases with Review of Literature

Metastasis to the nasal cavity and paranasal sinuses are very rare and only few cases have been reported so far. Metastatic nasal mass with silent primary renal cell carcinoma (RCC) is even rarer. So are giant cell tumors which rarely affects soft tissues whether superficial or deep. These rarely occur in nasal cavity. We would like to discuss 2 cases-one being a 74 year old female with a solitary asymptomatic extensive metastatic lesion in sinonasal area of silent primary renal cell carcinoma and other being a 38 year old female multiple lytic expansile lesions in facial and skull bones who was previously treated for giant cell tumor of long bone-tibia. We aim to bring their occurrence to notice as they are rare, to highlight importance of these tumors in differential diagnosis of sinonasal masses and treatment options for the same.

The Activation of PDGFRβ on Mononuclear Stromal/Tumor Cells in Giant Cell Tumor of Bone After Denosumab Treatment. An Immunohistochemical Study of Five Cases

Due to the relatively high recurrence rate and the destructive nature of the tumor, the treatment of giant cell tumor is still a challenge. Denosumab appeared to be a promising candidate as a therapeutic drug. However, several studies have reported that tumors can recur during/after treatment with denosumab. Based on activated receptor tyrosine kinase signaling pattern of the stromal/tumor cells, a combination treatment with denosumab and sunitinib has recently been proposed to inhibit recurrences. This prompted us to investigate the PDGFRβ expression of five denosumab treated cases using both primary and recurrent tumors during and after denosumab treatment. In addition, to recognise morphological changes, immunohistochemical analysis of H3F3A and PDGFRβ was also performed. As an effect of denosumab treatment, the permanent absence of giant cells associated with severe to mild fibrosis was the most consistent morphological change, but H3F3A positive stromal/tumor cells were observed in all cases. Furthermore, an increased immunopositivity of PDGFRβ in stromal/tumor cells was evident in all recurrent cases during denosumab treatment. Upon tumor recurrence (after the discontinuation of denosumab treatment) the intensity of PDGFRβ immunostaining in stromal/tumor cells was restored/decreased. Our results confirm (for the first time) the activation of PDGFRβ on mononuclear stromal/tumor cells at protein level as an effect of denosumab treatment, which has so far only been demonstrated by phosphoprotein array analysis (protein lysates). The decreased PDGFRβ activity after the discontinuation of denosumab treatmeant and the increased PDGFRβ activity during denosumab treatment underlines the need for denosumab and sunitinib combination therapy.

Denosumab in Giant Cell Tumor of Bone: Multidisciplinary Medical Management Based on Pathophysiological Mechanisms and Real-World Evidence

Simple Summary

The widely accepted local therapy in extremity giant cell tumor of bone (GCTB) is surgery, in the form of extended intralesional curettage with adequate disease clearance and retention of the limb, wherever possible. Denosumab is a relevant therapy option for advanced GCTB, to benefit tumor response and surgical down-staging. Most GCTB patients with localized disease can be successfully treated with surgical curettage; patients with primary unresectable lesions or metastases may experience long-term clinical and radiological remission and pain control with denosumab treatment, and in this clinical situation, denosumab is currently the treatment of choice.

Abstract

(1) Despite the benign nature of the giant cell tumor of bone (GCTB), it shows a local recurrence rate of up to 50% and a chance of malignant transformation. The widely accepted local therapy in extremity GCTB is surgery, in the form of extended intralesional curettage with adequate disease clearance and retention of the limb, wherever possible. Denosumab, a human monoclonal antibody directed against the RANKL and associated inhibition of the RANKL pathway, is a relevant therapy option for advanced GCTB, to benefit tumor response and surgical down-staging. (2) The literature review of patients with GCTB treated with denosumab is performed via PubMed, using suitable keywords from January 2009 to January 2021. (3) Current indications for denosumab use are not definitively clear and unambiguous. Most GCTB patients with localized disease can be successfully treated with surgical curettage, and the role of denosumab in preoperative therapy in this patient population remains unclear. (4) However, patients with primary unresectable lesions or metastases may experience long-term clinical and radiological remission and pain control with denosumab treatment, and in this clinical situation, denosumab is currently the treatment of choice.

Evaluating the Optimal Management of Inoperable Giant Cell Tumors of the Spine: A Systematic Review and Meta-Analysis

Simple Summary

Spine giant cell tumors (SGCTs) are intermediate malignant bone tumors, sometimes aggressive and responsible for debilitating axial pain and sensorimotor impairments. Non-surgical therapies, including denosumab, radiotherapy, and selective arterial embolization (SAE), have shown promising results in the treatment of patients with inoperable SGCTs. In this systematic review, we aimed to comprehensively analyze the current literature on denosumab, radiotherapy, and SAE for inoperable SGCTs, comparing treatment outcomes and complications using a random-effect model meta-analysis. We found that all three treatments were equally effective in providing symptom improvement and radiological tumor response, also showing low and comparable rates of treatment-related complications. Patients treated with denosumab showed lower rates of local recurrences and distant metastases.

Abstract

Background: Surgical resection remains the preferred treatment in spine giant cell tumors (SGCTs), but it is not always feasible. Conservative strategies have been studied for inoperable cases. We systematically reviewed the literature on inoperable SGCTs treated with denosumab, radiotherapy or selective arterial embolization (SAE). Methods: PubMed, Scopus, Web-of-Science, Ovid-EMBASE, and Cochrane were searched following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines to include studies of inoperable SGCTs treated with denosumab, radiotherapy or SAE. Treatment outcomes were analyzed and compared with a random-effect model meta-analysis. Results: Among the 17 studies included, 128 patients received denosumab, 59 radiotherapy, and 43 SAE. No significant differences in baseline patient characteristics were found between the three groups. All strategies were equally effective in providing symptom improvement (p = 0.187, I² = 0%) and reduction in tumor volume (p = 0.738, I² = 56.8%). Rates of treatment-related complications were low (denosumab: 12.5%; radiotherapy: 8.5%; SAE: 18.6%) and comparable (p = 0.311, I² = 0%). Patients receiving denosumab had significantly lower rates of local tumor recurrence (10.9%) and distant metastases (0%) compared to patients receiving radiotherapy (30.5%; 8.5%) or SAE (35.6%; 7%) (p = 0.003, I² = 32%; p = 0.002, I² = 47%). Denosumab was also correlated with significantly higher overall survival rates at 18 months (99.2%) and 24 months (99.2%) compared to radiotherapy (91.5%; 89.6%) and SAE (92.5%; 89.4%) (p = 0.019, I² = 8%; p = 0.004, I² = 23%). Mortality was higher in patients receiving SAE (20.9%) or radiotherapy (13.6%) compared to denosumab (0.8%) (p < 0.001), but deaths mostly occurred for unrelated diseases. Conclusions: Denosumab, radiotherapy, and SAE are safe and effective for inoperable SGCTs. Clinical and radiological outcomes are mostly comparable, but denosumab may provide superior tumor control.

Rapid Recurrence of Giant Cell Tumour of C2 Vertebra After Long-Term Denosumab Following Surgical Resection

A 25-year-old man presented with symptoms of cervical myelopathy for 10 days. Imaging revealed an expansile, lytic lesion involving the C2 vertebra completely and compressing the spinal cord, suggestive of giant cell tumor (GCT). Tumor resection and posterior stabilization from C1-C4 were done. Histopathology confirmed the diagnosis of GCT. The patient was kept on adjuvant Denosumab (D-ab) for two years with no signs of recurrence. However, discontinuation of D-ab therapy led to recurrence of the tumor within three months, which was managed with repeated surgical resection and anterior instrumentation followed by radiotherapy. To the best of our knowledge, this is the first reported case of GCT involving the upper cervical spine with rapid recurrence following the stoppage of D-ab therapy.

Clinical and pathological analysis of giant cell tumor of bone with denosumab treatment and local recurrence

BACKGROUND

Giant cell tumor of bone (GCTB) is a primary bone tumor which comprises giant cells and two types of stromal cells. Recent studies have suggested therapeutic risks of denosumab. No previous studies have reported changes in serum TRACP-5b and SUVmax of ¹⁸F-FDG-PET/CT in recurred GCTB after denosumab treatment. Therefore, we assessed the relationship between clinical and pathological features of GCTB which recurred after denosumab treatment.

METHODS

We retrospectively reviewed the medical records of 26 patients with GCTB who underwent curettage between 2010 and 2018. Fourteen patients treated with denosumab were defined as the denosumab group. We evaluated TRACP-5b and SUVmax values in the denosumab group. H&E staining and immunohistochemistry for H3.3 G34W were performed for pathological assessment. Twelve patients treated without denosumab were defined as the non-denosumab group and compared with denosumab group.

RESULTS

The local recurrence rate in the denosumab group was 57.4%. The mean TRACP-5b and SUVmax values were significantly decreased after denosumab therapy (P < 0.001, 1077 ± 161 to 74 ± 9 mU/dL and 8.88 ± 0.40 to 3.79 ± 0.56, respectively). Both parameters significantly increased with local recurrence. H&E staining after denosumab treatment revealed the disappearance of giant cells and histological changes in stromal cells. Specimens of local recurrence subjected to H&E staining and immunohistochemistry for H3.3 G34W demonstrated almost identical features to those in the first biopsy.

CONCLUSION

Although denosumab can prevent GCTB from osteolysis, local recurrence cannot be reduced by denosumab treatment. The clinical and pathological results were almost the same as those before denosumab treatment, suggesting that the changes of GCTB by denosumab are reversible.

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.

Multiple Pulmonary Metastases of Recurrent Giant Cell Tumor of Bone with Expression of VEGFR-2 Successfully Controlled by Denosumab and Apatinib: A Case Report and Literature Review

Giant cell tumor of bone (GCTB) is a rare, benign, but locally aggressive bone tumor. It has a high tendency for local recurrence, which may increase the incidence of lung metastasis. Currently, an optimal treatment strategy has not been established because of the rarity of pulmonary metastatic GCTB. Denosumab is the preferred regimen for unresectable metastatic lesions; however, there are no alternative treatment options when patients are resistant to denosumab. Apatinib is a small-molecule tyrosine kinase inhibitor that selectively competes for the vascular endothelial growth factor receptor 2 (VEGFR-2) ATP binding site, and several studies have analyzed the effectiveness of apatinib in advanced or metastatic tumors. However, there is no report of apatinib as an anti-angiogenesis therapy for pulmonary metastatic GCTB to date. Here, we present a case of a 26-year-old female who was diagnosed with recurrent and pulmonary metastatic GCTB. Immunohistochemical (IHC) staining indicated that the tumor cells were positive for VEGFR-2. Denosumab was administered to control the metastases; nevertheless, disease progression was confirmed after four months of treatment. Given the IHC results and rapid disease progression, apatinib was added to the treatment strategy. After 42 months of treatment, the patient showed noticeable symptomatic improvement and considerable tumor shrinkage.

Denosumab for Effective Tumor Size Reduction in Patients With Giant Cell Tumors of the Bone: A Systematic Review and Meta-Analysis

BACKGROUND

Denosumab is a human monoclonal antibody that has been used successfully in the treatment of giant cell tumors of bone. These tumors are rare and, in principle, benign, but they are highly aggressive, locally advanced, osteolytic bone tumors that can metastasize to the lungs. Denosumab is an effective treatment when these tumors cannot be surgically removed or when surgical resection is likely to lead to severe morbidity (eg, loss of limbs or joints). The aim of this systematic review and meta-analysis was to investigate patients with giant cell tumors of bone who experienced tumor progression during treatment with denosumab and to compare them with patients who experienced reduction of their giant cell tumors of bone during treatment with denosumab.

METHODS

Embase, Cochrane Library, and MEDLINE/PubMed databases were searched for trials submitted by January 7, 2020, that reported the efficacy and safety of denosumab in patients with giant cell tumors of bone.

RESULTS

Sixty studies were reviewed, involving a total of 1074 patients who had giant cell tumors of bone and were treated with denosumab. Of the 60 studies, 58% of the patients were from case series studies, 39% from open-label phase II studies, and 3% from case reports. The response rate for denosumab as a treatment for giant cell tumors of bone was 97.5%, with statistical significance (P < .0001). Pain in the limbs was statistically the most common adverse event for denosumab treatment in case series studies (P < .0001). No treatment-related deaths occurred in the reviewed studies.

CONCLUSION

Cumulative evidence supports the addition of surgery to optimal medical therapy with denosumab to reduce tumor size, clinical symptoms, and mortality among patients with giant cell tumors of bone.

Dynamic polarization shifting from M1 to M2 macrophages in reduced osteonecrosis of the jaw-like lesions by cessation of anti-RANKL antibody in mice

Denosumab-related osteonecrosis of the jaw (DRONJ), which mainly occurs in cancer patients receiving anti-receptor activator NF-kappaB ligand (RANKL) antibody, reduces oral health-related quality of life. However, the exact mechanisms of and definitive treatment strategies for DRONJ remain unknown. We hypothesized that cessation of denosumab heals and/or ameliorates DRONJ, since it is a protein-based antibody agent, although stopping denosumab should be avoided in clinical situations. Therefore, the aims of this study were: 1) to create a healing and/or amelioration murine model of DRONJ-like lesions induced by chemotherapy/anti-RANKL antibody (mAb) combination therapy and tooth extraction; and 2) to investigate histopathology and immunopathology in the extraction sockets by comparing the murine model of DRONJ-like lesions with the amelioration/healing model of DRONJ-like lesions. Eight-week-old, female C57B/6J mice received chemotherapeutic drug (cyclophosphamide: CY) and mAb combination therapy (CY/mAb) with tooth extraction. Open wounds were sustained in CY/mAb-treated mice at 2 and 4 weeks post-extraction. Impaired socket healing was diagnosed as CY/mAb-related ONJ-like lesions at 3 weeks post-extraction in this study. Next, mAb was discontinued for 2 and 4 weeks after diagnosis of CY/mAb-related ONJ-like lesions. mAb cessation for 2 weeks induced partial osseous wound healing and significantly improved soft tissue wound healing of the extraction sockets. Anti-angiogenesis and normal lymphangiogenesis with CY/mAb combination therapy was not changed by mAb discontinuation. However, mAb cessation for 2 weeks significantly increased the number of CD38⁺F4/80⁺ M1 and CD163⁺F4/80⁺ M2 macrophages, which significantly increased the M2/M1 ratio in the connective tissue of extraction sockets. No direct effects of mAb on macrophages were noted both in vivo and in vitro. Therefore, the developed healing and/or amelioration murine model of CY/mAb-related ONJ-like lesions is a useful tool to investigate the histopathology and immunopathology of DRONJ in humans. Dynamic polarization shifting from M1 to M2 macrophages induced by mAb cessation may play an important role in wound healing, rather than angiogenesis and lymphangiogenesis, in DRONJ.

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.

Giant cell tumors of the sacrum: is non-operative treatment effective?

PURPOSE

Giant cell tumors of sacrum in which surgery could endanger important neural components were treated with short term denosumab, angioembolisation and radiotherapy in different combinations to provide a non-operative function preserving treatment option.

METHODS

Between April 2013 and April 2017, 13 sacral GCTs [proximal extent of disease-S1 (10), S2 (2) and S3 (1)] were treated. Age ranged from 20 to 50 years. One patient had loss of bladder control at presentation. Treatment protocol included short term denosumab, angioembolisation and radiotherapy in different combinations. Patients were evaluated every 10-12 weeks. If disease ceased to progress no further treatment was advised. In case of progress, patient was advised additional denosumab and/or angioembolisation and/or radiotherapy till disease stopped progressing.

RESULTS

10 patients have non-progressive disease and are asymptomatic, 2 have non-progressive disease with occasional pain, 1 patient died. Follow-up duration (since final non-progression of disease) ranged from 15 to 54 months (mean 31 months). Total number of angio embolisation sessions ranged from 0 to 12 (mean = 4), total number of denosumab doses ranged from 5 to 16 (mean = 9). Five patients did not receive any radiotherapy, 5 received 50.4 Gy and one patient each received 50.4 + 30 + 12 Gy, 50.4 + 30 Gy and 50.4 + 12 Gy. The patient with loss of bladder control at presentation recovered. There were no other long-term complications.

CONCLUSION

This study offers a non-surgical management option that provides good mid-term local control while preserving neurological function in these complex lesions.

Denosumab in Giant Cell Tumor of Bone: Current Status and Pitfalls

Denosumab is a monoclonal antibody against RANK ligand for treatment of giant cell tumor of bone (GCTB). Clinical trials and case series have demonstrated that denosumab is relevant to beneficial tumor response and surgical down-staging in patients of GCTB. However, these trials or case series have limitations with a short follow-up. Recent increasing studies revealed that denosumab probably increased the local recurrence risk in patients treated with curettage. This may be caused by the thicken bone margin of tumor that trapped tumor cells from curettage. The direct bone formation by tumor cells in the margin after denosumab treatment also contributed to the local recurrence. in vitro studies showed denosumab resulted in a cytostatic instead of a true cytotoxic response on neoplastic stromal cells. More importantly, denosumab-treated GCTB exhibited morphologic overlap with malignancy, and a growing number of patients of malignant transformation of GCTB during denosumab treatment have been reported. The optimal duration, long term safety, maintenance dose, and optimum indications remain to be elucidated. With these concerns in mind, this review warns that the denosumab therapy of GCTB should be applied with caution.

Denosumab for Bone Giant Cell Tumor of the Distal Radius

There are conflicting reports regarding the outcome and effect of denosumab for distal radius giant cell tumor of bone (GCTB). The authors performed this study to evaluate the behavior of distal radius GCTB in relation to the type of treatment and the administration of denosumab. The files of 72 patients with distal radius GCTB treated from 1984 to 2018 were reviewed. Fourteen patients were administered denosumab. Surgical treatment consisted of curettage (25 patients) or resection (47 patients) and allograft or vascularized fibular head graft reconstruction. Median follow-up was 63.1 months (interquartile range [IQR], 35.5-107.1 months). The authors evaluated local recurrences, metastasis, function, and complications. The local recurrence rate was 30.6% at a median of 14.0 months (IQR, 10-19 months), with no difference between curettage and resection. The local recurrence rate was significantly higher in the patients who received denosumab. The metastasis rate was 9.7% at a median of 41.0 months (IQR, 15-114 months), with no difference regarding denosumab administration. Function was significantly better in patients after curettage. The complication rate was 25%; vascularized fibular graft reconstruction was associated with fewer complications. This study found that denosumab increases the risk of local recurrence after curettage, function is better after curettage, and vascularized fibular graft is the optimal reconstruction after resection of distal radius GCTB. [Orthopedics. 2020;43(5):284-291.].

Radiological findings of denosumab treatment for giant cell tumours of bone

Giant cell tumours of bone (GCTB) are benign giant cell-rich tumours typically occurring in the epi-metaphysis of skeletally mature patients. Despite their benign classification, GCTB may be locally aggressive with local recurrence as a challenging issue. Denosumab is a human monoclonal antibody that inhibits osteolysis via the RANK-RANK ligand pathway. There is currently no consensus on optimal treatment duration or imaging modality for monitoring patients on denosumab therapy. This review illustrates the radiological findings of GCTB on denosumab treatment seen on plain radiographs, CT, MRI, PET-CT and DEXA, with reference to the current literature. Recognizing imaging features indicative of a positive response to denosumab is important for therapeutic decision-making. Imaging findings with respect to duration of denosumab treatment, tumour upregulation during treatment, tumour recurrence and malignant transformation are discussed. The development of a sclerotic neocortex and varying degrees of matrix osteosclerosis are seen on plain radiographs. Reconstitution of subarticular bone and articular surface irregularity are optimally evaluated on CT which can also quantify tumour density. MRI demonstrates heterogeneous low signal matrix and is useful to assess decrease in size of cystic and/or soft tissue components of GCTB. A fat-suppressed fluid-sensitive MR sequence is important to detect tumour reactivation. Reduction in 18F-FDG-PET avidity represents an early sensitive sign of response to denosumab treatment. Regardless of imaging modality, close follow-up in a specialist centre and careful evaluation of nonresponders is necessary as local recurrence after cessation of denosumab treatment and malignant transformation of GCTB have been described.

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.

Denosumab-treated Giant Cell Tumors of Bone: A Clinicopathologic Analysis of 35 Cases From the French Group of Bone Pathology

Denosumab, an antibody directed against receptor activator of nuclear factor-κB ligand (RANKL), has recently been introduced in the treatment strategy of giant cell tumor of bone. In this study, we assessed the tumor changes induced by denosumab in a national multicentric series of 35 cases (French Bone Pathology Group network-ResOs). Tissue specimens collected before and after denosumab treatment were investigated for RANKL, H3.3 G34W, p63, and Ki-67 expression, and for H3F3A mutation. These parameters were put in correspondance with clinical and radiologic presentation to identify prognostic factors, and more specifically, predictive markers of an optimal histologic response to denosumab, identified as a ≥50% loss in giant cells with fibrosis and ossification. The main changes in posttreatment specimens showed an induction of ossification (P=2.10), an increased fibrosis (P=3.10), and a major decrease in giant cells (P=6.10). No significant change in mononuclear tumor cell density and in patterns of expression of RANKL (P=0.061) and H3.3 G34W was observed (P=0.061). An optimal histologic response to denosumab treatment was associated with an enhanced progression-free survival (P=0.010 in univariate analyses; P=0.040 in multivariate analyses). The initial number of giant cells was predictive of the histologic response to treatment (P=0.016). In summary, denosumab treatment induced radical changes in the tumor. The histologic response, despite the absence of objective regression of the mononuclear cells, was associated with an enhanced progression-free survival. Greater numbers of giant cells represented the only predictive indication of an optimal histologic response to denosumab treatment.

Denosumab in giant cell tumour of bone in the pelvis and sacrum: Long-term therapy or bone resection?

INTRODUCTION

Surgery of GCTB in sacrum and pelvis is challenging, with high rates of complications and local recurrence. Denosumab can consolidate the peripheral rim of the tumour, thus reducing the rate of morbidities of surgery. The aim of this paper is to evaluate the use of denosumab in pelvic/sacrum giant cell tumours of bone (GCTB).

PATIENTS AND METHODS

We retrospectively reviewed a cohort of 26 patients with aggressive GCTB in sacrum or pelvis treated with denosumab at two referral centres. Clinical response and local recurrence were recorded and the radiologic responses were evaluated with the MDA criteria.

RESULTS

69% of the pelvic GCTB treated with denosumab presented partial or good radiologic responses (type 2A or 2B) after 49 weeks of treatment. Denosumab was administered as adjuvant therapy prior and after surgery in 11 patients (group A), and as the only treatment in 15 patients (group B). In group A, 62% of local recurrence was observed in patients treated with intralesional curettage. No recurrences were identified after en bloc resection. In group B, 9 patients were on continuous bimonthly long term denosumab administration with type 2A and 2B responses. Six patients stopped denosumab and 66% remained stable after 10 months of follow-up.

CONCLUSIONS

Long-term denosumab therapy can be considered with curative intent for pelvic and sacrum GCTB. If surgical intervention is required wide resection may be advisable to reduce the risk of recurrence.

Total spondylectomy for Enneking stage III giant cell tumor of the mobile spine

PURPOSE

We reported the surgical outcomes of total en bloc spondylectomy (TES) with intralesional T-saw transpedicular osteotomy in patients with Enneking stage III spinal giant cell tumors (GCTs).

METHODS

The medical records and imaging and pathological studies of 25 consecutive patients with Enneking stage III spinal GCTs undergoing surgery at our institution who were followed for at least 2 years were retrospectively reviewed.

RESULTS

Eight men and 17 women (mean age: 34.2 years, range 16-51 years, at the time of surgery) were included. Six patients underwent previous tumor excision at another hospital, and one patient had a history of denosumab treatment. The GCTs were at the cervical, thoracic, and lumbar levels in three, nine, and 13 patients, respectively. TES was performed in 13 patients; 12 required intralesional pediculotomy. The remaining patients underwent total piecemeal spondylectomy with further intralesional tumor resection. During a mean follow-up of 99.2 months (range 24-216), two patients who underwent total piecemeal spondylectomy had local tumor recurrence, but no patients who underwent TES with intralesional pediculotomy had recurrence. The 2- and 10-year recurrence-free survival rates of patients treated with total piecemeal spondylectomy were 91.7% and 78.6%, respectively, while those of patients treated with TES were both 100%.

CONCLUSIONS

TES with intralesional pediculotomy had a good surgical outcome even in patients with Enneking stage III spinal GCT, suggesting that minimal intralesional procedures could radically cure spinal GCTs. These slides can be retrieved under Electronic Supplementary Material.

Denosumab does not decrease the risk of lung metastases from bone giant cell tumour

PURPOSE

There are conflicting reports on the effect of denosumab on lung metastases in patients with giant cell tumor (GCT) of bone. To address these reports, we performed this study to determine if denosumab prevents lung metastasis and to evaluate univariate and multivariate predictors for lung metastases in these patients.

MATERIALS AND METHODS

We retrospectively studied 381 GCT patients with surgery alone and 30 GCT patients with surgery and denosumab administration. The median follow-up was 85.2 months (IQR, 54.2-124.4 months). We evaluated lung metastases and local recurrences, univariate and multivariate predictors for lung metastases, response, and adverse events of denosumab administration.

RESULTS

The occurrence of lung metastases was similar (surgery alone 4.7%, 18 patients; denosumab administration 3.3%, 1 patient); however, the occurrence of local recurrences was significantly higher in the patients with denosumab administration. Denosumab administration was not an important predictor for lung metastases; Campanacci stage and type of surgery were the only univariate predictors for lung metastases, and type of surgery and local recurrence were the only multivariate predictors for lung metastases. Histology showed viable tumour in all tumor specimens of the patients with denosumab administration.

CONCLUSION

Denosumab does not decrease the risk of lung metastases in patients with bone GCT; the only important predictors for lung metastases in these patients are type of surgery and local recurrence. However, because the number of patients with lung metastases was small for a multivariate analysis, the possibility of denosumab's effect could not be completely eliminated.

Safety and efficacy of denosumab in the treatment of pulmonary metastatic giant cell tumor of bone

Background

Giant cell tumor (GCT) of bone is an intermittent and locally aggressive tumor with increasing pulmonary metastatic potential. In this study, we evaluated the interim clinical outcome of denosumab in patients with pulmonary metastatic GCT.

Materials and methods

We retrospectively reviewed seven patients with pulmonary metastatic GCT who received denosumab treatment after local tumor surgery during January 2014 and July 2016. Denosumab treatment for all patients lasted for at least 12 months. Serial chest computerized tomography scan was used to monitor the drug response and RECIST 1.1 standard was used to evaluate the therapeutic efficacy.

Results

All patients experienced chest pain relief in the first month of treatment. Three patients showed partial response. Four patients got stable disease after denosumab treatment. Adverse events included one patient with hypocalcemia and two patients with fever. No treatment-related deaths were reported. No patient with metastatic disease progression was found during an average of 28.6 months follow-up period.

Conclusion

We presented a promising interim clinical outcome using denosumab to treat patients with pulmonary metastatic GCT. Denosumab might be considered as the first-line treatment for patients with inoperable metastatic pulmonary GCT. However, Phase II clinical study with larger number of patients and longer follow-up period is needed to detect the further efficacy and safety of this drug for lung metastatic GCT.

Denosumab: a potential treatment option for aneurysmal bone cyst of the atlas

PURPOSE

Aneurysmal bone cysts (ABCs) of spine are conventionally treated with en-bloc resection or intralesional excision/curettage and reconstruction or filling of defects with bone cement. For the treatment of upper cervical ABCs, en-bloc resections are often not desirable considering the risk/benefit ratio while the risk of recurrence after intralesional excision is high. Hence, alternative management options are often necessary. We describe our clinical experience with one such treatment alternative-denosumab for the treatment of ABC of Atlas.

METHODS AND RESULTS

We present a case of 16-year-old boy who presented with neck pain and restriction of neck movements. A large lytic lesion with multiple fluid-fluid interfaces involving vertebral arch of atlas was identified on further imaging. There was destruction of right lateral mass and the lesion was found encasing the right vertebral artery. Core needle biopsy confirmed the diagnosis of ABC. With no visible CT response after first session of intra-lesional injection of Calcitonin and Methylprednisolone, the patient was treated with denosumab (120 mg SC once-a-month) for a period of 12 months. His symptoms resolved within 7 months of onset of treatment and serial CT scans over 12-month treatment period showed complete ossification of the lesion. Further there was no evidence of recurrence at 12 months after completion of treatment.

CONCLUSION

Our case report contributes to the accruing evidence on the effectiveness of denosumab for the treatment of spinal ABCs. However, long-term safety, risk of recurrence, optimal duration of treatment and consistency of denosumab are yet to be determined.

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.

Denosumab: an Emerging Therapy in Pediatric Bone Disorders

PURPOSE OF REVIEW

Denosumab is an inhibitor of receptor activator of nuclear factor kappa-B ligand (RANKL), and has emerged as an important novel therapy for skeletal disorders. This article examines the use of denosumab in children.

RECENT FINDINGS

Considerable safety and efficacy data exists for denosumab treatment of adults with osteoporosis, bone metastases, and giant cell tumors. Pediatric data is limited; however, evidence suggests denosumab may be beneficial in decreasing bone turnover, increasing bone density, and preventing growth of certain skeletal neoplasms in children. Denosumab's effect on bone turnover is rapidly reversible after drug discontinuation, representing a key difference from bisphosphonates. Rebound increased bone turnover has led to severe hypercalcemia in several pediatric patients. Denosumab is a promising therapy for pediatric skeletal disorders. At present, safety concerns related to rebounding bone turnover and mineral homeostasis impact use of denosumab in children. Research is needed to determine if and how these effects can be mitigated.

Giant cell tumour of bone in the denosumab era

Giant cell tumour of bone (GCTB) is an intermediate locally aggressive primary bone tumour, occurring mostly at the meta-epiphysis of long bones. Overexpression of receptor activator of nuclear factor kappa-B ligand (RANKL) by mononuclear neoplastic stromal cells promotes recruitment of numerous reactive multinucleated osteoclast-like giant cells, causing lacunar bone resorption. Preferential treatment is curettage with local adjuvants such as phenol, alcohol or liquid nitrogen. The remaining cavity may be filled with bone graft or polymethylmethacrylate (PMMA) bone cement; benefits of the latter are a lower risk of recurrence, possibility of direct weight bearing and early radiographic detection of recurrences. Reported recurrence rates are comparable for the different local adjuvants (27-31%). Factors increasing the local recurrence risk include soft tissue extension and anatomically difficult localisations such as the sacrum. When joint salvage is impossible, en-bloc resection and endoprosthetic joint replacement may be performed. Local tumour control on the one hand and maintenance of a functional native joint and quality of life on the other hand are the main pillars of surgical treatment for this disease. Current knowledge and development in the fields of imaging, functional biology and systemic therapy are forcing us into a paradigm shift from a purely surgical approach towards a multidisciplinary approach. Systemic therapy with denosumab (RANKL inhibitor) or zoledronic acid (bisphosphonates) blocks, respectively inhibits, bone resorption by osteoclast-like giant cells. After use of zoledronic acid, stabilisation of local and metastatic disease has been reported, although the level of evidence is low. Denosumab is more extensively studied in two prospective trials, and appears effective for the optimisation of surgical treatment. Denosumab should be considered in the standard multidisciplinary treatment of advanced GCTB (e.g. cortical destruction, soft tissue extension, joint involvement or sacral localisation) to facilitate surgery at a later stage, and thereby aiming at immediate local control. Even though several questions concerning optimal treatment dose, duration and interval and drug safety remain unanswered, denosumab is among the most effective drug therapies in oncology.

Benign Tumors of the Spine: Has New Chemotherapy and Interventional Radiology Changed the Treatment Paradigm?

STUDY DESIGN

Clinically based systematic review.

OBJECTIVE

To determine the role of (A) medical treatment and (B) interventional radiology as either adjuvant or stand-alone treatment in primary benign bone tumors of the spine.

METHODS

A multidisciplinary panel of spine surgeons, radiation oncologists, and medical oncologists elaborated specific focused questions regarding aneurysmal bone cyst, giant cell tumor, and osteoid osteoma. Denosumab, bisphosphonate, interferon, bone marrow aspirate, doxycycline, thermal ablation, and selective arterial embolization were identified as areas of interest for the article. A systematic review was performed through MEDLINE and EMBASE. Recommendations based on the literature review and clinical expertise were issued using the GRADE system.

RESULTS

The overall quality of the literature is very low with few multicenter prospective studies. For giant cell tumor, combination with Denosumab identified 14 pertinent articles with four multicenter prospective studies. Nine studies were found on bisphosphonates and six for selective arterial embolization. The search on aneurysmal bone cyst and selective arterial embolization revealed 12 articles. Combination with Denosumab, Doxycycline, and bone marrow aspirate identified four, two, and three relevant articles respectively. Eleven focused articles were selected on the role of thermal ablation in osteoid osteoma.

CONCLUSION

Alternative and adjuvant therapy for primary benign bone tumors have emerged. Their ability to complement or replace surgery is now being scrutinized and they may impact significantly the algorithm of treatment of these tumors. Most of the data are still emerging and further research is desirable. Close collaboration between the different specialists managing these pathologies is crucial.

LEVEL OF EVIDENCE

N/A.

Denosumab for Treatment of a Recurrent Cervical Giant-Cell Tumor

A 43-year-old male patient with C5 giant cell tumor (GCT) underwent tumor resection and anterior bone fusion of C4–C6. The tumor recurred locally 9 months after surgery with the patient complaining of neck and shoulder pain similar to his preoperative symptoms. Denosumab was administered and his pain disappeared after a two-month administration, with a sclerotic rim formation seen at the tumor site on computed tomography. He has been followed for 18 months with no evidence of tumor recurrence. Complete resection is generally recommended, but is not easy for many patients with cervical GCT because of the existence of neurovascular structures. Some patients suffer from recurrence and treatment becomes more difficult. As such, denosumab may be an efficacious option for treatment of recurrent GCT of the cervical spine, although long-term follow-up is required to monitor for presence or absence of recurrence.

Interest of Denosumab for the Treatment of Giant-cells Tumors and Aneurysmal Bone Cysts of the Spine. About Nine Cases

STUDY DESIGN

A prospective cohort study.

OBJECTIVE

The aim of this study was to evaluate the interest of denosumab in the treatment of spinal giant-cells tumors (GCTs) and aneurysmal bone cysts (ABCs).

SUMMARY OF BACKGROUND DATA

To treat GCTs and ABCs, surgical resection remains the best treatment to limit local recurrence (LR) but constitutes an aggressive treatment with potential morbidity. Denosumab, a human antibody anti-RankL, inhibiting the differentiation of osteoclasts, could be an alternative treatment to avoid aggressive surgery.

METHODS

Patients suffering from GCTs and ABCs of the spine were included. Patients received a monthly subcutaneous injection of denosumab (120 mg) during a minimum of 6 months either as a neoadjuvant or as an adjuvant therapy. In association with denosumab, an osteosynthesis was added in case of vertebral fracture and a laminectomy in case of spinal cord compression. Clinical and computed tomography (CT)-scan outcomes were analyzed.

RESULTS

Eight GCTs and one ABC were included. The mean age was 35 years (range: 22-55 yr). Five patients had neurologic deficit. All patients were operated: six osteosynthesis, one "en bloc" resection, four curettages, and two of them associated with an osteosynthesis. Average duration of denosumab therapy was 12.9 months (range: 3.2-24 months). Among them, four patients began denosumab 6 months at least before the surgery. With a mean follow-up of 19.3 months (range: 3.2-52.4 months), back pain and neurologic deficit improved for all patients. Systematic CT-scan at 6 months showed decrease of tumor size and bone consolidation. Regarding patients treated by neoadjuvant denosumab treatment, intraoperative histologic analysis showed an absence of giant cells and a maximum of 10% of alive tumor cells.

CONCLUSION

Denosumab allows bone formation and tumor regression with a maximum efficacy after 6 months of treatment without widely substituting surgery. Long-term results are mandatory to confirm the interest of denosumab and to evaluate LR when stopping denosumab.

LEVEL OF EVIDENCE

3.

Role of Denosumab in Endoscopic Endonasal Treatment for Juvenile Clival Giant Cell Tumor: A Case Report and Review of the Literature

BACKGROUND

Giant cell tumors (GCTs) are histologically benign bone neoplasms with a locally aggressive nature that primarily occur in the epiphyses of the long bones. A small proportion of these tumors, however, occur in the pelvis, spine, or skull bones. Among these, GCTs of the skull base cannot be completely resected and require adjuvant therapy. We report a juvenile case of clival GCT that was successfully treated by endoscopic endonasal transsphenoidal surgery and subsequent adjuvant therapy with denosumab, a monoclonal antibody to receptor activator of nuclear factor-κB ligand.

CASE DESCRIPTION

A 16-year-old boy was admitted to our hospital with progressively intolerable headache and right oculomotor nerve palsy. Computed tomography and magnetic resonance imaging showed a large tumor mass in the sphenoid sinus with extensive erosion of the clivus and compression of the right cavernous sinus. The tumor was resected by endonasal transsphenoidal surgery and histologically diagnosed as GCT. The giant cells showed positive immunostaining for CD68 and Mib-1 labeling index was less than 1.0%. Postoperative course was uneventful and the oculomotor disturbance was markedly improved. However, magnetic resonance imaging 2 weeks after surgery revealed marked enlargement of the tumor. Adjuvant therapy with denosumab was therefore initiated, resulting in marked reductions in tumor size.

CONCLUSIONS

This is the first report to describe beneficial effects of denosumab in the treatment of GCT of the skull base.

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.

Spondylectomy for Giant Cell Tumor After Denosumab Therapy

STUDY DESIGN

A case report.

OBJECTIVE

To report a case of the lumbar giant cell tumor (GCT) utilizing a new clinical treatment modality (denosumab therapy), which showed a massive tumor reduction combined with the L4 spondylectomy.

SUMMARY OF BACKGROUND DATA

There are some controversies about spinal GCT treatments. Denosumab has provided good clinical results in terms of tumor shrinkage, and local control in a short-time follow-up clinical study phase 2, although for spinal lesions, it has not been described. Nonetheless, "en bloc" spondylectomy has been accepted as being the best treatments modalities in terms of oncological control.

METHODS

A case study with follow-up examination and series radiological assessments 6 months after therapy started, followed by a complex spine surgery.

RESULTS

The denosumab therapy showed on the lumbar computed tomography scans follow-up 6 months later, a marked tumor regression around 90% associated to vertebral body calcification, facilitating a successful L4 spondylectomy with an anterior and posterior reconstruction. The patient recovered without neurological deficits.

CONCLUSION

A new therapeutic modality for spinal GCT is available and showing striking clinical results; however, it is necessary for well-designed studies to answer the real role of denosumab therapy avoiding or facilitating complex spine surgeries as spondylectomies for spinal GCT.

LEVEL OF EVIDENCE

5.

Systemic therapy for selected skull base sarcomas: Chondrosarcoma, chordoma, giant cell tumour and solitary fibrous tumour/hemangiopericytoma

This review highlights the data currently available on the activity of systemic therapy in chondrosarcoma, chordoma, giant cell tumour of the bone (GCTB) and solitary fibrous tumour, i.e., four rare sarcomas amongst mesenchymal malignancy arising from the skull base.

'Salvage Treatment' of Aggressive Giant Cell Tumor of Bones with Denosumab

Giant cell tumor of the bone (GCTB) presents as a lytic lesion of epiphyseometaphyseal regions of the long bones usually during the second to the fourth decade with female predilection. Histologically, they are formed of neoplastic mononuclear cells with a higher receptor activator of nuclear factor kappa-B ligand (RANKL) expression responsible for the aggressive osteolytic nature of the tumour. RANKL helps in the formation and functioning of osteoclasts. A newer molecule, Denosumab, is a monoclonal antibody directed against RANKL and thus prevents the formation and function of osteoclasts. Management of refractory, multicentric, recurrent, or metastatic GCTB remains challenging as achieving a tumor-free margin surgically is not always possible. Denosumab may play a crucial role, especially in the management of such difficult lesions. We present three cases of locally aggressive GCTB (involving proximal humerus, sacrum, and proximal femur) that were treated and responded very well to Denosumab therapy.