Malignancy in giant cell tumor of bone: analysis of an open-label phase 2 study of denosumab

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

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

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

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

Unusual Presentation of a Giant Cell Tumor of the Bone: A Case Report

Bone giant cell tumors (GCTs) are rare, non-cancerous tumors that mostly affect the meta-epiphyseal region of long bones in the legs and arms. We are reporting a case of GCT of bone of a 14-year-old male; it usually occurs in the age group of 20-40 years. The presence of multinucleated giant cells and stromal cells in the proximal diaphysis of the left tibia serves as a distinguishing characteristic. The majority of GCTs are benign; they have the potential to induce bone loss and can be locally aggressive. Treatment options often include surgery, and in some cases, medications like denosumab may be used to help shrink the tumor or manage recurrent cases.

Investigation of Giant Cell Tumor of Bone and Tissue Engineering Approaches for the Treatment of Giant Cell Tumor of Bone

Primary bone tumors such as Ewing sarcoma, osteosarcoma, and chondrosarcoma, secondary bone tumors developed from progressive malignancies, and metastasized bone tumors are more prevalent and studied descriptively through biology and medical research. Less than 0.2% of cancer diagnoses are caused by rare bone-originating tumors, which despite being rare are particularly difficult due to their high death rates and substantial disease burden. A giant cell tumor of bone (GCTB) is an intramurally invasive but rare and benign type of bone tumor, which seldom metastasizes. The most often prescribed medication for GCTB is Denosumab, a RANKL (receptor activator of nuclear factor κB ligand) inhibitor. Because pharmaceutical drug companies rely on two-dimensional and animal models, current approaches for investigating the diverse nature of tumors are insufficient. Cell line based medication effectiveness and toxicity studies cannot predict tumor response to antitumor medicines. It has already been investigated in detail why molecular pathways do not reproduce in vitro, a phenomenon known as flat biology. Due to physiological differences between human beings and animals, animal models do not succeed in identifying side effects of the treatment, emulating metastatic growth, and establishing the link between cancer and the immune system. This review summarizes and discusses GCTB, the disease, its cellular composition, various bone tumor models, and their properties and utilization in research. As a result, this study delves deep into in vitro testing, which is vital for scientists and physicians in various fields, including pharmacology, preclinical investigations, tissue engineering, and regenerative medicine.

Giant Cell Tumour of Bone: A Comprehensive Review of Pathogenesis, Diagnosis, and Treatment

The benign aggressive tumour known as a giant cell tumour of bone (GCTB) frequently affects the knee bones. Patients suffering from GCTB present with pain, swelling, joint effusion, loss of ability to bear weight on the involved extremity and a restriction in the range of motion of the afflicted joint may also exist, depending on the tumour's size. GCTB makes up 20% of benign skeletal tumours and 5% of all primary bone tumours. Although it has an equal distribution of the sexes, the majority reveal a higher frequency among women. Eighty per cent of GCTB instances were recorded in patients between the ages of 20 and 50 during the third decade. The femur, tibia and radius are where GCTB is most frequently discovered. Lesions can be rated using the Campanacci grading method based on the plain radiograph's results. Plain radiography, CT and MRI are used to diagnose the tumour. Surgery is the only curative treatment which is determined by the Campanacci grade and the tumour's location. Recurrence of GCTB is observed in about 25% of patients, with curettage being associated with rates as high as 50%. We evaluated the GCTB-related articles and summarised the developments in diagnosis, treatment and reducing risk of recurrence.

Giant cell-rich osteosarcoma: A match pair analysis of 11 new cases and literature review of 56 patients

BACKGROUND

Limited remains known on giant cell-rich osteosarcoma (GCRO) with current studies being case reports or smaller series. This investigation compared GCRO and conventional osteoblastic osteosarcoma (OOS) with regard to demographics and survival.

METHODS

An institutional tumor registry was used to identify 11 patients (six males) treated for GCRO. Mean age was 43 years. Staging showed American Joint Committee on Cancer (AJCC) stages IIA in four and IIB in seven patients. Mean follow-up was 14 years. Study initiatives were: (1) Comparison of demographics between GCRO and 167 OOS from our institutional registry, (2) Differences in survival between GCRO and 33 OOS case controls (based on sex and AJCC stage), as well as 10 OOS using an age-based propensity match, and (3) Summary of all GCRO cases reported in the literature.

RESULTS

(1) Sex (p = 0.53), grading (p = 0.56), AJCC stage (p = 0.42), and chemotherapeutic response rate (p = 0.67) did not differ between groups. Age was significantly increased in GCRO (p = 0.001). (2) Case-control and propensity-matched groups revealed no difference in disease-free survival, local recurrence, and distant disease-free survival at 2 years (p > 0.05). (3) Mean age of 56 patients (50% males) reported in the literature was 26 years. After merging with our 11 cases, the 2-year disease-free survival was 66%.

CONCLUSIONS

GCRO remains a rare disease with high short-term mortality. Although affecting older patients more than conventional osteosarcoma, GCRO should not be viewed as a predictor of survival compared to OOS.

Histomorphometric Analysis of 38 Giant Cell Tumors of Bone after Recurrence as Compared to Changes Following Denosumab Treatment

Giant cell tumor of bone (GCTB) is an osteolytic tumor driven by an H3F3A-mutated mononuclear cell with the accumulation of osteoclastic giant cells. We analyzed tissue from 13 patients with recurrence and 25 patients with denosumab therapy, including two cases of malignant transformation. We found a decrease in the total number of cells (p = 0.03), but not in the individual cell populations when comparing primary and recurrence. The patients treated with denosumab showed induction of osteoid formation increasing during therapy. The total number of cells was reduced (p < 0.0001) and the number of H3F3A-mutated tumor cells decreased (p = 0.0001), while the H3F3A wild-type population remained stable. The KI-67 proliferation rate dropped from 10% to 1% and Runx2- and SATB2-positive cells were reduced. The two cases of malignant transformation revealed a loss of the H3F3A-mutated cells, while the KI-67 rate increased. Changes in RUNX2 and SATB2 expression were higher in one sarcoma, while in the other RUNX2 was decreased and SATB2-positive cells were completely lost. We conclude that denosumab has a strong impact on the morphology of GCTB. KI-67, RUNX2 and SATB2 expression differed depending on the benign or malignant course of the tumor under denosumab therapy.

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.

Resection and reconstruction with and without neoadjuvant denosumab in campanacci grade III giant cell tumors of proximal humerus: a retrospective comparative study

BACKGROUND

Giant cell tumors (GCT) of the proximal humerus are rarely reported case that requires complex surgeries due to involvement of the shoulder joint. Therefore, we report the first retrospective comparative study where the postoperative functional outcomes, recurrence rate and complications in patients who underwent arthrodesis of shoulder after resection of grade III GCT with and without neoadjuvant denosumab are compared.

METHODS

A retrospective review of eight cases of grade III GCT of proximal humerus receiving resection and fibular strut graft and arthrodesis between January 2014 and December 2019 is performed. They were stratified into two groups: one group of four patients received once-weekly denosumab 120 mg for 4-weeks before resection and reconstruction, while the other group of four patients did not receive denosumab before surgery. Primary outcomes included the functional outcomes assessed by revised Musculoskeletal tumor society (MSTS) score and shoulder pain and disability index (SPDI) at 6-weeks and 12-months postoperatively while secondary outcomes included complications and recurrences.

RESULTS

There was no significant difference in terms of SPDI at 6 weeks and 12 months, MSTS at 12 months, complications, recurrence among denosumab and non-denosumab groups. At 6-weeks follow-up, a significantly better pain score in SPDI and MSTS was acquired in the denosumab group.

CONCLUSIONS

Resection and reconstruction with or without neoadjuvant denosumab for Grade III GCT of proximal humerus had similar functional outcomes and with no major differences in recurrence and complications. Hence, postoperative pain relief while long-term benefits were not discovered with the use of neoadjuvant denosumab.

A Retrospective Audit of Demography and Different Surgical Modalities Adopted for Giant Cell Tumor of Bone in Eastern India

Background and objective

There is scarce data on demography and different surgical treatment modalities for giant cell tumor of bone (GCTB) from eastern India. In light of this, the present study aimed to examine the demographic characteristics, different surgical treatment modalities, and recurrence rate of GCTB at a tertiary care institute in Bihar.

Materials and methods

A retrospective audit of 52 GCTB patients who were treated at the center from January 2016 to December 2020 was conducted. The minimum follow-up period was one year. GCTB patients underwent surgical procedures ranging from extended intralesional curettage with bone graft or bone cement with or without fixation to wide local excision to resection with or without reconstruction or amputation depending on the stage and site of the tumors.

Results

The mean age of patients was 31.86 years (range: 13-67 years). The distal femur (20 patients, 38.46%) and proximal tibia (11 patients, 21.15%) were the most common sites of the tumor. Sixty-eight confirmed cases (male: 32, female: 36) of GCTB were operated on, with a male-to-female ratio of 1:1.125. Sixteen patients (four males and 12 females) were lost to follow-up. So, the final study consisted of 52 patients with a median age of 28 years (first quartile: 24 years, third quartile: 38 years). The majority of patients (32 patients, 61.53%) were in the third and fourth decades of life.

Conclusion

Based on this retrospective audit, it is concluded that the knee region is the most common site of GCTB. Surgery is the mainstay of management. Most of the patients came under Campanacci Grade 3 with low compliance with follow-up and adherence to the treatment. Hence, educational programs, the establishment of early detection centers, and timely referral to expert treatment are necessary.

Malignant Transformation of Giant Cell Tumour of Bone: A Review of Literature and the Experience of a Referral Centre

Giant cell tumour of bone (GCTB) is a benign, locally aggressive primary bone neoplasm that represents 5% of all bone tumours. The principal treatment approach is surgery. Although generally GCTB is considered only a locally aggressive disease, it can metastasise, and lung metastases occur in 1–9% of patients. To date, only the use of denosumab has been approved as medical treatment for GCTB. Even more rarely, GCTB undergoes sarcomatous transformation into a malignant tumour (4% of all GCTB), but history of this malignant transformation is unclear and unpredictable. Considering the rarity of the event, the data in the literature are few. In this review, we summarise published data of GCTB malignant transformation and we analyse three cases of malignant transformation of GCTB, evaluating histopathology, genetics, and radiological aspects. Despite the rarity of this event, we conclude that a strict follow up is recommended to detect early malignant transformation.

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.

Clinicopathological and histological analysis of secondary malignant giant cell tumors of bone without radiotherapy

Giant cell tumor of bone (GCTB) is an intermediate bone tumor that rarely undergoes malignant transformation. Secondary malignant GCTB (SMGCTB) is defined as a lesion in which high-grade sarcoma occurs at the site of previously treated GCTB. The present study retrospectively reviewed the medical records of patients with GCTB treated at Okayama University Hospital between April 1986 and April 2020. The clinicopathological and histological features of patients with SMGCTB without prior radiotherapy were investigated. A total of three patients (4%) with SMGCTB were detected, and the tumor sites were the distal ulna, distal femur and sacrum. Two of the patients had been treated with curettage and bone graft, and one had been treated with denosumab. In all cases, the lesions were made up of two components, the conventional GCTB component and the malignant component. The Ki67 labeling index was higher in the malignant components of SMGCTB and metastatic lesions compared with that in primary and recurrent conventional GCTB, or the conventional GCTB component of SMGCTB. Moreover, p53 expression was higher in these same components in patients who underwent curettage and bone grafting; however, there was no difference in the patient that received denosumab treatment. In this patient, clinical cancer genomic profiling revealed loss of CDKN2A, CDKN2B and MTAP expression. All three patients developed distant metastasis. The patients with SMGCTB in the ulna and femur died 13 and 54 months after detection of malignant transformation, respectively. The patient with SMGCTB in the sacrum received carbon-ion radiotherapy to the sacrum and pazopanib; the treatment was effective and the patient was alive at the last follow-up 3 years later. In conclusion, p53 may be associated with malignant transformation in GCTB. Future studies should investigate the association of between denosumab treatment and malignant transformation, as well as molecular targeted therapy to improve the clinical outcomes of SMGCTB.

Malignant Transformation of Giant Cell Tumor of Bone and the Association with Denosumab Treatment: A Radiology and Pathology Perspective

Objective

Malignancy in giant cell tumor of bone (mGCTB) is categorized as primary (concomitantly with conventional GCTB) or secondary (after radiotherapy or other treatment). Denosumab therapy has been suggested to play a role in the etiology of secondary mGCTB. In this case series from a tertiary referral sarcoma center, we aimed to find distinctive features for malignant transformation in GCTB on different imaging modalities. Furthermore, we assessed the duration of denosumab treatment and lag time to the development of malignancy.

Methods

From a histopathology database search, 6 patients were pathologically confirmed as having initial conventional GCTB and subsequently with secondary mGCTB.

Results

At the time of mGCTB diagnosis, 2 cases were treated with denosumab only, 2 with denosumab and surgery, 1 with multiple curettages and radiotherapy, and 1 with surgery only. In the 4 denosumab treated patients, the mean lag time to malignant transformation was 7 months (range 2–11 months). Imaging findings suspicious of malignant transformation related to denosumab therapy are the absence of fibro-osseous matrix formation and absent neocortex formation on CT, and stable or even increased size of the soft tissue component.

Conclusion

In 4 patients treated with denosumab, secondary mGCTB occurred within the first year after initiation of treatment. Radiotherapy-associated mGCTB has a longer lag time than denosumab-associated mGCTB. Close clinical and imaging follow-up during the first months of denosumab therapy is key, as mGCTB tends to have rapid aggressive behavior, similar to other high-grade sarcomas. Nonresponders should be (re) evaluated for their primary diagnosis of conventional GCTB.

Secondary Malignancy in Giant Cell Tumor: A Single-Center Study

Giant cell tumor of bone (GCTB) undergoes a sarcomatous transformation. Secondary malignancy in giant cell tumor (MGCT) is associated with radiotherapy and has a dismal prognosis. We reviewed medical records to investigate the clinicopathological characteristics and prognosis of MGCT patients. The enrollment criterion was high-grade spindle-cell sarcoma, which developed at the site of prior GCTB treatment. Twelve patients were analyzed: six females and six males. The median age was 42.5 years. Benign recurrence occurred in five GCTB patients not treated with radiotherapy. No pulmonary implants were observed. The median latency to the malignant transformation was 63 months. Nine patients were AJCC stage IIB, and three were stage IVA. The median follow-up period after malignant transformation was 62.5 months. Five patients developed local recurrence, and six had distant metastasis. Five-year overall recurrence and metastasis-free survival rates were 61.9%, 66.7%, and 58.3%, respectively. Initial metastasis was a predictive factor for overall survival. Benign local recurrence of GCTB was also a negative factor for metastasis-free survival of MGCT patients. Differences in overall survival according to benign recurrence also showed a tendency toward significance. In our series, secondary MGCT did not occur after radiotherapy. The prognosis was better than previous findings. Benign recurrence of GCTB could reflect the prognosis of MGCT.

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.

SELNET clinical practice guidelines for bone sarcoma

Bone sarcoma are infrequent diseases, representing < 0.2% of all adult neoplasms. A multidisciplinary management within reference centers for sarcoma, with discussion of the diagnostic and therapeutic strategies within an expert multidisciplinary tumour board, is essential for these patients, given its heterogeneity and low frequency. This approach leads to an improvement in patient's outcome, as demonstrated in several studies. The Sarcoma European Latin-American Network (SELNET), aims to improve clinical outcome in sarcoma care, with a special focus in Latin-American countries. These Clinical Practice Guidelines (CPG) have been developed and agreed by a multidisciplinary expert group (including medical and radiation oncologist, surgical oncologist, orthopaedic surgeons, radiologist, pathologist, molecular biologist and representatives of patients advocacy groups) of the SELNET consortium, and are conceived to provide the standard approach to diagnosis, treatment and follow-up of bone sarcoma patients in the Latin-American context.

State of the Art and New Concepts in Giant Cell Tumor of Bone: Imaging Features and Tumor Characteristics

Giant cell tumor of bone (GCTB) is classified as an intermediate malignant tumor due to its locally aggressive behavior, burdened by high local recurrence rate. GCTB accounts for about 4-5% of all primary bone tumors and typically arises in the metaphysis and epiphyses of the long tubular bones. Mutation of gene H3F3A is at the basis of GCTB etiopathogenesis, and its immunohistochemical expression is a valuable method for practical diagnosis, even if new biomarkers have been identified for early diagnosis and for potential tumor recurrence prediction. In the era of computer-aided diagnosis, imaging plays a key role in the assessment of GCTB for surgical planning, patients' prognosis prediction and post treatment evaluation. Cystic changes, penetrating irregular margins and adjacent soft tissue invasion on preoperative Magnetic Resonance Imaging (MRI) have been associated with a higher rate of local recurrence. Distance from the tumor edge to the articular surface and thickness of unaffected cortical bone around the tumor should be evaluated on Computed Tomography (CT) as related to local recurrence. Main features associated with local recurrence after curettage are bone resorption around the graft or cement, soft tissue mass formation and expansile destruction of bone. A denosumab positive response is represented by a peripherical well-defined osteosclerosis around the lesion and intralesional ossification. Radiomics has proved to offer a valuable contribution in aiding GCTB pre-operative diagnosis through clinical-radiomics models based on CT scans and multiparametric MR imaging, possibly guiding the choice of a patient-tailored treatment. Moreover, radiomics models based on texture analysis demonstrated to be a promising alternative solution for the assessment of GCTB response to denosumab both on conventional radiography and CT since the quantitative variation of some radiomics features after therapy has been correlated with tumor response, suggesting they might facilitate disease monitoring during post-denosumab surveillance.

Effect of Adjuvant Chemotherapy on Localized Malignant Giant Cell Tumor of Bone: A Systematic Review

Simple Summary

The effect of adjuvant chemotherapy on localized malignant giant cell tumors of the bone (GCTB) is unclear. We compared the mortality associated with wide resection compared to wide resection plus adjuvant chemotherapy for localized primary and secondary localized malignant GCTB. Among 745 relevant studies, 9 were included, with 39 and 73 primary and secondary malignant patients. In primary localized malignant GCTB, the mortality rates were 40% (6/15 patients) and 33% (8/24 patients) in the surgery plus adjuvant chemotherapy and surgery-only groups, respectively. The overall pooled odds ratio was 1.07 (p = 0.92). In secondary localized malignant GCTB, the mortality rates were 30.6% (11/36 patients) and 62.2% (23/37 patients) in the surgery plus adjuvant chemotherapy and surgery-only groups, respectively. The overall pooled odds ratio was 0.31 (p = 0.04). The effect of adjuvant chemotherapy remains unclear for primary localized malignant GCTB, but adjuvant chemotherapy improved the survival of patients with secondary localized malignant GCTB.

Abstract

A malignant giant cell tumor of the bone (GCTB) is a rare primary malignant tumor classified as primary or secondary. Wide resection of the primary tumor is recommended for localized malignant GCTB, but the effect of adjuvant chemotherapy is unclear. A systematic review was performed to compare the mortality associated with wide resection with that of wide resection plus adjuvant chemotherapy for primary and secondary localized malignant GCTB. Among the 745 studies identified, 9 were included. A total of 112 cases of localized malignant GCTB were included, with 39 and 73 cases being primary and secondary malignant GCTB. In primary localized malignant GCTB, the mortality rates were 40% (6/15 patients) and 33% (8/24 patients) in the surgery plus adjuvant chemotherapy and surgery-only groups, respectively. Overall pooled odds ratio was 1.07 (95% confidence interval, 0.26–4.37; p = 0.92). In secondary localized malignant GCTB, the mortality rates were 30.6% (11/36 patients) and 62.2% (23/37 patients) in the surgery plus adjuvant chemotherapy and surgery-only groups, respectively. The overall pooled odds ratio was 0.31 (95% confidence interval, 0.10–0.95; p = 0.04). The effect of adjuvant chemotherapy remains unclear for primary localized malignant GCTB, but adjuvant chemotherapy improved the survival of patients with secondary localized malignant GCTB.

Current Concepts in the Treatment of Giant Cell Tumors of Bone

Simple Summary

According to the 2020 World Health Organization classification, a giant cell tumor of bone is an intermediate malignant bone tumor. Denosumab treatment before curettage should be avoided due to the increased risk of local recurrence. Administration of denosumab before en bloc resection of the giant cell tumors of the pelvis and spine facilitates en bloc resection. Nerve-sparing surgery after embolization is a possible treatment for giant cell tumors of the sacrum. Denosumab therapy with or without embolization is indicated for inoperable giant cell tumors of the pelvis, spine, and sacrum. A wait-and-see approach is recommended for lung metastases at first, then denosumab should be administered to the growing lesions. Radiotherapy is not recommended owing to the risk of malignant transformation. Local recurrence after 2 years or more should be indicative of malignant transformation. This review summarizes the treatment approaches for non-malignant and malignant giant cell tumors of bone.

Abstract

The 2020 World Health Organization classification defined giant cell tumors of bone (GCTBs) as intermediate malignant tumors. Since the mutated H3F3A was found to be a specific marker for GCTB, it has become very useful in diagnosing GCTB. Curettage is the most common treatment for GCTBs. Preoperative administration of denosumab makes curettage difficult and increases the risk of local recurrence. Curettage is recommended to achieve good functional outcomes, even for local recurrence. For pathological fractures, joints should be preserved as much as possible and curettage should be attempted. Preoperative administration of denosumab for pelvic and spinal GCTBs reduces extraosseous lesions, hardens the tumor, and facilitates en bloc resection. Nerve-sparing surgery after embolization is a possible treatment for sacral GCTBS. Denosumab therapy with or without embolization is indicated for inoperable pelvic, spinal, and sacral GCTBs. It is recommended to first observe lung metastases, then administer denosumab for growing lesions. Radiotherapy is associated with a risk of malignant transformation and should be limited to cases where surgery is impossible and denosumab, zoledronic acid, or embolization is not available. Local recurrence after 2 years or more should be indicative of malignant transformation. This review summarizes the treatment approaches for non-malignant and malignant GCTBs.

Late Local Recurrence of Bone Giant Cell Tumors Associated with an Increased Risk for Malignant Transformation

Simple Summary

In giant cell tumor of bone (GCTB), an intermediate malignant bone tumor, approximately 4% of cases can undergo malignant transformation. We analyzed risk factors for malignant transformation of GCTB treated without radiotherapy and retrospectively reviewed medical files of 461 patients with GCTB of the extremities who had undergone surgery alone, with no radiotherapy or denosumab therapy. Malignant transformation occurred in 15 of 461 patients (3.3%) at a median follow-up period of 192 months. The median follow-up duration was 89.4 months. Multivariate analysis revealed that local recurrence was an independent prognostic factor for unfavorable malignant transformation. The interval between the last surgery to local recurrence and malignant transformation was longer than that to local recurrence of benign GCTB, with a median of 15.2 (IQR, 5.2–25.4) years versus 1.3 (IQR, 0.8–2.6) months, respectively (p < 0.001). Late local recurrence of GCTB is associated with a higher risk of malignant transformation.

Abstract

In giant cell tumor of bone (GCTB), an intermediate malignant bone tumor, approximately 4% of all cases undergo malignant transformation. Accordingly, we analyzed risk factors for malignant transformation of GCTB treated without radiotherapy. We retrospectively reviewed medical records of 530 patients with GCTB of the extremities, admitted and treated at two institutions between January 1980 and December 2019. Overall, 4 patients with primary malignant GCTB, 4 patients with missing data, 3 patients with a history of radiotherapy, 22 patients with a follow-up of less than 6 months, and 36 patients who received denosumab were excluded. Accordingly, 461 patients were included for further analysis. Malignant transformation was observed in 15 of 461 patients (3.3%) at a median follow-up period of 192 months. The median follow-up duration was 89.4 months. Multivariate analysis revealed that local recurrence was an independent prognostic factor for unfavorable malignant transformation (Hazard ratio [HR], 11.33; 95% confidence interval [CI] 2.33–55.13; p = 0.003 for once versus none and HR, 11.24; 95% CI, 1.76–71.96; and p = 0.011 for twice or more versus none). The interval between the last surgery to local recurrence and malignant transformation was longer than that to local recurrence of benign GCTB, with a median of 15.2 years (interquartile range [IQR], 5.2–25.4) versus 1.3 months (IQR, 0.8–2.6), respectively (p < 0.001). Late local recurrence of GCTB is associated with a higher risk of malignant transformation.