Clinicopathological Features of a Series of 27 Cases of Post-Denosumab Treated Giant Cell Tumors of Bones: A Single Institutional Experience at a Tertiary Cancer Referral Centre, India

Histological assessment of extensive or unresectable central giant cell granulomas treated with denosumab: a case series

OBJECTIVE

The management of large central giant cell granuloma (CGCG) can pose a significant surgical challenge. In such circumstances, the use of denosumab has been proposed with the literature reporting varying degrees of success. Histopathological assessment of CGCG post-denosumab treatment remains unknown. The current case series aims to address this lack of information and supplement the literature and the debate with evidence.

STUDY DESIGN

The current case series is a retrospective review of historic cases accumulated from 3 different hospitals. Patients treated with denosumab for large or unresectable GCGC who subsequently underwent either surgical debulk or resection post drug treatment with histological tissue for assessment were included.

RESULTS

A total of 4 patients were included in this study. All cases showed radiographic response. However histological assessment identified giant cells in 3 of the 4 cases, 2 of which showed clinical recurrence. All cases demonstrated irregular woven bone formation toward the periphery of the lesion suggesting partial response.

CONCLUSIONS

The current case series provides some insight regarding the response of CGCG to denosumab and preliminary histopathological information toward the ongoing debate regarding the medical management of CGCG. (Oral Surg Oral Med Oral Pathol Oral Radiol YEAR;VOL:page range).

Immunohistochemical expression of H3.3 G34W in 100 giant cell tumors of bone and its diagnostic mimics, including its value in resolving uncommon diagnostic scenarios: A single institutional study at a tertiary cancer referral center, India

BACKGROUND

There can be a diagnostic challenge in differentiating giant cell tumor of bone (GCTB) from its mimics. Lately, histone H 3 F 3 A (Histone 3.3 ) G34W has been identified as a promising immunohistochemical marker.

AIMS

This study was aimed at evaluating H3.3 G34W immunostaining in 100 GCTBs, including its value in resolving diagnostic dilemmas.

MATERIALS AND METHODS

Immunohistochemical staining for H3.3 G34W was graded in terms of staining intensity (1+ to 3+) and the percentage of tumor cells showing crisp nuclear staining.

RESULTS

One hundred GCTBs occurred in 58 males and 42 females (M: F ratio = 1.3), of 7-66 years age (average = 31.3, median = 28), commonly in distal femur (26), followed by proximal tibia (17), distal radius (12), proximal humerus (7), metacarpals (7), sacrum (6), proximal fibula (6), and relatively unusual sites (19), including a single multicentric case. Out of 92 GCTBs, wherein H3.3 G34W immunostaining worked, 81 (88.1%) showed positive staining in the mononuclear cells, including tumors with fibrous histiocytoma-like areas, sparing osteoclast-like giant cells, with 3+ staining intensity in 65/81 (80%) tumors. All 7/7 (100%) malignant GCTBs showed positive staining, including the pleomorphic/sarcomatous cells. All 7/7 (100%) metastatic GCTBs showed positive immunostaining. Seven out of 10 post-denosumab treated GCTBs showed positive H3.3 G34W immunostaining in the residual mononuclear cells. None of the other 37 "giant cell-rich" lesions displayed H3.3 G34W immunostaining. Four of 9 GCTBs tested for H3.3 G34W mutation showed positive results.

CONCLUSIONS

The diagnostic sensitivity and specificity of H3.3 G34W for GCTB were 88.1% and 100%, respectively. This constitutes one of the first reports from our country, further validating the diagnostic value of H3.3 G34W in differentiating GCTB, including metastatic and malignant forms from its mimics, including small biopsy samples. Its value in various diagnostic dilemmas is presented and utility in identifying residual tumor cells in post-denosumab treated GCTBs is worth exploring.

Case Report: Unresectable pulmonary metastases of a giant cell tumor of bone treated with denosumab: a case report and review of literature

Giant cell tumors of bone (GCTB) sometimes metastasize to distant organs. In this case report, we present pulmonary metastases of GCTB mimicking malignancies. A 49-year-old man underwent two surgical treatments for a GCTB of the right proximal radius. At the time of the second surgery, no lesions were observed on chest radiography. Three years after surgery, the patient presented with cough and dyspnea, and chest radiography and computed tomography (CT) revealed multiple lung nodules. Positron emission tomography/CT revealed a high accumulation of 18F-fluoro-2-deoxy-D-glucose (18F-FDG) in multiple lesions. Based on the rapid growth and accumulation of 18F-FDG, a metastatic malignant tumor was suspected. CT-guided needle biopsy was performed, and the histology showed proliferation of spindle cells and multinuclear giant cells without malignant changes. Denosumab was administered because multiple lung lesions were unresectable. One month after denosumab treatment, CT showed marked shrinkage of the lesions, and the symptoms significantly improved. Eighteen months after the initial treatment with denosumab, the patient had no symptoms or tumor growth. Although its long-term efficacy and safety remain unclear, denosumab may be a treatment option for patients with unresectable pulmonary GCTB.

Outcome of re-operation for local recurrence following pre-operative denosumab administration and curettage for giant cell tumour of bone with difficult joint preservation

PURPOSE

Denosumab enables joint-sparing surgery (curettage) and surgical downstaging in patients with giant cell tumour of bone (GCTB), where joint preservation is not possible. However, denosumab treatment causes osteosclerosis of the lesion, making it difficult to curet the lesion, leaving the tumour behind, and increasing the local recurrence rate. We performed a three-centre retrospective study to investigate the postoperative local re-recurrence rate, joint preservation status, and functional outcomes of locally recurrent lesions after preoperative denosumab treatment and curettage in patients with difficult joint preservation.

METHODS

We included 38 of 142 patients with primary GCTB of the extremities who underwent preoperative denosumab and curettage between 2009 and 2021 with local recurrence. Preoperative denosumab was indicated in patients with minimal residual periarticular and subchondral bones, large extraosseous lesions (Campanacci stage 3), and pathological fractures that made joint preservation difficult.

RESULTS

Local re-recurrence occurred in 6 (15.8%) of the 38 patients. In 29 patients who underwent re-curettage, local re-recurrence occurred in six patients (20.7%); however, in nine patients who underwent en bloc resection, no local re-recurrence was observed. The joint preservation rate was 63.2% (24 of 38 patients), with a median Musculoskeletal Tumor Society score of 28 (interquartile range: 26.8-29.0). The median follow-up period after surgery for local recurrence was 63.5 months (interquartile range: 42.5-82.4).

CONCLUSION

Since the local re-recurrence rate after re-curettage for local recurrence was low, and the joint preservation rate and affected limb function were good, preoperative denosumab administration may be considered in patients who require downstaging to maintain good limb function (joint preservation).

Post-Denosumab-Treated Giant Cell Tumor of Bone: A Retrospective Histomorphological and Immunohistochemical Study

Introduction Giant cell tumors of bone (GCTBs) are treated with surgery with or without local adjuvants. Denosumab is a human monoclonal antibody that has recently emerged to be effective in treating unresectable and recurrent GCTBs.

Objective In this study, we analyzed the histomorphological changes in GCTB following treatment with denosumab. The expression of histone mutation H3.3G34W by immunohistochemistry (IHC) using mutant specific antibody was also determined.

Materials and Methods Of the total 109 GCTBs encountered during the study period, 14 cases with neoadjuvant denosumab therapy were analyzed retrospectively. The post-treatment changes on histopathology were examined on routine hematoxylin and eosin-stained sections. IHC was done using antihistone H3.3G34 antibodies. Statistical analysis was limited to descriptive statistics. No hypothesis testing was performed.

Results All these cases except three showed fibrosis with areas of hyalinization, prominent newly formed woven bone along with spindle cells in short fascicles and storiform pattern. There was complete absence and marked reduction in osteoclast-like giant cells in six and five patients, respectively. Only three patients showed a substantial amount of residual osteoclast-like giant cells. IHC with antihistone H3.3G34W antibody showed unequivocal nuclear positivity in the mononuclear cells in nine cases. The mononuclear cells rimming and entrapped within the woven bone were also positive on IHC. The spindle cells in the benign fibrous histiocytoma-like areas and septa of aneurysmal bone cyst-like areas also retained nuclear staining.

Conclusion Awareness of post-denosumab-related histopathological changes are necessary to avoid misdiagnosis as fibroosseous lesion and low-grade central osteosarcoma. Expression of mutant-specific H3.3 G34W antibody suggests that the neoplastic stromal cells are largely retained after denosumab therapy. The positive staining of cells both within and those rimming the newly formed woven bone point toward osteoblastic phenotype of the neoplastic stromal cells.

Grossing and reporting of bone tumor specimens in surgical oncology: Rationale with current evidence and recent updates

Primary bone tumors, including sarcomas, are rare tumors and require a multidisciplinary approach, including inputs from a radiologist, pathologist, medical oncologist, and surgical and radiation oncologist, for optimal management. Over the years, there has been a paradigm shift toward the treatment of bone sarcomas, from radical resections to conservative surgical procedures, to achieve improved clinical and functional outcomes. This has led to receiving and processing various types of specimens in orthopedic oncopathology. Grossing and reporting of bone tumors require expertise. This review focuses upon the types of biopsies, grossing techniques of various specimens in orthopedic oncology and reporting, with rationale and recommendations from pathologists, actively involved in reporting and pursuing a special interest in bone tumors, based on current evidence. Furthermore, there is a section on some of the updates in the diagnosis of bone tumors, based on the recent fifth edition of the World Health Organization classification of tumors of soft tissues and bone.

Clinical outcome of a conservative approach to giant cell tumor of ankle and foot bones

Giant cell tumor of the bone (GCTB) affecting foot and ankle is rare, and the literature available on their clinical behavior and reconstructive options is scarce. Many authors consider these sites a special subset with high rates of local recurrence. Eighteen patients with GCTB of foot and ankle were treated from (March 2014 to February 2020). Extended curettage was offered wherever feasible. Twelve patients underwent extended curettage, three underwent resection and reconstruction, one patient had ray amputation, one had below knee amputation. One patient with multifocal disease was treated conservatively with denosumab. There were 11 females and the mean age was 31.7 years. Distal tibia (11 patients) was the commonest location, followed by the first metatarsal (four patients). At a median follow up of 46 months, two patients out of the 17 operated had a local recurrence. GCTB affecting the foot and ankle have a clinical course comparable to those at other locations. They should be treated with a conservative approach, where radical resection and amputation are reserved for only the non-curettable tumors.

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.

Is a Short-course of Preoperative Denosumab as Effective as Prolonged Therapy for Giant Cell Tumor of Bone?

BACKGROUND

Denosumab is an inhibitor of monoclonal receptor activator of nuclear factor-ĸB ligand, approved to treat giant cell tumors of bone (GCTB). It is commonly used for unresectable tumors and for downstaging the tumor to perform less-morbid procedures. Although denosumab has been used extensively for GCTBs, there are no recommendations regarding the duration of therapy. The risk factors associated with local recurrence (LR) in patients receiving preoperative denosumab for GCTB also are unknown.

QUESTIONS/PURPOSES

(1) Is short-course (three doses or fewer) preoperative denosumab treatment as effective as longer course (more than three doses) of treatment in terms of achieving a clinical, radiologic, and histologic response in patients with GCTB? (2) Is there an increased risk of LR after short-course denosumab therapy compared with long-course denosumab therapy; and after controlling for confounding variables, what factors were associated with LR after surgery for GCTB in patients receiving preoperative denosumab?

METHODS

A retrospective study was performed using an institutional database of 161 skeletally mature patients with a histologic diagnosis of GCTB who received denosumab between November 2010 and July 2019 to downstage the tumor before surgery. In general, we used denosumab when we thought it would facilitate either resection or curettage (by formation of a sclerotic rim around the osteolytic lesion), when a less-morbid procedure than initially planned might be performed, and in patients with complex presentations like cortical breech and soft tissue extension, pathological fracture, thinning of more than three cortices of the extremity. From 2010 to late 2015, denosumab was administered for approximately 4 to 6 months; starting in late 2015 through 2020, the number of denosumab doses has been reduced. We divided patients into two groups: Those who received three or fewer doses of denosumab (short-course, n = 98) and those who received more than three doses of denosumab (long-course, n = 63). Comparing those in the long-course group with those in the short-course group whose procedures were performed at least 2 years ago, there were no differences in loss to follow-up before 2 years (3% [3 of 98] versus. 3% [2 of 63]). The mean patient age was 30 years (± 6.1) and the mean number of denosumab doses was 4.4 (range 1 to 14). Overall, 77% (37 of 48) of patients taking short-course denosumab and 75% (27 of 36) of patients on long-course denosumab underwent curettage, and the remaining patients with an inadequate bony shell around the tumor or destruction of articular cartilage in both groups underwent tumor resection. With the numbers available, the patients with short- and long-course denosumab were not different in terms of age, sex, MSTS score on presentation, lesion size, lesion location, Campanacci grade, presence of pathological fracture and pulmonary metastasis on presentation, and the type of surgery performed (curettage versus resection). We analyzed the change in the Musculoskeletal Tumor Society score, change in Campanacci grade, radiologic objective tumor response (defined as a partial or complete response, per the modified inverse Choi criteria), and histologic response (defined as reduction of more than 90% of osteoclast-like giant cells or a reduction of more than 50% of mesenchymal spindle-like stromal cells, along with evidence of lamellar or woven bone formation, when compared with the biopsy sample) between the two groups (short- and long-course denosumab). LR rates were compared between the two groups, and after controlling for confounding variables, factors associated with LR in all operated patients were analyzed with a Cox proportional hazards regression analysis.

RESULTS

With the numbers available, there was no difference between the short- and long-course denosumab groups in terms of mean percentage improvement in MSTS score (20 [± 18.5] versus 24 [± 12.6]; p = 0.37), radiologic objective tumor response (90% [43 of 48] versus 81% [29 of 36]; p = 0.24) and histologic response (79% [38 of 48] versus 83% [30 of 36]; p = 0.81). With the numbers available, there was no difference between the short- and long-course denosumab groups in terms of Kaplan-Meier survivorship free from LR at 5 years after surgery (73% [95% confidence interval, 68 to 76] versus 64% [95% CI 59 to 68]; log-rank p = 0.50). After controlling for potential confounding variables like age, sex, Campanacci grade and MSTS score on presentation, number of denosumab doses administered before surgery, clinical, radiologic and histologic response to denosumab, and time duration between denosumab therapy and surgery, we found that tumors involving the bones of the hand and the foot (hazard ratio 7.4 [95% CI 2.0 to 27.3]; p = 0.009) and curettage (HR 6.4 [95% CI 2.8 to 23.0]; p = 0.037) were independently associated with a higher risk of LR.

CONCLUSIONS

In this preliminary, single-center study, we found that a short-course of preoperative denosumab (three or fewer doses) was associated with no differences in clinical scores, histological and radiological response, or LR-free survivorship, compared with longer-course of denosumab (more than three doses). Fewer preoperative doses can reduce the complications and costs associated with more-prolonged therapy. Denosumab must be used cautiously before curettage for GCTB, and only if the benefit of joint salvage outweighs the possibility of LR. However, given the small number of patients, potentially clinically important differences might have been missed, and so our findings need to be confirmed by larger, multicenter, prospective trials.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Histomorphometric Analysis of Pre- and Post-Denosumab-Treated Giant Cell Tumor of Bone

Context. Denosumab is a monoclonal antibody against RANK ligand. Its administration in giant cell tumor of bone (GCTB) cases results in elimination of giant cells and new bone formation. Neoplastic stromal cells of GCTB harbor mutation of histone 3.3 and have pre-osteoblastic properties and thus express SATB2. Objectives. To (1) analyze histological changes in post-denosumab-treated GCTB, (2) analyze expression of H3.3G34W and SATB2 in pre- and post-denosumab-treated samples, and (3) to discuss why changes occur in the expression of not only H3.3G34W but also SATB2. Materials and Methods. Hematoxylin and eosin slides of 19 cases of denosumab-treated GCTB were reviewed. Immunohistochemical stains H3.3G34W and SATB2 were performed. The number of positive mononuclear cells were counted and graded. Results. Complete absence of osteoclast-like giant cells (OCLGCs) was noted in most cases along with a fibro-osseous component merging with peripheral shell of reactive bone. Irregular trabeculae of woven bone and osteoid with focal osteoblastic rimming was seen. Spindle cells were arranged predominantly in fascicular pattern. Morphometric analysis of H3.3G34W showed a mean of 68.8% positive stromal cells in pretreatment and a mean of 26.9% positive stromal cells in posttreated specimens with a statistically significant P value (.001). Mean percentage of SATB2-positive stromal cells in the pre- and posttreatment specimens was 36.46% and 20.8%, respectively. Conclusions. Our study validates that denosumab treatment results in marked reduction of OCLGCs with increased osteoblastic activity. Decreased expression of H3.3G34W in posttreatment may be a result of decreased antigenicity of neoplastic mononuclear cells. No significant change in SATB2 expression was noted.

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.

Spectrum of histological features of Denosumab treated Giant Cell Tumor of Bone; potential pitfalls and diagnostic challenges for pathologists

OBJECTIVES

Denosumab is Receptor Activator of Nuclear factor Kappa-B Ligand (RANKL) inhibitor which is being used in the treatment of locally advanced, recurrent and metastatic Giant Cell Tumor of Bone (GCTB). It causes reduction in monocyte recruitment and Osteoclast-Like Giant Cell (OLGC) formation which limits bone destruction. After Denosumab treatment, GCTB exhibit diverse morphological features which can pose diagnostic challenge. Our aim was to study the spectrum of histologic features seen in Denosumab treated GCTB which could be helpful in establishing correct diagnosis.

METHODS

We retrieved and reviewed H&E stained microscopic glass slides of 38 GCTB cases who received Denosumab as neoadjuvant treatment. These cases were treated at different institutes and diagnosed at our institute between January 2017 and October 2019. Morphologic features such as presence of residual OLGC, appearances of mononuclear stromal and bony components were assessed along with other non-specific features.

RESULTS

Patients' median age was 29 years. Male to female ratio was 1.53:1. Femur was the most commonly involved bone. Microscopically, peripheral shell of reactive bone was observed in all cases. In 20 (52.6%) cases, there was complete elimination of OLGC. Mononuclear stromal cells were predominantly bland spindle shaped and arranged in fascicular and storiform patterns. Focal atypia was noted in 3 cases. Bony component manifested as trabeculae of woven bone with osteoblastic rimming and immature trabeculae of unmineralized osteoid with haphazardly present osteoblasts. Spectrum of stromal changes included cystic spaces, foamy macrophages, inflammatory infiltrate, hemangiopericytoma-like (HPC-like) vessels, hyalinization, edematous areas and hemosiderin pigment. The tumors showed areas which resembled other bony and soft tissue lesions such non-ossifying fibroma, fibrous dysplasia, osteoblastoma, sclerosing epithelioid fibrosarcoma and osteosarcoma.

CONCLUSION

Denosumab treatment induces a variety of changes in GCTB. Clinical history and knowledge of these features are necessary for excluding differential diagnoses and avoiding misdiagnosis.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

LEVEL OF EVIDENCE

IV.

Denosumab for treating aneurysmal bone cysts in children

BACKGROUND

Aneurysmal bone cyst (ABC) is a benign tumour whose progression involves the RANK/RANKL signalling pathway. Surgery is the reference standard treatment but carries risks that vary with the site of the tumour. Denosumab is a human monoclonal IgG2 antibody that targets the RANK/RANKL pathway and may therefore hold promise for inhibiting ABC progression. The objective of this study was to evaluate denosumab use in paediatric patients (younger than 18 years) with ABC and to describe the clinical and radiological outcomes, as well as the side effect profile.

HYPOTHESIS

Denosumab is a viable option in children with ABC refractory to standard treatments.

MATERIAL AND METHODS

We retrospectively reviewed the medical files of paediatric patients given denosumab to treat ABC in any of 32 centres affiliated with the French Paediatric Cancer Society (Société Française du Cancer de l'Enfant, SFCE) and French Sarcoma Group (Groupe Sarcome Français, GSF-GETO). We identified 5 patients treated between March 2015 and June 2018. Median age was 8 years (range, 7-17 years). Pain was a symptom in all 5 patients and neurological deficits were present in 3 patients. Surgery was performed in 4 patients, either before (n=3) or after (n=1) denosumab therapy; the remaining patient had no surgery. Denosumab was given as monthly injections in a dosage of 70mg/m² for a median of 12 months (range, 4-23 months). The clinical outcomes and changes in computed tomography and/or magnetic resonance imaging findings were evaluated.

RESULTS

Abnormalities in calcium and phosphate levels secondary to the ABC occurred in 2 patients. At median of 24 months (range, 0-28 months) after denosumab initiation, all 5 patients were free of pain, and the neurological deficits in 3 patients had improved. Central remineralisation and cortical reconstitution were demonstrated consistently by the imaging studies.

DISCUSSION

Denosumab is a viable treatment option in selected paediatric patients with inoperable ABC. The immediate adverse effect profile is acceptable. A larger study with a longer follow-up would be welcome to further assess the contribution of denosumab to the treatment of ABC.

LEVEL OF EVIDENCE

IV.

A new computerized tomography classification to evaluate response to Denosumab in giant cell tumors in the extremities

Objectives

The aim of this study was to describe the cohort of patients who have been treated with Denosumab as neoadjuvant therapy prior to surgery for aggressive giant cell tumor of bone in the extremities, to evaluate the radiological responses to Denosumab comparing Choi criteria and a newly described computerized tomography (CT) classification, and to evaluate the risk of local recurrence after intralesional curettage or radical excision.

Methods

We retrospectively evaluated 36 patients (20 females and 16 males; mean age at diagnosis 36 years (range, 18–64)) treated with neoadjuvant Denosumab therapy prior to surgery for aggressive giant cell tumor of bone in the extremities. The radiological responses to Denosumab treatment were analyzed on the preoperative images after the neoadjuvant course with the Choi criteria and with a newly proposed classification based on CT. All these images were independently reviewed by two of the researchers. Surgical intervention methods were noted and local recurrence rates were evaluated. The correlation between radiological response amount and local recurrence were analyzed for both Choi criteria and the new CT classification.

Results

Denosumab was administered for a mean of 21 weeks (range 7–133). Five patients also had a short postoperative course. According to Choi criteria there was a radiological response in 32 patients (89%), while the new CT classification identified responses in all the 36 patients (100%). The identification of changes after 7 weeks of treatment was higher using the CT classification compared to Choi criteria (p = 0.043 vs p = 0.462). The surgical interventions after Denosumab comprised curettage in 29 patients (74%) and resection in 7 (26%). Local recurrence was higher in patients managed with intralesional curettage than in those treated with en bloc resection (55.1% vs 0%, p < 0.001). At last follow up 19 patients (53%) required en bloc resections. Good responders to Denosumab (type 2C) had lower risk of local recurrence (p = 0.047) after either resection or curettage.

Conclusion

The new CT classification evaluated more accurately the response to Denosumab. Our experience suggests that the requirement for radical bone resection remains high despite the use of Denosumab.

Level of evidence

Level IV, Therapeutic Study.

Local Tumor Recurrence and Escape from Suppression of Bone Resorption With Denosumab Treatment in Two Adolescents With Giant Cell Tumors of Bone

Giant cell tumors of bone (GCTB) may be difficult to resect because of size or location. We describe two adolescents who were treated with denosumab and followed for tumoral and biochemical responses. Denosumab was effective in achieving sufficient regression to allow surgical resection and in preserving peritumor cortical bone. Reactivation of bone resorption markers was noted while the patients were receiving monthly denosumab. One patient suffered a local tumor recurrence. Denosumab was safe in enabling surgical resection of GCTB. However, the effect was transient, with an escape of resorption markers and tumor recurrence. © 2019 The Authors. JBMR Plus published by Wiley Periodicals, Inc. on behalf of American Society for Bone and Mineral Research.

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

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

Preoperative Denosumab With Curettage and Cryotherapy in Giant Cell Tumor of Bone: Is There an Increased Risk of Local Recurrence?

BACKGROUND

Denosumab is a monoclonal RANKL antibody, which was originally introduced for the treatment of osteoporosis and bone metastases from solid tumors, but more recently has been used for treatment of giant cell tumor of bone (GCTB). In GCTB, denosumab has been used as a single agent in patients with inoperable tumors; it also has been used before surgery in some patients with the aim to downstage the tumor to facilitate a joint-preserving procedure (curettage) rather than a resection. However, few studies are available evaluating the benefits and risks of denosumab for the latter indication.

QUESTIONS/PURPOSES

(1) Does preoperative treatment with denosumab reduce the risk of local recurrence in patients treated for GCTB? (2) Are there adverse effects of short-term denosumab use before surgery and, if so, what are they?

METHODS

All patients with a diagnosis of GCTB surgically treated at our institution from June 2009 to June 2016 with curettage and cryotherapy were retrospectively evaluated to compare patients treated with curettage alone versus patients treated with curettage after preoperative therapy with denosumab. During that period, we treated 97 patients for GCTB; 30 patients were excluded because they received a resection; 34 patients were excluded because they received curettage without cryotherapy. Of the remaining 33 patients, four were excluded because they received denosumab only after surgery, one because she received zoledronic acid, one because she received a curettage after her refusal of a resection that was the advised procedure, two because they were lost to followup early, and four because they were treated for recurrence rather than a new diagnosis of GCTB. The remaining 21 patients were included. Twelve lesions had been treated with surgery after denosumab and nine with surgery alone. During the study period, we preferentially used denosumab for the more aggressive-looking lesions. After curettage, cryotherapy of the residual bone walls was performed with argon cryoprobes to -150° C after pouring gel into the cavity, and we then used cement (17 patients) or morcellized allograft (four patients). Tumors were Campanacci Grade 3 in eight of 12 patients in the denosumab group and in two of nine patients in the surgery-only group (p = 0.08), but the extent of epiphyseal juxtaarticular bone involvement was not different between the groups with the numbers available. Median followup was 39 months (range, 14-55 months) in the denosumab group and 27 months (range, 18-92 months) in the surgery-only group. We used chart review to record the proportion of patients in each treatment group who had a local recurrence and to tally adverse events.

RESULTS

With the numbers available, there was no difference in the proportion of patients experiencing a recurrence (five of 12 in the denosumab group and one of nine in the surgery-only group; p = 0.18). We found no adverse effects associated with denosumab either during or after treatment; specifically, we found no alterations in electrolyte levels, blood count, or liver and renal function parameters. In this small series, no patient has developed osteonecrosis of the jaw.

CONCLUSIONS

In this small series, use of denosumab before surgery for GCTB appeared to allow the reforming of a bone peripheral rim around the tumor, perhaps facilitating curettage rather than osteoarticular resection in some patients. However, we did not observe a decrease in the risk of local recurrence with the use of denosumab, suggesting that it may not decrease the aggressiveness of the disease; according to our preliminary results, we cannot exclude that the rate of local recurrence could be even higher after curettage in denosumab-treated patients than in nontreated patients, and until or unless larger studies demonstrate such a reduction, primary intralesional surgery without denosumab seems more prudent when curettage is feasible at presentation. We did not observe any adverse effects with denosumab, but we caution readers that this study was underpowered to detect even relatively common complications and relatively large differences in the risk of local recurrence. Future studies should evaluate denosumab prospectively; given the relative rarity of this tumor, we suspect multicenter studies are needed to achieve this.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Prognosis of metastatic giant cell tumor of bone in the pre-denosumab era. A systematic review and a meta-analysis

Background

Data on long-term prognosis of metastatic GCT (mGCT) is scant. The frequency of spontaneous regressions (SRs) is unknown. We aimed to estimate the prognosis of mGCT.

Methods

We searched electronic scientific literature databases and generic Internet from January 1980 to August 2017. After identifying eligible studies we performed descriptive analyses and meta-analyses to estimate overall survival (OS), disease specific survival (DSS) and frequency of SRs in the years before the widespread use of denosumab. We performed pre-specified subgroup analyses of studies published before and after 2000 and of those with more and less than 10 years of follow-up.

Results

After retrieving and combining data from 26 relevant retrospective case-series totaling 242 patients with a median follow-up of 6.9 years, the estimated pooled OS was 86.9% (95% CI 78.0-94.2). Pooled DSS was 88.0% (95% CI 79.7-94.7). SRs were observed in 4.5% of patients. In the subgroup of studies published after 2000 mGCT was the only cause of death of affected subjects. In case-series with a follow-up longer than 10 years pooled DSS was 69.7% (95% CI 25.5-99.8).

Conclusions

To our knowledge this is the first study to derive estimated pooled OS and DSS of mGCT based on a large dataset. SRs were not exceptional phenomena. In a long run the disease could impact in a significant way on the life expectancy of affected subjects.

Expression of MMP-2 and TIMP-3 with incidence and prognosis of giant-cell tumor of the bone

The expression of matrix metalloproteinase-2 (MMP-2) and tissue inhibitor of matrix metalloproteinase-3 (TIMP-3) in giant-cell tumor of bone (GCT), and the correlation of their expression with the clinicopathologic features and prognosis were investigated. A total of 70 GCT patients treated in our hospital from September, 2013 to September, 2015, were selected, and the tumor and para-carcinoma tissues were obtained by surgery. The expression levels of MMP-2 and TIMP-3 in GCT and para-carcinoma tissues were detected via semi-quantitative polymerase chain reaction (PCR) and western blot analysis, as well as immunohistochemical staining. Moreover, the clinicopathological data of the GCT patients were collected to study the correlation of MMP-2 and TIMP-3 with clinicopathological features and prognosis of GCT. The results of semi-quantitative PCR and western blot analysis revealed that the expression level of MMP-2 in tissues of the 70 GCT patients was significantly higher than that in para-carcinoma tissues, and the difference was statistically significant (P<0.01), while the expression level of TIMP-3 was obviously lower than that in para-carcinoma tissues (P<0.01). The results of immunohistochemical staining revealed that the positive expression rate of MMP-2 was 57.6% in GCT tissues and 18.9% in para-carcinoma tissues, while that of TIMP-3 was 63.2% in GCT tissues and 13.8% in para-carcinoma tissues, and the differences were statistically significant (P<0.01). The expression levels of MMP-2 and TIMP-3 were correlated with the diameter of tumor, clinical staging, lymph node metastasis and relapse of GCT (P<0.01), but were not correlated with the age and sex of GCT patients (P>0.05). There was a negative correlation between MMP-2 and TIMP-3 expression levels (r=−0.258, P<0.05). The expression levels of MMP-2 and TIMP-3 are closely related to the clinicopathological features and prognosis of patients, which can be used as one of the clinical examination indexes of GCT and also provide new insights for the clinical treatment of GCT.

Response evaluation of giant-cell tumor of bone treated by denosumab: Histogram and texture analysis of CT images

BACKGROUND

This study aimed to compare computed tomography (CT) features, including tumor size and textural and histogram measurements, of giant-cell tumors of bone (GCTBs) before and after denosumab treatment and determine their applicability in monitoring GCTB response to denosumab treatment.

METHODS

This retrospective study included eight patients (male, 3; female, 5; mean age, 33.4 years) diagnosed with GCTB, who had received treatment by denosumab and had undergone pre- and post-treatment non-contrast CT between January 2010 and December 2016. This study was approved by the institutional review board. Pre- and post-treatment size, histogram, and textural parameters of GCTBs were compared by the Wilcoxon signed-rank test. Pathological findings of five patients who underwent surgery after denosumab treatment were evaluated for assessment of treatment response.

RESULTS

Relative to the baseline values, the tumor size had decreased, while the mean attenuation, standard deviation, entropy (all, P = 0.017), and skewness (P = 0.036) of the GCTBs had significantly increased post-treatment. Although the difference was statistically insignificant, the tumors also exhibited increased kurtosis, contrast, and inverse difference moment (P = 0.123, 0.327, and 0.575, respectively) post-treatment. Histologic findings revealed new bone formation and complete depletion or decrease in the number of osteoclast-like giant cells.

CONCLUSION

The histogram and textural parameters of GCTBs changed significantly after denosumab treatment. Knowledge of the tendency towards increased mean attenuation and heterogeneity but increased local homogeneity in post-treatment CT histogram and textural features of GCTBs might aid in treatment planning and tumor response evaluation during denosumab treatment.

TGF-β induced PAR-1 expression promotes tumor progression and osteoclast differentiation in giant cell tumor of bone

Although protease activated receptor-1 (PAR-1) has been confirmed as an oncogene in many cancers, the role of PAR-1 in giant cell tumor (GCT) of bone has been rarely reported. The mechanism of PAR-1 in tumor-induced osteoclastogenesis still remains unclear. In the present study, we detected that PAR-1 was significantly upregulated in GCT of bone compared to normal tissues, while TGF-β was also overexpressed in GCT tissues and could promote the expression of PAR-1 in a dose and time dependent manner. Using the luciferase reporter assay, we found that two downstreams of TGF-β, Smad3 and Smad4, could activate the promoter of PAR-1, which might explain the mechanism of TGF-β induced PAR-1 expression. Meanwhile, PAR-1 was also overexpressed in microvesicles from stromal cells of GCT (GCTSCs), and might be transported from GCTSCs to monocytes through microvesicles. In addition, knockout of PAR-1 by TALENs in GCTSCs inhibited tumor growth, angiogenesis and osteoclastogenesis in GCT in vitro. Using the chick CAM models, we further showed that inhibition of PAR-1 suppressed tumor growth and giant cell formation in vivo. Using microarray assay, we detected a number of genes involved in osteoclastogenesis as the possible downstreams of PAR-1, which may partly explain the mechanism of PAR-1 in GCT. In brief, for the first time, these results reveal an upstream regulatory role of TGF-β in PAR-1 expression, and PAR-1 expression promotes tumor growth, angiogenesis and osteoclast differentiation in GCT of bone. Hence, PAR-1 represents a novel potential therapeutic target for GCT of bone.

Denosumab: Current Use in the Treatment of Primary Bone Tumors

Denosumab, a human monoclonal antibody that inhibits bone resorption by binding on the receptor activator of the nuclear factor kappa-β ligand, has recently emerged as an additional option in the treatment of musculoskeletal osteolytic tumors. This article focuses on the recent literature regarding the effectiveness of denosumab in the management of giant cell tumor, multiple myeloma, aneurysmal bone cyst, and osteosarcoma. The mechanism of action of denosumab in the management of these tumors and the associated side effects are discussed in detail. [ Orthopedics. 2017; 40(4):204-210.].

How safe and effective is denosumab for bone giant cell tumour?

Recent clinical studies have suggested that denosumab is associated with beneficial tumour response, surgical down-staging, and reduced surgical morbidity in patients with giant cell tumour of bone. However, these studies reported results of patients still on denosumab treatment, or patients after denosumab treatment but with a short follow-up. Other studies reported that the new osseous tumour matrix and thickened cortical bone that develop with denosumab treatment does not allow the surgeon to delineate the true extent of the tumour, and probably increases the risk for local recurrence. A study showed that cell proliferation is only diminished by denosumab; the cells continue to proliferate in vitro, albeit at a slower rate. More importantly, nine cases of malignant transformation of GCT during denosumab therapy without previous radiation exposure have been reported; inhibition of RANKL may increase the risk of new malignancies due to immunosuppression. With these concerns in mind, this article is an attempt to put essential information in one place, creating a comprehensive review that the curious reader would find interesting and informative.