Pulmonary metastasis from giant cell tumor of bone: clinical outcome prior to the introduction of molecular target therapy

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

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

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

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

Non‑surgical outcomes and risk factors for pulmonary metastasis from giant cell tumor of bone

The present study detailed four factors associated with an increased risk of pulmonary metastasis, age, pathological fracture, local recurrence and mode of treatment. Local recurrence and pathological fracture were independent risk factors for developing metastasis. From January 2016 to December 2021, data from 50 patients diagnosed with giant cell tumor of bone (GCTB) treated in Khon Kaen Hospital, Thailand, were retrospectively analyzed. The risk factors, including age at diagnosis, location of GCTB, clinical presentation, Campanacci stage and no. of local recurrences, for GCTB-induced pulmonary metastasis were evaluated using univariate and multivariable logistic regression analyses. Of the 50 patients analyzed, 9 patients (18%), with a mean age of 46.3 years (range, 18-68 years), developed pulmonary metastasis. No patients died from pulmonary metastasis in the present study. Statistically significant associations were observed between the development of metastasis and both clinical fracture [odds ratio (OR), 6.107; 95% confidence interval (CI), 1.08-34.70] and local recurrence (OR, 6.48; 95% CI, 1.03-40.87). Patients presenting with both a clinical fracture and local tumor recurrence require more rigorous clinical observation due to the significantly elevated risk of disease progression.

Diffuse Pulmonary Metastases at Presentation of Giant Cell Tumor of Bone: A Case Report and Synthesis of Literature

CASE

We present a 23-year-old man with acute-on-chronic shoulder pain with an aggressive-appearing, destructive lesion of the left proximal humerus and diffuse lung metastases. Biopsy revealed conventional giant cell tumor of bone (GCTB) without sarcomatous differentiation, treated with resection and proximal humerus reconstruction. Without systemic treatment, his pulmonary metastases demonstrated modest spontaneous regression, with no impairment of pulmonary function.

CONCLUSIONS

Although GCTB is known to metastasize to lungs, these deposits most commonly follow local recurrence. We describe a young adult with diffuse pulmonary nodules at initial presentation, although still following an indolent clinical course without the need for additional systemic therapy.

Metastatic giant cell tumour of bone: a narrative review of management options and approaches

Giant cell tumour of bone (GCTB) is a locally aggressive bone neoplasm with a rare tendency to metastasise, most commonly to the lungs. The management of metastatic GCTB (metGCTB) is controversial due to its unpredictable behaviour. Asymptomatic patients should be monitored radiologically and undergo treatment only when disease progression occurs. Surgery is recommended for resectable metGCTB. Denosumab, a monoclonal antibody which inhibits receptor activator of nuclear factor-κB ligand, is recommended for unresectable metGCTB with evidence from phase II trials demonstrating its safety and efficacy. Relapse after denosumab withdrawal may occur and prolonged treatment may be associated with serious adverse events, thus further research is warranted to inform a maintenance regimen with reduced dosing and frequency. Combined denosumab and bisphosphonate therapy has the potential to achieve sustained disease control or remission in unresectable metGCTB without requiring long-term treatment and should be evaluated in prospective trials. Various novel agents have demonstrated in vitro and anecdotal efficacy and warrant further evaluation.

Current management of giant-cell tumor of bone in the denosumab era

Giant-cell tumor of bone is a rare, locally aggressive and rarely metastasizing primary bone tumor. The mainstay of treatment remains controversial and is decided by the balance between adequate surgical margin and sufficient adjacent joint function. Although curettage with a high-speed burr and local adjuvants can maintain normal joint function, many reports have revealed a high local recurrence rate. Conversely, en bloc resection and reconstruction with prostheses for highly aggressive lesions have reportedly lower local recurrence rates and poorer functional outcomes. Denosumab-a full human monoclonal antibody that inhibits receptor activator of nuclear factor-kappa β ligand-was approved by the Food and Drug Authority in 2013 for use in surgically unresectable or when resection is likely to result in severe morbidity for skeletally mature adolescents and adults with giant-cell tumor of bone. However, subsequent studies have suggested that the local recurrence rate would be increased by preoperative use of denosumab. In systematic reviews of the local recurrence rate after preoperative use of denosumab, conclusions vary due to the small sample sizes of the studies reviewed. Therefore, controversy regarding the treatment of giant-cell tumor of bone is ongoing. Here, this review elucidates the management of giant-cell tumor of bone, especially with the local adjuvant and neoadjuvant use of denosumab, and presents the current, evidence-based treatment for giant-cell tumor of bone.

Metastasectomy Versus Non-Metastasectomy for Giant Cell Tumor of Bone Lung Metastases

Approximately 2% to 9% of giant cell tumor of bone (GCTB) metastasizes systemically, mainly to the lungs. The biological behaviors and clinical courses of lung metastases are difficult to predict, and their treatment recommendations vary, including metastasectomy and non-metastasectomy with chemotherapy (denosumab, interferon-alfa, bisphosphonates), with radiation therapy, or with observation alone. However, it is unclear whether metastasectomy for GCTB lung metastases decreases the mortality rate of these patients. Therefore, the authors performed this systematic review to compare metastasectomy and non-metastasectomy for GCTB patients with operable lung metastasis. Of the 919 relevant studies, 16 studies (138 patients) were included for analysis; 61.6% of patients had metastasectomy and 38.4% had non-metastasectomy. Analysis showed that mortality rates were similar for the patients who had metastasectomy compared with those who did not; the proportion of patients who died of disease was 7.1% in the metastasectomy group and 17.0% in the non-metastasectomy group, with an overall pooled odds ratio of 0.64 (P=.36). Therefore, physicians should reconsider the potential risks and benefits of metastasectomy for patients with GCTB and lung metastasis, because metastasectomy does not reduce the mortality rate in these patients. [Orthopedics. 2021;44(6):e707-e712.].

Primary Giant Cell Tumors of the Lung: A Clinicopathologic and Immunohistochemical Study of 3 Cases

Three cases of primary giant cell tumors of the lung akin to those described in the soft tissues are presented. The patients are 3 men between the ages of 43 and 54 years who presented with nonspecific symptoms of cough, chest pain, and shortness of breath. None of the patients had any prior history of malignancy anywhere else. Diagnostic imaging disclosed the presence of an intrapulmonary mass. All the patients underwent lobectomy. Grossly, the tumors were described as solid, slightly hemorrhagic, and measuring between 1.8 and 2.4 cm in greatest diameter. Histologically, the tumors were characterized by a dual population of multinucleated giant cells admixed with a mononuclear proliferation. Nuclear atypia was mild to moderate, and mitotic activity varied but was under 5 mitotic figures per 10 high power fields. Immunohistochemical stains showed positive staining for vimentin, CD68, and cathepsin K, whereas the tumors were negative for keratin, TTF-1, p40, S-100 protein, and SABT-2. Clinical follow-up was obtained in 2 patients who have remained alive and without evidence of recurrence or metastasis up to 12 months after surgery. One patient was lost to follow-up. The current neoplasms represent a tumor that to the best of our knowledge has not been reported as a primary neoplasm of the lung. The cases herein described represent an unusual occurrence and should be maintained in the differential diagnosis of primary pulmonary tumors rich in multinucleated giant cells.

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.

Risk factors and oncological outcomes of pulmonary metastasis in patients with giant cell tumor of bone

BACKGROUND

Giant cell tumor (GCT) of bone has a rare potential for metastatic spread. This study aimed at evaluating the incidence of chest metastases in GCT and their oncological outcome and identifying possible risk factors.

METHODS

Medical records of 466 (313 de novo and 153 recurrent) patients with primary GCT of bone were retrospectively reviewed. Fifteen (3.2%) patients developed chest metastasis. Time from diagnosis of the primary bone lesion to the diagnosis of metastasis, treatment modalities of metastasis, and the course of treatment were revised. The functional outcome was evaluated using the Musculoskeletal Tumor Society (MSTS) scoring system, and postoperative complications were recorded.

RESULTS

This study included 7 males and 8 females with a mean age of 27.3 ± 7.9 years. The most common site of the primary tumor was the distal femur. All fifteen patients were recurrent cases. The mean follow-up period was 67.7 ± 33.2 months. Chest metastasis was diagnosed after a mean time of 28.1 ± 28.9 months from the initial diagnosis of the bone lesion. One patient died of disease (DOD) 18 months after the surgical intervention. The incidence of chest metastasis in recurrent cases was 9.8%, while de novo cases did not develop chest metastasis, P < 0.001. Previous curettage was associated with a higher incidence of chest metastasis (14.6%) compared to previous resection (4.2%), P = 0.03.

CONCLUSIONS

Chest metastasis following GCT of bone is rare. Risk factors include recurrent cases, especially following previous curettage. Patients have a good prognosis and a low mortality rate.

LEVEL OF EVIDENCE

Level IV, retrospective.

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.

Prognostic Factors for Survival in Patients with Malignant Giant Cell Tumor of Bone: A Risk Nomogram Analysis Based on the Population

Background

Malignant giant cell tumor of bone (MGCTB) is a rare histological type of malignant tumor that has a high tendency for local relapse and distant metastasis and ultimately leads to a poor prognosis. The purpose of this study was to describe the epidemiological features, identify the prognostic factors, and construct nomograms for patients with MGCTB.

Material/Methods

Patients with MGCTB that was histologically diagnosed between 1973 and 2014 were selected from the Surveillance, Epidemiology, and End Results (SEER) database as a training set. Survival analysis, Lasso regression, and random forests were used to identify the prognostic variables and establish the nomograms for patients with MGCTB, while an external cohort of 37 patients from our own institution and an external cohort of 163 patients from the SEER database in 2016 were used to validate the generalization performance of the nomograms.

Results

In total, univariate and multivariable analysis indicated that age, International Classification of Diseases for Oncology, historical stage, primary site, surgery information, radiotherapy, and chemotherapy were independent prognostic variables for overall survival or cause-specific survival. Nomograms based on the multivariable models were built to predict survival, and we achieved a higher C-index in subsequent multidimensional validation.

Conclusions

Age, historical stage, and chemotherapy were independent prognostic variables for overall survival and cause-specific survival of MGCTB patients, and radiotherapy and primary site were independent prognostic variables for overall survival. Nomograms based on significant clinicopathological features and clinical experience can be effective in predicting the probability of survival for MGCTB patients.

Pulmonary metastasis of giant cell tumour: a retrospective study of three hundred and ten cases

BACKGROUND

Giant cell tumour (GCT) is an invasive benign bone tumour, and the incidence of pulmonary metastasis is rare. We are aiming to analyze risk factors of pulmonary metastasis and clinical prognosis for giant cell tumour patients with pulmonary metastasis.

METHOD

We performed a retrospective study of 310 patients with GCT between December 2004 and December 2016. Risk factors of pulmonary metastasis were analyzed by univariate and multivariate logistic regression analysis. Then, the influence of risk factors of overall LR (local recurrence), recurrent tumor at presentation, LR after our therapy, and with soft tissue mass on the pulmonary metastasis-free survival rates was analyzed.

RESULTS

The mean follow-up of the present cohort was 45.6 ± 35.3 months (median, 36.6 months; range, 6.1-193.4 months). Eighteen (5.8%) of 310 patients developed pulmonary metastasis. The average interval from surgery of primary tumour to detection of pulmonary metastasis was 15 months. Multivariate logistic regression analysis showed overall local recurrence was the independent risk factor of developing pulmonary metastasis. Among 18 patients with pulmonary metastasis, sixteen cases had history of local recurrence (88.9%, 16/18), including eleven (68.8%, 11/16) with local recurrence at presentation before receiving our therapy and seven (43.8%, 7/16) with local recurrence after receiving treatment in our hospital. Time to local recurrence had obvious difference between patients with and without pulmonary metastasis. Patients with pulmonary metastasis were prone to recur earlier. Furthermore, overall local recurrence, local recurrence after our therapy, recurrent tumor at presentation, and tumour with a soft tissue mass showed statistical differences in the pulmonary metastasis-free survival rates.

CONCLUSIONS

Giant cell tumour patients with soft tissue mass and overall local recurrence are prone to develop pulmonary metastasis. Although giant cell tumour is a benign tumor, more attention should be paid to the problem of pulmonary metastatic lesions, and chest CT scan should be recommended during follow-up.

Outcome of lung metastases due to bone giant cell tumor initially managed with observation

Background

The outcomes of patients with lung metastases from giant cell tumor of bone (GCTB) vary from spontaneous regression to uncontrolled growth. To investigate whether observation is an appropriate first-line management approach for patients with lung metastases from GCTB, we evaluated the outcomes of patients who were initially managed by observation.

Methods

We retrospectively reviewed the data of 22 patients with lung metastases from histologically confirmed GCTB who received observation as a first-line treatment approach. The median follow-up period was 116 months.

Results

Disease progression occurred in 12 patients (54.5%). The median interval between the discovery of lung metastases and progression was 8 months. Eight patients underwent metastasectomy following initial observation. The median interval between the discovery of lung metastases and treatment by metastasectomy was 13.5 months. None of the patients experienced spontaneous regression. Of the 22 patients, 36.4% needed a metastasectomy, and 9.1% required denosumab treatment during the course of the follow-up period. Disease progression occurred in 45.5% of the 11 patients with lung nodules ≤ 5 mm, while all five of the patients with lung nodules > 5 mm experienced disease progression. Progression-free survival was significantly worse in the group with lung nodules > 5 mm compared to the group with lung nodules ≤ 5 mm (p = 0.022).

Conclusions

Observation is a safe first-line method of managing patients with lung metastases from GCTB. According to radiological imaging, approximately half of the patients progressed, and approximately half required a metastasectomy or denosumab treatment. However, patients with lung nodules > 5 mm should receive careful observation because of the high rate of disease progression in this group.

Giant cell tumor of bone: Unusual features of a rare tumor

Giant cell tumor of bone is a benign tumor with an aggressive behavior. Its typical subarticular location and high recurrence risk can be associated with significant morbidity. Although benign, it can rarely metastasize especially to the lungs. Also, it can be multicentric in less than 1% of patients. Late malignant transformation, although rare, can occur with a very poor prognosis. This series reports on these unusual and challenging features and management considerations of giant cell tumor of bone. This retrospective study included review of the medical records of patients with a confirmed histopathological diagnosis of giant cell tumor of bone. A total of 25 patients (16 females and 9 males) with a mean age of 34.5 years were included; 22 had primary tumors, while 3 were referred with recurrent tumors. Pain was the most common presenting symptom. Most patients had grade III tumors. Tumors around the knee were the most common. Multicentric tumors were detected in three patients. Twenty-three patients (20 primary giant cell tumor of bone and 3 with recurrence) received treatment. Most patients (15/23) were treated with intralesional curettage with or without adjuvants. Seven patients had wide excision. Recurrence was seen in 45% (9/20) of primary giant cell tumor of bone especially with difficult anatomical locations. Most recurrences occurred more than 4 years after treatment. Pulmonary nodules were detected in four patients; two of them showed resolution during follow-up. One patient developed secondary sarcoma transformation with a fatal outcome. Giant cell tumor of bone was more common in females. Long bones were more affected, especially around the knee. Intralesional curettage was the most frequently used treatment. Recurrence was associated with inadequate tumor resection (especially in difficult anatomical location), younger age, male gender, and advanced local tumor grade. Denosumab can be used in the treatment of pulmonary metastasis, multicentric and recurrent giant cell tumor of bone. Due to late recurrence and malignant transformation, a prolonged follow-up is warranted.

Increased Risk of Lung Metastases in Patients with Giant Cell Bone Tumors: A Systematic Review

Giant cell tumors of the bone are rare, usually benign, tumors consisting of large, multinucleated bone cells. Remarkably, these tumors are characterized by aggressive growth. They tend to recur frequently and, in rare cases, metastasize to the lungs. Previous studies tried to identify risk factors for lung metastasis by giant cell bone tumors. Those studies reported different results due to a small number of patients. Therefore, a particularly high risk associated with this type of bone tumor prompted this systematic review and meta-analysis to identify risk factors for the development of lung metastases. The risk factors for lung metastasis by giant cell bone tumors searched for in this study were gender, age, lung metastasis and recurrence period, follow-up time, primary or recurrent tumor, Campanacci grading, tumor localization, disease course, treatment of primary and recurrent tumors, and pulmonary metastases treated by surgery, radiation, and chemotherapy. This meta-analysis identified the features outlined above by comparing the groups of patients with giant cell bone tumors and lung metastases with the control group consisting of patients without lung metastases. The search for suitable studies revealed 63 publications with a total of 4,295 patients with giant cell bone tumors. Of these, 247 (5.8%; 95% confidence interval (95%CI) 5.1-6.5%) patients had lung metastases. Further, the risk factors for lung metastases were the following: recurrence (p < 0.0001), lung metastasis time (p < 0.0001), Campanacci grade II (p = 0.028) and grade III (p = 0.006), localization in the lower limbs (p = 0.0007), curettage (p = 0.0005), and local irradiation of the primary tumor (p = 0.008). All studies showed a high-risk bias due to the absence of blinding of the participants, personnel, and outcome assessment. Special attention should be paid to tumor recurrence in the long follow-up time, since more advanced giant cell bone tumors, particularly in lower extremities, tend to reoccur and metastasize to the lung. Surgical treatment and local irradiation should be performed thoughtfully, with extended follow-up periods.

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.

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.

Development and validation of a prognostic index to predict pulmonary metastasis of giant cell tumor of bone

Purpose

Giant cell tumor of bone (GCTB) is an intermittent tumor with a low probability of pulmonary metastasis. Our aim was to investigate the risk factors and establish a nomogram predictive model for GCTB pulmonary metastasis.

Methods

We retrospectively evaluated GCTB patients at our center from 1991 to 2014. The cohort was randomized into training and validation sets. Univariate and multivariate analyses were used to evaluate the risk factors of pulmonary metastasis. A nomogram was established. Internal validation was achieved based on ROC curve and C-index values in the validation set. Decision curve analysis was performed to assess the clinical performance of the nomogram.

Results

417 patients were studied, including benign and malignant GCTBs. The average follow up was 79 months. Pulmonary metastases were observed in 27 cases. Four independent risk factors were identified: malignancy, tumor bearing time, times of recurrence and tumor size. A nomogram was developed to predict pulmonary metastasis with C-index values of 0.857 and 0.785 in the training and validation groups. In the decision curve analysis, patients could benefit from the nomogram, which differentiates patients at high risk for pulmonary metastasis and avoids unnecessary examination. According to the nomogram, patients with final risks of more than 0.06 should be scheduled for further chest scans.

Conclusion

Malignancy, tumor bearing time, times of recurrence and tumor size were independent risk factors for pulmonary metastasis in GCTB patients. The nomogram can accurately predict the risk of pulmonary metastasis and help doctors to make clinical decisions for further chest examinations.