Neurological Recovery in Two Patients with Cauda Equina Syndrome Secondary to L5 Lumbar Spine Giant Cell Tumour after Treatment with Denosumab without Surgery

The risk of neurological deterioration while using neoadjuvant denosumab on patients with giant cell tumor of the spine presenting with epidural disease: a meta-analysis of the literature

BACKGROUND CONTEXT

Giant cell tumor (GCT) of bone is most commonly a benign but locally aggressive primary bone tumor. Spinal GCTs account for 2.7% to 6.5% of all GCTs in bone. En bloc resection, which is the preferred treatment for GCT of the spine, may not always be feasible due to the location, extent of the tumor, and/or the patient's comorbidities. Neoadjuvant denosumab has recently been shown to be effective in downstaging GCT, decreasing the size and extent of GCTs. However, the risk of neurologic deterioration is of major concern for patients with epidural spinal cord compression due to spinal GCT. We experienced this concern when a patient presented to our institution with a midthoracic spinal GCT with progressive epidural disease. The patient was not a good surgical candidate due to severe cardiac disease and uncontrolled diabetes. In considering nonoperative management for this patient, we asked ourselves the following question: What is the risk that this patient will develop neurologic deterioration if we do not urgently operate and opt to treat him with denosumab instead?

PURPOSE

The purpose of this study was to assess the literature to (1) determine the risk of neurological deterioration in patients receiving neoadjuvant denosumab for the treatment of spinal GCT and (2) to evaluate the secondary outcomes including radiographic features, surgical/technical complexity, and histological features after treatment.

STUDY DESIGN/SETTING

Meta-analysis of the literature.

PATIENT SAMPLE

Surgical cases of spinal GCT that (1) presented with type III Campanacci lesions, (2) had epidural disease classified as Bilsky type 1B or above and (3) received neoadjuvant denosumab therapy.

OUTCOME MEASURES

The primary outcome measure of interest was neurologic status during denosumab treatment. Secondary outcome measures of interest included radiographic features, surgical/technical complexity, histological features, tumor recurrence, and metastasis.

METHODS

Using predetermined inclusion and exclusion criteria, PubMed and Embase electronic databases were searched in August 2022 for articles reporting spinal GCTs treated with neoadjuvant denosumab and surgery. Keywords used were "Spine" AND "Giant Cell Tumor" AND "Denosumab."

RESULTS

A total of 428 articles were identified and screened. A total of 22 patients from 12 studies were included for review. 17 patients were female (17/22, 77%), mean age was 32 years (18-62 years) and average follow-up was 21 months. Most GCTs occurred in the thoracic and thoracolumbar spine (11 patients, 50%), followed by 36% in the lumbar spine and 14% in the cervical spine. Almost half of the patients had neurological deficits at presentation (10/22 patients, 45%), and more than 60% had Bilsky 2 or 3 epidural spinal cord compression. None of the patients deteriorated neurologically, irrespective of their neurological status at presentation (p-value=.02, CI -2.58 to -0.18). There were no local recurrences reported. One patient was found to have lung nodules postoperatively. More than 90% of cases had decreased overall tumor size and increased bone formation. Surgical dissection was facilitated in more than 85% of those who had documented surgical procedures. Four patients (18%) underwent initial spinal stabilization followed by neoadjuvant denosumab and then surgical excision of the GCT. Regarding the histologic analyses, denosumab eradicated the giant cells in 95% of cases. However, residual Receptor Activator of Nuclear Factor Kappa B Ligand (RANKL)-positive stromal cells were noted, in 27% (6 cases).

CONCLUSIONS

Neoadjuvant denosumab was a safe and effective means of treating spinal GCTs prior to surgery. Neurologic status remained stable or improved in all cases included in our review, irrespective of the presenting neurologic status. The most appropriate dosage and duration of denosumab therapy is yet to be determined. We recommend future well-designed studies to further evaluate the use of neoadjuvant denosumab for patients with spinal GCT.

Diagnosis and Treatment of Lumbar Giant Cell Tumor of the Spine: Update on Current Management Strategies

(1) Background: Giant Cell Tumor of the spine remains a difficult tumor to treat. Recent advances in adjuvant therapy such as denosumab and innovations in surgical technique in the last 5 years have given providers new options for treatment after a successful diagnosis of the tumor. (2) Methods: Articles published between 1927 and 2021 were selected from PubMed and Scopus searches using key words “Giant Cell Tumor” AND “Lumbar Spine” AND “Treatment”. Relevant articles were reviewed and selected by the authors. (3) Results: A total of 191 articles were discovered. Complete en bloc spondylectomy remains the most definitive treatment option; however, this surgery is challenging and carries a high rate of complication. New adjuvant therapies including denosumab offer a viable alternative to surgery. (4) En bloc spondylectomy remains the gold standard treatment for Giant Cell Tumor of the spine with the lowest published recurrence rate. The use of (neo)adjuvant denosumab improves recurrence rates. More data are needed to determine if denosumab alone is a viable standalone definitive treatment.

Denosumab in the treatment of giant cell tumor of the spine. Preliminary report, review of the literature and protocol proposal

BACKGROUND

The interest on the role of Denosumab in the treatment strategy of giant cell tumor of the spine is growing. En bloc resection is considered the Enneking appropriate treatment, but morbidity and functional loss are sometimes unacceptable. Denosumab could play a role as a stand-alone treatment, but also as preoperative treatment or as postoperative after intralesional surgery.

MATERIALS AND METHODS

A cohort of 10 out of 12 cases of spinal GCT consecutively treated with Denosumab are analyzed and discussed compared to the cases reported in the literature. A staging of the radiological effect of the treatment is proposed.

RESULTS

The stand-alone and postoperative treatments are still running (12 to 88 months). One therapy was stopped after 15 months, once a satisfactory local effect was achieved, but the treatment had to be restarted 2 months later due to the recurrence of the erosive images. The new treatment was successful. At 1-year follow-up after the gross total excision followed by postoperative Denosumab treatment, no evidence of local recurrence was found. The preoperative treatment duration ranged from 3 to 24 months. No local recurrence followed the en bloc resections.

CONCLUSIONS

Denosumab alone is effective in relieving pain, increasing the ossification and sometimes reducing the tumor volume. It can be considered an excellent solution in spine GCTs whose surgical treatment cannot be Enneking appropriate or is associated with unacceptable morbidity or loss of functions. It is still impossible to state when to safely stop the treatment. Denosumab also plays a role as preoperative protocol. These slides can be retrieved under Electronic Supplementary Material.

Giant cell tumor of the thoracic spine completely removed by total spondylectomy after neoadjuvant denosumab therapy

PURPOSE

Denosumab, a novel monoclonal antibody that targets the receptor activator of nuclear factor-κB (RANK) ligand (RANKL), has recently been used to treat patients with giant cell tumor of bone (GCTB). However, few reports have described the clinical results of denosumab therapy for spinal GCTB and evaluated treatment efficacy with respect to the entirety of the resected vertebra after denosumab therapy.

METHODS

We present the case of a 51-year-old man with T12 GCTB that was completely removed by a total spondylectomy following 10 courses of neoadjuvant denosumab therapy. Post-therapy radiological findings indicated epidural tumor reduction in the spinal canal and sclerotic rim formation. However, the affected vertebra collapsed despite denosumab therapy and a massive bridging callus formation was present between the spinal GCTB and adjacent vertebra.

RESULTS

These morphological changes made the tumor margins unclear and increased the difficulty of dissection of the segmental arteries from the vertebral body and en bloc corpectomy by a posterior-approach. Pathological findings indicated increased woven bone at the peripheral lesion of the resected vertebra and RANKL-positive stromal cells remained around the woven bone.

CONCLUSIONS

These findings support that GCTB stromal cells survived around the newly formed woven bone after long-term denosumab treatment and total surgical resection of such primary spinal lesions as the gold-standard treatment, even following administration of denosumab. Surgeons should note that prolonged adjuvant denosumab therapy may increase the difficulty of performing a posterior-approach total en bloc spondylectomy.