The dilemma of denosumab: Salvage of a femoral head giant cell tumour

Giant Cell Tumor of the Femoral Head: A Case Report and Review of the Literature

Introduction

Giant cell tumors (GCTs) of the bone are uncommon primary bone neoplasms that occur mainly in the epiphysis of long bones. GCT of the femoral head is rarely encountered.

Case Report

We report a rare case of GCT of the femoral head in a 20-year-old female. The patient presented with pathological fracture. The patient underwent total hip arthroplasty (THA). The aim of this paper is to present a case study with pathological fracture of the femoral head and to report the results of a literature review.

Conclusion

The treatment of choice for GCT of the proximal femur is a hip arthroplasty with either a standard THA for small confined tumors or endoprosthesis insertion for more extensive tumors. Joint preserving procedures have a high revision rate (47.06%). Denosumab has been tried as a neoadjuvant treatment with some success in certain cases.

Repurposing denosumab in breast cancer beyond prevention of skeletal related events: Could nonclinical data be translated into clinical practice?

INTRODUCTION

Denosumab is a human monoclonal antibody inhibiting the receptor activator of nuclear factor kappa-B ligand (RANKL). Initially approved as antiosteοporotic agent, denosumab is being currently pursued as a candidate for drug repurposing in oncology, especially breast cancer.

AREAS COVERED

The present review provides an overview of the therapeutic potential of denosumab in breast cancer beyond prevention of skeletal-related events (SREs), with focus on prevention of carcinogenesis in BRCA mutation carriers and on adjuvant treatment in early breast cancer patients. Study search was conducted on the following electronic databases: PubMed, Google scholar, Scopus.com, ClinicalTrials.gov, and European Union Clinical Trials Register from 2008 until June 2020.

EXPERT OPINION

Nonclinical data have established links between RANKL signaling and breast cancer initiation and progression, rationalizing exploring the potential bone-independent anticancer role of denosumab beyond SREs prevention. Preclinical and preliminary clinical data show that denosumab may inhibit carcinogenesis in BRCA mutation carriers. Denosumab adjuvant in early breast cancer has been shown, though inconsistently, to provide a disease-free survival benefit for a subgroup of patients. Despite promising results, the incorporation of denosumab in preventive and therapeutic protocols of breast cancer beyond prevention of SREs cannot be endorsed until further research consolidates its efficacy.

Does Denosumab Change the Giant Cell Tumor Treatment Strategy? Lessons Learned From Early Experience

BACKGROUND

Although giant cell tumors (GCTs) are benign, their aggressiveness and tendency to recur locally challenge the orthopaedic surgeon's ability to perform joint-preserving intralesional surgery with an acceptably low risk of local recurrence. Denosumab has emerged as a possible medical treatment of GCT because it seems to halt the progression of GCT, alleviate pain, and increase perilesional bone formation, but its exact role has been questioned, and specifically its efficacy and associated complications are not well characterized.

QUESTIONS/PURPOSES

(1) Does denosumab reduce the risk of recurrence after resection or intralesional surgery? (2) What are the complications associated with the use of denosumab?

METHODS

Fifty-four patients with 30 primary and 25 recurrent tumors between November 2013 and July 2016 were treated with denosumab after a confirmed histopathologic diagnosis of GCT. Another 17 patients in the same period were treated without denosumab. During the study period, we encouraged the use of denosumab in all patients except those who refused, could not afford it, or where it was contraindicated (eg, in pregnancy). In all patients undergoing intralesional surgery, we arbitrarily planned six doses before surgery. Variations in total doses before surgery were dependent on patient-related factors; in some, we gave less doses because patients expressed the inability to afford any more doses, whereas in some patients, extra doses were added when the patient wished to delay surgery as well as the because of surgeon judgment wherein in some patients, we stopped before six doses when we thought adequate bone had formed for intralesional curettage. The mean number of doses was 6.8 per patient (median, 6; range, 3-17) preoperatively. The minimum followup was 12 months (median, 27 months; range, 12-42 months). Every patient showed improvement clinically in terms of pain and halting of tumor progression within three to four doses. This was seen radiologically as a sharply defined soft tissue mass as well as hazy ossification within the tumor. For a case-matched comparison study, we identified controls as 34 patients undergoing curettage from the retrospective analysis of 68 patients curetted without denosumab between February 2010 and July 2016 matched to 25 denosumab-treated patients in terms of site, size, Campanacci grade, and recurrent versus primary status, and with a minimum 2 years followup for the control group. Fisher's exact test was used for statistical study. Patients undergoing resection were planned for surgery after three doses of denosumab to allow the tumor to solidify and potentially decrease tumor spillage at the time of surgery. The resections could not be case-matched for comparison owing to the smaller numbers.

RESULTS

We observed 14 recurrences out of the 37 curetted tumors (38%). In the case-matched analysis, 11 of 25 patients in the denosumab-treated curettage group had recurrences (44%) compared with seven of 34 (21%) in the nondenosumab-treated control group. The risk of denosumab-treated patients experiencing local recurrence as compared with the nondenosumab-treated patients was nonsignificant with a two-tailed p value of 0.085 (significance at p < 0.05) as derived from Fisher's exact test (odds ratio, 3.03; 95% confidence interval, 0.96-9.54). There was no recurrence in the resection group. Because we do not have a control group for resection, we are unable to comment on the importance of this finding. One major complication that we observed was a recurrence with malignant transformation in a patient with a proximal humeral GCT. We did not observe any other complications related to the denosumab therapy.

CONCLUSIONS

Although we could not demonstrate a higher risk of local recurrence with preoperative denosumab for intralesional surgery in the dose and frequency we administered, we advise caution in its routine use for intralesional procedures because it may be important to curette up to margins on pretreatment imaging owing to the potential residual tumor within the denosumab-mediated thick bony shell, which may result in local recurrence. We believe that denosumab treatment before resection of a large tumor aids resection without tumor spillage, particularly where important structures like the neurovascular bundle are dissected away from the tumor margin, although we cannot confirm that it helps lower the incidence of recurrence. We are concerned regarding the malignancy-causing potential from our observation in one patient as well as reports of this by others and recommend judicious use of this drug in patients with GCT.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Giant Cell Tumors of the Bone: Changes in Image Features after Denosumab Administration

Purpose:

To assess the clinical importance in the feature change in giant cell tumors of the bone (GCTB) after denosumab treatment, detected by MRI.

Methods:

In 12 patients, MRI and CT of GCTB obtained before and after the treatment retrospectively compared. The tumor size, the signal intensity (SI) ratio between the solid part of the GCTB and muscle, cystic part size, gadolinium enhancement and apparent diffusion coefficient (ADC) value were measured on MRI. The bone formation in the tumor was observed on CT and X-ray.

Results:

The mean number of denosumab injections was 19 ± 10. The follow-up period was up to 2 years. One case showed partial remission, while the other 11 cases were stable. A mean SI ratio on T₂-weighted image statistically significantly decreased from 3.9 to 1.9 after the treatment. A cystic component in the tumor was observed in five cases before the treatment, and the diameter of the cystic part decreased after the treatment in 80% of cases (4/5). All the tumors showed contrast enhancement on T₁-weighted image pre- and post-treatment (11/11). The averaged ADC values were 1.52 × 10⁻³ mm²/s before and 1.44 × 10⁻³ mm²/s after the treatment (P = 0.63). Bone formation in the tumor was observed in 58% of cases (7/12).

Conclusion:

The decrease of SI ratio on T₂-weighted image, shrinkage of cystic part and bone formation should be regarded as the effectiveness of denosumab treatment despite of no substantial change in the tumor size.

Denosumab Therapy for Giant Cell Tumor of Bone Pulmonary Metastasis

Case

A 68-year-old female was diagnosed with giant cell tumor of bone (GCTB) metastatic to her lungs. The patient was treated with IV denosumab for the course of 4.5 years for these metastases. The metastatic tumor burden decreased significantly after only 3 months of therapy. The size of the metastases has been stable for over 4 years.

Conclusion

Denosumab therapy has promise in the treatment of GCTB, including pulmonary metastasis. However, the long-term role of denosumab for pulmonary metastases is yet to be determined.

Current status and unanswered questions on the use of Denosumab in giant cell tumor of bone

Denosumab is a monoclonal antibody to RANK ligand approved for use in giant cell tumour (GCT) of bone. Due to its efficacy, Denosumab is recommended as the first option in inoperable or metastatic GCT. Denosumab has also been used pre-operatively to downstage tumours with large soft tissue extension to allow for less morbid surgery. The role of Denosumab for conventional limb GCT of bone is yet to be defined. Further studies are required to determine whether local recurrence rates will be decreased with the adjuvant use of Denosumab along with surgery. The long term use and toxicity of this agent is unknown as is the proportion of patients with primary or secondary resistance. It is advised that complicated cases of GCT requiring Denosumab treatment should be referred and followed up at expert centres. Collaborative studies involving further clinical trials and rigorous data collection are strongly recommended to identify the optimum use of this drug.