Combining of serial embolization and denosumab for large sacropelvic giant cell tumor: Case report of 3 cases

RATIONALE: Both serial arterial embolization (SAE) and denosumab have been proved to be effective in treatment for giant cell tumor (GCT). There is potential synergic effect of combining two methods. The purpose of current study is to justify a new treatment strategy of combination of SAE and denosumab as neoadjuvant or stand-alone treatment for large sacropelvic giant cell tumor. PATIENT CONCERNS: Pelvic and sacral GCTs tend to be very large size and vascular. The concerns of surgical treatment were invasiveness of extensive surgery, intraoperative hemorrhage, nerve function jeopardized and local recurrence. However, SAE alone may not be adequate for complete removal of the tumor. DIAGNOSES: All the three cases were proved to be GCT by core-needle biopsy. Post-treatment pathological change was confirmed by further biopsy. INTERVENTIONS: The patient in Case 1 diagnosed of large recurrent sacral GCT received 6 times of endovascular embolizations with 2-month interval and started on denosumab simultaneously after first session of embolization. The second case was a 22-year-old female presented with a massive iliosacral tumor. SAE was performed for 3 sessions and the denosumab was started simultaneously. The patients was on treatment for half year. Both patients experienced a dramatic decrease in symptoms and concomitant improvement in function after the first embolization and weekly injection of denosumab. Tumor removal was performed on patient in case 2. The last case was a pelvic GCT and the patient received SAE and denosumab for half year. The tumor was then removed with purpose of complete cure. OUTCOMES: The first patient was still on denosumab with stable tumor. The other two patients were both free of recurrence after surgical removal of the tumors. No denosumab was used postoperatively. LESSONS: We reported the first three cases treated by combination of SAE and denosumab in the literature and aim to raise an alternative method for large GCT at challenging anatomical locations, for which surgery would carry significant risk. SAE and denosumab can synergically promote sclerosis and result in significant decrease in pain. It is reasonable to consider using SAE combined with denosumab neoadjuvantly to reduce the extensiveness and morbidity of surgery, however further investigation is warranted.