Modern Treatment of Skull Base Chordomas: From Endoscopes to Genetics
Eric Wang, Paul Gardner, Carl Snyderman, Georgios Zenonos
Introduction: Chordoma is a rare bony malignancy that commonly involves the clivus. Radical surgical resection remains the most proven treatment and endoscopic endonasal approaches (EEA) have shown great promise. Variations in long-term prognosis are not well predicted with basic histological parameters.
Objective: To study the efficacy of EEA in a large series of clival chordoma and evaluate molecular parameters that might predict prognosis.
Methods: Medical record review was performed looking at outcomes of EEA for chordoma and evaluating recurrence based on multiple molecular parameters.
Results: Until 2015, 106 patients underwent 151 EEAs for cranial base chordoma at UPMC. The gross total resection (GTR) rate for primary tumors was 73%, with GTR rates for all tumors increasing steadily with experience. Inferior and lateral tumor extensions remain a challenge and may require other approaches to achieve GTR. New or worsened cranial nerve palsies only occurred in 8% of cases.
Tumors can be divided into 3 prognostic categories based on FISH for 1p36 and 9p21: those with 1p36 0-15% and 9p21 0-3% have a good prognosis and can perhaps withhold adjuvant radiation; those with 1p36>15% and 9p21>25% have a very poor prognosis and should be considered for experimental chemo- or immunotherapies in addition to radiotherapy. The remaining majority of patients are currently treated with standard postoperative radiation.
Conclusions: Cranial base chordoma treatment has expanded rapidly over the last 2 decades. A combination of development and refinement of EEAs and improving molecular understanding of this rare tumor is driving their modern treatment paradigm.