The impact of expanded endoscopic approaches on oncologic and functional outcomes for clival malignancies:a case series

Introduction: Clival malignancies pose particular surgical challenges due to complex skull base anatomy and the involvement of vital neurovascular structures. While endoscopic endonasal approached are widely used, the outcomes for clival malignancies remain poorly understood. In this study we assessed the impact of endoscopic and open surgical approaches on PFS, time to initiation of radiotherapy, KPS, and GTR rates for clival malignancies. Methods: A retrospective case series for clival malignancies operated between 1993 and 2019 was conducted. Inclusion criteria were age over 18 and a follow-up of at least a 6 months. Statistical analyses were conducted using STATA version 15 statistical software package StataCorp. Results: For the whole cohort (113 patients), and for upper and middle lesions, open surgical approaches increased odds of disease progression, compared to EEA (HR 2.10 to HR 2.43), p < 0.05. EEA had a shorter time interval from surgery to initiation of radiotherapy. No difference in 6 and 12 month KPS was found between surgical groups. Patients undergoing open surgery were less likely to achieve GTR for upper clival lesions. Conclusions: EEA was found to be associated with increased PFS, for upper and middle clival malignancies. The time to initiation of radiotherapy was shorter for patients undergoing EEA compared to open surgery for patients with middle clival involvement. GTR rates were found to be significantly better with EEA for patients with upper clival malignancies.