Salvage Surgery and Salvage Stereotactic Radiosurgery in Recurrent Skull Base Chordomas: A Meta-Analysis of Survival Outcomes

Introduction: Chordomas are rare, locally aggressive tumors arising from notochordal remnants, with an incidence of approximately 0.08 per 100,000 persons. Skull base chordomas represent one-third of cases, most often involving the clivus, where their proximity to critical neurovascular structures complicates management. The natural history of untreated disease is poor, with median survival estimated at less than one year. While gross total resection (GTR) followed by particle therapy is the gold standard for initial management, recurrence rates exceed 50% at 10 years due to limitations in achieving complete resection and tumor resistance to conventional radiotherapy and chemotherapy. For recurrent skull base chordomas, salvage options include repeat surgery and stereotactic radiosurgery (SRS). However, the relative survival benefits, complication rates, and durability of control for these salvage strategies remain uncertain, highlighting the need for pooled analyses. Methods: A systematic review and meta-analysis were performed according to PRISMA guidelines. PubMed, Embase, and Web of Science were searched through April 2025 using predefined terms. Studies were eligible if they included adult patients (≥18 years) with recurrent skull base chordomas undergoing salvage surgery or SRS, stratified outcomes by modality, and reported survival endpoints. Primary outcomes were 5-year overall survival (OS) and progression-free survival (PFS). Secondary outcomes included extent of resection (EOR) and complication rates. Data extraction captured study characteristics, patient demographics, treatment modality, Kaplan–Meier curves, and survival estimates. Time-to-event outcomes were reconstructed from published curves, and pooled Kaplan–Meier analyses were performed using R version 4.4.2. Random-effects meta-analysis was used to calculate pooled complication rates. Risk of bias was assessed with ROBINS-I. Results: From 782 identified studies, 4 met inclusion criteria. Most patients underwent salvage surgery, with fewer treated by salvage SRS alone or combined surgery plus SRS. GTR was achieved in 24% of salvage surgeries, while 73% underwent subtotal resection (STR). Median OS following salvage surgery was 52.5 months, with a 5-year OS of 33.3%. In contrast, surgery plus adjuvant SRS was associated with a shorter median OS of 17.3 months and a 5-year OS of 12.8%. For PFS, long-term control remained poor, with 5-year PFS of 5.3% for salvage surgery and 6.9% for salvage SRS. Complication rates were relatively low: 12% (95% CI, 6–25%) for surgery and 11% (95% CI, 2–20%) for SRS. Conclusion: Salvage strategies for recurrent skull base chordomas achieve modest disease stabilization but limited long-term control. Surgery alone provided the most favorable overall survival, while inferior outcomes in surgery plus SRS likely reflect selection bias, as patients in this group frequently had prior radiation, larger tumor burden, or unresectable disease. Complication rates remained low across modalities, supporting the safety of both approaches. These findings emphasize the need for individualized treatment strategies based on prior radiation status, tumor volume, and anatomical constraints. Future prospective, recurrence-specific studies incorporating systemic therapies are essential to improve outcomes in this challenging patient population. Publication History Article published online: 27 February 2026 © 2026. Thieme. All rights reserved. Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany