LAUSR

BACKGROUND Clival chordomas are challenging because of their proximity to critical neurovascular structures. Stereotactic radiosurgery (SRS) has been proven effective with minimal adverse effects. OBJECTIVE To compare the outcomes of histologically confirmed primary clival chordomas in adults who underwent SRS alone (SRS group) vs SRS after fractionated radiotherapy (FRT+SRS group). METHODS We collected patient data from 10 institutions affiliated with the International Radiosurgery Research Foundation. We evaluated overall survival, tumor control, and freedom from additional treatment (FFAT). RESULTS Fifty-seven (77%) patients were included in the SRS group and 17 (23%) in the FRT+SRS group. The median radiological follow-up was 48 months (IQR, 24-85) in the SRS group and 36 months (IQR, 25-41) in the FRT+SRS group. During the follow-up, 8 SRS and 2 FRT+SRS patients died (P = .80). The groups had comparable 10-year overall survival (SRS: 76% vs FRT+SRS: 80%; logrank test, P = .75) and tumor control rates (SRS: 34% vs FRT+SRS: 45%; logrank test, P = .29). The SRS group had a superior 10-year FFAT rate (40%) compared with FRT+SRS (23%; logrank test, P = .02). This finding persisted in the multivariate analysis of the Cox proportional hazards illustrating a 2.40-fold increase in the relative risk of requiring additional treatment among the FRT+SRS group (P = .04). CONCLUSION Adjuvant FRT with subsequent boost SRS did not provide superior overall survival or tumor control compared with patients who underwent adjuvant SRS alone. Further studies are required to refine management guidelines among adults with clival chordomas.