Local Recurrence Free Survival and Overall Survival after En Bloc Resections Alone Versus with Radiotherapy of Sacral Chordomas: A Single-Center Retrospective Cohort Study

Introduction: There are unique surgical and clinical considerations of sacral chordomas compared to the mobile spine. The purpose of this study was to compare local recurrence-free survival (LRFS) and overall survival (OS) among patients with sacral chordomas undergoing en bloc resections alone versus en bloc resections with radiotherapy (RT).

Methods: Patients with a sacral/sacrococcygeal chordoma who underwent en bloc resections with or without a form of neoadjuvant or adjuvant RT at a single institution between January 2004 and February 2024 were included. Primary outcome measures were radiographic LRFS and OS. Unadjusted estimates of survival from surgery were computed using Kaplan-Meier methods.

Results: 36 patients were included. Median follow-up was 7.8 years (IQR 2.6-11). 27 patients (75%) underwent en bloc resections alone and 9 patients (25%) underwent neoadjuvant or postoperative adjuvant photon-based stereotactic radiosurgery or proton beam radiation with doses ranging from 24 Gy single fraction to 70 Gy in 35 fractions. Wide margins were achieved in 35 patients (97%). The 1-, 3-, and 5-year LRFS rates (95% CI) were 89% (78%, 100%), 67% (51%, 89%), and 67% (51%, 89%), respectively among patients undergoing en bloc resections alone versus 100% (100%, 100%; no events) among patients undergoing neoadjuvant or adjuvant RT.The 1-, 3-, and 5-year OS rates (95% confidence interval [CI]) were 100% (100%, 100%), 87% (74%, 100%), and 67% (49%, 91%), respectively among patients undergoing en bloc resections alone versus 100% (100%, 100%) at all time points (no deaths) among patients undergoing neoadjuvant or adjuvant RT.

Conclusion : En bloc resections has been considered the standard of care for solitary primary sacral chordoma. However, the addition of a RT regimen has been demonstrated in this and other recent studies to improve the overall OS and LRFS. Our study demonstrates a clear benefit to radiation in the armamentarium of chordoma treatment.