Management for chordoma of the spine and sacrum with stereotactic radiosurgery.

Objective: Resection for spinal and sacral chordoma is associated with significant morbidity and high rates of local recurrence. Stereotactic radiosurgery (SRS) offers radiobiological benefits over conventional radiation therapy and has emerged as a viable treatment option for these historically radioresistant tumors. There are relatively few studies that have reported on the treatment of spinal chordoma with SRS, given its rarity. Thus, the aim of this study was to identify long-term outcomes after SRS in patients with spinal and sacral chordoma.

Methods: A prospectively collected database analysis of patients with chordomas in the mobile spine and sacrum treated with SRS was conducted at a large quaternary referral center from February 2002 to January 2024. Patient demographic and histological data, prior treatment history, dosimetry, fractionation, and outcomes, including local control (LC), overall survival (OS), and resolution of neurological deficits and pain, were identified. SRS was used alone (9 tumors, 20%), as postoperative adjuvant therapy (12 tumors, 27%), and as salvage therapy for recurrent disease (23 tumors, 52%). The median single-fraction prescription dose was 21.25 Gy (range 13.5-25 Gy). Multifractionated treatment used prescription doses of 21-42 Gy in 3-5 fractions.

Results: Twenty-four patients (median age 65 years) with 44 chordomas were included. The median follow-up duration was 20 months (range 1-203 months). The 1-, 2-, and 5-year LC rates were 87%, 64%, and 49%, respectively. The 1- and 2-year LC rates were 100% and 83% for SRS alone and 90% and 80% for postoperative adjuvant SRS, respectively. Rates of OS were 90%, 84%, and 51% at 1, 2, and 5 years, respectively. Univariate analysis showed that multifractionated SRS was associated with superior LC (HR 0.26, 95% CI 0.10-0.71; p = 0.008); however, no significant difference in LC was observed when accounting for the biologically effective dose. Among patients presenting with neurological deficits, complete or partial resolution occurred for 8 of 20 tumors (40%). In symptomatic patients, pain was fully or partially alleviated for 27 of 36 tumors (75%). Six adverse radiation events (14%) were observed following treatment, including vertebral compression fracture (n = 2, 5%), pharyngoesophageal toxicity (n = 1, 2%), and transient peripheral neuropathy (n = 1, 2%).

Conclusions: This series is among the largest to date evaluating outcomes of SRS for spinal and sacral chordomas, demonstrating durable LC and symptom relief with acceptable rates of toxicity when used alone and as an adjunct to surgery. SRS is also an effective treatment option for patients with recurrent disease who seek noninvasive treatment or are not candidates for resection.