Low incidence of late failure and toxicity after spine stereotactic radiosurgery: Secondary analysis of phase I/II trials with long-term follow-up. (September 2019)

• Record Type: Journal Article
• Authors: Ning, Matthew S.; Deegan, Brian J.; Ho, Jennifer C.; Chapman, Bhavana V.; Bishop, Andrew J.; Allen, Pamela K.; Tannir, Nizar M.; Amini, Behrang; Briere, Tina M.; Wang, Xin A.; Tatsui, Claudio E.; Rhines, Laurence D.; Brown, Paul D.; Li, Jing; Ghia, Amol J.
• Is Part Of: Radiotherapy and oncology. Volume 138(2019)
• Page Start: 80
• Page End: 85
• Publication Date: 2019-09
• Subjects: Survivorship -- Spinal cord injuries -- Fractures -- Bone -- Spinal metastases -- Radiosurgery; Oncology -- Periodicals; Radiotherapy -- Periodicals; Tumors -- Periodicals; Medical Oncology -- Periodicals; Neoplasms -- radiotherapy -- Periodicals; Radiotherapy -- Periodicals; Radiothérapie -- Périodiques; Cancérologie -- Périodiques; Tumeurs -- Périodiques; Electronic journals; 616.9940642
• DOI: 10.1016/j.radonc.2019.06.003
• Languages: English
• ISSNs: 0167-8140

Abstract

Highlights: 5-year local control by site was 91%, with late failures occurring in 3% of sites. Overall and Grade ≥3 late toxicities were observed in only 5% and 2% of all sites. Neurologic events occur much earlier than fractures, with last noted at 2.1 years. No toxicities occurred after 4.1 years through end of follow-up (median 6.7 years) These data support the high therapeutic ratio of SSRS with long-term follow-up. Abstract: Background and purpose: To characterize local control and late toxicity in long-term survivors prospectively-treated with spine stereotactic radiosurgery (SSRS). Materials and methods: From 2002 to 2011, 228 patients were prospectively-treated on protocol for metastatic disease of 261 vertebral sites. A subset of 52 patients surviving >4 years following treatment were collectively treated for 58 sites (encompassing 69 vertebrae) and underwent secondary analysis. Of all sites, 9% received prior radiation, and 16% encompassed multiple contiguous vertebrae. Radiation prescriptions were most commonly 24 Gy in 1 and 27 Gy in 3 fractions. Outcomes were evaluated via Kaplan–Meier, and associations analyzed via logistic regression. Results: Median follow-up was 6.7 years (range: 49–142 months). Five-year local control by site was 91%, with late failures (>2 years) occurring in 3%. Overall and Grade ≥3 late toxicities (>2 years) were observed in 5% and 2% of sites. The last known neurologic event (grade 2 radiculopathy) was noted 2.1 years post-treatment, while the last documented fracture occurred at 4.1 years. No Grade ≥3 events were witnessed after 3.1 years post-SSRS, and no toxicities were noted after 4.1 years through end of follow-up. Re-irradiation, number of segments treated per site (1 vs. 2–3), and fractionation (1 vs. 3–5) were not associated with failure or toxicity. Conclusion: SSRS maintains excellent disease control and a favorable late toxicity profile even among long-term survivors, with very few failures or toxicities after 2 years in this prospectively-treated population. Overall, these data support the durable control and long-term safety of SSRS with extended follow-up.