Outcomes and Toxicity for Hypofractionated and Single-Fraction Image-Guided Stereotactic Radiosurgery for Sarcomas Metastasizing to the Spine

• Published in: International journal of radiation oncology, biology, physics Vol. 88; no. 5; pp. 1085 - 1091
• Main Authors: Folkert, Michael R., MD, PhD, Bilsky, Mark H., MD, Tom, Ashlyn K., BA, Oh, Jung Hun, PhD, Alektiar, Kaled M., MD, Laufer, Ilya, MD, Tap, William D., MD, Yamada, Yoshiya, MD
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01-04-2014
• Subjects: Adult; Aged; Aged, 80 and over; Cohort Studies; Dose Fractionation; Female; HAZARDS; Hematology, Oncology and Palliative Medicine; Humans; Male; METASTASES; Middle Aged; MULTIVARIATE ANALYSIS; Neoplasm Metastasis; PATIENTS; Prognosis; Proportional Hazards Models; RADIATION DOSES; Radiation Injuries - diagnosis; Radiology; RADIOLOGY AND NUCLEAR MEDICINE; RADIOSENSITIVITY; Radiosurgery - adverse effects; Radiosurgery - methods; RADIOTHERAPY; Radiotherapy Dosage; RISK ASSESSMENT; Sarcoma - mortality; Sarcoma - pathology; Sarcoma - surgery; SARCOMAS; Spinal Neoplasms - mortality; Spinal Neoplasms - secondary; Spinal Neoplasms - surgery; SURGERY; TOXICITY; Treatment Outcome; VERTEBRAE
• ISSN: 0360-3016; 1879-355X
• DOI: 10.1016/j.ijrobp.2013.12.042

Purpose Conventional radiation treatment (20-40 Gy in 5-20 fractions, 2-5 Gy per fraction) for sarcoma metastatic to the spine provides subtherapeutic doses, resulting in poor durable local control (LC) (50%-77% at 1 year). Hypofractionated (HF) and/or single-fraction (SF) image-guided stereotactic radiosurgery (IG-SRS) may provide a more effective means of managing these lesions. Methods and Materials Patients with pathologically proven high-grade sarcoma metastatic to the spine treated with HF and SF IG-SRS were included. LC and overall survival (OS) were analyzed by the use of Kaplan-Meier statistics. Univariate and multivariate analyses were performed by the use of Cox regression with competing-risks analysis; all confidence intervals are 95%. Toxicities were assessed according to Common Terminology Criteria for Adverse Events, version 4.0. Results From May 2005 to November 11, 2012, 88 patients with 120 discrete metastases received HF (3-6 fractions; median dose, 28.5 Gy; n=52, 43.3%) or SF IG-SRS (median dose, 24 Gy; n=68, 56.7%). The median follow-up time was 12.3 months. At 12 months, LC was 87.9% (confidence interval [CI], 81.3%-94.5%), OS was 60.6% (CI, 49.6%-71.6%), and median survival was 16.9 months. SF IG-SRS demonstrated superior LC to HF IG-SRS (12-month LC of 90.8% [CI, 83%-98.6%] vs 84.1% [CI, 72.9%-95.3%] P =.007) and retained significance on multivariate analysis ( P =.030, hazard ratio 0.345; CI, 0.132-0.901]. Treatment was well tolerated, with 1% acute grade 3 toxicity, 4.5% chronic grade 3 toxicity, and no grade >3 toxicities. Conclusions In the largest series of metastatic sarcoma to the spine to date, IG-SRS provides excellent LC in the setting of an aggressive disease with low radiation sensitivity and poor prognosis. Single-fraction IG-SRS is associated with the highest rates of LC with minimal toxicity.