Treatment outcomes of stereotactic radiosurgery for thyroid cancer spine metastases-systematic review.

Spinal metastases from thyroid carcinoma (TCSMs) are uncommon but clinically challenging, often occurring in patients with relatively long survival. The role of stereotactic radiosurgery (SRS) in managing TCSMs has been defined. We performed a systematic review to evaluate the efficacy, safety, and outcomes of SRS for TCSMs. A systematic literature search was conducted using PubMed/MEDLINE, Scopus, and Embase databases. Of 474 records identified, 432 studies underwent title and abstract screening after duplicate removal. Eleven articles were reviewed in full, and four studies met the inclusion criteria. Extracted data included patient demographics, thyroid cancer histology, spinal metastasis characteristics, prior treatments, SRS treatment parameters, clinical outcomes [local tumor control (LTC), overall survival (OS), pain response], treatment-related toxicity, and prognostic factors. Across included studies, SRS was delivered using heterogeneous dose and fractionation schemes, most commonly single-fraction regimens ranging from 12 to 24 Gy, with hypofractionated schedules delivering 18–30 Gy. Median follow-up ranged from 15 to 29 months. Overall, LTC ranged from 72% to 91%. One-, two-, and three-year LTC rates ranged from 67 to 96%, 56–89%, and 34–79%, respectively, with a reported 5-year LTC of 82% in one study. Median OS ranged from 28.9 to 43 months, with 1- and 2-year OS rates of 55–86% and 44–74%, respectively. Pain outcomes generally improved or remained stable following SRS. Treatment-related toxicity was infrequent and predominantly low grade, including dysphagia, esophagitis, radiculopathy, pain flare, vertebral compression fracture, and rare esophageal stenosis. Factors associated with improved outcomes included younger age, lower Bilsky score, non-papillary histology, prior radiation therapy, controlled extra-spinal disease, and multifraction SRS. SRS provides effective and durable local control for TCSMs with acceptable toxicity. Favorable survival outcomes reflect the radiosensitive nature of thyroid cancer and the prolonged survival of this patient population.