The impact of radiosensitivity on clinical outcomes of spinal metastases treated with stereotactic body radiotherapy

Abstract

BACKGROUND: To evaluate the impact of radiosensitivity on outcomes of spinal metastases treated with stereotactic body radiotherapy (SBRT) and identify the correlated prognostic factors. METHODS: The authors retrospectively reviewed the records of all patients who underwent SBRT with no prior radiation for spinal metastases between October 2015 and October 2020 at Sun Yat-sen University Cancer Center. On the basis of radiosensitivity, patients were divided into two groups-radiosensitive and radioresistant. The endpoints included local control (LC), overall survival (OS), pain relief, and time to pain relief. RESULTS: A total of 259 (82.5%) patients with 451 lesions were assessable with a median follow-up time of 10.53 months. The 1-, 2-, and 3-year OS rates were 59%, 52%, and 44%, respectively. The median survival was 33.17 months. Higher Karnofsky Performance Scale score and shorter time to diagnosis of spinal metastases from primary cancer at consult predicted for better OS (p = 0.02 and p < 0.001, respectively). The presence of other metastases (p = 0.04) and pain at enrollment assessed by the Brief Pain Inventory predicted for worse OS (p = 0.01). The 6-, 12-, and 24-month LC rates were 88%, 86%, and 82%, respectively. Younger age was identified for better LC and pain relief (p < 0.001 and p = 0.04, respectively). There was no variable independently associated with time to pain relief. As for toxicity, no Grade ≥3 toxicity was observed. CONCLUSIONS: Regardless of radiosensitivity, SBRT is feasible and appears to be an effective treatment paradigm for patients with spinal metastases, with limited accepted toxicities.