Prognostic Factors after Surgical Treatment for Spinal Metastases

Study Design: A retrospective multicenter case series was conducted. Purpose: This study aimed to investigate survival and prognostic factors after surgery for a metastatic spinal tumor. Overview of Literature: Prognostic factors after spinal metastasis surgery remain controversial. Methods: A retrospective multicenter study was conducted. The study participants included 345 patients who underwent surgery for spinal metastases from 2010 to 2020 at nine referral spine centers in Japan. Data for each patient were extracted from medical records. To identify the factors predicting survival prognosis after surgery, univariate analyses were performed using a Cox proportional hazards model. Results: The mean age was 65.9 years. Common primary tumors were lung (n=72), prostate (n=61), and breast (n=39), and 67.8% (n=234) presented with osteolytic lesions. The epidural spinal cord compression scale score 2 or 3 was recognized in 79.0% (n=271). Frankel grade A paralysis accounted for 1.4% (n=5), and 73.3% (n=253) were categorized as intermediate or high risk according to the new Katagiri score. The overall survival rates were -71.0% at 6 months, 57.4% at 12, and 43.3% at 24. In the univariate analysis, Frankel grade A (hazard ratio [HR], 3.59; 95% confidence interval [CI], 1.23-10.50; p <0.05), intermediate risk (HR, 3.34; 95% CI, 2.10-5.32; p <0.01), and high risk (HR, 7.77; 95% CI, 4.72-12.8; p <0.01) in the new Katagiri score were significantly associated with poor survival. On the contrary, postoperative chemotherapy (HR, 0.23; 95% CI, 0.15-0.36; p <0.01), radiation therapy (HR, 0.43; 95% CI, 0.26-0.70; p <0.01), and both adjuvant therapy (HR, 0.21; 95% CI, 0.14-0.32; p <0.01) were suggested to improve survival. Conclusions: Surgical indications for patients with Frankel grade A or intermediate or high risk in the new Katagiri score should be carefully considered because of poor survival. Chemotherapy or radiation therapy should be considered after surgery for better survival.