Changes in performance status and predictive factors for poor improvement following surgery for spinal metastasis: a nationwide multicenter prospective cohort study

Background Context: Spinal metastasis affects the activities of daily living (ADL) of patients, and spinal surgery is aimed at improving or maintaining ADL. The Eastern Cooperative Oncology Group Performance status (ECOG-PS) is a measure of ADL, and its change after surgery can influence decisions regarding cancer treatment options. However, few detailed, large-scale studies have examined changes in ECOG-PS after surgery for spinal metastases. Purpose: (1) To investigate the effects of spinal surgery for metastatic spinal tumors on ECOG-PS, and (2) To identify the risk factors for poor postoperative improvement. Study Design: Prospective multicenter cohort study Patient Sample: Four hundred and 4 symptomatic patients who underwent surgical treatment for metastatic spinal tumors. Outcome Measures: ECOG-PS was designated as the primary outcome and Barthel Index (BI) as the secondary outcome. Both were assessed preoperatively and at 1 and 6 months postsurgery. Methods: Changes in ECOG-PS and BI were analyzed using the Friedman test or a general mixed-effect model. Poor outcomes were defined as a ECOG-PS score of 3, 4, or death. Preoperative factors associated with poor outcomes were analyzed using multivariate logistic regression analyses with complete or multiple imputed datasets. Results: Preoperative ECOG-PS and BI scores improved at 1 and 6 months postoperatively. Patients with a ECOG-PS score of ≤2 at 1 month had significantly higher rates of receiving systemic therapy than those with a ECOG-PS score of ≥3. No use of bone-modifying agents, Frankel grade ≥C, ECOG-PS score of ≥3, or a high C-reactive protein/albumin ratio (CAR) were the preoperative factors associated with poor PS at 1 month, whereas history of systemic therapy, ECOG-PS score of ≥3, primary tumor type, anemia, and high CAR were the preoperative factors associated with poor ECOG-PS at 6 months. Conclusion: Spinal surgery can improve ADL in patients with spinal metastases; however, not all patients experience favorable outcomes. The present findings indicate that the preoperative severity of paralysis and ADL impairment, laboratory data, and treatment history are important for predicting ADL after surgery for spinal metastasis.