Remaining Systemic Treatment Options: A Valuable Predictor of Survival and Functional Outcomes after Surgical Treatment for Spinal Metastasis

OBJECTIVES: To evaluate survival and functional outcomes in surgically‐treated spinal metastasis patients and to identify the prognostic value of the remaining options for systemic treatment. METHODS: The current study reviewed 100 consecutive patients who received surgery for spinal metastasis in a single center from March 2012 to June 2016. The decision for surgery had been made in a weekly multidisciplinary tumor board after considering multiple factors. Among these factors, those associated with the functional outcome were identified using crosstab and logistic regression analyses. Survival analysis applying the Kaplan–Meier curve and the Cox proportional hazards model was used to identify factors associated with improved survival. RESULTS: Of the 100 patients, there were 62 men and 38 women, with a mean age of 60.4 years at the time of surgery. The median postoperative survival of the whole cohort was 16.2 months (95% confidence interval: 10.1–22.3). When patients were stratified by the functional outcome, a significantly large proportion of patients with good functional outcome (Eastern Cooperative Oncology Group performance status better than 3) had an available option for systemic treatment at the time of surgery (P < 0.001, Pearson χ(2)‐test). Logistic regression analysis found that the presence of remaining options for systemic treatment at the time of decision‐making for surgery was associated with improved postoperative functional performance status (P = 0.004, odds ratio = 7.59). Survival analysis also found that the availability of remaining options for systemic treatment was associated with improved survival (P = 0.001, hazard ratio = 0.22). This finding was statistically more significant in a group of patients with a low revised Tokuhashi score of 0 to 8 (P < 0.001) when compared to the group of patients with a high revised Tokuhashi score of 9 to 15 (P = 0.082). CONCLUSIONS: Availability of remaining options for systemic treatment is an important factor to consider when deciding on surgical treatment for spinal metastasis.