Predicting survival for metastatic spine disease: a comparison of nine scoring systems

Background context: Despite advances in spinal oncology, research in patient-based prognostic calculators for metastatic spine disease is lacking. Much of the literature in this area investigates the general predictive accuracy of scoring systems in heterogeneous populations, with few studies considering the accuracy of scoring systems based on patient specifics such as type of primary tumor.

Purpose: The aim of the present study was to compare the ability of widespread scoring systems to estimate both overall survival at various time points and tumor-specific survival for patients undergoing surgical treatment for metastatic spine disease in order to provide surgeons with information to determine the most appropriate scoring system for a specific patient and timeline.

Study design: This is a retrospective study.

Patient sample: Patients who underwent surgical resection for metastatic spine disease at a single institution were included.

Outcome measures: Areas under the receiver operating characteristic curves were generated from comparison of actual survival of patients and survival as predicted by application of prevalent scoring systems.

Methods: A preoperative score for all 176 patients was retrospectively calculated utilizing the Skeletal Oncology Research Group (SORG) Classic Scoring Algorithm, SORG Nomogram, original Tokuhashi, revised Tokuhashi, Tomita, original Bauer, modified Bauer, Katagiri, and van der Linden scoring systems. Univariate and multivariate Cox proportional hazard models were constructed to assess the association of patient variables with survival. Receiver operating characteristic analysis modeling was utilized to quantify the accuracy of each test at different end points and for different primary tumor subgroups. No funds were received in support of this work. The authors have no conflicts of interest to disclose.

Results: Among all patients surgically treated for metastatic spine disease, the SORG Nomogram demonstrated the highest accuracy at predicting 30-day (area under the curve [AUC] 0.81) and 90-day (AUC 0.70) survival after surgery. The original Tokuhashi was the most accurate at predicting 365-day survival (AUC 0.78). Multivariate analysis demonstrated multiple preoperative factors strongly associated with survival after surgery for spinal metastasis. The accuracy of each scoring system in determining survival probability relative to primary tumor etiology and time elapsed since surgery was assessed.

Conclusions: Among the nine scoring systems assessed, the present study determined the most accurate scoring system for short-term (30-day), intermediate (90-day), and long-term (365-day) survival, relative to primary tumor etiology. The findings of the present study may be utilized by surgeons in a personalized effort to select the most appropriate scoring system for a given patient.