Are spine metastasis survival scoring systems outdated and do they underestimate life expectancy? Caution in surgical recommendation guidance

OBJECTIVE Survival scoring systems for spine metastasis (SPM) were designed to help surgical practice. The authors sought to validate the prognostic accuracy of the main preoperative scoring systems for SPM. METHODS It was hypothesized that true patient survival in SPM was better than that predicted using prognosis scores. To investigate this hypothesis, the authors designed a French national retrospective study of a prospectively collected multicenter database involving 739 patients treated for SPM between 2014 and 2017. RESULTS In this series, the median survival time for all patients from an SPM diagnosis was 17.03 ± 1.5 months. Sensitivity and specificity were estimated using the area under the curve (AUC). The AUC of Tomita's prognosis score was the lowest and poorest (0.4 ± 0.023, range 0.35-0.44), whereas the AUC of the Tokuhashi score was the highest (0.825). The Lei score presented an AUC of 0.686 ± 0.022 (range 0.64-0.7), and the Rades score showed a weaker AUC (0.583 ± 0.020, range 0.54-0.63). Differences among AUCs were all statistically significant (p < 0.001). The modified Bauer score and the Rades score had the highest rate of agreement in predicting survival, with a weighted Cohen's kappa of 0.54 and 0.41, respectively, indicating a moderate agreement. The revised Tokuhashi and Lei scores had a fair rate of agreement (weighted Cohen's kappa = 0.24 and 0.22, respectively). The van der Linden and Tomita scores demonstrated the worst performance, with only a "slight" rate of agreement (weighted Cohen's kappa = 0.19 and 0.16, respectively) between what was predicted and the actual survival. CONCLUSIONS The use of prognostic scoring systems in the estimation of survival in patients with SPM has become obsolete and therefore underestimates survival. Surgical treatment decisions should no longer be based on survival estimations alone but must also take into account patient symptoms, spinal instability, and quality of life.