Evaluation of prognostic scoring systems for spinal metastases in 196 patients treated during 2005-2010

Estimating the survival time of patients with spinal metastases based on pre-treatment parameters is important for the best choice of therapy. Following two previous studies, this sequel analyzes possible changes in the impact of various parameters and scoring systems and includes a comparison to the previous dataset for the purpose to find the most predictive parameters and scores for this patient group.

Included were 196 patients retrospectively with confirmed spinal metastases treated between 2005 and 2010 (35% surgery, 65% conservative). Possible prognostic factors [primary tumor, Karnofsky Performance Scale (KPS), visceral metastases, number of bone metastases, pathological fracture and neurologic status] and six scoring systems (Tokuhashi original/revised, Tomita, van der Linden, Bauer original and modified) were analyzed using Kaplan-Meier curves and Cox-regression models.

Median overall survival was 7 months with 9% of all patients alive at the time of analysis. Stepwise multivariate analysis showed significant influence on survival for visceral metastases (p<0.0001), primary tumor (p<0.0001), KPS (p<0.0001) and number of spinal metastases (p=0.0271). All scoring systems significantly predicted longer survival at a better score (absolute scores, p<0.001) in this dataset. Significant differentiation between the prognostic groups was seen only for the Tokuhashi original, the Bauer original and modified scores (p<0.001). In comparison to the previous dataset with varying age, gender and primary tumor distribution, the Bauer original and modified scores were the least influenced by the different patient collectives.

The Bauer modified score has shown consistent impact on predicting the remaining survival in patients with spinal metastases and is simultaneously simple in clinical use.