Development and Validation of a Prognostic Nomogram for the Overall Survival of Patients Living with Spinal Metastases

Introduction: The primary goal of treatment in spinal metastasis is typically to extend patients' lifespan as much as possible, and optimally to relieve the symptoms and so improve quality of life. It is crucial to avoid over- or under-treatment, according to each patient's individual situation. Thus, this study aimed to identify significant prognostic factors for patients living with metastatic spine disease, and create a new nomogram for the prediction of survival rates.

Methods: Data from patients who had undergone operations for spinal metastasis between 2005 and 2016 were retrieved retrospectively, and randomized into training (70%) and validation groups (30%). A selection of pre-operative factors was analyzed using univariable and multivariable COX model for the training group. A nomogram was then developed using significant predictors in multivariable analysis. Accuracy was validated using a concordance index (C-index) and calibration curve for the training and validation groups, respectively.

Results: A total of 244 participants were enrolled, including 171 in the training group and 73 in the validation group. Primary tumor, Frankel Grade, Karnofsky Performance Score (KPS) and adjuvant therapy were found to be significant for predicting survival rates. A nomogram was developed by utilizing these predictors. The C-indexes for the two groups were 0.711 and 0.703 respectively. Moreover, a favorable consistency between the predicted and actual survival probabilities was demonstrated using calibration curves.

Conclusions: A user-friendly nomogram model for facilitating medical procedures during clinical encounters was established to aid clinical decision making for individual patients.