61. Development and external validation of predictive algorithms for six-week mortality in spinal metastasis using 4304 patients from five institutions.

Historically, spine surgeons used expected postoperative survival of three months to help select candidates for operative intervention in spinal metastasis. However, this cutoff has been challenged by the development of minimally invasive techniques, novel biologics and advanced radiotherapy. Recent studies have suggested that life expectancy of six weeks may be enough to achieve significant improvements in postoperative health-related quality of life. The purpose of this study was to develop a model capable of predicting six-week mortality in patients with spinal metastases treated with radiation or surgery. Retrospective review was conducted at five large tertiary centers in the United States and Taiwan. The development cohort consisted of 3,001 patients undergoing radiotherapy and/or surgery for spinal metastases from one institution. The validation institutional cohort consisted of 1,303 patients from four independent, external institutions. The primary outcome was six-week mortality. Five models were considered to predict six-week mortality, and the model with the best performance across discrimination, calibration, decision-curve analysis and overall performance was integrated into an open access web-based application. The most important variables for prediction of six-week mortality were albumin, primary tumor histology, absolute lymphocyte, three or more spine metastasis, and ECOG score. The elastic-net penalized logistic model was chosen as the best performing model with AUC 0.84 on evaluation in the independent testing set. On external validation in the 1,303 patients from the four independent institutions, the model retained good discriminative ability with an area under the curve of 0.81. As spinal metastasis patients with shorter life expectancy are considered for operative intervention, the algorithm developed and externally validated in this study may be helpful for preoperative planning, multidisciplinary management, and shared decision-making. This abstract does not discuss or include any applicable devices or drugs. [ABSTRACT FROM AUTHOR]