Identifying new predictive factors for survival after surgery for spinal metastases: an exploratory in-depth retrospective analysis

Objectives: In selected patients with symptomatic spinal metastasis from solid tumors, surgery improves quality of life. Since selection is key, inaccurate survival prognostication may result in poor decisions and outcomes. However, most prognostic scores suffer from suboptimal external validation and subsequent mediocre performance. This warrants the ongoing search for factors that better capture the oncological status. This exploratory study aims to identify new preoperative variables that predict survival. Methods: A retrospective analysis was conducted on 62 patients from a tertiary care referral center who underwent debulking and/or reconstruction surgery for spinal metastases between 2006 and 2018, and in whom detailed clinical, oncological, surgical and biochemical variables were collected. Univariate and multivariate analyses were performed for overall survival. Results: Median survival was 13.2 months. Multivariate analysis for overall survival identified that a higher number of organs with metastases, a shorter time to progression on the last line of systemic therapy before surgery (TTPbs), low serum albumin, high alkaline phosphatase, high C-reactive peptide (CRP), presence of brain metastasis and the index spinal level located in the cervical region were independently associated with shorter survival. Conclusion: We confirmed previously known predictors and identified CRP and TTPbs as new variables that were strongly associated with survival. The latter variable may replace primary tumor type, as improved cancer treatments make the primary tumor type less relevant as a predictor. This study is exploratory and its findings need to be validated, preferably in large prospective multicenter studies that are aiming at improving existing models.