The predictive ability of routinely collected laboratory markers for surgically treated spinal metastases: a retrospective single institution study

Abstract

Purpose: We aimed to identify effective routinely collected laboratory biomarkers for predicting postoperative outcomes in surgically treated spinal metastases and attempted to establish an effective prediction model.

Methods: This study included 268 patients with spinal metastases surgically treated at a single institution. We evaluated patient laboratory biomarkers to determine trends to predict survival. The markers included white blood cell (WBC) count, platelet count, neutrophil count, lymphocyte count, hemoglobin, albumin, alkaline phosphatase, creatinine, total bilirubin, calcium, international normalized ratio (INR), platelet-to-lymphocyte ratio (PLR), and neutrophil-to-lymphocyte ratio (NLR). A nomogram based on laboratory markers was established to predict postoperative 90-day and 1-year survival. The discrimination and calibration were validated using concordance index (C-index), area under curves (AUC) from receiver operating characteristic curves, and calibration curves. Another 47 patients were used as a validation group to test the accuracy of the nomogram. The prediction accuracy of the nomogram was compared to Tomita, revised Tokuhashi, modified Bauer, and Skeletal Oncology Research Group machine-learning (SORG ML).

Results: WBC, lymphocyte count, albumin, and creatinine were shown to be the independent prognostic factors. The four predictive laboratory markers and primary tumor, were incorporated into the nomogram to predict the 90-day and 1-year survival probability. The nomogram performed good with a C-index of 0.706 (0.702-0.710). For predicting 90-day survival, the AUC in the training group and the validation group was 0.740 (0.660-0.819) and 0.795 (0.568-1.000), respectively. For predicting 1-year survival, the AUC in the training group and the validation group was 0.765 (0.709-0.822) and 0.712 (0.547-0.877), respectively. Our nomogram seems to have better predictive accuracy than Tomita, revised Tokuhashi, and modified Bauer, alongside comparable prediction ability to SORG ML.

Conclusions: Our study confirmed that routinely collected laboratory markers are closely associated with the prognosis of spinal metastases. A nomogram based on primary tumor, WBC, lymphocyte count, albumin, and creatinine, could accurately predict postoperative survival for patients with spinal metastases.

Keywords: Spine metastases; laboratory markers; nomogram; prognosis; survival.

Fig. 1

a-d Kaplan-Meier curves of overall survival based on four independent prognostic laboratory markers

Fig. 2

Our nomogram for survival prediction of patients with spinal metastases

Fig. 3

Calibration curve for 90-day survival prediction using our nomogram

Fig. 4

Calibration curve for 1-year survival prediction using our nomogram

Fig. 5

ROC curves of our nomogram at predicting 90-day survival in the training cohort and the validation cohort

Fig. 6

ROC curves of our nomogram at predicting 1-year survival in the training cohort and the validation cohort

Fig. 7

ROC curves of the revised Tokuhashi, Tomita, modified Bauer, SORG ML, and our nomogram at predicting 90-day survival

Fig. 8

ROC curves of the revised Tokuhashi, Tomita, modified Bauer, SORG ML, and our nomogram at predicting 1-year survival