Biochemical Variables are Predictive for Patient Survival after Surgery for Skeletal Metastasis. A Prediction Model Development and External Validation Study

Abstract

Background: Predicting survival for patients with metastatic bone disease in the extremities (MBDex) is important for ensuring the implant will outlive the patient. Hitherto, prediction models for these patients have been constructed using subjective assessments, mostly lacking biochemical variables. Objectives: To develop a prediction model for survival after surgery due to MBDex using biochemical variables and externally validate the model. Methods: We created Bayesian Belief Network models to estimate likelihood of survival 1, 3, 6, and 12 months after surgery using 140 patients. We validated the models using the data of 130 other patients and calculated the area under the Receiver Operator Characteristic curve (ROC). Variables included: hemoglobin, neutrophil-count, C-reactive protein, alkaline phosphatase, primary cancer, Karnofsky-score, ASA-score, visceral metastases, bone metastases, days from diagnose of primary cancer to index surgery for MBDex, ischemic heart disease, diabetes, fracture/impending-fracture and age. Results: Survival probabilities were influenced by all biochemical variables. Validation showed ROC for the 1, 3, 6, and 12-months model: 68% (C.I.: 55%-80%), 69% (C.I.: 60%-78%), 81% (C.I.: 74%-87%) and 84% (C.I.: 77%-90%). Conclusion: Biochemical markers can be incorporated into a prediction model for survival in patients having surgery for MBDex allowing surgeons to offer more objective and individualized treatment options.

Development and comparison of 1-year survival models in patients with primary bone sarcomas: External validation of a Bayesian belief network model and creation and external validation of a new gradient boosting machine model

“…Owing to the variety and heterogeneity of bone sarcomas, management is based on individual decision-making. While several prediction models for short-term survival have been developed for patients with metastatic bone disease 8,26 and soft tissue tumors, 9 only separate prognostic factors for survival have been identified for patients with bone sarcoma. 1,27 The decision to perform surgery and which surgical intervention to choose often relies on estimated survival based on the presence of the prognostic factors.…”

“…Nevertheless, to strengthen the model and circumvent observational bias, the use of objective variables, such as biochemical markers, should be considered. Several biochemical markers have proven well suited as features for prediction models in patients with bone metastasis; 26 serum lactate dehydrogenase and molecular markers, such as p-53 and p-glycoprotein, have been reported to have prognostic value for patients with osteosarcoma. 39 Thorn et al 40 found a positive correlation between high YKL-40 protein expression in tumor tissue and longer overall survival in osteosarcoma patients.…”