Usefulness of an inflammation-based prognostic score (mGPS) for predicting survival in patients with unresectable malignant biliary obstruction.

Background: An inflammation-based prognostic score, the modified Glasgow Prognostic Score (mGPS), has been established as a useful tool for predicting postoperative outcome in patients with cancer. However, no studies have investigated the usefulness of the mGPS for prognostication in patients undergoing palliative surgery for unresectable malignant biliary obstruction (UMBO). The present study was conducted to investigate whether the mGPS is useful for predicting the postoperative survival of patients undergoing intraoperative placement of an expandable metal stent for UMBO, or not.

Methods: The mGPS was calculated as follows: patients with both an elevated level of C-reactive protein (CRP) (>1.0 mg/dL) and hypoalbuminemia (<3.5 g/dL) were allocated a score of 2. Patients with only an elevated CRP level were allocated a score of 1, and patients without an elevated CRP level (≤1.0 mg/dL) were allocated a score of 0. Postoperative survival was evaluated by Kaplan-Meier analysis and log rank test. The significance of risk factors for postoperative survival was evaluated with the Cox proportional hazards model.

Results: Kaplan-Meier analysis revealed that patients with mGPS 0 (n = 36) and 1 (n = 7) had better postoperative survival (p = 0.017) than patients with mGPS 2 (n = 17). The 6-month and 1-year survival rates of patients with mGPS 0 and 1 were 58.1 and 27.3 %, and those for patients with mGPS 2 were 25.0 and 6.2 %, respectively. Multivariate analysis revealed that mGPS (0, 1/2) was a significant risk factor for postoperative survival (hazard ratio 3.271; 95 % CI 1.109-9.649; p = 0.032).

Conclusion: The mGPS is not only one of the most significant predictors of postoperative survival for UMBO patients receiving intraoperative biliary stenting but also a useful indicator capable of dividing such patients into two independent groups before surgery.