Simple Clinical Score to Predict 24-Week Survival Times in Patients with Inoperable Malignant Distal Biliary Obstruction as a Tool for Selecting Palliative Metallic or Plastic Stents

Abstract

Background and aim: Endoscopic biliary drainage (EBD) is the mainstay treatment for inoperable malignant distal biliary obstruction (MDBO). Some authorities suggest that metallic stents are more cost-effective than plastic stents in patients with expected survival of at least 6 months. However, studies attempting to define the predictive factors for such survival times are limited. This study aims to develop a scoring system for predicting a survival time of <24 weeks in these patients.

Method: Patients with MDBO from inoperable periampullary cancers who underwent EBD at Songklanagarind Hospital during 2004-2009 were retrospectively analyzed. Baseline clinical, laboratory, and imaging data were retrieved. The survival time data were retrieved from the medical records and Thailand's civil registration database. Multivariate Cox regression model coefficients were used in the development of a survival time prediction scoring system.

Results: Ninety-eight patients were included. The overall median survival was 17.6 weeks. Fifty-seven (58.1%) survived <24 weeks. By multivariate analysis, cancer type and liver metastasis were significant predictive factors. The Simple Clinical Score (SCS) was calculated from (2× liver metastasis) + (1× pancreatic cancer) - (2× ampullary cancer) - (1× cholangiocarcinoma), when 1 and 0 were used for the presence and absence of each factor, respectively. The cutoff value of the score ≥0 had a sensitivity and specificity of 0.77 and 0.63, respectively, for predicting a survival time of <24 weeks, with AUC of 0.76. The median survival of patients with SCS <0 and ≥0 was 36.6 and 13.1 weeks, respectively.

Conclusion: The scoring system from this study may be beneficial for clinicians to select the appropriate stents in endoscopic biliary drainage in inoperable MDBO patients.

Keywords: Ampullary cancer; Biliary stent; Cholangiocarcinoma; Distal biliary obstruction; Malignant biliary obstruction; Malignant distal biliary obstruction; Malignant distal biliary stricture; Metallic stents; Pancreatic cancer; Plastic stents; Predictive factors; Survival; Survival predictor.