Percutaneous Preoperative Biliary Drainage for Resectable Perihilar Cholangiocarcinoma: No Association with Survival and No Increase in Seeding Metastases

Background. Endoscopic biliary drainage (EBD) and percutaneous transhepatic biliary drainage (PTBD) are both used to resolve jaundice before surgery for perihilar cholangiocarcinoma (PHC). PTBD has been associated with seeding metastases. The aim of this study was to compare overall survival (OS) and the incidence of initial seeding metastases that potentially influence survival in patients with preoperative PTBD versus EBD. Methods. Between 1991 and 2012, a total of 278 patients underwent preoperative biliary drainage and resection of PHC at 2 institutions in the Netherlands and the United States. Of these, 33 patients were excluded for postoperative mortality. Among the 245 included patients, 88 patients who underwent preoperative PTBD (with or without previous EBD) were compared to 157 patients who underwent EBD only. Survival analysis was done with Kaplan-Meier and Cox regression with propensity score adjustment. Results. Unadjusted median OS was comparable between the PTBD group (35 months) and EBD-only group (41 months; P = 0.26). After adjustment for propensity score, OS between the PTBD group and EBD-only group was similar (hazard ratio, 1.05; 95 % confidence interval, 0.74-1.49; P = 0.80). Seeding metastases in the laparotomy scar occurred as initial recurrence in 7 patients, including 3 patients (3.4 %) in the PTBD group and 4 patients (2.7 %) in the EBD-only group (P = 0.71). No patient had an initial recurrence in percutaneous catheter tracts. Conclusions. The present study found no effect of PTBD on survival compared to patients with EBD and no increase in seeding metastases that developed as initial recurrence. These data suggest that PTBD can safely be used in preoperative management of PHC

Fumaric acid production by fermentation

The potential of fumaric acid as a raw material in the polymer industry and the increment of cost of petroleum-based fumaric acid raises interest in fermentation processes for production of this compound from renewable resources. Although the chemical process yields 112% w/w fumaric acid from maleic anhydride and the fermentation process yields only 85% w/w from glucose, the latter raw material is three times cheaper. Besides, the fermentation fixes CO2. Production of fumaric acid by Rhizopus species and the involved metabolic pathways are reviewed. Submerged fermentation systems coupled with product recovery techniques seem to have achieved economically attractive yields and productivities. Future prospects for improvement of fumaric acid production include metabolic engineering approaches to achieve low pH fermentations

Preoperative biliary drainage in perihilar cholangiocarcinoma: identifying patients who require percutaneous drainage after failed endoscopic drainage

Background and study aims: Preoperative biliary drainage is often initiated with endoscopic retrograde cholangiopancreatography (ERCP) in patients with potentially resectable perihilar cholangiocarcinoma (PHC), but additional percutaneous transhepatic catheter (PTC) drainage is frequently required. This study aimed to develop and validate a prediction model to identify patients with a high risk of inadequate ERCP drainage. Patients and methods: Patients with potentially resectable PHC and (attempted) preoperative ERCP drainage were included from two specialty center cohorts between 2001 and 2013. Indications for additional PTC drainage were failure to place an endoscopic stent, failure to relieve jaundice, cholangitis, or insufficient drainage of the future liver remnant. A prediction model was derived from the European cohort and externally validated in the USA cohort. Results: Of the 288 patients, 108 (38 %) required additional preoperative PTC drainage after inadequate ERCP drainage. Independent risk factors for additional PTC drainage were proximal biliary obstruction on preoperative imaging (Bismuth 3 or 4) and predrainage total bilirubin level. The prediction model identified three subgroups: patients with low risk (7%), moderate risk (40 %), and high risk (62 %). The high-risk group consisted of patients with a total bilirubin level above 150 mu mol/L and Bismuth 3a or 4 tumors, who typically require preoperative drainage of the angulated left bile ducts. The prediction model had good discrimination (area under the curve 0.74) and adequate calibration in the external validation cohort. Conclusions: Selected patients with potentially resectable PHC have a high risk (62 %) of inadequate preoperative ERCP drainage requiring additional PTC drainage. These patients might do better with initial PTC drainage instead of ERCP