소화기내과 R2. 임형석 / Pf. 동석호

B ACKGROUND  Unresectable malignant bile duct obstruction  Plastic stents (~1990s)  Stainless steel self-expandable metal stents (SEMSs)  Tumor ingrowth, epithelial hyperplasia, biofilm deposition, sludge limits median SEMS patency to 120 days  Ongoing biliary obstruction leads to significant mortality

B ACKGROUND  organic polymers(nitinol) coated SEMSs  Endobiliary photodynamic therapy  But, increased cholecystitis, pancreatitis, prolonged cholangitis, and hemobilia

B ACKGROUND  Radiofrequency ablation (RFA)  percutaneous delivery of heat energy  localized tumor necrosis  Endobiliary RFA  has not been used in human subjects (2011)  This study is the first human use of endoscopic RFA  Preliminary animal studies provided the basis for the power and duration of endobiliary therapy delivered

M ETHODS  Study design  single-center, open-label pilot study  to demonstrate safety and biliary patency  Patients  22 patients were recruited  between January 2009 and April 2010  Patients with unresectable pancreatic or bile duct cancer

M ETHODS  Exclusion criteria  uncorrected coagulopathy  cardiac pacemaker  failure to insert guidewire across a biliary stricture  Karnofsky < 40%  Prospective data  ERCP complications  patient survival  stent patency as long as 90 days after the procedure  presence of biliary obstruction

M ETHODS  RFA catheter (Olympus TJF-260 duodenoscopes)  The Habib EndoHPB (EMcision UK, London, United Kingdom) catheter  bipolar RFA probe  8F (2.6 mm), 1.8 m long, compatible with standard (3.2-mm working channel) side-viewing endoscopes, passes over inch guidewires  The catheter has 2 ring electrodes 8 mm apart with the distal electrode 5 mm from the leading edge  providing local coagulative necrosis over a 2.5-cm length  RFA generator (1500 RF generator; RITA Medical Systems Inc, Fremont, Calif)  electrical energy at 400 kHz at 7 to 10 W for 2 minutes  with a rest period of 1 minute before moving the catheter  After RFA treatment, uncovered SEMSs were deployed

R ESULTS

Preventing bile duct damage: Cylindrical heating pattern Spread energy between the 2 electrodes

R ESULTS

 no difficulties placing the RFA catheter across the biliary stricture  30 day patency was maintained in all other patients  At 90-day follow-up, 4/22 lost patency  1: who failed to demonstrate biliary decompression(had died)  3: Biliary obstruction developed  1: had died of disease progression with a patent stent

R ESULTS  Asymptomatic biochemical pancreatitis (amylase 1450 U/L)  1 patient  Cholecystitis requiring PTGBD  2 patients -> had tumor encasement of the cystic duct  Total 8 patients had tumor encasement of the cystic duct  did not demonstrate biliary decompression  1 patient  subsequent review demonstrated significant intrahepatic biliary malignancy

R ESULTS  Complications identified in the preclinical pig model  RFA burn into local structures  difficulty reintroducing catheters into the bile duct after RFA  hemorrhage and abscess formation  These complications were not apparent in our patients

C ONCLUSION  RFA burn d/t high energy  Deep tissue damage  some damage to an adjacent healthy bile duct  immediately followed by insertion of SEMSs  any biliary injury was empirically treated  Despite the limitations described, this study demonstrates 30-day safety and 90-day biliary patency  Randomized studies are warranted.