Malignant Tumor of Extrahepatic Bile Duct Clinical Trial
Official title:
A Randomized Trial Comparing a Winged Perimeter Stent and Traditional Polyethylene Plastic Stent in the Management of Malignant Distal Biliary Strictures
Strictures in the bile duct cause a blockage of flow of bile. This leads to potential
problems including jaundice, itch and infection in the bile duct. The usual first step in
this situation would be to allow flow of bile by placing a stent across the stricture. This
is usually done by a special type of endoscopy procedure called an endoscopic retrograde
cholangiopancreatography, or ERCP.
The most commonly used stent are made from a plastic material called polyethylene and has a
central lumen in which bile drains through it. Health Canada has approved the sale and use of
another stent with a winged perimeter (the VIADUCT stent) for placement in bile duct
strictures and is used routinely in our hospitals. However, the investigators do not know
which stent is better at treating bile duct strictures. In order to determine which stent
would be more useful, the VIADUCT stent and the usual polyethylene flanged stent must be
studied under carefully controlled circumstances. This will be done by a randomized,
subject-blinded study. Other trials in the past have looked at other stents in this way, but
this is the first time the VIADUCT stent has been looked at in this manner. The investigators
suspect that the design of the VIADUCT stent will allow it to work for a longer period of
time compared to the traditional polyethylene stent.
Biliary obstruction usually presents with jaundice, pruritis, cholangitis, and steatorrhoea.
Strictures which are a common cause of biliary obstruction, may be secondary to benign or
malignant conditions. Common benign conditions include chronic pancreatitis, primary
sclerosing cholangitis, autoimmune pancreatitis, prior surgery and recurrent pyogenic
cholangitis. Cholangiocarcinomas, ampullary and pancreatic tumours are more common causes of
malignant biliary obstruction.
The principles of managing biliary strictures are to determine the underlying cause of the
stricture, whilst achieving drainage of the biliary tree, initially with the placement of a
plastic stent via an endoscopic retrograde cholangiopancreatography (ERCP). Strictures are
sampled using biliary brush cytology and/or biliary biopsy to assess for underlying
malignancy. Malignant strictures are usually staged for resectability with computed
tomography (CT), magnetic resonance cholangiopancreatography (MRCP) and/or endoscopic
ultrasound (EUS).
The Viaduct stent (GI Supply, Camp Hill, Pennsylvania, USA) is a unique stent design and has
a winged perimeter, which channels flow of bile around the stent, rather than through a
central lumen. Theoretically this may enhance flow and biliary drainage, and prevent
obstruction. Both polyethylene and Viaduct plastic stents are approved for use by Health
Canada for benign and malignant biliary conditions. It is not known whether one stent is
superior to the other in maintaining symptomatic relief from bile duct strictures as there
have been no studies to date comparing the two stents.
There is limited published data on the Viaduct stent. A pilot study of the winged stent
design was published in 2006. Five patients had winged stents inserted and followed for 2
weeks. The were no problems with stent insertion and symptoms of obstruction and jaundice
improved over this time. One study published in abstract form retrospectively compared 34
Viaduct stents matched with 240 "conventional" stents over a five year period. There was no
statistical difference with stent dysfunction, and a trend towards patency with the Viaduct
stent.
The primary aim of this study is to compare the stent patency time in the Viaduct and
polyethylene stent groups in subjects with malignant bile duct strictures. The secondary aims
are to determine the etiology of stent failure in the two treatment groups, to identify and
compare device-related adverse events in the two treatment groups, to identify other patient
factors associated with stent failure, and to compare survival between the Viaduct and
polyethylene stent groups.
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