Review Article
Current Concepts
NEJM Volume 344:1681-1687

May 31, 2001

Number 22
Expandable Metal Stents for the Treatment of Cancerous Obstruction of the
Gastrointestinal Tract
Todd H. Baron, M.D. Expandable metal stents have been approved by the Food
and Drug Administration for the treatment of gastrointestinal obstruction
due to cancer. Although they have not been approved for use in benign
disease, there are specific clinical indications for which expandable metal
stents may be beneficial. This article reviews the uses of expandable metal
stents for gastrointestinal obstruction due to cancer.
General Concepts
Gastrointestinal stents are placed by gastroenterologists under endoscopic
guidance with the aid of fluoroscopy or by interventional radiologists using
fluoroscopic guidance alone. Expandable metal stents are made of metal
alloys and have varying shapes and sizes, depending on the manufacturer and
the organ in which they will be placed ( Figure 1
<http://content.nejm.org/cgi/content/full/344/22/#F1> ). The stents are
mounted in a preloaded constrained position on a delivery catheter ( Figure
2 <http://content.nejm.org/cgi/content/full/344/22/#F2> ). A guide wire is
passed through the lumen of the catheter, and when the wire has been
advanced beyond the obstruction, the stent is passed over it and positioned
across the stricture. The constraining mechanism is released, which causes
the length of the stent to decrease and its diameter to increase ( Figure 2
<http://content.nejm.org/cgi/content/full/344/22/#F2> ). The radial
expansile forces and the degree of shortening differ among different types
of stents. 1 <http://content.nejm.org/cgi/content/full/344/22/#R1>  Covered
metal stents have a membrane to prevent reobstruction due to ingrowth of
tumor through the mesh wall.


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Figure 1. Several Commercially Available, Fully Deployed Expandable Metal
Stents for Gastrointestinal Use.
The stents are, from left to right, a covered esophageal stent, an uncovered
duodenal stent, an uncovered biliary stent, and an uncovered colorectal
stent.



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Figure 2. Mechanism of Deployment of an Expandable Metal Stent.
This covered esophageal stent has been partially deployed. The constraining
system on the proximal end (right side of photograph) has been withdrawn,
demonstrating the difference in diameter between the undeployed portion
(left side of photograph) and the deployed portion.

Specimens obtained from animals 2
<http://content.nejm.org/cgi/content/full/344/22/#R2>  and from humans at
autopsy or surgery 3 <http://content.nejm.org/cgi/content/full/344/22/#R3>
show that metal stents embed themselves in the tumor and surrounding tissue
with pressure necrosis and are incorporated into the wall of the organ.
Completely covered stents do not become embedded, and as a result, migration
of the stent is possible. Therefore, partially covered stents are used to
prevent tumor ingrowth and permit anchoring of the stent ( Figure 2
<http://content.nejm.org/cgi/content/full/344/22/#F2> ). One of the possible
adverse effects is erosion through the gastrointestinal wall ( Figure 3
<http://content.nejm.org/cgi/content/full/344/22/#F3> ). Most metal stents
appear safe for patients undergoing magnetic resonance imaging (MRI);
specific details of the stent and its orientation to the magnetic field
should be obtained before MRI is performed. 4
<http://content.nejm.org/cgi/content/full/344/22/#R4> , 5
<http://content.nejm.org/cgi/content/full/344/22/#R5>


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Figure 3. Autopsy Findings in a Patient with a Fatal Complication after
Placement of an Expandable Metal Esophageal Stent.
Extrinsic dysphagia due to malignant lymphadenopathy (L) from lung cancer
developed in this patient. Three months after insertion of the stent,
hemorrhage occurred. An aortoesophageal fistula (arrow) is seen where the
bare metal wires have eroded through normal esophageal tissue into the aorta
(A). This specimen also illustrates the open conduit created between the
stomach (S) and the esophagus when the stent is placed across the
gastroesophageal junction.

Esophageal Stents
Esophageal carcinoma accounts for most cases of dysphagia due to cancer, and
usually the tumor is unresectable. Dysphagia may also result from extrinsic
compression due to lung cancer or malignant lymphadenopathy. Among many
endoscopic and nonendoscopic treatment alternatives for palliation of
dysphagia due to cancer, expandable metal stents are one of the main
options. They are useful for patients with poor functional status who cannot
tolerate radiation or chemotherapy, who have advanced metastatic disease, or
in whom previous therapy has failed. 6
<http://content.nejm.org/cgi/content/full/344/22/#R6>
The small diameter of expandable metal stents before deployment makes
aggressive dilation of the esophagus before or after deployment unnecessary.
Despite the substantially higher cost of expandable metal stents as compared
with traditional rigid plastic esophageal stents, there are substantial
overall cost savings resulting from the reduction in the number of days of
hospitalization due to complications. 7
<http://content.nejm.org/cgi/content/full/344/22/#R7> , 8
<http://content.nejm.org/cgi/content/full/344/22/#R8> , 9
<http://content.nejm.org/cgi/content/full/344/22/#R9>  One study showed that
the rate of complications associated with stent insertion was lower overall
for expandable metal stents than for plastic stents, but the rate of
subacute complications was higher. 10
<http://content.nejm.org/cgi/content/full/344/22/#R10>  In the United
States, expandable metal stents have replaced plastic stents for use in the
esophagus. 11 <http://content.nejm.org/cgi/content/full/344/22/#R11>
Dysphagia is relieved in approximately 90 percent of patients who receive
expandable metal stents. 7
<http://content.nejm.org/cgi/content/full/344/22/#R7> , 8
<http://content.nejm.org/cgi/content/full/344/22/#R8> , 9
<http://content.nejm.org/cgi/content/full/344/22/#R9>
The data from comparisons of different options for the palliation of
dysphagia due to cancer are limited. A retrospective study compared
expandable metal stents with a variety of conventional endoscopic palliative
techniques in patients with inoperable esophageal carcinoma without
tracheoesophageal fistula. Patients with expandable metal stents underwent
significantly fewer procedures and spent fewer days in the hospital. 12
<http://content.nejm.org/cgi/content/full/344/22/#R12>  In a prospective,
randomized, controlled trial of patients with esophageal carcinoma, patients
with expandable metal stents had significantly more improvement in symptoms
and a lower rate of reintervention than those treated by esophageal laser
recanalization. 13 <http://content.nejm.org/cgi/content/full/344/22/#R13>
An advantage of expandable metal stents over other endoscopic palliative
methods is that they can be used to treat dysphagia due to compression
caused by cancer, 14 <http://content.nejm.org/cgi/content/full/344/22/#R14>
, 15 <http://content.nejm.org/cgi/content/full/344/22/#R15>  although the
improvement in dysphagia is less than for patients with esophageal cancer.
14 <http://content.nejm.org/cgi/content/full/344/22/#R14>
Esophageal expandable metal stents are also used to treat tracheoesophageal
fistulas due to cancer ( Figure 4A
<http://content.nejm.org/cgi/content/full/344/22/#F4> ). 16
<http://content.nejm.org/cgi/content/full/344/22/#R16> , 17
<http://content.nejm.org/cgi/content/full/344/22/#R17>  Tracheoesophageal
fistulas develop in patients with advanced esophageal and lung cancer and
lead to continuous aspiration of saliva. Tracheoesophageal fistula is the
only condition in which covered expandable metal stents may increase
survival as compared with other therapies. Although there have been no
prospective trials comparing covered metal stents with other types for the
treatment of tracheoesophageal fistulas, the covered metal stent is now
accepted as the primary treatment option. Closure of the fistula is
successful in 70 to 100 percent of patients. 16
<http://content.nejm.org/cgi/content/full/344/22/#R16> , 17
<http://content.nejm.org/cgi/content/full/344/22/#R17>  For persistent
fistulas, placement of an airway stent to close the fistula 18
<http://content.nejm.org/cgi/content/full/344/22/#R18>  ( Figure 4A
<http://content.nejm.org/cgi/content/full/344/22/#F4> ) or surgical
esophageal bypass for physiologically fit patients 19
<http://content.nejm.org/cgi/content/full/344/22/#R19>  are additional
palliative options.


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Figure 4. The Application of Expandable Metal Stents within the
Gastrointestinal Tract.
The large panel shows several cancers for which stent placement is an
appropriate treatment. Panel A shows esophageal obstruction with a
tracheoesophageal fistula treated with a completely covered esophageal stent
(left) and combined tracheal and esophageal stenting (right). Panel B shows
the treatment of unresectable bile-duct obstruction by placement of an
expandable metal stent. Panel C shows malignant duodenal and bile-duct
obstruction treated by placement of an expandable metal stent across each
obstruction. Panel D shows placement of an expandable metal stent to treat
obstruction of the sigmoid colon by primary colorectal carcinoma.

Expandable metal stents are best suited for midesophageal lesions. Tumors at
the gastroesophageal junction are amenable to stent placement with a high
rate of technical and clinical success, but stents at this location produce
an open conduit for free reflux of gastric contents, with consequent severe
regurgitation and aspiration. 11
<http://content.nejm.org/cgi/content/full/344/22/#R11>  Newer stents prevent
reflux and aspiration by means of a one-way flap valve on the gastric side
of the stent. 20 <http://content.nejm.org/cgi/content/full/344/22/#R20>
Placement of expandable metal stents for very proximal esophageal lesions is
technically difficult because of the proximity of the stent to the upper
esophageal sphincter and the lack of an uninvolved proximal margin. However,
in studies of small numbers of patients with dysphagia due to esophageal
obstruction caused by cancer high in the cervical esophagus, expandable
metal stents were successfully placed and improved symptoms in most
patients. 21 <http://content.nejm.org/cgi/content/full/344/22/#R21>
Placement of an esophageal expandable metal stent can lead to severe
complications. 11 <http://content.nejm.org/cgi/content/full/344/22/#R11>
Intraprocedural complications include those associated with conscious
sedation, aspiration, malpositioning of the stent, and esophageal
perforation. Immediate postprocedural complications may include chest pain,
bleeding, and tracheal compression, with resultant airway compromise and
respiratory arrest. Late complications include distal stent migration,
formation of an esophageal fistula, bleeding, perforation, and stent
occlusion. Although most migrated stents can be retrieved endoscopically or
will simply pass through the gastrointestinal tract, small-bowel obstruction
develops in some patients. Approximately 0.5 to 2 percent of patients who
undergo the procedure die as a direct result of placement of an expandable
metal stent ( Figure 3
<http://content.nejm.org/cgi/content/full/344/22/#F3> ). 11
<http://content.nejm.org/cgi/content/full/344/22/#R11>
Several studies strongly suggest that the rates of delayed esophageal
complications caused by expandable metal stents are higher in patients who
have previously been treated with radiation, chemotherapy, or both. 6
<http://content.nejm.org/cgi/content/full/344/22/#R6> , 22
<http://content.nejm.org/cgi/content/full/344/22/#R22> , 23
<http://content.nejm.org/cgi/content/full/344/22/#R23>  These complications
are presumably due to stent-induced pressure necrosis within devitalized
esophageal tissue. Unfortunately, patients who have recurrent or persistent
dysphagia or a tracheoesophageal fistula after chemoradiation therapy often
have no alternative to a stent for palliation of their symptoms. In contrast
to other studies, one prospective study found that patients undergoing
chemoradiation therapy after placement of an expandable metal stent had
significantly longer survival than patients who received only a stent. 24
<http://content.nejm.org/cgi/content/full/344/22/#R24>  However, shrinkage
of the tumor by chemoradiation therapy could increase the risk of stent
migration.
Patients with esophageal stents must modify their diet to prevent large
boluses of food from becoming impacted within the stent. If a stent without
an antireflux valve crosses the gastroesophageal junction, strict antireflux
precautions and aggressive acid suppression are needed to prevent
gastroesophageal reflux and aspiration. If the stent lumen becomes occluded
by tissue ingrowth, overgrowth, or hyperplasia, a second stent may be placed
through the first stent with good results. 25
<http://content.nejm.org/cgi/content/full/344/22/#R25>  Alternatively,
endoscopic laser therapy, electrocautery, or photodynamic therapy may be
used to treat stent occlusion.
Biliary Stents
Treatment of obstructive jaundice due to cancer relieves pruritus, improves
appetite, and reduces fat malabsorption. 26
<http://content.nejm.org/cgi/content/full/344/22/#R26>  Surgical palliation
of this condition involves the creation of an anastomosis between the bile
duct and the duodenum or jejunum to bypass the obstructed biliary tree.
Nonsurgical palliation is achieved by placing stents endoscopically (with
the use of endoscopic retrograde cholangiopancreatography), or with
radiologic guidance (by the percutaneous transhepatic approach) across the
cancerous stricture to restore biliary continuity ( Figure 4B
<http://content.nejm.org/cgi/content/full/344/22/#F4> ). Insertion of
plastic biliary stents provides an effective alternative to open palliative
surgical bypass of the biliary tree for the management of obstructive
jaundice due to cancer. 27
<http://content.nejm.org/cgi/content/full/344/22/#R27> , 28
<http://content.nejm.org/cgi/content/full/344/22/#R28>  Unfortunately,
bacterial encrustation frequently leads to occlusion of plastic stents, 29
<http://content.nejm.org/cgi/content/full/344/22/#R29>  requiring their
replacement in terminally ill patients. Plastic stents of larger diameter
take longer to become occluded. 30
<http://content.nejm.org/cgi/content/full/344/22/#R30>
The maximal stent diameter is limited by the endoscopes that must
accommodate them and the size of the tract made through the liver when they
are placed percutaneously. In comparison with plastic stents, expandable
metal biliary stents have a smaller diameter before placement and a larger
diameter after placement. Their small diameter before placement makes
percutaneous placement less traumatic and permits them to be completely
placed during one procedure. Their large diameter after placement eliminates
occlusion by bacterial biofilm.
Expandable metal biliary stents are much more costly than plastic stents. In
two randomized, prospective trials comparing endoscopically placed,
uncovered metal biliary stents and plastic stents for the palliation of
jaundice in patients with previously untreated distal malignant bile-duct
obstruction, the metal stents had significantly longer patency. 31
<http://content.nejm.org/cgi/content/full/344/22/#R31> , 32
<http://content.nejm.org/cgi/content/full/344/22/#R32>  Decreases in the
rates of endoscopic procedures and rehospitalization offset the initial high
cost of metal stents. Similar results were found in a large prospective,
randomized trial in which stents were placed by the percutaneous
transhepatic route for palliation of distal cancerous biliary obstruction.
33 <http://content.nejm.org/cgi/content/full/344/22/#R33>  Expandable metal
stents are more cost effective for patients who survive longer than four to
six months, whereas a single procedure with placement of a less costly
plastic stent would suffice in patients expected to have shorter survival.
34 <http://content.nejm.org/cgi/content/full/344/22/#R34> , 35
<http://content.nejm.org/cgi/content/full/344/22/#R35>  Another disadvantage
of a metal stent in the biliary tree, as compared with a plastic stent, is
the fact that the device cannot be removed once it is implanted. Therefore,
in patients with potentially resectable cancer, removable plastic stents
should be used.
Expandable metal biliary stents may become occluded because of tumor
ingrowth or biliary epithelial hyperplasia induced by the stent. Occlusion
from either cause may be treated by the insertion of a plastic stent or
another metal stent through the original stent. 31
<http://content.nejm.org/cgi/content/full/344/22/#R31> , 35
<http://content.nejm.org/cgi/content/full/344/22/#R35> , 36
<http://content.nejm.org/cgi/content/full/344/22/#R36>  Preliminary studies
suggest that occlusion due to tumor ingrowth or epithelial hyperplasia may
be prevented by the use of partially covered metal biliary stents. 37
<http://content.nejm.org/cgi/content/full/344/22/#R37>  Overgrowth of tumor
beyond the ends of the stent may result in reobstruction, necessitating
placement of another stent.
Prolonged patency has been observed in expandable biliary stents used to
treat low- or distal-bile-duct obstruction, but not in cases of obstruction
by a tumor involving the proximal biliary system at or above the bifurcation
of the right and left hepatic ducts (Klatskin's tumor). However, one small
randomized trial and several uncontrolled studies suggest that expandable
metal stents are more effective than plastic stents in these locations as
well. 38 <http://content.nejm.org/cgi/content/full/344/22/#R38>
Complications related to expandable metal biliary stents include entrapment
of the stent-delivery system in small or nondilated intrahepatic ducts,
malpositioning of the stent, and trauma to the duodenal wall opposite the
papilla, with resultant bleeding or perforation if an excessive amount of
the distal portion of the stent protrudes into the lumen. There is no
apparent increase in complications in patients who have previously received
chemoradiation therapy or who receive it concomitantly. 39
<http://content.nejm.org/cgi/content/full/344/22/#R39>  Although expandable
metal stents are generally not removable, there are case reports of
successful endoscopic removal of such biliary stents for the treatment of
late complications.
Gastroduodenal Stents
Successful placement of expandable metal stents for palliation of cancerous
obstruction of the upper gastrointestinal tract has been reported in several
series, with clinical success rates similar to those of surgical palliative
bypass. 40 <http://content.nejm.org/cgi/content/full/344/22/#R40> , 41
<http://content.nejm.org/cgi/content/full/344/22/#R41> , 42
<http://content.nejm.org/cgi/content/full/344/22/#R42>  Approximately 90
percent of patients with gastroduodenal stents improve clinically. 40
<http://content.nejm.org/cgi/content/full/344/22/#R40>  Advanced carcinoma
of the pancreatic head is the most common cancer that obstructs the gastric
outlet ( Figure 4C <http://content.nejm.org/cgi/content/full/344/22/#F4> ).
Gastric carcinoma or disease that metastasizes to the duodenum or jejunum
may also cause obstruction. 43
<http://content.nejm.org/cgi/content/full/344/22/#R43>  Patients with
cancerous duodenal obstruction often also have biliary obstruction that
occurs first. 43 <http://content.nejm.org/cgi/content/full/344/22/#R43>
Given the difficulties in obtaining access to the biliary tree through the
mesh wall of a duodenal stent placed across the papilla, an expandable metal
biliary stent should be placed before the duodenal stent is placed if there
is known or impending biliary obstruction. Bile flows effectively through
the biliary and duodenal stents as they cross within the duodenum ( Figure
4C <http://content.nejm.org/cgi/content/full/344/22/#F4> ). To treat biliary
obstruction after placement of a duodenal stent, a percutaneous transhepatic
approach is usually required. Stenting of both the duodenum and the bile
duct is the nonsurgical equivalent of a traditional double surgical bypass.
Endoscopic placement of gastroduodenal stents under fluoroscopic guidance is
technically easier than their placement by interventional radiologists using
fluoroscopic guidance alone, because the obstruction can be reached directly
and because there is a mechanical advantage in passing the stent through the
endoscope channel. Successful relief of obstruction in the proximal jejunum
can be achieved endoscopically. 43
<http://content.nejm.org/cgi/content/full/344/22/#R43>
Patients may resume oral intake almost immediately after uncomplicated
placement of expandable metal stents in the upper gastrointestinal tract.
They should be advised to advance from liquids to solids as tolerated and to
avoid leafy vegetables, which may result in stent occlusion. Gastroduodenal
stents are often placed in outpatient procedures.
Complications after placement of expandable metal stents in the upper
gastrointestinal tract include perforation, bleeding, stent migration, stent
malpositioning, and occlusion of the stent by tumor overgrowth or ingrowth
or by food impaction. The condition of some patients with advanced cancer
and gastroduodenal obstruction will not improve after successful stent
placement because of gastrointestinal obstruction due to tumor at other,
unidentified sites, diffuse peritoneal carcinomatosis with bowel encasement,
or functional gastric-outlet obstruction due to neural involvement by tumor
(e.g., of the celiac axis). 43
<http://content.nejm.org/cgi/content/full/344/22/#R43>  There are no data
about the safety of expandable metal stents in the stomach or small bowel in
patients who have already received or are currently receiving chemoradiation
therapy.
Colorectal Stents
Placement of a colorectal stent should be considered for preoperative
decompression and for palliation of cancerous large-bowel obstruction. 40
<http://content.nejm.org/cgi/content/full/344/22/#R40>  Up to 30 percent of
patients with primary colorectal carcinoma present with large-bowel
obstruction. 40 <http://content.nejm.org/cgi/content/full/344/22/#R40>  The
traditional method of managing complete or subtotal colonic obstruction due
to cancer, particularly left-sided obstruction, involves the creation of a
diverting colostomy. Patients with complete or subtotal colonic obstruction
and a potentially resectable tumor cannot undergo a one-stage operative
resection of the tumor and immediate reanastomosis, because stool within the
uncleansed proximal colon leads to breakdown of the anastomosis. Therefore,
the initial surgery includes resection of the primary tumor and colostomy,
with reanastomosis at a second operation. Patients with complete colonic
obstruction tend to be acutely ill, with advanced disease. Because
preoperative placement of an expandable metal colorectal stent permits
clinical stabilization with preoperative decompression and cleansing, a
one-stage operation can then be performed and colostomy avoided. 44
<http://content.nejm.org/cgi/content/full/344/22/#R44> , 45
<http://content.nejm.org/cgi/content/full/344/22/#R45>  The stent is removed
en bloc at the time of resection of the primary tumor, after serving as a
bridge to surgery. If the patient is a poor candidate for surgical resection
because of underlying illness or has unresectable or widely metastatic
disease discovered by imaging studies, the stent can remain in place for
palliation. A recent multicenter study of patients with primary colon
carcinoma evaluated the effectiveness of preoperative placement of metal
stents inserted radiologically. 45
<http://content.nejm.org/cgi/content/full/344/22/#R45>  Successful stent
placement, with clinical resolution of large-bowel obstruction within 96
hours, was achieved in 66 of 71 patients (93 percent). Sixty-five patients
underwent elective single-stage surgery with a primary colonic anastomosis a
mean of 8.6 days after stent placement. A severe complication (intestinal
perforation) occurred in one patient.
In a retrospective study of the management of acute cancerous colonic
obstruction, consecutive patients with colorectal carcinoma who received
expandable metal stents were compared with a similar group of consecutive
patients who underwent traditional surgical treatment at the same
institution. 46 <http://content.nejm.org/cgi/content/full/344/22/#R46>  When
the data for patients who subsequently underwent a curative resection were
analyzed, a cost savings of 28.8 percent was seen in the group receiving
stents, because of decreases in the total number of days in the hospital,
the number of days in the intensive care unit, and the number of surgical
procedures. Despite these promising results, no completed randomized,
prospective studies have compared preoperative stents with standard surgery
in a group of patients with potentially resectable primary colorectal cancer
and obstruction. One such study is under way in the United States. It
remains to be seen whether long-term results, such as tumor-recurrence
rates, are altered by the use of preoperative placement of colorectal
stents.
Candidates for placement of a colorectal stent for palliation include
patients with colorectal carcinoma and obstruction who have extensive local
or metastatic disease or who are poor candidates for surgical resection, and
patients with colonic obstruction secondary to noncolonic pelvic cancers
(e.g., bladder or ovarian carcinoma) or metastatic cancer (e.g., breast
carcinoma) ( Figure 4D
<http://content.nejm.org/cgi/content/full/344/22/#F4> ). 44
<http://content.nejm.org/cgi/content/full/344/22/#R44> , 47
<http://content.nejm.org/cgi/content/full/344/22/#R47> , 48
<http://content.nejm.org/cgi/content/full/344/22/#R48>  Successful
palliation of obstruction with avoidance of colostomy can be achieved in 85
to 100 percent of patients, with some stents remaining patent and in place
for more than one year. 48
<http://content.nejm.org/cgi/content/full/344/22/#R48> , 49
<http://content.nejm.org/cgi/content/full/344/22/#R49>  Randomized trials
are needed to confirm these findings. At present, however, it is difficult
to deny such patients the option of receiving a stent in order to avoid a
permanent colostomy. Partially covered colonic stents have also been used to
close cancerous colovesical and colovaginal fistulas, with an acceptable
risk of stent migration. 50
<http://content.nejm.org/cgi/content/full/344/22/#R50>
Complications of the placement of colonic stents include perforation, stent
migration, bleeding, stent malpositioning, and occlusion of the stent by
stool. Colonic perforation during insertion of colonic stents may be
devastating, because fecal material is spilled into the abdominal cavity,
resulting in peritonitis. The peritonitis may be difficult to manage
surgically, because the patient may become even more acutely ill,
potentially worsening the surgical outcome. Stents placed low in the rectum
may produce tenesmus or fecal incontinence.
Stents may be placed endoscopically in the right colon, 46
<http://content.nejm.org/cgi/content/full/344/22/#R46>  whereas with
radiologic guidance alone, stent placement is limited to the left colon.
Patients with widespread advanced cancer may not have clinical improvement
after successful placement of a colonic stent because of obstruction at
other sites or peritoneal carcinomatosis. 44
<http://content.nejm.org/cgi/content/full/344/22/#R44>
After receiving a palliative colorectal stent, patients should consume a
low-residue diet and use stool softeners or laxatives to prevent stool
impaction and stent occlusion. The effects of previous or concomitant
chemoradiation therapy on rates of local complications are unknown.
Future Directions
Biodegradable and bioabsorbable expandable stents are being developed for
the treatment of benign disease. 51
<http://content.nejm.org/cgi/content/full/344/22/#R51>  Such stents may be
useful in treating gastrointestinal strictures that are refractory to
dilation, such as peptic esophageal strictures, anastomotic or
radiation-induced strictures, or strictures related to Crohn's disease. In
patients with cancer, the use of expandable metal stents that emit radiation
52 <http://content.nejm.org/cgi/content/full/344/22/#R52>  or release
chemotherapeutic agents 53
<http://content.nejm.org/cgi/content/full/344/22/#R53>  may cause tumor
regression.

Source Information
From the Department of Medicine, Division of Gastroenterology and
Hepatology, Mayo Foundation, Rochester, Minn.
Address reprint requests to Dr. Baron at 200 First St. SW, Eisenberg 8A,
Rochester, MN 55905, or at [log in to unmask] <mailto:[log in to unmask]>
.
References
1.      Chan AC, Shin FG, Lam YH, et al. A comparison study on physical
properties of self-expandable esophageal metal stents. Gastrointest Endosc
1999;49:462-465. [Medline]
<http://content.nejm.org/cgi/external_ref?access_num=10202059&link_type=MED>
2.      Silvis SE, Sievert CE Jr, Vennes JA, Abeyta BK, Brennecke LH. Comparison
of covered versus uncovered wire mesh stents in the canine biliary tract.
Gastrointest Endosc 1994;40:17-21. [Medline]
<http://content.nejm.org/cgi/external_ref?access_num=8163131&link_type=MED>
3.      Bethge N, Sommer A, Gross U, von Kleist D, Vakil N. Human tissue
responses to metal stents implanted in vivo for the palliation of malignant
stenoses. Gastrointest Endosc 1996;43:596-602. [Medline]
<http://content.nejm.org/cgi/external_ref?access_num=8781940&link_type=MED>
4.      Taal BG, Muller SH, Boot H, Koops W. Potential risks and artifacts of
magnetic resonance imaging of self-expandable esophageal stents.
Gastrointest Endosc 1997;46:424-429. [Medline]
<http://content.nejm.org/cgi/external_ref?access_num=9402116&link_type=MED>
5.      Nitatori T, Hanaoka H, Hachiya J, Yokoyama K. MRI artifacts of metallic
stents derived from imaging sequencing and the ferromagnetic nature of
materials. Radiat Med 1999;17:329-334. [Medline]
<http://content.nejm.org/cgi/external_ref?access_num=10510909&link_type=MED>
6.      Bethge N, Sommer A, von Kleist D, Vakil N. A prospective trial of
self-expanding metal stents in the palliation of malignant esophageal
obstruction after failure of primary curative therapy. Gastrointest Endosc
1996;44:283-286. [Medline]
<http://content.nejm.org/cgi/external_ref?access_num=8885347&link_type=MED>
7.      Knyrim K, Wagner H-J, Bethge N, Keymling M, Vakil N. A controlled trial
of an expansile metal stent for palliation of esophageal obstruction due to
inoperable cancer. N Engl J Med 1993;329:1302-1307. [Abstract/Full Text]
<http://content.nejm.org/cgi/ijlink?linkType=ABST&journalCode=nejm&resid=329
/18/1302>
8.      De Palma GD, di Matteo E, Romano G, Fimmano A, Rondinone G, Catanzano C.
Plastic prosthesis versus expandable metal stents for palliation of
inoperable esophageal thoracic carcinoma: a controlled prospective study.
Gastrointest Endosc 1996;43:478-482. [Medline]
<http://content.nejm.org/cgi/external_ref?access_num=8726762&link_type=MED>
9.      Roseveare CD, Patel P, Simmonds N, Goggin PM, Kimble J, Shepherd HA.
Metal stents improve dysphagia, nutrition and survival in malignant
oesophageal stenosis: a randomized controlled trial comparing modified
Gianturco Z-stents with plastic Atkinson tubes. Eur J Gastroenterol Hepatol
1998;10:653-657. [Medline]
<http://content.nejm.org/cgi/external_ref?access_num=9744693&link_type=MED>
10.     Kozarek RA, Ball TJ, Brandabur JJ, et al. Expandable versus conventional
esophageal prostheses: easier insertion may not preclude subsequent
stent-related problems. Gastrointest Endosc 1996;43:204-208. [Medline]
<http://content.nejm.org/cgi/external_ref?access_num=8857134&link_type=MED>
11.     Ramirez FC, Dennert B, Zierer ST, Sanowski RA. Esophageal
self-expandable metallic stents -- indications, practice, techniques, and
complications: results of a national survey. Gastrointest Endosc
1997;45:360-364. [Medline]
<http://content.nejm.org/cgi/external_ref?access_num=9165315&link_type=MED>
12.     Nicholson DA, Haycox A, Kay CL, Rate A, Attwood S, Bancewicz J. The cost
effectiveness of metal oesophageal stenting in malignant disease compared
with conventional therapy. Clin Radiol 1999;54:212-215. [Medline]
<http://content.nejm.org/cgi/external_ref?access_num=10210338&link_type=MED>
13.     Adam A, Ellul J, Watkinson AF, et al. Palliation of inoperable
esophageal carcinoma: a prospective randomized trial of laser therapy and
stent placement. Radiology 1997;202:344-348. [Abstract]
<http://content.nejm.org/cgi/ijlink?linkType=ABST&journalCode=radiology&resi
d=202/2/344>
14.     Bethge N, Sommer A, Vakil N. Palliation of malignant esophageal
obstruction due to intrinsic and extrinsic lesions with expandable metal
stents. Am J Gastroenterol 1998;93:1829-1832. [Medline]
<http://content.nejm.org/cgi/external_ref?access_num=9772039&link_type=MED>
15.     Gupta NK, Boylan CE, Razzaq R, England RE, Mirra L, Martin DF.
Self-expanding oesophageal metal stents for the palliation of dysphagia due
to extrinsic compression. Eur Radiol 1999;9:1893-1897. [Medline]
<http://content.nejm.org/cgi/external_ref?access_num=10602971&link_type=MED>
16.     Morgan RA, Ellul JP, Denton ER, Glynos M, Mason RC, Adam A. Malignant
esophageal fistulas and perforations: management with plastic-covered
metallic endoprostheses. Radiology 1997;204:527-532. [Medline]
<http://content.nejm.org/cgi/external_ref?access_num=9240548&link_type=MED>
17.     Raijman I, Siddique I, Ajani J, Lynch P. Palliation of malignant
dysphagia and fistulae with coated expandable metal stents: experience with
101 patients. Gastrointest Endosc 1998;48:172-179. [Medline]
<http://content.nejm.org/cgi/external_ref?access_num=9717783&link_type=MED>
18.     Freitag L, Tekolf E, Steveling H, Donovan TJ, Stamatis G. Management of
malignant esophagotracheal fistulas with airway stenting and double
stenting. Chest 1996;110:1155-1160. [Abstract]
<http://content.nejm.org/cgi/ijlink?linkType=ABST&journalCode=chest&resid=11
0/5/1155>
19.     Low DE, Kozarek RA. Comparison of conventional and wire mesh expandable
prostheses and surgical bypass in patients with malignant
esophagorespiratory fistulas. Ann Thorac Surg 1998;65:919-923. [Abstract]
<http://content.nejm.org/cgi/ijlink?linkType=ABST&journalCode=annts&resid=65
/4/919>
20.     Kocher M, Dlouhy M, Neoral C, et al. Esophageal stent with antireflux
valve for tumors involving the cardia: work in progress. J Vasc Interv
Radiol 1998;9:1007-1010. [Abstract]
<http://content.nejm.org/cgi/ijlink?linkType=ABST&journalCode=jvascir&resid=
9/6/1007>
21.     Bethge N, Sommer A, Vakil N. A prospective trial of self-expanding metal
stents in the palliation of malignant esophageal strictures near the upper
esophageal sphincter. Gastrointest Endosc 1997;45:300-303. [Medline]
<http://content.nejm.org/cgi/external_ref?access_num=9087839&link_type=MED>
22.     Kinsman KJ, DeGregorio BT, Katon RM, et al. Prior radiation and
chemotherapy increase the risk of life-threatening complications after
insertion of metallic stents for esophagogastric malignancy. Gastrointest
Endosc 1996;43:196-203. [Medline]
<http://content.nejm.org/cgi/external_ref?access_num=8857133&link_type=MED>
23.     Siersema PD, Hop WC, Dees J, Tilanus HW, van Blankenstein M. Coated
self-expanding metal stents versus latex prostheses for esophagogastric
cancer with special reference to prior radiation and chemotherapy: a
controlled, prospective study. Gastrointest Endosc 1998;47:113-120.
[Medline]
<http://content.nejm.org/cgi/external_ref?access_num=9512274&link_type=MED>
24.     Ludwig D, Dehne A, Burmester E, Wiedemann GJ, Stange EF. Treatment of
unresectable carcinoma of the esophagus or the gastroesophageal junction by
mesh stents with or without radiochemotherapy. Int J Oncol 1998;13:583-588.
[Medline]
<http://content.nejm.org/cgi/external_ref?access_num=9683797&link_type=MED>
25.     Lagattolla NR, Rowe PH, Anderson H, Dunk AA. Restenting malignant
oesophageal strictures. Br J Surg 1998;85:261-263. [Medline]
<http://content.nejm.org/cgi/external_ref?access_num=9501831&link_type=MED>
26.     Ballinger AB, McHugh M, Catnach SM, Alstead EM, Clark ML. Symptom relief
and quality of life after stenting for malignant bile duct obstruction. Gut
1994;35:467-470. [Abstract]
<http://content.nejm.org/cgi/ijlink?linkType=ABST&journalCode=gutjnl&resid=3
5/4/467>
27.     Smith AC, Dowsett JF, Russell RC, Hatfield AR, Cotton PB. Randomised
trial of endoscopic stenting versus surgical bypass in malignant low
bileduct obstruction. Lancet 1994;344:1655-1660. [Medline]
<http://content.nejm.org/cgi/external_ref?access_num=7996958&link_type=MED>
28.     Speer AG, Cotton PB, Russell RC, et al. Randomised trial of endoscopic
versus percutaneous stent insertion in malignant obstructive jaundice.
Lancet 1987;2:57-62. [Medline]
<http://content.nejm.org/cgi/external_ref?access_num=2439854&link_type=MED>
29.     Speer AG, Cotton PB, Rode J, et al. Biliary stent blockage with
bacterial biofilm: a light and electron microscopy study. Ann Intern Med
1988;108:546-553. [Medline]
<http://content.nejm.org/cgi/external_ref?access_num=2450501&link_type=MED>
30.     Speer AG, Cotton PB, MacRae KD. Endoscopic management of malignant
biliary obstruction: stents of 10 French gauge are preferable to stents of 8
French gauge. Gastrointest Endosc 1988;34:412-417. [Medline]
<http://content.nejm.org/cgi/external_ref?access_num=2460394&link_type=MED>
31.     Davids PH, Groen AK, Rauws EA, Tytgat GN, Huibregtse K. Randomised trial
of self-expanding metal stents versus polyethylene stents for distal
malignant biliary obstruction. Lancet 1992;340:1488-1492. [Medline]
<http://content.nejm.org/cgi/external_ref?access_num=1281903&link_type=MED>
32.     Knyrim K, Wagner HJ, Pausch J, Vakil N. A prospective, randomized,
controlled trial of metal stents for malignant obstruction of the common
bile duct. Endoscopy 1993;25:207-212. [Medline]
<http://content.nejm.org/cgi/external_ref?access_num=8519239&link_type=MED>
33.     Lammer J, Hausegger KA, Fluckiger F, et al. Common bile duct obstruction
due to malignancy: treatment with plastic versus metal stents. Radiology
1996;201:167-172. [Abstract]
<http://content.nejm.org/cgi/ijlink?linkType=ABST&journalCode=radiology&resi
d=201/1/167>
34.     Yeoh KG, Zimmerman MJ, Cunningham JT, Cotton PB. Comparative costs of
metal versus plastic biliary stent strategies for malignant obstructive
jaundice by decision analysis. Gastrointest Endosc 1999;49:466-471.
[Medline]
<http://content.nejm.org/cgi/external_ref?access_num=10202060&link_type=MED>
35.     Prat F, Chapat O, Ducot B, et al. A randomized trial of endoscopic
drainage methods for inoperable malignant strictures of the common bile
duct. Gastrointest Endosc 1998;47:1-7. [Medline]
<http://content.nejm.org/cgi/external_ref?access_num=9468416&link_type=MED>
36.     Tham TC, Carr-Locke DL, Vandervoort J, et al. Management of occluded
biliary Wallstents. Gut 1998;42:703-707. [Abstract/Full Text]
<http://content.nejm.org/cgi/ijlink?linkType=ABST&journalCode=gutjnl&resid=4
2/5/703>
37.     Shim CS, Lee YH, Cho YD, et al. Preliminary results of a new covered
biliary metal stent for malignant biliary obstruction. Endoscopy
1998;30:345-350. [Medline]
<http://content.nejm.org/cgi/external_ref?access_num=9689506&link_type=MED>
38.     Wagner HJ, Knyrim K, Vakil N, Klose KJ. Plastic endoprostheses versus
metal stents in the palliative treatment of malignant hilar biliary
obstruction: a prospective and randomized trial. Endoscopy 1993;25:213-218.
[Medline]
<http://content.nejm.org/cgi/external_ref?access_num=7686100&link_type=MED>
39.     Eschelman DJ, Shapiro MJ, Bonn J, et al. Malignant biliary duct
obstruction: long-term experience with Gianturco stents and
combined-modality radiation therapy. Radiology 1996;200:717-724. [Abstract]
<http://content.nejm.org/cgi/ijlink?linkType=ABST&journalCode=radiology&resi
d=200/3/717>
40.     Mauro MA, Koehler RE, Baron TH. Advances in gastrointestinal
intervention: the treatment of gastroduodenal and colorectal obstructions
with metallic stents. Radiology 2000;215:659-669. [Abstract/Full Text]
<http://content.nejm.org/cgi/ijlink?linkType=ABST&journalCode=radiology&resi
d=215/3/659>
41.     Feretis C, Benakis P, Dimopoulos C, Manouras A, Tsimbloulis B,
Apostolidis N. Duodenal obstruction caused by pancreatic head carcinoma:
palliation with self-expandable endoprostheses. Gastrointest Endosc
1997;46:161-165. [Medline]
<http://content.nejm.org/cgi/external_ref?access_num=9283868&link_type=MED>
42.     Jung GS, Song HY, Kang SG, et al. Malignant gastroduodenal obstructions:
treatment by means of a covered expandable metallic stent -- initial
experience. Radiology 2000;216:758-763. [Abstract/Full Text]
<http://content.nejm.org/cgi/ijlink?linkType=ABST&journalCode=radiology&resi
d=216/3/758>
43.     Yates MR III, Morgan DE, Baron TH. Palliation of malignant gastric and
small intestinal strictures with self-expandable metal stents. Endoscopy
1998;30:266-272. [Medline]
<http://content.nejm.org/cgi/external_ref?access_num=9615875&link_type=MED>
44.     Baron TH, Dean PA, Yates MR III, Canon C, Koehler RE. Expandable metal
stents for the treatment of colonic obstruction: techniques and outcomes.
Gastrointest Endosc 1998;47:277-286. [Medline]
<http://content.nejm.org/cgi/external_ref?access_num=9540883&link_type=MED>
45.     Mainar A, De Gregorio Ariza MA, Tejero E, et al. Acute colorectal
obstruction: treatment with self-expandable metallic stents before scheduled
surgery -- results of a multicenter study. Radiology 1999;210:65-69.
[Abstract/Full Text]
<http://content.nejm.org/cgi/ijlink?linkType=ABST&journalCode=radiology&resi
d=210/1/65>
46.     Binkert CA, Ledermann H, Jost R, Saurenmann P, Decurtins M, Zollikofer
CL. Acute colonic obstruction: clinical aspects and cost-effectiveness of
preoperative and palliative treatment with self-expanding metallic stents --
a preliminary report. Radiology 1998;206:199-204. [Abstract]
<http://content.nejm.org/cgi/ijlink?linkType=ABST&journalCode=radiology&resi
d=206/1/199>
47.     de Gregorio MA, Mainar A, Tejero E, et al. Acute colorectal obstruction:
stent placement for palliative treatment -- results of a multicenter study.
Radiology 1998;209:117-120. [Abstract]
<http://content.nejm.org/cgi/ijlink?linkType=ABST&journalCode=radiology&resi
d=209/1/117>
48.     Fernandez Lobato R, Pinto I, Paul L, et al. Self-expanding prostheses as
a palliative method in treating advanced colorectal cancer. Int Surg
1999;84:159-162. [Medline]
<http://content.nejm.org/cgi/external_ref?access_num=10408289&link_type=MED>
49.     Camunez F, Echenagusia A, Simo G, Turegano F, Vazquez J, Barreiro-Meiro
I. Malignant colorectal obstruction treated by means of self-expanding
metallic stents: effectiveness before surgery and in palliation. Radiology
2000;216:492-497. [Abstract/Full Text]
<http://content.nejm.org/cgi/ijlink?linkType=ABST&journalCode=radiology&resi
d=216/2/492>
50.     Repici A, Reggio D, De Angelis C, et al. Covered metal stents for
management of inoperable malignant colorectal strictures. Gastrointest
Endosc 2000;52:735-740. [Medline]
<http://content.nejm.org/cgi/external_ref?access_num=11115905&link_type=MED>
51.     Tamai H, Igaki K, Kyo E, et al. Initial and 6-month results of
biodegradable poly-l-lactic acid coronary stents in humans. Circulation
2000;102:399-404. [Abstract/Full Text]
<http://content.nejm.org/cgi/ijlink?linkType=ABST&journalCode=circulationaha
&resid=102/4/399>
52.     Zamora PO, Osaki S, Som P, et al. Radiolabeling brachytherapy sources
with Re-188 through chelating microfilms: stents. J Biomed Mater Res
2000;53:244-251. [Medline]
<http://content.nejm.org/cgi/external_ref?access_num=10813764&link_type=MED>
53.     Herdeg C, Oberhoff M, Karsch KR. Antiproliferative stent coatings: Taxol
and related compounds. Semin Interv Cardiol 1998;3:197-199. [Medline]
<http://content.nejm.org/cgi/external_ref?access_num=10406693&link_type=MED>




Edward E. Rylander, M.D.
Diplomat American Board of Family Practice.
Diplomat American Board of Palliative Medicine.