First data on the Evolution duodenal stent for palliation of malignant gastric outlet obstruction (DUOLUTION study): a prospective multicenter study

• Introduction
• Patients and methods
• Patients
• Data collection
• Definitions and end points
• Stent and placement procedure
• Statistical analysis
• Results
• Baseline characteristics
• Technical aspects
• Clinical outcomes
• Complications
• Discussion
• Conclusion
• References

Background and study aims: Enteral stent placement has emerged as a safe and effective palliative treatment option for patients with malignant gastric outlet obstruction (GOO). In an attempt to further optimize this treatment new enteral stents have been designed. This study is the first to describe the results regarding technical success, clinical success, complication rate, and stent dysfunction of the Evolution duodenal stent (Cook Medical, Limerick, Ireland).

Patients and methods: A total of 46 patients with symptomatic malignant GOO were included in this prospective multicenter cohort study. All patients who successfully received an Evolution duodenal stent were followed until death.

Results: The technical and clinical success rates were 89 % (95 % confidence interval [CI] 77 % – 95 %) and 72 % (95 %CI 58 % – 83 %), respectively. The GOO Scoring System score, the Global Health Score, and the EuroQol visual analog scale improved significantly (GOOSS and Global Health Score P < 0.0001; EuroQol P = 0.005) when scores before stenting were compared with scores after stent placement. Median survival was 87 days, and stent patency was observed in 67 % for up to 395 days, accounting for death unrelated to the stent as a competing risk. Stent dysfunction occurred in 14 patients (30 %) (stent ingrowth n = 9; stent migration n = 2; extrinsic compression on the stent n = 2; food impaction n = 1).

Conclusion: These first data on the new Evolution duodenal stent show that it is safe and effective for the palliative treatment of symptomatic malignant GOO.

Introduction

For over a decade, endoscopic placement of self-expandable metallic stents (SEMS) has emerged as an alternative to surgical gastrojejunostomy for palliative treatment in patients with malignant gastric outlet obstruction (GOO) [1] [2] [3]. Most studies have shown high technical and clinical success rates, no intervention-related mortality, a significantly shorter procedure-related hospital stay, and oral intake that is usually tolerated the day after stent placement [4] [5] [6] [7] [8] [9]. However, there are complications associated with duodenal stent placement, either severe due to perforation or bleeding, or minor due to obstruction, migration, pain or biliary problems. Severe complications occur in up to 4 % of cases [10] whereas minor complications have been reported in up to 44 % [6]. Moreover, a recently published randomized trial showed a higher rate of re-obstruction and re-interventions after enteral stent placement compared with gastrojejunostomy, which was mainly caused by stent-related complications [5]. Therefore, current research focuses on finding an optimal stent design that guarantees long term stent patency.

This is the first study to investigate the new Evolution duodenal stent (Evolution Controlled Release; Cook Medical, Limerick, Ireland). This stent exhibits a novel configuration that is designed to reduce complications such as migration, tissue ingrowth, perforation, and inadequate stent release. The results regarding safety and efficacy of this new enteral stent in patients with malignant gastroduodenal obstruction due to incurable gastric, periampullary or duodenal cancer are reported in this study.

Patients and methods

The DUOLUTION study was designed as a single-arm, prospective, observational clinical trial to evaluate the efficacy and safety of the Evolution duodenal stent in two academic hospitals. The protocol was approved by the Medical Ethical Committee of the Academic Medical Center in Amsterdam and the University Medical Center Utrecht in Utrecht. The study was conducted at the Department of Gastroenterology and Hepatoloy of the abovementioned centers. Written informed consent was obtained from each patient.

Patients

From November 2008 to July 2011, all consecutive patients 18 years or older with a malignancy of the periduodenal area with typical GOO symptoms (i. e. early satiety, nausea, and vomiting) and/or a GOO Scoring System (GOOSS) score of ≤ 2 ([Table 1]) [11] were considered for inclusion in the study.

Patients were excluded if they met one of the following criteria: potentially curable disease; pre-procedural evidence of additional, more distally located strictures in the small bowel or colon; previous treatment with SEMS for the same condition; participation in another study [12]; inability to undergo upper gastrointestinal endoscopy; or inability to complete quality of life (QoL) questionnaires.

Data collection

Immediately after inclusion, the following data were collected by a research nurse: medical history, medication use, disease-specific information (primary tumor site, level of obstruction, biliary obstruction/drainage), severity of obstruction (symptoms compatible with GOO [i. e. early satiety, nausea, and vomiting] and GOOSS score), additional therapy (biliary drainage, chemotherapy, radiotherapy), World Health Organization (WHO) performance score, body mass index (BMI), and validated QoL questionnaires (European Organization for Research and Treatment of Cancer [EORTC] QLQ-C30, EQ-5 D including the EuroQol visual analog scale [EQ-VAS]).

After stent placement, follow-up data were obtained during visits to the inpatient clinic when the patient was still hospitalized or either by mail or by telephone interviews for patients who were at home. Information on GOO symptoms, GOOSS scores, and complications were collected at 7 and 14 days and monthly thereafter. Additionally, QoL questionnaire scores and information on general condition (BMI, WHO performance score) were collected bimonthly.

All data were collected until withdrawal of informed consent or death, whichever came first.

Definitions and end points

The following definitions and endpoints were used for the study. The primary outcome was defined as improvement of the GOOSS score for the remainder of the patient’s life. Secondary outcomes were: clinical success, defined as improvement of GOOSS score of at least one point and/or relief of symptoms compatible with GOO (i. e. early satiety, nausea, and vomiting) 1 week after intervention; technical success, defined as successful stent placement and deployment at the site of stricture; procedure- and stent-related complications including 30-day mortality; median time to regain oral intake and median procedure-related hospitalization; median survival; stent patency, defined as the time period between stent placement and the recurrence of obstructive symptoms caused by an endoscopically confirmed stent-related complication (e. g. tissue ingrowth/overgrowth, stent migration, stent collapse, food impaction); impact on general condition as reflected by WHO scores; and global QoL as reflected by the Global Health Score (QL2) scale, a sub-score from the EORTC QLQ-C30 version 3 measure, and the EQ-VAS [13] [14].

Stent and placement procedure

All patients in this study were treated by placement of the Evolution duodenal stent. This is a Conformité Européenne (CE) approved uncovered through-the-scope SEMS. The stent is made from nitinol, which is flexible and exerts an evenly distributed radial force, characteristics that are designed to prevent perforation. These properties are combined with proximal and distal flanges, which act as anti-migration features, and a small mesh design to prevent tissue ingrowth ([Fig. 1]). In addition, accurate placement is thought to be facilitated by a new controlled release system including re-capturing facilities ([Fig. 2]).

The stents are available in lengths of 6, 9, and 12 cm, with a diameter of 22 to 27 mm (body/flare) at full expansion. It may take up to 24 hours before the stent is fully expanded.

Adequate drainage of the biliary tree, observed either endoscopically or radiologically, was achieved at least 48 hours prior to enteral stenting, in cases of co-existent biliary obstruction. If there was suspicion of biliary obstruction (elevated cholestatic liver enzymes) in patients without biliary endoprotheses in situ, a SEMS was placed endoscopically or radiologically. If patients already had a plastic biliary stent for biliary obstruction, this was replaced by a SEMS regardless of liver function test results.

Details of the duodenum stent placement procedure have been reported previously [7].

Statistical analysis

Descriptive statistics were used for the baseline characteristics. For continuous data, means (± SD) or medians (interquartile range [IQR]) were used depending on data distributions. Counts are given for categorical data. Wilson’s 95 % confidence intervals (CI) are reported for clinical success, technical success, and complication rates. The number of patients for whom primary outcome data were available was 40. This patient number was sufficient for an 84 % power at a significance level of 0.05 and with an estimated SD of 1 to detect a difference of at least 0.5 (effect size 0.5 or larger) between the mean GOOSS score during follow-up and at baseline, using a two-sided Wilcoxon test, assuming that the actual distribution was normal. Depending on distributional proportions, Wilcoxon matched-pairs signed-ranks test (WHO score, GOOSS score) or paired sample t test (Global Health Score, EQ-VAS, BMI) were used to assess improvements from baseline, after calculation of the average score per patient from available follow-up assessments until death. Overall survival was calculated using Kaplan – Meyer statistics. Stent patency was assessed by performing an actual cumulative incidence analysis, accounting for death unrelated to the stent as a competing risk [15].

Statistics were performed using the SPSS statistical software package (version 18.0, Chicago, Illinois, USA). Statistical significance was set at P < 0.05.

Results

Baseline characteristics

A total of 46 patients (24 men, 22 women; mean ± SD age 65.8 ± 11.8 years) were included at the two participating centers. Three patients who met the inclusion criteria were not included due to unwillingness to participate (n = 1) or being missed during screening (n = 2). Two patients were excluded because of inability to complete the QoL questionnaires. No patients were lost because of participation in another study.

Of the included patients, 25 (54 %) were diagnosed with pancreatic cancer. In the remaining patients, GOO was caused by cholangiocarcinoma (n = 7), gastric cancer (n = 5), metastatic disease (n = 5), duodenal cancer (n = 3), and gallbladder cancer (n = 1) ([Table 2]).

At inclusion, median GOOSS score was 1 (IQR 0 – 1). The baseline GOOSS score was not recorded on the case record form of one patient. However, this patient was not considered for follow-up because no stent was placed due to the inability to pass a guide wire across the stenosis (see below). Patient demographics and clinical characteristics are summarized in [Table 2].

In 34 /46 (74 %) patients, biliary drainage had already been performed prior to inclusion in the study. Of these patients, four had a plastic stent, which was changed to a metal stent after inclusion and prior to enteral stenting (three endoscopically, one percutaneously). In the remaining 12 patients, no biliary stents were present and laboratory testing after inclusion showed no elevated cholestatic liver enzymes. According to the protocol no biliary intervention was performed prior to enteral stent placement in the latter group of patients.

Technical aspects

Technical success was achieved in 41 /46 patients (89 %; 95 %CI 77 % – 95 %). In two patients technical failure occurred because of the inability to pass the guide wire across the stricture. In both cases adequate positioning of the guide wire was hampered by the tightness and strong angulation of the stenosis. One of these patients underwent successful gastrojejunostomy for palliation of obstructive symptoms. The other patient was not a candidate for surgery because of poor clinical condition caused by progressive tumor cachexia; this patient died 3 days after the attempted stent placement without procedure- or stent-related complications.

Unsuccessful deployment of the stent caused technical failure in one patient, who was successfully treated during the same procedure by removal of the undeployed stent and placement of another stent. However, the endoscopist accidentally placed a WallFlex enteral stent (Boston Scientific Corporation, Natick, Massachusetts, USA) instead of another Evolution stent. Because this was a violation of the protocol, this patient was excluded from further follow-up. In another patient, the endoscopist inadvertently placed an Evolution colonic stent, which had a different length and diameter. This patient was also excluded from further follow-up. In one patient no stenosis was seen during endoscopy and therefore stent placement was not attempted. Therefore, the technical success rate, if evaluated only in patients with an indication for stenting in whom the correct procedure was attempted, was 95 % (41 /43 patients).

In total, 44 Evolution enteral stents were successfully placed in 41 patients during the first endoscopic procedure: 38 patients required a single stent to transverse the obstruction; three patients required two stents because of the length of the stricture (n = 1) or because the first stent was placed too distally (n = 2). Placement of an additional stent was successful and was performed during the same procedure in all three cases. Of the 44 enteral stents, 21 (48 %) were 9 cm, 19 (43 %) were 6 cm, and 4 (9 %) were 12 cm.

Clinical outcomes

The baseline GOOSS score was recorded in 45 /46 patients. Before stent placement, 12 patients (27 %) had no oral intake (GOOSS score 0), 28 patients (62 %) were only tolerating liquids (score 1), four patients (9 %) were able to tolerate soft solids (score 2), and one patient (2 %) could eat a low-residue or full diet (score 3) but had severe symptoms of early satiety, nausea, and vomiting ([Table 2]). This resulted in a median baseline GOOSS score of 1.0 (IQR 0 – 1). The GOOSS scores during follow-up were recorded in 39 patients ([Table 3]), with the median of the mean scores being 2.4 (IQR 1.1 – 3.0). For the remaining six patients, scores were not available due to exclusion from further follow-up (n = 4: two technical failures, one placement of colonic stent, and no stenosis found in one patient), lost to follow-up (n = 1), and death within 1 week after stent placement (n = 1).

The primary endpoint showed a statistically significant difference (P < 0.0001) between the median GOOSS score before stent placement and the median of the mean scores during follow-up until death ([Fig. 3]).

At the time point of 1 week after stent placement, deterioration of the GOOSS score by a single point occurred in one patient despite technically successful stent placement. In 11 patients the score did not improve; however, GOO symptoms were alleviated in six of these patients. Furthermore, the GOOSS score improved by one point in 10 patients, by two points in 13 patients, and by three points in 4 patients ([Table 3]). Of these 27 patients with an improved GOOSS score, 21 patients also reported cessation of their GOO complaints 1 week after stenting. Of the remaining six patients, two had no GOO symptoms either at baseline or at 1 week, one developed GOO symptoms despite an improvement in oral intake capacity, and in two patients data on GOO symptoms were unfortunately not recorded. Clinical success was therefore achieved in 33 of 39 patients (85 %), resulting in an overall clinical success (intention-to-treat) of 72 % (33 /46 patients; 95 %CI 58 % – 83 %). Median time to regain oral intake was 0 days (range 0 – 1). Median procedure-related hospital stay was 3 days (IQR 1 – 9).

The QL2 and EQ-VAS scores both showed a statistically significant improvement when the pre-stenting scores where compared with mean scores during total follow-up (QL2 difference = 21.1, 95 %CI 13.8 – 28.5, P < 0.0001; EQ-VAS difference = 12.8, 95 %CI 4.2 – 21.4, P = 0.005). The BMI and WHO performance scores demonstrated non-significant changes overtime (P = 0.089 and P = 0.292, respectively).

Complications

A total of 26 /46 (57 %) patients suffered from one or more complications. A summary of complications is shown in [Table 4]. There were no clear procedure- or stent-related deaths, although one patient died with clinical signs of an acute abdomen 42 days after stent placement. This might have been caused by a late-onset stent perforation; however, this patient refused further treatment and it was therefore not possible to establish a final diagnosis.

Procedure-related complications occurred in 4 /46 patients (9 %). One patient suffered from a guide wire perforation, which was treated conservatively with antibiotics. Another patient suffered from a mild pancreatitis after a re-intervention (additional enteral stent placement). Pain after stent placement occurred in one patient, which could be treated with analgesics without clinical admission. The fourth patient developed cholangitis one day after enteral stenting. Endoscopy and computed tomography scan revealed proximal migration of the enteral stent, which had caused biliary obstruction. This patient did not have a biliary stent and a percutaneous approach to achieve biliary drainage was decided as the treatment of choice. However, the patient refused further treatment.

Six other patients developed cholangitis after a median of 300 days (IQR 60 – 491) despite placement of a biliary SEMS prior to enteral stenting. These patients underwent successful percutaneous drainage with placement of an additional biliary SEMS and an internal – external drain, which had to be repeated in three patients due to recurrent biliary SEMS ingrowth.

Stent dysfunction was clinically suspected in 19 /46 (41 %) patients. Upper endoscopy was performed in all of these patients and confirmed a diagnosis of stent dysfunction in 14 /46 (30 %) patients. In nine patients (20 %) stent dysfunction was caused by tissue ingrowth, which was treated with stent-in-stent placement as an effective single-step treatment in five patients, while in the remaining four patients additional stent placement had to repeated because of recurrent ingrowth (one additional procedure in two patients and two additional procedures in the other two patients). In the other five patients stent dysfunction was caused by stent compression (n = 2), stent migration (n = 2), and food impaction (n = 1), all of which were treated successfully with an endoscopic intervention (balloon dilation, additional stent placement, and removal of food bolus). Stent patency was 67 % for up to 395 days (accounting for death unrelated to the stent as a competing risk).

In five patients stent dysfunction was suspected but endoscopy showed that the stents were open. In addition, no evidence was seen of more distally located obstruction with contrast radiography. These patients were therefore classified as having a motility disorder and were all treated conservatively with erythromycin (n = 1) or a duodenal feeding tube (n = 4). In four of these patients a motility disorder was diagnosed after clinical success was achieved, and in the remaining patient stent placement did not prove to be effective at all.

A total of eight patients died within 30 days after the initial procedure due to the underlying disease (30-day mortality rate 17 %; 95 %CI 9 % – 31 %)). Median overall survival was 87 days (IQR 35 – 237).

Discussion

This study reports the results of the new Evolution duodenal stent with regard to safety and efficacy in patients with malignant GOO.

In recent years, enteral stent placement has emerged as a palliative treatment option for patients with malignant GOO. There is evidence that enteral stent placement is superior to surgical bypass in terms of speed of improvement of food intake, a shorter hospital stay, fewer severe complications, and lower medical costs [5] [16] [17]. Nonetheless, the risk of recurrent stent obstruction in the longer term is increased, which subsequently leads to more re-interventions [5]. Therefore, several efforts have been made to try to prolong stent patency by modifying the stent design. So far, these attempts have not succeeded in a stent design that is superior to others in terms of success and patency rates [6] [18] [19] [20].

The new Evolution duodenal stent is an uncovered SEMS that has proximal and distal flanges to reduce the risk of stent migration and a small mesh width to reduce or even prevent tissue ingrowth. Furthermore, the stent is highly flexible with an evenly distributed radial force, which is a characteristic that should minimize the risk of perforation and hemorrhage.

Technical success with the Evolution stent was achieved in 89 % (41 /46) of patients, which is in line with results of other publications [7] [21] [22] [23]. In one patient, technical failure was caused by insufficient deployment of the stent. In the literature unsuccessful deployment is frequently attributed to a tortuous anatomy, resulting in too many bends that are too sharp for the delivery device and impeding the deployment force [22]. However, in this specific case the endoscopist did not notice a specific cause for the unsuccessful deployment. In two other cases, the inability to pass the guide wire across the stricture precluded completion of the procedure. This is the most frequently encountered cause of technical failure [4]. It is arguable whether adjustments to the deployment system or stent design could prevent this [23] [24] [25]. In the two remaining patients, there was no real technical failure, as stent placement was not attempted in the first patient because no stenosis was seen and in the other patient an Evolution colonic stent was placed instead of an Evolution duodenal stent.

The overall clinical success rate was relatively low (72 %). Most publications report that clinical success is achieved in more than 80 % of patients [4] [6] [7] [22] [23]. However, comparison between different studies is controversial because of patient heterogeneity and the use of different definitions for clinical success and different follow-up periods. Moreover, clinical success is a parameter that only evaluates an improvement of the GOOSS score and GOO-related symptoms at one time point. Therefore the observation that the GOOSS score during total follow-up until death improved significantly after stent placement is clinically more important. In addition, the QoL parameters, QL2 and EQ-VAS, both showed a significant improvement whereas the BMI and WHO scores showed no significant changes during follow-up. These results suggest that placement of the Evolution duodenal stent is an effective palliative treatment in patients with malignant GOO as it improves QoL and keeps the general condition stable.

The DUOLUTION study is the third study from our institute to evaluate a duodenal stent in a prospective study [7] [21]. To date, the QoL outcomes from the DUOLUTION study are the most positive results, despite comparable or even lower technical and clinical success rates and a higher complication rate ([Table 5]). As discussed in the DUONITI study, it is therefore difficult to indicate why QoL results were better in the current study [21]. Only a randomized trial comparing these different stent designs could probably provide better insight.

Regarding complications, stent dysfunction was seen in 14 patients. Despite the smaller mesh width of the Evolution stent, recurrent obstruction due to stent ingrowth remained the main cause of stent dysfunction occurring in nine patients (20 %). This percentage is in line with the results of other studies [4] [21] [22]. The covering of enteral stents with a membrane effectively prevents tumor ingrowth; however, this happens at the expense of high migration rates of up to 32 % [6]. Fully migrated stents may be completely asymptomatic and sometimes pass out through the rectum, but may also get stranded in the intestine and lead to obstruction, bleeding or perforation, requiring surgical intervention [8] [19] [22]. Therefore, mostly uncovered stents are currently used for the treatment of malignant GOO. In the current study, only partial stent migration occurred in two patients (4 %), which is an acceptable percentage for an uncovered stent [21] [22]. All cases of stent ingrowth and stent migration could be treated effectively with placement of a new Evolution stent through the old stent (stent-in-stent).

In two patients (4 %) external compression of the stent lumen by tumor growth was observed after 7 and 21 days; the conditions were treated by balloon dilation and coaxial stent placement, respectively. This complication was also observed in 4 % of patients in a large prospective study in which a double-layered stent design was used [22]. The early stent collapse in the current study might be attributed to the high malleability of the Evolution stent, which possibly results in a reduced ability to withstand external compression. Conversely, the high malleability of the stent might have prevented severe complications such as stent perforation and hemorrhage, which can occur either during placement or at a later point in time as a result of progressive erosion of the duodenal or gastric mucosa by the bare metal ends of the stent [6] [26].

Median survival of the patients who received an Evolution stent was 87 days, and stent patency was observed in 67 % for up to 395 days (accounting for death unrelated to the stent as a competing risk). This suggests that adequate resolution of GOO is achieved with the Evolution stent in the majority of patients.

Furthermore, seven patients (15 %) developed cholangitis, which is a relatively high figure compared with the results reported in the literature [4] [21] [22]. One of these patients did not show any signs of biliary obstruction prior to enteral stenting. According to the study protocol, biliary drainage was therefore not performed. Unfortunately, cholangitis developed 1 day after enteral stent placement, which was attributed to stent occlusion of the ampulla of Vater due to proximal stent migration. One could argue that the small mesh design of the Evolution stent is more likely to hamper the flow of bile than stents with a larger mesh diameter. However, a study by Kim et al. showed no difference in biliary obstruction rates between uncovered and covered stents placed across the ampulla [27]. Moreover, it remains difficult to distinguish stent occlusion of the ampulla from progression of the underlying malignancy as the cause of biliary obstruction. The other six patients suffering from cholangitis during follow-up all had a biliary SEMS in situ, and recurrence of biliary obstruction occurred at a median of 300 days (IQR 60 – 491) after enteral stent placement. These patients were successfully treated with percutaneous decompression and antegrade placement of an additional biliary SEMS side by side with the enteral stent. Some authors advocate prophylactic biliary stenting in order to avoid a percutaneous approach [28]. However, we suggest that only patients with objective signs of biliary obstruction should be treated because the majority of patients will not develop biliary problems after enteral stenting and therefore may be unnecessarily exposed to the risks associated with biliary stent insertion [4].

This study has several limitations. As this study was a single arm evaluating one type of stent, it is not possible to obtain information on its safety and effectiveness compared with other stent types or versus surgical bypass interventions. Moreover, a potential selection bias might have occurred as three patients who met the inclusion criteria were not included in the study. If these patients had been included, their results could have influenced study outcomes, either positively or negatively. Furthermore, the inclusion of patients with a baseline GOOSS score of 3 biased the results regarding the primary outcome (improvement of GOOSS score for remainder of life). Logically these patients cannot improve their GOOSS score and therefore this causes an underestimation of the primary outcome. However, as there was only one patient with a baseline GOOSS score of 3, we did not anticipate a relevant bias and this is also reflected by a high level of statistical significance for the primary outcome.

Conclusion

Placement of the Evolution enteral stent is safe and provides a statistically significant improvement of oral intake capacity as well as a significant improvement in QoL in patients with incurable malignant GOO.

Competing interests: None.

• References

• 1 Nevitt AW, Vida F, Kozarek RA et al. Expandable metallic prostheses for malignant obstructions of gastric outlet and proximal small bowel. Gastrointest Endosc 1998; 47: 271-276
  CrossrefPubMedSearch in Google Scholar
• 2 Soetikno RM, Lichtenstein DR, Vandervoort J et al. Palliation of malignant gastric outlet obstruction using an endoscopically placed Wallstent. Gastrointest Endosc 1998; 47: 267-270
  CrossrefPubMedSearch in Google Scholar
• 3 Venu RP, Pastika BJ, Kini M et al. Self-expandable metal stents for malignant gastric outlet obstruction: a modified technique. Endoscopy 1998; 30: 553-558
  Thieme ConnectPubMedSearch in Google Scholar
• 4 Dormann A, Meisner S, Verin N et al. Self-expanding metal stents for gastroduodenal malignancies: systematic review of their clinical effectiveness. Endoscopy 2004; 36: 543-550
  Thieme ConnectPubMedSearch in Google Scholar
• 5 Jeurnink SM, Steyerberg EW, van Hooft JE et al. Surgical gastrojejunostomy or endoscopic stent placement for the palliation of malignant gastric outlet obstruction (SUSTENT study): a multicenter randomized trial. Gastrointest Endosc 2010; 71: 490-499
  CrossrefPubMedSearch in Google Scholar
• 6 Kim CG, Choi IJ, Lee JY et al. Covered versus uncovered self-expandable metallic stents for palliation of malignant pyloric obstruction in gastric cancer patients: a randomized, prospective study. Gastrointest Endosc 2010; 72: 25-32
  CrossrefPubMedSearch in Google Scholar
• 7 van Hooft JE, Uitdehaag MJ, Bruno MJ et al. Efficacy and safety of the new WallFlex enteral stent in palliative treatment of malignant gastric outlet obstruction (DUOFLEX study): a prospective multicenter study. Gastrointest Endosc 2009; 69: 1059-1066
  CrossrefPubMedSearch in Google Scholar
• 8 Lee KM, Choi SJ, Shin SJ et al. Palliative treatment of malignant gastroduodenal obstruction with metallic stent: prospective comparison of covered and uncovered stents. Scand J Gastroenterol 2009; 44: 846-852
  CrossrefPubMedSearch in Google Scholar
• 9 Maetani I, Isayama H, Mizumoto Y. Palliation in patients with malignant gastric outlet obstruction with a newly designed enteral stent: a multicenter study. Gastrointest Endosc 2007; 66: 355-360
  CrossrefPubMedSearch in Google Scholar
• 10 Havemann MC, Adamsen S, Wojdemann M. Malignant gastric outlet obstruction managed by endoscopic stenting: a prospective single-centre study. Scand J Gastroenterol 2009; 44: 248-251
  CrossrefPubMedSearch in Google Scholar
• 11 Adler DG, Baron TH. Endoscopic palliation of malignant gastric outlet obstruction using self-expanding metal stents: experience in 36 patients. Am J Gastroenterol 2002; 97: 72-78
  CrossrefPubMedSearch in Google Scholar
• 12 van Hooft JE, Vleggaar FP, Le MO et al. Endoscopic magnetic gastroenteric anastomosis for palliation of malignant gastric outlet obstruction: a prospective multicenter study. Gastrointest Endosc 2010; 72: 530-535
  CrossrefPubMedSearch in Google Scholar
• 13 Aaronson NK, Ahmedzai S, Bergman B et al. The European Organization for Research and Treatment of Cancer QLQ-C30: a quality-of-life instrument for use in international clinical trials in oncology. J Natl Cancer Inst 1993; 85: 365-376
  CrossrefPubMedSearch in Google Scholar
• 14 Rabin R, de Charro F. EQ-5D: a measure of health status from the EuroQol Group. Ann Med 2001; 33: 337-343
  CrossrefPubMedSearch in Google Scholar
• 15 Ludbrook J, Royse AG. Analysing clinical studies: principles, practice and pitfalls of Kaplan-Meier plots. ANZ J Surg 2008; 78: 204-210
  CrossrefPubMedSearch in Google Scholar
• 16 Ly J, O’Grady G, Mittal A et al. A systematic review of methods to palliate malignant gastric outlet obstruction. Surg Endosc 2010; 24: 290-297
  CrossrefPubMedSearch in Google Scholar
• 17 Hosono S, Ohtani H, Arimoto Y et al. Endoscopic stenting versus surgical gastroenterostomy for palliation of malignant gastroduodenal obstruction: a meta-analysis. J Gastroenterol 2007; 42: 283-290
  CrossrefPubMedSearch in Google Scholar
• 18 Shi D, Liao SH, Geng JP. A newly designed big cup nitinol stent for gastric outlet obstruction. World J Gastroenterol 2010; 16: 4206-4209
  CrossrefPubMedSearch in Google Scholar
• 19 Song HY, Shin JH, Yoon CJ et al. A dual expandable nitinol stent: experience in 102 patients with malignant gastroduodenal strictures. J Vasc Interv Radiol 2004; 15: 1443-1449
  CrossrefPubMedSearch in Google Scholar
• 20 Kim YW, Choi CW, Kang DH et al. A double-layered (comvi) self-expandable metal stent for malignant gastroduodenal obstruction: a prospective multicenter study. Dig Dis Sci 2011; 56: 2030-2036
  CrossrefPubMedSearch in Google Scholar
• 21 van Hooft JE, van Montfoort ML, Jeurnink SM et al. Safety and efficacy of a new non-foreshortening nitinol stent in malignant gastric outlet obstruction (DUONITI study): a prospective, multicenter study. Endoscopy 2011; 43: 671-675
  Thieme ConnectPubMedSearch in Google Scholar
• 22 Kim JH, Song HY, Shin JH et al. Metallic stent placement in the palliative treatment of malignant gastroduodenal obstructions: prospective evaluation of results and factors influencing outcome in 213 patients. Gastrointest Endosc 2007; 66: 256-264
  CrossrefPubMedSearch in Google Scholar
• 23 Shaw JM, Bornman PC, Krige JE et al. Self-expanding metal stents as an alternative to surgical bypass for malignant gastric outlet obstruction. Br J Surg 2010; 97: 872-876
  CrossrefPubMedSearch in Google Scholar
• 24 Baron TH, Harewood GC. Enteral self-expandable stents. Gastrointest Endosc 2003; 58: 421-433
  CrossrefPubMedSearch in Google Scholar
• 25 Bessoud B, de Baere T, Denys A et al. Malignant gastroduodenal obstruction: palliation with self-expanding metallic stents. J Vasc Interv Radiol 2005; 16: 247-253
  CrossrefPubMedSearch in Google Scholar
• 26 Phillips MS, Gosain S, Bonatti H et al. Enteral stents for malignancy: a report of 46 consecutive cases over 10 years, with critical review of complications. J Gastrointest Surg 2008; 12: 2045-2050
  CrossrefPubMedSearch in Google Scholar
• 27 Kim SY, Song HY, Kim JH et al. Bridging across the ampulla of Vater with covered self-expanding metallic stents: is it contraindicated when treating malignant gastroduodenal obstruction?. J Vasc Interv Radiol 2008; 19: 1607-1613
  CrossrefPubMedSearch in Google Scholar
• 28 Baron TH. Expandable metal stents for the treatment of cancerous obstruction of the gastrointestinal tract. N Engl J Med 2001; 344: 1681-1687
  CrossrefPubMedSearch in Google Scholar

Corresponding author

• References

• 1 Nevitt AW, Vida F, Kozarek RA et al. Expandable metallic prostheses for malignant obstructions of gastric outlet and proximal small bowel. Gastrointest Endosc 1998; 47: 271-276
  CrossrefPubMedSearch in Google Scholar
• 2 Soetikno RM, Lichtenstein DR, Vandervoort J et al. Palliation of malignant gastric outlet obstruction using an endoscopically placed Wallstent. Gastrointest Endosc 1998; 47: 267-270
  CrossrefPubMedSearch in Google Scholar
• 3 Venu RP, Pastika BJ, Kini M et al. Self-expandable metal stents for malignant gastric outlet obstruction: a modified technique. Endoscopy 1998; 30: 553-558
  Thieme ConnectPubMedSearch in Google Scholar
• 4 Dormann A, Meisner S, Verin N et al. Self-expanding metal stents for gastroduodenal malignancies: systematic review of their clinical effectiveness. Endoscopy 2004; 36: 543-550
  Thieme ConnectPubMedSearch in Google Scholar
• 5 Jeurnink SM, Steyerberg EW, van Hooft JE et al. Surgical gastrojejunostomy or endoscopic stent placement for the palliation of malignant gastric outlet obstruction (SUSTENT study): a multicenter randomized trial. Gastrointest Endosc 2010; 71: 490-499
  CrossrefPubMedSearch in Google Scholar
• 6 Kim CG, Choi IJ, Lee JY et al. Covered versus uncovered self-expandable metallic stents for palliation of malignant pyloric obstruction in gastric cancer patients: a randomized, prospective study. Gastrointest Endosc 2010; 72: 25-32
  CrossrefPubMedSearch in Google Scholar
• 7 van Hooft JE, Uitdehaag MJ, Bruno MJ et al. Efficacy and safety of the new WallFlex enteral stent in palliative treatment of malignant gastric outlet obstruction (DUOFLEX study): a prospective multicenter study. Gastrointest Endosc 2009; 69: 1059-1066
  CrossrefPubMedSearch in Google Scholar
• 8 Lee KM, Choi SJ, Shin SJ et al. Palliative treatment of malignant gastroduodenal obstruction with metallic stent: prospective comparison of covered and uncovered stents. Scand J Gastroenterol 2009; 44: 846-852
  CrossrefPubMedSearch in Google Scholar
• 9 Maetani I, Isayama H, Mizumoto Y. Palliation in patients with malignant gastric outlet obstruction with a newly designed enteral stent: a multicenter study. Gastrointest Endosc 2007; 66: 355-360
  CrossrefPubMedSearch in Google Scholar
• 10 Havemann MC, Adamsen S, Wojdemann M. Malignant gastric outlet obstruction managed by endoscopic stenting: a prospective single-centre study. Scand J Gastroenterol 2009; 44: 248-251
  CrossrefPubMedSearch in Google Scholar
• 11 Adler DG, Baron TH. Endoscopic palliation of malignant gastric outlet obstruction using self-expanding metal stents: experience in 36 patients. Am J Gastroenterol 2002; 97: 72-78
  CrossrefPubMedSearch in Google Scholar
• 12 van Hooft JE, Vleggaar FP, Le MO et al. Endoscopic magnetic gastroenteric anastomosis for palliation of malignant gastric outlet obstruction: a prospective multicenter study. Gastrointest Endosc 2010; 72: 530-535
  CrossrefPubMedSearch in Google Scholar
• 13 Aaronson NK, Ahmedzai S, Bergman B et al. The European Organization for Research and Treatment of Cancer QLQ-C30: a quality-of-life instrument for use in international clinical trials in oncology. J Natl Cancer Inst 1993; 85: 365-376
  CrossrefPubMedSearch in Google Scholar
• 14 Rabin R, de Charro F. EQ-5D: a measure of health status from the EuroQol Group. Ann Med 2001; 33: 337-343
  CrossrefPubMedSearch in Google Scholar
• 15 Ludbrook J, Royse AG. Analysing clinical studies: principles, practice and pitfalls of Kaplan-Meier plots. ANZ J Surg 2008; 78: 204-210
  CrossrefPubMedSearch in Google Scholar
• 16 Ly J, O’Grady G, Mittal A et al. A systematic review of methods to palliate malignant gastric outlet obstruction. Surg Endosc 2010; 24: 290-297
  CrossrefPubMedSearch in Google Scholar
• 17 Hosono S, Ohtani H, Arimoto Y et al. Endoscopic stenting versus surgical gastroenterostomy for palliation of malignant gastroduodenal obstruction: a meta-analysis. J Gastroenterol 2007; 42: 283-290
  CrossrefPubMedSearch in Google Scholar
• 18 Shi D, Liao SH, Geng JP. A newly designed big cup nitinol stent for gastric outlet obstruction. World J Gastroenterol 2010; 16: 4206-4209
  CrossrefPubMedSearch in Google Scholar
• 19 Song HY, Shin JH, Yoon CJ et al. A dual expandable nitinol stent: experience in 102 patients with malignant gastroduodenal strictures. J Vasc Interv Radiol 2004; 15: 1443-1449
  CrossrefPubMedSearch in Google Scholar
• 20 Kim YW, Choi CW, Kang DH et al. A double-layered (comvi) self-expandable metal stent for malignant gastroduodenal obstruction: a prospective multicenter study. Dig Dis Sci 2011; 56: 2030-2036
  CrossrefPubMedSearch in Google Scholar
• 21 van Hooft JE, van Montfoort ML, Jeurnink SM et al. Safety and efficacy of a new non-foreshortening nitinol stent in malignant gastric outlet obstruction (DUONITI study): a prospective, multicenter study. Endoscopy 2011; 43: 671-675
  Thieme ConnectPubMedSearch in Google Scholar
• 22 Kim JH, Song HY, Shin JH et al. Metallic stent placement in the palliative treatment of malignant gastroduodenal obstructions: prospective evaluation of results and factors influencing outcome in 213 patients. Gastrointest Endosc 2007; 66: 256-264
  CrossrefPubMedSearch in Google Scholar
• 23 Shaw JM, Bornman PC, Krige JE et al. Self-expanding metal stents as an alternative to surgical bypass for malignant gastric outlet obstruction. Br J Surg 2010; 97: 872-876
  CrossrefPubMedSearch in Google Scholar
• 24 Baron TH, Harewood GC. Enteral self-expandable stents. Gastrointest Endosc 2003; 58: 421-433
  CrossrefPubMedSearch in Google Scholar
• 25 Bessoud B, de Baere T, Denys A et al. Malignant gastroduodenal obstruction: palliation with self-expanding metallic stents. J Vasc Interv Radiol 2005; 16: 247-253
  CrossrefPubMedSearch in Google Scholar
• 26 Phillips MS, Gosain S, Bonatti H et al. Enteral stents for malignancy: a report of 46 consecutive cases over 10 years, with critical review of complications. J Gastrointest Surg 2008; 12: 2045-2050
  CrossrefPubMedSearch in Google Scholar
• 27 Kim SY, Song HY, Kim JH et al. Bridging across the ampulla of Vater with covered self-expanding metallic stents: is it contraindicated when treating malignant gastroduodenal obstruction?. J Vasc Interv Radiol 2008; 19: 1607-1613
  CrossrefPubMedSearch in Google Scholar
• 28 Baron TH. Expandable metal stents for the treatment of cancerous obstruction of the gastrointestinal tract. N Engl J Med 2001; 344: 1681-1687
  CrossrefPubMedSearch in Google Scholar