- Email: [email protected]
Palliative Treatment of Malignant Gastric Outlet Obstructions with a Large-diameter Metallic Stent: Prospective Preliminary Study
Palliative Treatment of Malignant Gastric Outlet Obstructions with a Large-diameter Metallic Stent: Prospective Preliminary Study Jin Hyoung Kim, MD, Ho-Young Song, MD, PhD, Hong Tao Hu, MD, Yoon-Koo Kang, MD, Hwoon-Yong Jung, MD, Jeong Hwan Yook, MD, and Byung Sik Kim, MD
Large-diameter (24 mm) stent placement was prospectively performed in seven patients with mild malignant gastric outlet obstruction (ie, allowing passage of adult endoscope) or unusual obstruction location. The degree of dysphagia was categorized into five grades: 0 (regular diet), 1 (some solid food), 2 (soft diet), 3 (liquid diet), and 4 (complete dysphagia). One month after stent placement, all patients had improvement of at least one grade in their level of dysphagia. Large-diameter stent placement may be clinically effective in gastric outlet obstruction cases with a high risk of stent migration as a result of mild obstructions or unusual obstruction location. J Vasc Interv Radiol 2010; 21:1125–1128
PLACEMENT of uncovered or covered self-expanding metallic stents has been increasingly used for the palliative treatment of malignant gastric outlet obstruction because it is associated with higher clinical success rates, shorter hospital stay, and less morbidity and mortality than palliative surgery (1– 6). However, metallic stent placement for malignant gastric outlet obstruction has several potential disadvantages, including stent migration, tumor ingrowth or overgrowth, formation of granulation tissue, obstructive jaundice, and food impaction (5,6). Covered metallic stents have been widely used to prevent stent obstruction caused by tumor ingrowth (5,7–11). The diameter of conventional covered gas-
From the Department of Radiology and Research Institute of Radiology (J.H.K., H.Y.S., H.T.H.) and Departments of Internal Medicine (Y.K.K., H.Y.J.) and Surgery (J.H.Y., B.S.K.), Asan Medical Center, University of Ulsan College of Medicine, 388-1, Poongnap-2dong, Songpa-gu, Seoul, 138-736, Korea. Received April 17, 2009; final revision received October 23, 2009; accepted March 19, 2010. Address correspondence to H.Y.S.; E-mail: [email protected] None of the authors have identified a conflict of interest. © SIR, 2010 DOI: 10.1016/j.jvir.2010.03.010
troduodenal stents is usually 16 mm or 18 mm (5,7–11). However, a major limitation of these stents has been the high rates of stent migration (17%–26%) (7– 9). Because of this high risk, conventional covered stent placement is usually not indicated in patients with mild gastric outlet obstruction in whom an endoscope can be passed through the strictures (5) or in patients whose obstruction is such that both ends of the stent cannot fix themselves into the wall because they project freely into the stomach. In our clinical practice, it is infrequent to see patients with severe symptoms who have such mild strictures or gastric outlet obstruction at an aforementioned location. We, therefore, hypothesized that placement of a large-diameter stent may be a safe and effective therapeutic strategy in the palliative treatment of these patients. The aim of this preliminary prospective study is to report the clinical results of large-diameter stent placement in seven patients with inoperable malignant gastric outlet obstructions.
MATERIALS AND METHODS Patient Characteristics Between August 2006 and May 2008, seven patients with gastric outlet ob-
struction caused by primary or recurrent gastric carcinoma underwent largediameter (24 mm) stent placement at our institution. The inclusion criteria for large-diameter stent placement included (i) documented unresectable malignancy; (ii) gastric outlet obstruction resulting in nausea, vomiting, and dysphagia; (iii) risk of migration with conventional stent placement in patients in whom an adult endoscope could be passed through the malignant obstruction or in whom malignant obstruction involved the gastric body; and (iv) life expectancy greater than 1 month. Written informed consent was obtained from each patient, and our institutional review board approved the design of this prospective clinical trial. Patient characteristics and the clinical outcomes of the seven study patients (four men) are summarized in the Table. Ages ranged from 43 to 60 years (mean, 55.8 y ⫾ 8.4). Before stent placement, the duration of their obstructive symptoms ranged from 8 to 42 days (median, 18 d). The degree of dysphagia was categorized into five grades: 0, regular diet; 1, ability to eat some but not all solids; 2, ability to eat a soft diet; 3, ability to eat liquids only; and 4, complete dysphagia (12,13). All patients presented with a severe degree of dysphagia; six patients showed grade 4 (ie,
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Summary of Patient Characteristics and Clinical Outcomes Dysphagia Score Pt. No.
Age (y)/ Sex
1
60/M
2 3 4 5 6 7
68/M 53/F 43/F 62/M 56/M 49/F
Cause of Obstruction* Recurrent AGC AGC (III) AGC (III) AGC (IV) AGC (IV) AGC (IV) AGC (IV)
Site of Obstruction GD site Lower Lower Upper Lower Upper Lower
body body body body body body
to antrum to antrum to antrum to antrum to antrum
Previous Treatment Stent, chemotherapy None None Chemotherapy None None Chemotherapy
Obstruction Before After Survival Size (cm) Stent Stent Complications (d) 5
4
2
None
40
5 4 3 4 8 5
4 4 3 4 4 4
2 0 2 0 0 0
None Pain None None Pain None
306 317 60 247 204 225
Note.—AGC ⫽ advanced gastric carcinoma; GD ⫽ gastroduodenostomy. *Roman numerals in parentheses indicate Borman type obstruction.
complete) dysphagia and the remaining patient showed grade 3 dysphagia (ie, could consume only liquids). Six patients underwent a large-diameter stent placement because of mild strictures, and the remaining patient (patient 4) underwent large-diameter stent placement because the stricture was located in the upper body of the stomach. One patient (patient 1) had previously undergone stent placement (18 mm in diameter), but the stent had migrated 1 month later. Stent Design We used dual-design expandable metallic stents (S&G Biotech, Seongnam, Korea; Fig 1), each of which consisted of an outer partially covered stent, and an inner bare nitinol stent. The inner bare nitinol stent was 24 mm in diameter and both of its ends were flared to 32 mm. The outer partially covered stent has three parts: a proximal bare nitinol stent (32 mm in diameter), a nylon mesh (24 mm in diameter), and a distal bare nitinol stent (32 mm in diameter). The inner bare stent acts to expand the nylon mesh portion of the outer stent and increases the radial power of the dual stent.
Figure 1. The large-diameter dual-design metallic stent used in the present report has an outer partially covered stent (a) and an inner bare stent (b). (Available in color online at www.jvir.org.)
guidance. After delineation of the full length of the stricture with the use of water-soluble contrast medium, the stent was inserted over a stiff wire under fluoroscopic guidance.
Stent Placement Endoscopy was performed 1–5 days before stent placement to evaluate the site, severity, and length of the stricture. The stent placement techniques have previously been described in detail (10). Briefly, the stricture was cannulated with a catheter and a hydrophilic exchange guide wire under fluoroscopic
Follow-up After stent placement, patients were advised to resume oral intake of liquids within 24 hours. Patients were not permitted a soft or solid diet until a follow-up barium study 1–3 days later showed full stent expansion. The barium study was also used to confirm the
position and patency of the stent. Patients also underwent endoscopy and a barium study 1 month after stent placement to explore the possibility of delayed complications. The status of oral food intake was monitored at 1-month intervals through an outpatient clinic. When it was not possible to perform clinical examinations, patients or their families were contacted by telephone every month until their death for information regarding nausea, vomiting, and food intake capacity. All data were obtained prospectively by completion of clinical surveys.
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Figure 2. Stent placement in a 49-year-old woman with gastric carcinoma (patient 7). (a,b) Injection of water-soluble nonionic contrast medium through a catheter shows a mild stricture (5 cm in length; arrowheads) in the antrum and lower body of the stomach. (c) Upper gastrointestinal series immediately after placement of a large-diameter dual stent shows good flow of contrast medium through the stent.
Data Definition and Analysis Technical success was defined as successful placement of the stent in the proper position and good passage of contrast medium through the stenotic area and downstream. Clinical success was defined by an increase of at least one grade on the dysphagia score 1 month after stent placement. After stent placement, technical/clinical success, improvement of dysphagia, and complications were evaluated.
RESULTS Stent placement was technically successful without difficulty in all seven patients (Figs 2,3). Each patient required only one stent to transverse the site of obstruction. Immediately after stent placement, two patients described abdominal pain, which was relieved by analgesic agents within 4 hours after stent placement. One month after stent placement, all seven patients had improvement of at least one grade in their level of oral intake (Table), for a clinical success rate of 100%. The median dysphagia score also improved from 4 to 1. During the follow-up period, no complications such as stent migration, tumor or tissue overgrowth, or food impaction occurred. All seven patients died 40 –317 days after stent placement (median, 226 d) as a result of disease progression.
DISCUSSION Given that a large-diameter stent has increased expansion force, it may theoretically reduce the risk of stent migra-
Figure 3. Stent placement in a 33-year-old man with gastric carcinoma (patient 4). (a) Upper gastrointestinal series 2 days before stent placement shows a stricture (arrow) in the upper body of the stomach. (b) A large-diameter dual stent was placed in the obstruction in the upper body of the stomach.
tion or food impaction. In a previous report (13) comparing small-diameter (16 or 18 mm) and large-diameter (20 –23 mm) stents in the palliative treatment of patients with an inoperable malignant obstruction of the esophagus or the gastric cardia, dysphagia from stent migration, tissue overgrowth, and food impaction occurred more frequently in patients with a small-diameter stent than in those with a large-diameter stent. However, to our knowledge, there have been no reports on clinical results of large-diameter stent placement in patients with gastric outlet obstruction. In previous studies (5,7–11,14) reporting the clinical results of small-diameter (16 or 18 mm) covered metallic stent placement in patients with malignant gastric outlet obstruction, technical and clinical success was achieved in
75%–100% and 67%–100% of patients, respectively. However, a major drawback to the use of these stents was the high rates of stent migration (17%–26%) (7–9). In addition, the rate of stent obstruction caused by tumor ingrowth or overgrowth, stent collapse, or food impaction ranged from 11% to 26% (5,9,11,14). A recent large cohort study (5) of partially covered dual stents (18 mm in diameter) in 213 patients with malignant obstructions (through which an adult endoscope was not capable of being passed) in the peripyloric region, duodenum, or gastroenterostomy indicated a lower frequency of stent migration (4%) than shown in previous studies; however, this study (5) found a 14% incidence of stent obstruction caused by tumor or tissue overgrowth (8%), stent collapse (4%), or food impaction (2%)
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during the median follow-up period of 45 days (range, 2– 657 d). Conversely, in the present study, technical and clinical success was achieved after large-diameter stent placement in all patients with malignant gastric outlet obstruction. During the follow-up period, complications, including stent migration, tumor overgrowth, and food impaction, did not occur. In agreement with the previous study (13) comparing the results of small- and large-diameter stents for malignant esophageal obstructions, we assume that large-diameter stents may reduce the risk of stent migration or recurrent obstruction from tumor overgrowth or food impaction in patients with malignant gastric outlet obstruction. In patients with advanced gastric cancer involving a large area of the stomach wall (ie, Borman type IV), the obstructive symptoms can be severe even in patients with mild obstructions because of the decreased motility of the stomach. In this situation, a small-diameter stent theoretically has a high risk of stent migration. In the present study, six patients received a large-diameter stent for the aforementioned reason. After stent placement, no migration occurred until the time of their deaths. Chemotherapy after stent placement may increase the risk of stent migration by reducing the tumor burden (5). One of the patients in the present study received chemotherapy after placement of a small-diameter (18 mm) stent. As the small-diameter stent migrated, the patient had a second, large-diameter stent implanted, which did not migrate, indicating that patients in the aforementioned situation may benefit from largediameter stent placement. In the present study, as one patient had obstruction in the high body of the stomach, both ends of the stent projected freely into the stomach without being fixed into the wall when the stent was placed in this area. However, placement of a small-diameter stent in this location may present a high risk of stent migration. In addition, free projection of the proximal end of a small-diameter stent without being fixed into the stomach wall may lead to frequent food impaction. To prevent stent migration and food impaction, we placed a large-diameter stent in this patient with obstruction of the upper body of the stomach. As expected, there was no stent migration
or food impaction after stent placement during the entire follow-up period. On the contrary, a large-diameter stent with increased expansion force may theoretically cause more pressurerelated complications, such as hemorrhage, perforation, and pain. The dualdesign stent used in the present study was supposed to have high confirmability to the stricture (15). We experienced no serious complications such as hemorrhage or perforation. Two patients presented with abdominal pain after stent placement, but the pain was relieved with analgesic agents within 4 hours after stent placement. However, the safety and efficacy of large-diameter stent placement in the case of a severe obstruction or an angled area, eg, duodenal location, is still unknown based on the results of the present study. As a large-diameter stent may have less flexibility and a higher expansion force than a small-diameter stent (13), it may theoretically increase the risk of hemorrhage or perforation when it is placed in a severe obstruction or in an angled area. Further study to evaluate large-diameter stent placement in severe obstructions and in angled areas will be required. In conclusion, large-diameter stent placement may be clinically effective in gastric outlet obstruction cases with a high risk for stent migration. However, further study will be needed to evaluate the safety and efficacy of large-diameter stent placement in angled or severe gastric outlet obstruction. References 1. Del Piano M, Ballare M, Montino F, et al. Endoscopy or surgery for malignant GI outlet obstruction? Gastrointest Endosc 2005; 61:421– 426. 2. Maetani I, Tada T, Ukita T, Inoue H, Sakai Y, Nagao J. Comparison of duodenal stent placement with surgical gastrojejunostomy for palliation in patients with duodenal obstructions caused by pancreaticobiliary malignancies. Endoscopy 2004; 36:73–78. 3. Maetani I, Akatsuka S, Ikeda M, et al. Self-expandable metallic stent placement for palliation in gastric outlet obstructions caused by gastric cancer: a comparison with surgical gastrojejunostomy. J Gastroenterol 2005; 40:932– 937. 4. Baron TH. Expandable metal stents for the treatment of cancerous obstruction of the gastrointestinal tract. N Engl J Med 2001; 344:1681–1687.
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5. 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. 6. Maetani I, Ukita T, Tada T, Shigoka H, Omuta S, Endo T. Metallic stents for gastric outlet obstruction: reintervention rate is lower with uncovered versus covered stents, despite similar outcomes. Gastrointest Endosc 2009; 69: 806 – 812. 7. Park KB, Do YS, Kang WK, et al. Malignant obstruction of gastric outlet and duodenum: palliation with flexible covered metallic stents. Radiology 2001; 219:679 – 683. 8. 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. 9. Jeong JY, Han JK, Kim AY, et al. Fluoroscopically guided placement of a covered self-expandable metallic stent for malignant antroduodenal obstructions: preliminary results in 18 patients. AJR Am J Roentgenol 2002; 178: 847– 852. 10. 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. 11. Seo EH, Jung MK, Park MJ, et al. Covered expandable nitinol stents for malignant gastroduodenal obstructions. J Gastroenterol Hepatol 2008; 23:1056 – 1062. 12. Kim JH, Song HY, Shin JH, et al. Palliative treatment of unresectable esophagogastric junction tumors: balloon dilation combined with chemotherapy and/or radiation therapy and metallic stent placement. J Vasc Interv Radiol 2008; 19:912–917. 13. Verschuur EML, Steyerberg EW, Kuipers EJ, Siersema PD. Effect of stent size on complications and recurrent dysphagia in patients with esophageal or gastric cardia cancer. Gastrointest Endosc 2007; 65:592– 601. 14. Jung GS, Song HY, Seo TS, et al. Malignant gastric outlet obstructions: treatment by means of coaxial placement of uncovered and covered expandable nitinol stents. J Vasc Interv Radiol 2002; 13:275–283. 15. Kim JH, Song HY, Shin JH, et al. Anastomotic recurrence of gastric cancer after total gastrectomy with esophagojejunostomy: palliation with covered expandable metallic stents. J Vasc Interv Radiol 2007; 18:964 –969.
Large-diameter (24 mm) stent placement was prospectively performed in seven patients with mild malignant gastric outlet obstruction (ie, allowing passage of adult endoscope) or unusual obstruction location. The degree of dysphagia was categorized into five grades: 0 (regular diet), 1 (some solid food), 2 (soft diet), 3 (liquid diet), and 4 (complete dysphagia). One month after stent placement, all patients had improvement of at least one grade in their level of dysphagia. Large-diameter stent placement may be clinically effective in gastric outlet obstruction cases with a high risk of stent migration as a result of mild obstructions or unusual obstruction location. J Vasc Interv Radiol 2010; 21:1125–1128
PLACEMENT of uncovered or covered self-expanding metallic stents has been increasingly used for the palliative treatment of malignant gastric outlet obstruction because it is associated with higher clinical success rates, shorter hospital stay, and less morbidity and mortality than palliative surgery (1– 6). However, metallic stent placement for malignant gastric outlet obstruction has several potential disadvantages, including stent migration, tumor ingrowth or overgrowth, formation of granulation tissue, obstructive jaundice, and food impaction (5,6). Covered metallic stents have been widely used to prevent stent obstruction caused by tumor ingrowth (5,7–11). The diameter of conventional covered gas-
From the Department of Radiology and Research Institute of Radiology (J.H.K., H.Y.S., H.T.H.) and Departments of Internal Medicine (Y.K.K., H.Y.J.) and Surgery (J.H.Y., B.S.K.), Asan Medical Center, University of Ulsan College of Medicine, 388-1, Poongnap-2dong, Songpa-gu, Seoul, 138-736, Korea. Received April 17, 2009; final revision received October 23, 2009; accepted March 19, 2010. Address correspondence to H.Y.S.; E-mail: [email protected] None of the authors have identified a conflict of interest. © SIR, 2010 DOI: 10.1016/j.jvir.2010.03.010
troduodenal stents is usually 16 mm or 18 mm (5,7–11). However, a major limitation of these stents has been the high rates of stent migration (17%–26%) (7– 9). Because of this high risk, conventional covered stent placement is usually not indicated in patients with mild gastric outlet obstruction in whom an endoscope can be passed through the strictures (5) or in patients whose obstruction is such that both ends of the stent cannot fix themselves into the wall because they project freely into the stomach. In our clinical practice, it is infrequent to see patients with severe symptoms who have such mild strictures or gastric outlet obstruction at an aforementioned location. We, therefore, hypothesized that placement of a large-diameter stent may be a safe and effective therapeutic strategy in the palliative treatment of these patients. The aim of this preliminary prospective study is to report the clinical results of large-diameter stent placement in seven patients with inoperable malignant gastric outlet obstructions.
MATERIALS AND METHODS Patient Characteristics Between August 2006 and May 2008, seven patients with gastric outlet ob-
struction caused by primary or recurrent gastric carcinoma underwent largediameter (24 mm) stent placement at our institution. The inclusion criteria for large-diameter stent placement included (i) documented unresectable malignancy; (ii) gastric outlet obstruction resulting in nausea, vomiting, and dysphagia; (iii) risk of migration with conventional stent placement in patients in whom an adult endoscope could be passed through the malignant obstruction or in whom malignant obstruction involved the gastric body; and (iv) life expectancy greater than 1 month. Written informed consent was obtained from each patient, and our institutional review board approved the design of this prospective clinical trial. Patient characteristics and the clinical outcomes of the seven study patients (four men) are summarized in the Table. Ages ranged from 43 to 60 years (mean, 55.8 y ⫾ 8.4). Before stent placement, the duration of their obstructive symptoms ranged from 8 to 42 days (median, 18 d). The degree of dysphagia was categorized into five grades: 0, regular diet; 1, ability to eat some but not all solids; 2, ability to eat a soft diet; 3, ability to eat liquids only; and 4, complete dysphagia (12,13). All patients presented with a severe degree of dysphagia; six patients showed grade 4 (ie,
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Summary of Patient Characteristics and Clinical Outcomes Dysphagia Score Pt. No.
Age (y)/ Sex
1
60/M
2 3 4 5 6 7
68/M 53/F 43/F 62/M 56/M 49/F
Cause of Obstruction* Recurrent AGC AGC (III) AGC (III) AGC (IV) AGC (IV) AGC (IV) AGC (IV)
Site of Obstruction GD site Lower Lower Upper Lower Upper Lower
body body body body body body
to antrum to antrum to antrum to antrum to antrum
Previous Treatment Stent, chemotherapy None None Chemotherapy None None Chemotherapy
Obstruction Before After Survival Size (cm) Stent Stent Complications (d) 5
4
2
None
40
5 4 3 4 8 5
4 4 3 4 4 4
2 0 2 0 0 0
None Pain None None Pain None
306 317 60 247 204 225
Note.—AGC ⫽ advanced gastric carcinoma; GD ⫽ gastroduodenostomy. *Roman numerals in parentheses indicate Borman type obstruction.
complete) dysphagia and the remaining patient showed grade 3 dysphagia (ie, could consume only liquids). Six patients underwent a large-diameter stent placement because of mild strictures, and the remaining patient (patient 4) underwent large-diameter stent placement because the stricture was located in the upper body of the stomach. One patient (patient 1) had previously undergone stent placement (18 mm in diameter), but the stent had migrated 1 month later. Stent Design We used dual-design expandable metallic stents (S&G Biotech, Seongnam, Korea; Fig 1), each of which consisted of an outer partially covered stent, and an inner bare nitinol stent. The inner bare nitinol stent was 24 mm in diameter and both of its ends were flared to 32 mm. The outer partially covered stent has three parts: a proximal bare nitinol stent (32 mm in diameter), a nylon mesh (24 mm in diameter), and a distal bare nitinol stent (32 mm in diameter). The inner bare stent acts to expand the nylon mesh portion of the outer stent and increases the radial power of the dual stent.
Figure 1. The large-diameter dual-design metallic stent used in the present report has an outer partially covered stent (a) and an inner bare stent (b). (Available in color online at www.jvir.org.)
guidance. After delineation of the full length of the stricture with the use of water-soluble contrast medium, the stent was inserted over a stiff wire under fluoroscopic guidance.
Stent Placement Endoscopy was performed 1–5 days before stent placement to evaluate the site, severity, and length of the stricture. The stent placement techniques have previously been described in detail (10). Briefly, the stricture was cannulated with a catheter and a hydrophilic exchange guide wire under fluoroscopic
Follow-up After stent placement, patients were advised to resume oral intake of liquids within 24 hours. Patients were not permitted a soft or solid diet until a follow-up barium study 1–3 days later showed full stent expansion. The barium study was also used to confirm the
position and patency of the stent. Patients also underwent endoscopy and a barium study 1 month after stent placement to explore the possibility of delayed complications. The status of oral food intake was monitored at 1-month intervals through an outpatient clinic. When it was not possible to perform clinical examinations, patients or their families were contacted by telephone every month until their death for information regarding nausea, vomiting, and food intake capacity. All data were obtained prospectively by completion of clinical surveys.
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Figure 2. Stent placement in a 49-year-old woman with gastric carcinoma (patient 7). (a,b) Injection of water-soluble nonionic contrast medium through a catheter shows a mild stricture (5 cm in length; arrowheads) in the antrum and lower body of the stomach. (c) Upper gastrointestinal series immediately after placement of a large-diameter dual stent shows good flow of contrast medium through the stent.
Data Definition and Analysis Technical success was defined as successful placement of the stent in the proper position and good passage of contrast medium through the stenotic area and downstream. Clinical success was defined by an increase of at least one grade on the dysphagia score 1 month after stent placement. After stent placement, technical/clinical success, improvement of dysphagia, and complications were evaluated.
RESULTS Stent placement was technically successful without difficulty in all seven patients (Figs 2,3). Each patient required only one stent to transverse the site of obstruction. Immediately after stent placement, two patients described abdominal pain, which was relieved by analgesic agents within 4 hours after stent placement. One month after stent placement, all seven patients had improvement of at least one grade in their level of oral intake (Table), for a clinical success rate of 100%. The median dysphagia score also improved from 4 to 1. During the follow-up period, no complications such as stent migration, tumor or tissue overgrowth, or food impaction occurred. All seven patients died 40 –317 days after stent placement (median, 226 d) as a result of disease progression.
DISCUSSION Given that a large-diameter stent has increased expansion force, it may theoretically reduce the risk of stent migra-
Figure 3. Stent placement in a 33-year-old man with gastric carcinoma (patient 4). (a) Upper gastrointestinal series 2 days before stent placement shows a stricture (arrow) in the upper body of the stomach. (b) A large-diameter dual stent was placed in the obstruction in the upper body of the stomach.
tion or food impaction. In a previous report (13) comparing small-diameter (16 or 18 mm) and large-diameter (20 –23 mm) stents in the palliative treatment of patients with an inoperable malignant obstruction of the esophagus or the gastric cardia, dysphagia from stent migration, tissue overgrowth, and food impaction occurred more frequently in patients with a small-diameter stent than in those with a large-diameter stent. However, to our knowledge, there have been no reports on clinical results of large-diameter stent placement in patients with gastric outlet obstruction. In previous studies (5,7–11,14) reporting the clinical results of small-diameter (16 or 18 mm) covered metallic stent placement in patients with malignant gastric outlet obstruction, technical and clinical success was achieved in
75%–100% and 67%–100% of patients, respectively. However, a major drawback to the use of these stents was the high rates of stent migration (17%–26%) (7–9). In addition, the rate of stent obstruction caused by tumor ingrowth or overgrowth, stent collapse, or food impaction ranged from 11% to 26% (5,9,11,14). A recent large cohort study (5) of partially covered dual stents (18 mm in diameter) in 213 patients with malignant obstructions (through which an adult endoscope was not capable of being passed) in the peripyloric region, duodenum, or gastroenterostomy indicated a lower frequency of stent migration (4%) than shown in previous studies; however, this study (5) found a 14% incidence of stent obstruction caused by tumor or tissue overgrowth (8%), stent collapse (4%), or food impaction (2%)
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during the median follow-up period of 45 days (range, 2– 657 d). Conversely, in the present study, technical and clinical success was achieved after large-diameter stent placement in all patients with malignant gastric outlet obstruction. During the follow-up period, complications, including stent migration, tumor overgrowth, and food impaction, did not occur. In agreement with the previous study (13) comparing the results of small- and large-diameter stents for malignant esophageal obstructions, we assume that large-diameter stents may reduce the risk of stent migration or recurrent obstruction from tumor overgrowth or food impaction in patients with malignant gastric outlet obstruction. In patients with advanced gastric cancer involving a large area of the stomach wall (ie, Borman type IV), the obstructive symptoms can be severe even in patients with mild obstructions because of the decreased motility of the stomach. In this situation, a small-diameter stent theoretically has a high risk of stent migration. In the present study, six patients received a large-diameter stent for the aforementioned reason. After stent placement, no migration occurred until the time of their deaths. Chemotherapy after stent placement may increase the risk of stent migration by reducing the tumor burden (5). One of the patients in the present study received chemotherapy after placement of a small-diameter (18 mm) stent. As the small-diameter stent migrated, the patient had a second, large-diameter stent implanted, which did not migrate, indicating that patients in the aforementioned situation may benefit from largediameter stent placement. In the present study, as one patient had obstruction in the high body of the stomach, both ends of the stent projected freely into the stomach without being fixed into the wall when the stent was placed in this area. However, placement of a small-diameter stent in this location may present a high risk of stent migration. In addition, free projection of the proximal end of a small-diameter stent without being fixed into the stomach wall may lead to frequent food impaction. To prevent stent migration and food impaction, we placed a large-diameter stent in this patient with obstruction of the upper body of the stomach. As expected, there was no stent migration
or food impaction after stent placement during the entire follow-up period. On the contrary, a large-diameter stent with increased expansion force may theoretically cause more pressurerelated complications, such as hemorrhage, perforation, and pain. The dualdesign stent used in the present study was supposed to have high confirmability to the stricture (15). We experienced no serious complications such as hemorrhage or perforation. Two patients presented with abdominal pain after stent placement, but the pain was relieved with analgesic agents within 4 hours after stent placement. However, the safety and efficacy of large-diameter stent placement in the case of a severe obstruction or an angled area, eg, duodenal location, is still unknown based on the results of the present study. As a large-diameter stent may have less flexibility and a higher expansion force than a small-diameter stent (13), it may theoretically increase the risk of hemorrhage or perforation when it is placed in a severe obstruction or in an angled area. Further study to evaluate large-diameter stent placement in severe obstructions and in angled areas will be required. In conclusion, large-diameter stent placement may be clinically effective in gastric outlet obstruction cases with a high risk for stent migration. However, further study will be needed to evaluate the safety and efficacy of large-diameter stent placement in angled or severe gastric outlet obstruction. References 1. Del Piano M, Ballare M, Montino F, et al. Endoscopy or surgery for malignant GI outlet obstruction? Gastrointest Endosc 2005; 61:421– 426. 2. Maetani I, Tada T, Ukita T, Inoue H, Sakai Y, Nagao J. Comparison of duodenal stent placement with surgical gastrojejunostomy for palliation in patients with duodenal obstructions caused by pancreaticobiliary malignancies. Endoscopy 2004; 36:73–78. 3. Maetani I, Akatsuka S, Ikeda M, et al. Self-expandable metallic stent placement for palliation in gastric outlet obstructions caused by gastric cancer: a comparison with surgical gastrojejunostomy. J Gastroenterol 2005; 40:932– 937. 4. Baron TH. Expandable metal stents for the treatment of cancerous obstruction of the gastrointestinal tract. N Engl J Med 2001; 344:1681–1687.
July 2010
JVIR
5. 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. 6. Maetani I, Ukita T, Tada T, Shigoka H, Omuta S, Endo T. Metallic stents for gastric outlet obstruction: reintervention rate is lower with uncovered versus covered stents, despite similar outcomes. Gastrointest Endosc 2009; 69: 806 – 812. 7. Park KB, Do YS, Kang WK, et al. Malignant obstruction of gastric outlet and duodenum: palliation with flexible covered metallic stents. Radiology 2001; 219:679 – 683. 8. 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. 9. Jeong JY, Han JK, Kim AY, et al. Fluoroscopically guided placement of a covered self-expandable metallic stent for malignant antroduodenal obstructions: preliminary results in 18 patients. AJR Am J Roentgenol 2002; 178: 847– 852. 10. 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. 11. Seo EH, Jung MK, Park MJ, et al. Covered expandable nitinol stents for malignant gastroduodenal obstructions. J Gastroenterol Hepatol 2008; 23:1056 – 1062. 12. Kim JH, Song HY, Shin JH, et al. Palliative treatment of unresectable esophagogastric junction tumors: balloon dilation combined with chemotherapy and/or radiation therapy and metallic stent placement. J Vasc Interv Radiol 2008; 19:912–917. 13. Verschuur EML, Steyerberg EW, Kuipers EJ, Siersema PD. Effect of stent size on complications and recurrent dysphagia in patients with esophageal or gastric cardia cancer. Gastrointest Endosc 2007; 65:592– 601. 14. Jung GS, Song HY, Seo TS, et al. Malignant gastric outlet obstructions: treatment by means of coaxial placement of uncovered and covered expandable nitinol stents. J Vasc Interv Radiol 2002; 13:275–283. 15. Kim JH, Song HY, Shin JH, et al. Anastomotic recurrence of gastric cancer after total gastrectomy with esophagojejunostomy: palliation with covered expandable metallic stents. J Vasc Interv Radiol 2007; 18:964 –969.