- Email: [email protected]
Radiologic Placement of Uncovered Stents for the Treatment of Malignant Colorectal Obstruction
Radiologic Placement of Uncovered Stents for the Treatment of Malignant Colorectal Obstruction Sue Yon Kim, MD, Se Hwan Kwon, MD, and Joo Hyeong Oh, MD
PURPOSE: To evaluate the effectiveness of radiologic placement of uncovered stents for the treatment of malignant colorectal obstruction. MATERIALS AND METHODS: From May 2003 to January 2008, 116 radiologic placements of uncovered stents were attempted in 99 patients (M:F, 59:40; mean age, 65 years) with malignant colorectal obstructions. The location of stent insertion, technical and clinical success, complication rates, and patency rates of the stents in a palliative group were also evaluated. In the palliative group, the follow-up period was 2– 455 days (mean, 100 ⴞ 129 days). RESULTS: Radiologic stent placement was technically successful in 110 of 116 cases (94.8%). Fifty cases of stent placement were preoperative (45.5%, 50 of 110) and 60 (54.5%, 60 of 110) were performed with palliative intents. In five of six failed cases, the replacement of the stent was later performed with the assistance of colonoscopy. One patient underwent an emergency operation. In 98 of 110 cases, the symptoms of obstruction were relieved, for a clinical success rate of 89.1%. Of the 50 stents that were placed successfully with preoperative intent, 44 patients underwent surgery within a mean of 10.3 days. In the palliative group, the patency rates were 89.7% at 1 month, 85.6% at 3 months, 80.8% at 6 months, and 72.7% at 12 months. CONCLUSIONS: The radiologic placement of uncovered stents for the treatment of malignant colorectal obstruction is feasible and safe and provides acceptable clinical results not only for preoperative decompression but also for palliative cases, especially in left-sided colonic obstructions. J Vasc Interv Radiol 2010; 21:1244 –1249
THE placement of stents for the treatment of malignant colorectal obstruction was first described by Dohmoto in 1991 (1). Since then, various covered and uncovered metallic stents have been placed by endoscopic or fluoro-
From the Department of Radiology, Kyung Hee University Medical Center, 1, Heoki-dong Dongdaemun-gu, Seoul 130-702, Korea. Received August 26, 2008; final revision received February 15, 2010; accepted April 3, 2010. Address correspondence to J.H.O.; E-mail: [email protected] S.Y.K. and S.H.K. contributed equally to this study. This Research was supported by the Program of Kyung Hee University for the Young Researcher in Medical Science (KHU-20091436). None of the authors have identified a conflict of interest © SIR, 2010 DOI: 10.1016/j.jvir.2010.04.009
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scopic approaches in more than 700 cases (2–5). Many reports have established the effectiveness of colorectal stent insertion for treatment in preoperative cases as well as in palliative cases, and the insertion of a stent is considered a reliable treatment for malignant colorectal obstruction (2–5). Previous studies have found that covered stents are more resistant to tumor ingrowth but have the disadvantages of stent migration and are more difficult to deliver to stricture sites because of their rigidity. On the other hand, uncovered stents are more flexible and easily applicable but are associated with the tendency for reobstruction because of tumor ingrowth. For these reasons, uncovered stents are thought to be more suitable for palliation (3,5– 8). However, to date, the majority of reported studies
have been based on a relatively small number of cases. In addition, few instances of this type of treatment using uncovered stents alone have been reported, and the long-term results have not been assessed sufficiently. In this study, we review our experience with a series of uncovered stent placements under radiologic control alone to evaluate the efficacy of uncovered stents in treatment of colorectal obstruction for preoperative and palliative purposes.
MATERIALS AND METHODS The medical records of patients who underwent colorectal stenting between May 2003 and January 2008 were reviewed retrospectively, and their clinical outcomes were evaluated. The inclusion criteria were as follows: (a) documented malignancy, (b)
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Table 1 Patient Demographics Palliative Intent (n ⫽ 47)
Preop. Intent (n ⫽ 52) n Sex Male Female Age, mean (range), year
%
n
31 59.6 21 40.4 66 (28–99)
symptoms and signs of colorectal obstruction, and (c) uncovered stent placement. In this study, there were 116 attempts at radiologic placement of a stent in 99 patients (M:F ⫽ 59:40; mean age, 65 years; range, 28 –99 years) (Table 1). Informed consent was obtained from all patients involved, and the study was approved by our hospital institutional review board. This report was written in accordance with Society of Interventional Radiology (SIR) reporting standard (9). The patients received diagnoses and were classified with imaging and colonoscopy before the stent placement procedure. Indications for the use of a self-expandable metallic stent in colorectal obstruction were (a) preoperative intent when used for relief of colonic obstruction and bowel preparation that allows subsequent elective operation and (b) palliative intent in patients with colorectal malignancy where resection is not feasible to cure the patient, either because of metastatic disease or significant medical comorbidities. Patients who had bowel necrosis, perforation, cancer extending to ⬍ 5 cm from the anal verge, or cancer located near the ileocecal valve were excluded from stent placement. The procedure was performed under fluoroscopic guidance alone, and an uncovered stent was used in all patients. All patients received a cleansing enema a few hours before the procedure. Neither analgesia nor sedation was administered during the procedure, and prophylactic antibiotics were not used. The visualization of the length and the proximal and distal ends of the stricture was achieved by injecting intraluminal water-soluble contrast media. When the opening of the stricture was visible, a 150-cm-
%
29 61.7 18 38.3 63 (36–89)
Total (n ⫽ 99) n
%
60 60.6 39 39.4 65 (28–99)
long, 0.038-inch hydrophilic guide wire (Radifocus M; Terumo, Japan) was advanced through the stricture. Once the guide wire was passed through the lesion, a 5-F angiographic catheter was advanced to the most proximal point, and contrast media was injected to evaluate the tumor length. The 0.035-inch Amplatz superstiff guide wire (Boston Scientific, Massachusetts) was then inserted, and a stent was placed using the delivery system. Balloon dilation was not used. Contrast medium was injected to ensure that the stent was placed properly across the tumor and to assess the stent patency (Fig 1). There was no routine administration of antibiotics. We used two commercially manufactured self-expandable nitinol stents (Hanaro, Solco Intermed, Seoul, Korea and EGIS, S & G Biotech, Seongnam, Korea), 22 mm in diameter and 60, 80, 100, 120, 140, or 160 mm in length. Depending on the availability of stents, the type and length of the stricture and the possibility of tortuous bowel segments below or above different stents were used during the study period. A stent at least 40 mm longer than the stricture was chosen so that the stricture was fully covered. When one stent was not long enough to cover the lesion, a second stent was inserted to overlap the first. We used at least 20 mm overlap between the two stents. An abdominal radiograph was taken during hospitalization 1 to 3 days after placement to confirm the correct deployment and expansion. Patients with palliative stent insertion underwent clinical follow-up and abdominal radiographs every 4 to 8 weeks. Computed tomography examination or an endoscopic procedure was performed if there was persis-
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tence or reappearance of symptoms such as abdominal pain, constipation, or rectal bleeding. In the palliative group, the follow-up period was 2– 455 days (mean, 100 ⫾ 129 days). The technical and clinical success, complication rates, and patency rates for the stents in the palliative group were evaluated via radiologic and clinical examination. Technical success was defined as the deployment of the stent under fluoroscopic guidance alone. Clinical success was defined as the relief of symptoms or signs within 48 hours after stent deployment. Patency rates were determined based on combination of physical and imaging findings at 1, 3, 6, and 12 months. The Kaplan-Meier method (DBSTAT Version 4.1, DBSTAT Co., Chunchon, Korea:) was used to estimate the patency rates of the stent in the palliative group.
RESULTS In total, 116 cases of radiologic stent placement were attempted in 99 patients with malignant colorectal obstructions. The technical success rates for stent insertion are shown in Table 2. Of 116 cases, 110 were technically successful, giving an overall technical success rate of 94.8%. Stent placement was successful under fluoroscopic guidance alone in 50 of 53 cases in the preoperative group and in 60 cases of 63 cases in the palliative group, with technical success rates of 94.3% and 95.2%, respectively. In four of six failed cases, the tumor was located in the ascending colon, and in the remaining two failed cases, the tumor was located in the sigmoid colon. In five of six failed cases, stent placement failed under fluoroscopic guidance because of the redundancy of the colon, and in these cases, the placement of the stent was later performed with the assistance of a colonoscope (Fig 2). In the remaining patient, the stent could not pass the obstructive segment after the stiff guide wire had crossed the obstruction. The patient had complete colonic obstruction from cancer with severe abdominal pain. An emergency loop ileostomy was performed on this patient. Four months later, the patient had low anterior resection and an ileostomy takedown operation with chemotherapy before and after the operation.
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Figure 1. An 83-year-old woman with sigmoid colon cancer. (a) Supine plain abdominal radiograph shows dilated bowel loops, suggesting obstruction of the colon. (b) Abdominal CT shows the tumor involves the sigmoid colon (arrows). (c) Under fluoroscopic guidance, an uncovered stent was implanted at the obstructed portion (arrows). (d) Plain abdominal radiograph after 1 week shows further self-expansion and good positioning of the stent (arrows). The dilation of the colonic loops markedly improved after successful placement of the uncovered stent.
Table 2 Technical Success Rate for the Radiologic Placement of an Uncovered Stent Palliative Intent (n ⫽ 63)
Preop. Intent (n ⫽ 53)
Technical success* Technical failure
Total (n ⫽ 116)
n
%
n
%
n
%
50 3
94.3 5.7
60 3
95.2 4.8
110 6
94.8 5.2
Note.—Total n ⫽ total attempts of radiologic placement of uncovered stent. * Based on the number of successfully inserted stents under only fluoroscopic guidance.
Among the technically successful cases, the locations of the malignant obstructions were in the ascending colon (n ⫽ 1, 0.9%) (Fig 3), transverse colon (n ⫽ 10, 9.1%), descending colon (n ⫽ 20, 18.2%), sigmoid colon (n ⫽ 55, 50.0%) and rectum (n ⫽ 24, 21.8%) (Table 3). In 98 of 110 cases, the symptoms of colonic obstruction were relieved, giving a clinical success rate of 89.1% (98 of 110) (Table 4). The clinical success rate was 96.0% (48 of 50) for the preoperative group and 83.3% (50 of 60) for the palliative group. Fifty cases of stent placement were performed successfully with preoperative intent (45.5%, 50 of 110), and of these, 44 patients underwent surgery within a mean of 10.3 days. Sixty cases of stent placement were done with palliative intent (54.5 %, 60 of 110). In the palliative group, the patency rates were 89.7% at 1 month, 85.6% at 3 months, 80.8% at 6 months and 72.7% at 12 months (Fig 4).
There were no procedure-related major complications such as major bleeding or colon perforation. Stentrelated complications were noted in two patients. The stent migration that was seen in one patient (n ⫽ 1, 0.9%, 1 of 110) developed within 2 weeks. Incomplete expansion of the stent was noted in one case (n ⫽ 1, 0.9%, 1 of 110), in which the cancer was located at the rectum. Other minor complications, such as abdominal or anal pain (n ⫽ 33, 30.0%, 33 of 110), tenesmus (n ⫽ 17, 15.4%, 17 of 110), and transient bleeding (n ⫽ 13, 11.8%, 13 of 110) was improved with conservative management. No other procedural or delayed complications were noted.
DISCUSSION Recent trends in the treatment of malignant colorectal obstructions indicate that the placement of metallic expandable stents is the preferred method, either for efficient preopera-
tive decompression or for palliation in unresectable malignancy, as a minimally invasive and low-risk alternative to emergent surgery with a high success rate (2–5). To obtain better results, various types of self-expandable nitinol stents, including covered or uncovered metallic stents with endoscopic or fluoroscopic guidance, have been tried, and their advantages and disadvantages are well known (3,5– 8). Generally, a covered stent is more resistant to tumor ingrowth that results in a longer stent patency, but the disadvantages include stent migration and rigidity. On the other hand, an uncovered stent is flexible and easily applicable, but tumor ingrowth into the stent and resultant obstruction is more frequent. Therefore, uncovered stents are preferred in preoperative cases as a bridge to surgery because of the shorter stent patency from tumor ingrowth (10 –11). However, it is also noteworthy that coverage did not have a clinically meaningful influence in the patients treated for palliative relief. That is, the functional patency was not significantly different between uncovered and covered stents, and the advantage of the uncovered stent, namely the prevention of migration, exceeds its disadvantage of tumor ingrowth (4). We reviewed our experience with uncovered metallic stent insertions under fluoroscopic guidance alone. This study had a larger number of cases (n ⫽ 110) compared with the smaller sample size of about 50 or less from previous studies involving a colorectal stent (18). This study evalu-
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Figure 2. An 81-year-old man with distal ascending colon cancer. (a) Palliative uncovered colonic stent placement was attempted under fluoroscopic guidance. However, the guide wire could not reach the obstruction point because of the severely redundant and tortuous colonic contour. (b) With the assistance of endoscopy, an uncovered stent was placed at the obstruction site. (c) Plain abdominal radiograph 4 months after stent placement shows the stent is adequately positioned with full expansion (arrows). (Available in color online at www.jvir.org.)
Figure 3. An 83-year-old man with distal ascending colon cancer. (a) Initial abdominal CT shows distal ascending colon cancer (arrows). (b,c) An uncovered stent was deployed successfully to the distal ascending colon (arrows) under fluoroscopic guidance without the help of an endoscope. (d) Plain abdominal radiograph 10 months after stent placement shows the stent is adequately positioned with full expansion (arrows).
Table 3 Distribution of Different Tumor Locations in Technically Successful Cases Preop. Intent (n ⫽ 50)
Location of obstruction Ascending colon Transverse colon Descending colon Sigmoid colon Rectum
Palliative Intent (n ⫽ 60)
Total (n ⫽ 110)
n
%
n
%
n
%
0 4 9 28 9
0 8 18 56 18
1 6 11 27 15
1.7 10.0 18.3 45 25
1 10 20 55 24
0.9 9.1 18.2 50.0 21.8
Note.—Total n ⫽ Total number of technically successful cases.
ated the efficacy of using uncovered stents for colorectal obstruction as bridge to surgery in 50 cases and as palliation in 60 cases. The technical success rate in our series was 94.8% (110 of 116 cases), which corresponds well with the success rates (80%–100%) from earlier studies on the feasibility of this technique (4–5,12). In 98 of 110 cases, the symptoms of colonic obstruction were relieved, giving a clinical success rate of 89.1%. This result is also comparable with the clinical success rates of other studies, which range between 80% and 100% (4–5,12). It is known that lesions proximal to the descending colon are hard to ac-
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Table 4 Clinical Success Rate for Uncovered Stent Insertion in Technically Successful Cases Preop. Intent (n ⫽ 50)
Clinical success* Clinical failure
Palliative Intent (n ⫽ 60)
Total (n ⫽ 110)
n
%
n
%
n
%
48 2
96.0 4.0
50 10
83.3 16.7
98 12
89.1 10.9
Note.—Total n ⫽ Total number of technically successful cases. * Relief of symptom/sign in the first 48 hours.
Figure 4.
Stent patency in the palliative group after stent insertion.
cess because it is technically difficult to deploy the stent using fluoroscopic guidance in the proximal colon, and in some cases, the length of the guide wire is not long enough to reach the obstruction site. Stent placement in these lesions has only been reported in a few cases (13). We were only able to insert 11 stents successfully into lesions proximal to the descending colon (10%, 11 of 110), one in the ascending colon and 10 in the transverse colon. One stent insertion in the ascending colon was technically successful because the patient had a relatively short length of bowel compared with the average. The rest of the insertion sites were descending (n ⫽ 20, 18.2%), sigmoid colon (n ⫽ 55, 50.0%), and rectum (n ⫽ 24, 21.8%), with the majority located in the rectosigmoid area. The complications of colorectal stenting include migration, reobstruction, perforation, bleeding, pain, stent fracture, and inadequate expansion of the stent. The overall complication rate has been reported to range from 14% to 42% (14 –17). However, in our
study, clinically relevant complications like perforation were not noted except for in one case of migration, which occurred at 2 weeks after stent insertion, and in one case of incomplete expansion of the stent (n ⫽ 2, 1.8%, 2 of 110). No other procedural or delayed complications were noted. Our average complication rate was quite low compared with rates in previous reports; this can be explained by our technical expertise in placing uncovered stents under radiologic control. Lee et al (4) reported that uncovered and covered stents are similarly effective treatment modalities for malignant colorectal obstruction for preoperative purposes. In addition they postulated that there are no advantages to using covered stents over uncovered stents during the follow-up period in palliative cases, which is in agreement with our results. Kim et al (19) compared the patency period between the uncovered stent and covered stent groups in the palliative group, and the median periods of pa-
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tency of the uncovered stents and covered stents were 68 and 81 days, respectively. The difference between the groups was not statistically significant. In our study, we used two types of commercially manufactured selfexpandable nitinol uncovered stents with a diameter of 22 mm and a length of 60 –160 mm in the palliative group, with a patency rate of 89.7% at 1 month, 85.6% at 3 months, 80.8% at 6 months, and 72.7% at 12 months. Considering limited life expectancies of receiving patients and the luminal diameter of the average colon, an uncovered stent with a diameter of 22 mm is sufficient to keep the lumen patent. Uncovered stents have an advantage over covered stents in the palliative treatment of malignant colorectal obstructions, or at least there is no significant difference between the two types of stents, because uncovered stents have relatively high patency rates and also provide long-term stability by preventing migration. This study has several limitations. First, there is a potential for recall bias caused by our retrospective study design. Second, the differentiation between the preoperative group and palliative group is controversial and necessarily subjective. Third, patient selection was incompletely randomized, and there might have been selection bias. Among 116 stent attempts, 15 cases involved lesions proximal to the descending colon, which is a very small percentage. This can be explained by the low emergency surgery risk with proximal colon cancer because of the larger caliber of the proximal colon. One of the other reasons could be the small number of referrals for placing stents in proximal colonic obstructions. Generally, clinicians are well aware of the fact that with rightside colon cancer, it is difficult to deploy the stent without endoscopic assistance, and even with the assistance of the endoscope, there is some chance of failure. So clinicians typically do not even refer to the interventional department for stent insertion in cases of proximal colonic obstruction. A prospective randomized study is needed to overcome the limitations of our study, and further studies are needed to corroborate the results presented here to establish the specific clinical indications for uncovered stent insertion and to standardize the radio-
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logic colorectal stent placement techniques. In conclusion, the purpose of uncovered metallic expandable stent placement in the treatment of malignant colorectal obstruction is to avoid more invasive surgical treatments and to provide an enhanced quality of life by relieving symptoms, especially, in cases in which radical surgery is unsuitable because of the patient’s age or the presence of remote metastasis. The accurate and stable placement of an uncovered stent accomplishes these goals, and we recommend this technically easy and well-tolerated procedure for treatment of malignant colorectal obstructions, especially for the left-sided colon. References 1. Dohmoto M. New method: endoscopic implantation of rectal stent in palliative treatment of malignant stenosis. Endoscopia Digestiva 1991; 3: 1507–1512. 2. Dauphine CE, Tan P, Beart RW Jr, Vukasin P, Cohen H, Corman ML. Placement of self-expanding metal stents for acute malignant large-bowel obstruction: a collective review. Ann Surg Oncol 2002; 9:574 –579. 3. Song HY, Kim JH, Shin JH et al. A dual-design expandable colorectal stent for malignant colorectal obstruction: results of a multicenter study. Endoscopy 2007; 39:448 – 454. 4. Lee KM, Shin SJ, Hwang JC, et al. Comparison of uncovered stent with covered stent for treatment of malig-
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5.
6.
7.
8.
9.
10.
11.
12.
nant colorectal obstruction. Gastrointest Endosc 2007; 66:931–936. Choi JS, Choo SW, Park KB, et al. Interventional management of malignant colorectal obstruction: use of covered and uncovered stents. Korean J Radiol 2007; 8:57– 63. Miyayama S, Matsui O, Kifune K, et al. Malignant colonic obstruction due to extrinsic tumor: palliative treatment with a self-expanding nitinol stent. AJR Am J Roentgenol 2000; 175:1631–1637. 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. Shin SJ, Kim TI, Kim BC, Lee YC, Song SY, Kim WH. Clinical application of self-expandable metallic stent for treatment of colorectal obstruction caused by extrinsic invasive tumors. Dis Colon Rectum 2008; 51:578 –583. Sacks D, McClenny TE, Cardella JF, et al. Society of Interventional Radiology clinical practice guidelines. J Vasc Interv Radiol 2003; 14:S199 –S202. Tominaga K, Yoshida M, Maetani I, Sakai Y. Expandable metal stent placement in the treatment of a malignant anastomotic stricture of the transverse colon. Gastrointest Endosc 2001; 53: 524 –527. 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. Maetani I, Tada T, Ukita T, et al. Self-expandable metallic stent placement as palliative treatment of obstructed
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14.
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18.
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colorectal carcinoma. J Gastroenterol 2004; 39:334 –338. Elsberger B, Rourke K, Brush J, Glancy S, Collie M. Self-expanding metallic stent insertion in the proximal colon. Colorectal Dis 2008; 10:194 –196. 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. Camúñez F, Echenagusia A, Simó G, Turégano F, Vázquez 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. Choo IW, Do YS, Suh SW, et al. Malignant colorectal obstruction: treatment with a flexible covered stent. Radiology 1998; 206:415– 421. 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. Watt AM, Faragher IG, Griffin TT, et al. Self-expanding metallic stents for relieving malignant colorectal obstruction: a systemic review. Ann Surg 2007; 246:24 –30. Kim H, Kim SH, Choi SY, et al. Fluoroscopically guided placement of self-expandable metallic stents and stent-grafts in the treatment of acute malignant colorectal obstruction. J Vasc Interv Radiol 2008; 19:1709 – 1716.
PURPOSE: To evaluate the effectiveness of radiologic placement of uncovered stents for the treatment of malignant colorectal obstruction. MATERIALS AND METHODS: From May 2003 to January 2008, 116 radiologic placements of uncovered stents were attempted in 99 patients (M:F, 59:40; mean age, 65 years) with malignant colorectal obstructions. The location of stent insertion, technical and clinical success, complication rates, and patency rates of the stents in a palliative group were also evaluated. In the palliative group, the follow-up period was 2– 455 days (mean, 100 ⴞ 129 days). RESULTS: Radiologic stent placement was technically successful in 110 of 116 cases (94.8%). Fifty cases of stent placement were preoperative (45.5%, 50 of 110) and 60 (54.5%, 60 of 110) were performed with palliative intents. In five of six failed cases, the replacement of the stent was later performed with the assistance of colonoscopy. One patient underwent an emergency operation. In 98 of 110 cases, the symptoms of obstruction were relieved, for a clinical success rate of 89.1%. Of the 50 stents that were placed successfully with preoperative intent, 44 patients underwent surgery within a mean of 10.3 days. In the palliative group, the patency rates were 89.7% at 1 month, 85.6% at 3 months, 80.8% at 6 months, and 72.7% at 12 months. CONCLUSIONS: The radiologic placement of uncovered stents for the treatment of malignant colorectal obstruction is feasible and safe and provides acceptable clinical results not only for preoperative decompression but also for palliative cases, especially in left-sided colonic obstructions. J Vasc Interv Radiol 2010; 21:1244 –1249
THE placement of stents for the treatment of malignant colorectal obstruction was first described by Dohmoto in 1991 (1). Since then, various covered and uncovered metallic stents have been placed by endoscopic or fluoro-
From the Department of Radiology, Kyung Hee University Medical Center, 1, Heoki-dong Dongdaemun-gu, Seoul 130-702, Korea. Received August 26, 2008; final revision received February 15, 2010; accepted April 3, 2010. Address correspondence to J.H.O.; E-mail: [email protected] S.Y.K. and S.H.K. contributed equally to this study. This Research was supported by the Program of Kyung Hee University for the Young Researcher in Medical Science (KHU-20091436). None of the authors have identified a conflict of interest © SIR, 2010 DOI: 10.1016/j.jvir.2010.04.009
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scopic approaches in more than 700 cases (2–5). Many reports have established the effectiveness of colorectal stent insertion for treatment in preoperative cases as well as in palliative cases, and the insertion of a stent is considered a reliable treatment for malignant colorectal obstruction (2–5). Previous studies have found that covered stents are more resistant to tumor ingrowth but have the disadvantages of stent migration and are more difficult to deliver to stricture sites because of their rigidity. On the other hand, uncovered stents are more flexible and easily applicable but are associated with the tendency for reobstruction because of tumor ingrowth. For these reasons, uncovered stents are thought to be more suitable for palliation (3,5– 8). However, to date, the majority of reported studies
have been based on a relatively small number of cases. In addition, few instances of this type of treatment using uncovered stents alone have been reported, and the long-term results have not been assessed sufficiently. In this study, we review our experience with a series of uncovered stent placements under radiologic control alone to evaluate the efficacy of uncovered stents in treatment of colorectal obstruction for preoperative and palliative purposes.
MATERIALS AND METHODS The medical records of patients who underwent colorectal stenting between May 2003 and January 2008 were reviewed retrospectively, and their clinical outcomes were evaluated. The inclusion criteria were as follows: (a) documented malignancy, (b)
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Table 1 Patient Demographics Palliative Intent (n ⫽ 47)
Preop. Intent (n ⫽ 52) n Sex Male Female Age, mean (range), year
%
n
31 59.6 21 40.4 66 (28–99)
symptoms and signs of colorectal obstruction, and (c) uncovered stent placement. In this study, there were 116 attempts at radiologic placement of a stent in 99 patients (M:F ⫽ 59:40; mean age, 65 years; range, 28 –99 years) (Table 1). Informed consent was obtained from all patients involved, and the study was approved by our hospital institutional review board. This report was written in accordance with Society of Interventional Radiology (SIR) reporting standard (9). The patients received diagnoses and were classified with imaging and colonoscopy before the stent placement procedure. Indications for the use of a self-expandable metallic stent in colorectal obstruction were (a) preoperative intent when used for relief of colonic obstruction and bowel preparation that allows subsequent elective operation and (b) palliative intent in patients with colorectal malignancy where resection is not feasible to cure the patient, either because of metastatic disease or significant medical comorbidities. Patients who had bowel necrosis, perforation, cancer extending to ⬍ 5 cm from the anal verge, or cancer located near the ileocecal valve were excluded from stent placement. The procedure was performed under fluoroscopic guidance alone, and an uncovered stent was used in all patients. All patients received a cleansing enema a few hours before the procedure. Neither analgesia nor sedation was administered during the procedure, and prophylactic antibiotics were not used. The visualization of the length and the proximal and distal ends of the stricture was achieved by injecting intraluminal water-soluble contrast media. When the opening of the stricture was visible, a 150-cm-
%
29 61.7 18 38.3 63 (36–89)
Total (n ⫽ 99) n
%
60 60.6 39 39.4 65 (28–99)
long, 0.038-inch hydrophilic guide wire (Radifocus M; Terumo, Japan) was advanced through the stricture. Once the guide wire was passed through the lesion, a 5-F angiographic catheter was advanced to the most proximal point, and contrast media was injected to evaluate the tumor length. The 0.035-inch Amplatz superstiff guide wire (Boston Scientific, Massachusetts) was then inserted, and a stent was placed using the delivery system. Balloon dilation was not used. Contrast medium was injected to ensure that the stent was placed properly across the tumor and to assess the stent patency (Fig 1). There was no routine administration of antibiotics. We used two commercially manufactured self-expandable nitinol stents (Hanaro, Solco Intermed, Seoul, Korea and EGIS, S & G Biotech, Seongnam, Korea), 22 mm in diameter and 60, 80, 100, 120, 140, or 160 mm in length. Depending on the availability of stents, the type and length of the stricture and the possibility of tortuous bowel segments below or above different stents were used during the study period. A stent at least 40 mm longer than the stricture was chosen so that the stricture was fully covered. When one stent was not long enough to cover the lesion, a second stent was inserted to overlap the first. We used at least 20 mm overlap between the two stents. An abdominal radiograph was taken during hospitalization 1 to 3 days after placement to confirm the correct deployment and expansion. Patients with palliative stent insertion underwent clinical follow-up and abdominal radiographs every 4 to 8 weeks. Computed tomography examination or an endoscopic procedure was performed if there was persis-
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tence or reappearance of symptoms such as abdominal pain, constipation, or rectal bleeding. In the palliative group, the follow-up period was 2– 455 days (mean, 100 ⫾ 129 days). The technical and clinical success, complication rates, and patency rates for the stents in the palliative group were evaluated via radiologic and clinical examination. Technical success was defined as the deployment of the stent under fluoroscopic guidance alone. Clinical success was defined as the relief of symptoms or signs within 48 hours after stent deployment. Patency rates were determined based on combination of physical and imaging findings at 1, 3, 6, and 12 months. The Kaplan-Meier method (DBSTAT Version 4.1, DBSTAT Co., Chunchon, Korea:) was used to estimate the patency rates of the stent in the palliative group.
RESULTS In total, 116 cases of radiologic stent placement were attempted in 99 patients with malignant colorectal obstructions. The technical success rates for stent insertion are shown in Table 2. Of 116 cases, 110 were technically successful, giving an overall technical success rate of 94.8%. Stent placement was successful under fluoroscopic guidance alone in 50 of 53 cases in the preoperative group and in 60 cases of 63 cases in the palliative group, with technical success rates of 94.3% and 95.2%, respectively. In four of six failed cases, the tumor was located in the ascending colon, and in the remaining two failed cases, the tumor was located in the sigmoid colon. In five of six failed cases, stent placement failed under fluoroscopic guidance because of the redundancy of the colon, and in these cases, the placement of the stent was later performed with the assistance of a colonoscope (Fig 2). In the remaining patient, the stent could not pass the obstructive segment after the stiff guide wire had crossed the obstruction. The patient had complete colonic obstruction from cancer with severe abdominal pain. An emergency loop ileostomy was performed on this patient. Four months later, the patient had low anterior resection and an ileostomy takedown operation with chemotherapy before and after the operation.
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Figure 1. An 83-year-old woman with sigmoid colon cancer. (a) Supine plain abdominal radiograph shows dilated bowel loops, suggesting obstruction of the colon. (b) Abdominal CT shows the tumor involves the sigmoid colon (arrows). (c) Under fluoroscopic guidance, an uncovered stent was implanted at the obstructed portion (arrows). (d) Plain abdominal radiograph after 1 week shows further self-expansion and good positioning of the stent (arrows). The dilation of the colonic loops markedly improved after successful placement of the uncovered stent.
Table 2 Technical Success Rate for the Radiologic Placement of an Uncovered Stent Palliative Intent (n ⫽ 63)
Preop. Intent (n ⫽ 53)
Technical success* Technical failure
Total (n ⫽ 116)
n
%
n
%
n
%
50 3
94.3 5.7
60 3
95.2 4.8
110 6
94.8 5.2
Note.—Total n ⫽ total attempts of radiologic placement of uncovered stent. * Based on the number of successfully inserted stents under only fluoroscopic guidance.
Among the technically successful cases, the locations of the malignant obstructions were in the ascending colon (n ⫽ 1, 0.9%) (Fig 3), transverse colon (n ⫽ 10, 9.1%), descending colon (n ⫽ 20, 18.2%), sigmoid colon (n ⫽ 55, 50.0%) and rectum (n ⫽ 24, 21.8%) (Table 3). In 98 of 110 cases, the symptoms of colonic obstruction were relieved, giving a clinical success rate of 89.1% (98 of 110) (Table 4). The clinical success rate was 96.0% (48 of 50) for the preoperative group and 83.3% (50 of 60) for the palliative group. Fifty cases of stent placement were performed successfully with preoperative intent (45.5%, 50 of 110), and of these, 44 patients underwent surgery within a mean of 10.3 days. Sixty cases of stent placement were done with palliative intent (54.5 %, 60 of 110). In the palliative group, the patency rates were 89.7% at 1 month, 85.6% at 3 months, 80.8% at 6 months and 72.7% at 12 months (Fig 4).
There were no procedure-related major complications such as major bleeding or colon perforation. Stentrelated complications were noted in two patients. The stent migration that was seen in one patient (n ⫽ 1, 0.9%, 1 of 110) developed within 2 weeks. Incomplete expansion of the stent was noted in one case (n ⫽ 1, 0.9%, 1 of 110), in which the cancer was located at the rectum. Other minor complications, such as abdominal or anal pain (n ⫽ 33, 30.0%, 33 of 110), tenesmus (n ⫽ 17, 15.4%, 17 of 110), and transient bleeding (n ⫽ 13, 11.8%, 13 of 110) was improved with conservative management. No other procedural or delayed complications were noted.
DISCUSSION Recent trends in the treatment of malignant colorectal obstructions indicate that the placement of metallic expandable stents is the preferred method, either for efficient preopera-
tive decompression or for palliation in unresectable malignancy, as a minimally invasive and low-risk alternative to emergent surgery with a high success rate (2–5). To obtain better results, various types of self-expandable nitinol stents, including covered or uncovered metallic stents with endoscopic or fluoroscopic guidance, have been tried, and their advantages and disadvantages are well known (3,5– 8). Generally, a covered stent is more resistant to tumor ingrowth that results in a longer stent patency, but the disadvantages include stent migration and rigidity. On the other hand, an uncovered stent is flexible and easily applicable, but tumor ingrowth into the stent and resultant obstruction is more frequent. Therefore, uncovered stents are preferred in preoperative cases as a bridge to surgery because of the shorter stent patency from tumor ingrowth (10 –11). However, it is also noteworthy that coverage did not have a clinically meaningful influence in the patients treated for palliative relief. That is, the functional patency was not significantly different between uncovered and covered stents, and the advantage of the uncovered stent, namely the prevention of migration, exceeds its disadvantage of tumor ingrowth (4). We reviewed our experience with uncovered metallic stent insertions under fluoroscopic guidance alone. This study had a larger number of cases (n ⫽ 110) compared with the smaller sample size of about 50 or less from previous studies involving a colorectal stent (18). This study evalu-
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Figure 2. An 81-year-old man with distal ascending colon cancer. (a) Palliative uncovered colonic stent placement was attempted under fluoroscopic guidance. However, the guide wire could not reach the obstruction point because of the severely redundant and tortuous colonic contour. (b) With the assistance of endoscopy, an uncovered stent was placed at the obstruction site. (c) Plain abdominal radiograph 4 months after stent placement shows the stent is adequately positioned with full expansion (arrows). (Available in color online at www.jvir.org.)
Figure 3. An 83-year-old man with distal ascending colon cancer. (a) Initial abdominal CT shows distal ascending colon cancer (arrows). (b,c) An uncovered stent was deployed successfully to the distal ascending colon (arrows) under fluoroscopic guidance without the help of an endoscope. (d) Plain abdominal radiograph 10 months after stent placement shows the stent is adequately positioned with full expansion (arrows).
Table 3 Distribution of Different Tumor Locations in Technically Successful Cases Preop. Intent (n ⫽ 50)
Location of obstruction Ascending colon Transverse colon Descending colon Sigmoid colon Rectum
Palliative Intent (n ⫽ 60)
Total (n ⫽ 110)
n
%
n
%
n
%
0 4 9 28 9
0 8 18 56 18
1 6 11 27 15
1.7 10.0 18.3 45 25
1 10 20 55 24
0.9 9.1 18.2 50.0 21.8
Note.—Total n ⫽ Total number of technically successful cases.
ated the efficacy of using uncovered stents for colorectal obstruction as bridge to surgery in 50 cases and as palliation in 60 cases. The technical success rate in our series was 94.8% (110 of 116 cases), which corresponds well with the success rates (80%–100%) from earlier studies on the feasibility of this technique (4–5,12). In 98 of 110 cases, the symptoms of colonic obstruction were relieved, giving a clinical success rate of 89.1%. This result is also comparable with the clinical success rates of other studies, which range between 80% and 100% (4–5,12). It is known that lesions proximal to the descending colon are hard to ac-
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Table 4 Clinical Success Rate for Uncovered Stent Insertion in Technically Successful Cases Preop. Intent (n ⫽ 50)
Clinical success* Clinical failure
Palliative Intent (n ⫽ 60)
Total (n ⫽ 110)
n
%
n
%
n
%
48 2
96.0 4.0
50 10
83.3 16.7
98 12
89.1 10.9
Note.—Total n ⫽ Total number of technically successful cases. * Relief of symptom/sign in the first 48 hours.
Figure 4.
Stent patency in the palliative group after stent insertion.
cess because it is technically difficult to deploy the stent using fluoroscopic guidance in the proximal colon, and in some cases, the length of the guide wire is not long enough to reach the obstruction site. Stent placement in these lesions has only been reported in a few cases (13). We were only able to insert 11 stents successfully into lesions proximal to the descending colon (10%, 11 of 110), one in the ascending colon and 10 in the transverse colon. One stent insertion in the ascending colon was technically successful because the patient had a relatively short length of bowel compared with the average. The rest of the insertion sites were descending (n ⫽ 20, 18.2%), sigmoid colon (n ⫽ 55, 50.0%), and rectum (n ⫽ 24, 21.8%), with the majority located in the rectosigmoid area. The complications of colorectal stenting include migration, reobstruction, perforation, bleeding, pain, stent fracture, and inadequate expansion of the stent. The overall complication rate has been reported to range from 14% to 42% (14 –17). However, in our
study, clinically relevant complications like perforation were not noted except for in one case of migration, which occurred at 2 weeks after stent insertion, and in one case of incomplete expansion of the stent (n ⫽ 2, 1.8%, 2 of 110). No other procedural or delayed complications were noted. Our average complication rate was quite low compared with rates in previous reports; this can be explained by our technical expertise in placing uncovered stents under radiologic control. Lee et al (4) reported that uncovered and covered stents are similarly effective treatment modalities for malignant colorectal obstruction for preoperative purposes. In addition they postulated that there are no advantages to using covered stents over uncovered stents during the follow-up period in palliative cases, which is in agreement with our results. Kim et al (19) compared the patency period between the uncovered stent and covered stent groups in the palliative group, and the median periods of pa-
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tency of the uncovered stents and covered stents were 68 and 81 days, respectively. The difference between the groups was not statistically significant. In our study, we used two types of commercially manufactured selfexpandable nitinol uncovered stents with a diameter of 22 mm and a length of 60 –160 mm in the palliative group, with a patency rate of 89.7% at 1 month, 85.6% at 3 months, 80.8% at 6 months, and 72.7% at 12 months. Considering limited life expectancies of receiving patients and the luminal diameter of the average colon, an uncovered stent with a diameter of 22 mm is sufficient to keep the lumen patent. Uncovered stents have an advantage over covered stents in the palliative treatment of malignant colorectal obstructions, or at least there is no significant difference between the two types of stents, because uncovered stents have relatively high patency rates and also provide long-term stability by preventing migration. This study has several limitations. First, there is a potential for recall bias caused by our retrospective study design. Second, the differentiation between the preoperative group and palliative group is controversial and necessarily subjective. Third, patient selection was incompletely randomized, and there might have been selection bias. Among 116 stent attempts, 15 cases involved lesions proximal to the descending colon, which is a very small percentage. This can be explained by the low emergency surgery risk with proximal colon cancer because of the larger caliber of the proximal colon. One of the other reasons could be the small number of referrals for placing stents in proximal colonic obstructions. Generally, clinicians are well aware of the fact that with rightside colon cancer, it is difficult to deploy the stent without endoscopic assistance, and even with the assistance of the endoscope, there is some chance of failure. So clinicians typically do not even refer to the interventional department for stent insertion in cases of proximal colonic obstruction. A prospective randomized study is needed to overcome the limitations of our study, and further studies are needed to corroborate the results presented here to establish the specific clinical indications for uncovered stent insertion and to standardize the radio-
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logic colorectal stent placement techniques. In conclusion, the purpose of uncovered metallic expandable stent placement in the treatment of malignant colorectal obstruction is to avoid more invasive surgical treatments and to provide an enhanced quality of life by relieving symptoms, especially, in cases in which radical surgery is unsuitable because of the patient’s age or the presence of remote metastasis. The accurate and stable placement of an uncovered stent accomplishes these goals, and we recommend this technically easy and well-tolerated procedure for treatment of malignant colorectal obstructions, especially for the left-sided colon. References 1. Dohmoto M. New method: endoscopic implantation of rectal stent in palliative treatment of malignant stenosis. Endoscopia Digestiva 1991; 3: 1507–1512. 2. Dauphine CE, Tan P, Beart RW Jr, Vukasin P, Cohen H, Corman ML. Placement of self-expanding metal stents for acute malignant large-bowel obstruction: a collective review. Ann Surg Oncol 2002; 9:574 –579. 3. Song HY, Kim JH, Shin JH et al. A dual-design expandable colorectal stent for malignant colorectal obstruction: results of a multicenter study. Endoscopy 2007; 39:448 – 454. 4. Lee KM, Shin SJ, Hwang JC, et al. Comparison of uncovered stent with covered stent for treatment of malig-
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colorectal carcinoma. J Gastroenterol 2004; 39:334 –338. Elsberger B, Rourke K, Brush J, Glancy S, Collie M. Self-expanding metallic stent insertion in the proximal colon. Colorectal Dis 2008; 10:194 –196. 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. Camúñez F, Echenagusia A, Simó G, Turégano F, Vázquez 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. Choo IW, Do YS, Suh SW, et al. Malignant colorectal obstruction: treatment with a flexible covered stent. Radiology 1998; 206:415– 421. 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. Watt AM, Faragher IG, Griffin TT, et al. Self-expanding metallic stents for relieving malignant colorectal obstruction: a systemic review. Ann Surg 2007; 246:24 –30. Kim H, Kim SH, Choi SY, et al. Fluoroscopically guided placement of self-expandable metallic stents and stent-grafts in the treatment of acute malignant colorectal obstruction. J Vasc Interv Radiol 2008; 19:1709 – 1716.