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WallFlex colonic stent placement for management of malignant colonic obstruction: a prospective study at two centers
ORIGINAL ARTICLE: Clinical Endoscopy
WallFlex colonic stent placement for management of malignant colonic obstruction: a prospective study at two centers Alessandro Repici, MD, Giuseppe De Caro, MD, Carmelo Luigiano, MD, Carlo Fabbri, MD, Nico Pagano, MD, Paoletta Preatoni, MD, Silvio Danese, MD, Lorenzo Fucci, MD, Pierluigi Consolo, MD, Alberto Malesci, MD, Nicola D’Imperio, MD, Vincenzo Cennamo, MD Milano, Bologna, Italy
Background: Self-expanding metal stents (SEMSs) can alleviate malignant colonic obstruction and avoid emergency decompressive surgery. The use of colonic larger-diameter SEMSs may improve bowel function and reduce migration risk. Objective: To evaluate the effectiveness and safety of a novel large-diameter SEMS (WallFlex) designed for delivery through the endoscope in treating malignant colonic obstruction. Design: Prospective clinical cohort study. Setting: Two Italian study centers. Patients: Forty-two consecutive patients with malignant colonic obstruction: 23 requiring palliation and 19 bridging to surgery. Interventions: Colorectal SEMS placement. Main Outcome Measurements: Technical success, defined as accurate SEMS deployment across the stricture on the first attempt; clinical success, ie, complete relief of bowel obstruction without complications; and bridging to surgery, denoting the performance of elective one-stage surgery. Results: The rate of technical success was 93% (95% CI, 81%-99%) and of initial clinical success was 95% (95% CI, 84%-99%). In 58% (95% CI, 40%-84%) of the palliation group, clinical success was maintained after 6 months. All 19 patients with operable tumors were successfully bridged to one-stage elective surgery within a median of 5 days. One perforation and one stent migration occurred. All complications could be resolved nonsurgically. Limitations: No control group was included. Conclusions: In a prospective study of through-the-scope WallFlex stent placement for malignant colonic obstruction, high rates of technical and initial clinical success, and bridging to surgery were achieved. Complications could be readily managed. (Gastrointest Endosc 2008;67:77-84.)
Primary or recurrent adenocarcinoma, pelvic malignancies, and metastatic diseases can lead to the development of malignant colorectal strictures. Acute complete or partial obstruction occurs in 8% to 29% of patients with colorectal cancer.1 Although colorectal obstruction needs to be relieved as quickly as possible, patients with acute or chronic large-bowel obstruction are challenging to manage because they are often in poor general health; present with a painful, distended abdomen and with dehydration; Abbreviations: SEMS, self-expanding metal stent; TTS, through the scope. Copyright ª 2008 by the American Society for Gastrointestinal Endoscopy 0016-5107/$32.00 doi:10.1016/j.gie.2007.08.019
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and face relatively high risks as surgical candidates. The dilated bowel wall proximal to the obstruction is often friable, which complicates emergency surgical interventions.2 Self-expanding metallic stents (SEMSs) were developed as a minimally invasive modality for rapid decompression of colonic occlusion. Since the first report on the use of SEMSs for palliation in colorectal cancer in 1991,3 a growing number of reports and reviews have demonstrated the effectiveness of SEMSs for both palliation in patients with advanced, nonresectable carcinoma and as a bridge to surgery in those patients with resectable disease.4-7 A high success rate has been reported in accurate stent deployment and clinical relief of obstruction, with a low rate of morbidity and mortality. The SEMS placement procedure, typically Volume 67, No. 1 : 2008 GASTROINTESTINAL ENDOSCOPY 77
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performed with the patient under conscious sedation, entails less-acute debilitation, more rapid recovery, and a shorter hospital stay compared with surgical alternatives.8-11 According to a decision model of colonic-stent placement versus emergency surgery for obstructing cancer of the left side of the colon, preoperative colonic SEMS placement would decrease operative procedures by an estimated 23% and reduce the need for a stoma from 43% to 7%.12 Complications of SEMS placement include perforation and migration. In some cases, accurate SEMS positioning may be hampered by inadequate fluoroscopic visualization. Initially, the stents used for relief of a colorectal obstruction were designed for esophageal or tracheobronchial indications, and their internal diameters were smaller than would be ideal for colorectal strictures. A number of dedicated colonic stents and delivery systems have now been introduced. The attributes of the ideal stent have been described as compatibility with a smalldiameter delivery system, which allows passage through the endoscope, high flexibility, and strong expansile force.6 In addition, a large internal stent diameter is a desirable property for colonic stenting, to minimize the likelihood of stool impaction or other stent occlusion and to decrease the likelihood of stent migration. Among the advantages of endoscopic colorectal stent placement, compared with radiologic techniques, are greater accessibility to obstructions proximal to the sigmoid colon and better control of stent delivery in patients with extremely angulated strictures.13 The endoscope provides better fixation of the sigmoid colon than a guidewire alone, which can be very valuable in patients with a twisted sigmoid colon.6 Endoscopic placement also allows biopsy specimens to be collected and facilitates the passage of the guidewire through the stenosis.14 The most frequently used through-the-scope (TTS) colorectal stent to date is the enteral Wallstent (Microvasive Endoscopy, Boston Scientific Corp, Natick, Mass), with an 18-mm to 22-mm internal diameter. Larger internal diameter colorectal stents have been placed over a guidewire.15,16 A newly developed noncovered nitinol stent, the WallFlex colonic stent (Microvasive), with either a 22-mm or 25-mm mid diameter is suitable for placement through the endoscope, because of its narrow-profile delivery system. The present study evaluated the effectiveness and safety of this new nitinol stent in patients with malignant colonic obstruction that requires either palliation or bridging to surgery.
PATIENTS AND METHODS Patients This prospective study was conducted at two Italian centers between May 2004 and January 2007. Approval of the study protocol was granted by the institutional 78 GASTROINTESTINAL ENDOSCOPY Volume 67, No. 1 : 2008
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Capsule Summary What is already known on this topic d
Emergency surgery for malignant colonic obstruction can be avoided by placement of self-expanding, large-diameter stents, which improve bowel function and reduce the likelihood of migration.
What this study adds to our knowledge d
d
In a prospective study of 42 patients with malignant colonic obstruction, large-diameter stents placed by through-the-scope procedures had a 93% rate of technical success and 95% rate of initial clinical success, with only one perforation and one stent migration. All operable tumors were successfully bridged to one-stage elective surgery.
ethics committees of the participating centers, and all patients rendered their informed consent in writing. Eligibility was predicated on the presence of largebowel obstruction secondary to malignancy as confirmed by erect and supine abdominal radiograph imaging and CT. Consecutive patients of age R18 years old who required stents for palliation or a bridge to surgery were enrolled. Exclusion criteria were composed of the following: benign stricture, perforated colon, concurrent radiotherapy for the colorectal stricture, treatment with an investigational drug or device within the preceding 4 weeks, placement of another metal stent for the same stricture, and a terminal condition. The assignment of patients to palliation rather than surgery was based on an unacceptable surgical risk because of advanced age or comorbidities or because of the presence of locally advanced disease or distant metastases.
Patient assessments Baseline assessment encompassed patient demographics and medical history, the type of malignancy, the stricture location, and the degree of occlusion. Patients were assessed at the time of SEMS placement and, in those patients who received stents for palliation, at follow-up evaluations approximately 1 month after stent placement. Additional observation of the palliation group was conducted every 3 months by telephone and communications with the primary care physicians of the patients. The follow-up of patients with resectable disease continued until elective surgery and periodically thereafter to document postoperative complications. For all patients, obstructivebowel symptoms, any therapeutic interventions, and the occurrence of adverse events were recorded at each follow-up evaluation. Obstructive-bowel symptoms were defined as the inability to pass flatus or stool through the anus for more than 24 hours, in conjunction with bowel distension and radiographic evidence of ileus. Observation www.giejournal.org
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extension 1 to 2 cm beyond both stricture margins. The selected SEMSs were then deployed through the endoscope. At the end of the procedure, contrast material was injected through the endoscope to rule out the occurrence of a perforation (Fig. 2A to C). Patients attaining clinical relief of obstruction were allowed to resume an oral diet after 2 days.
Outcomes The primary study outcome measures were technical and clinical success and bridging to surgery. The definition of technical success was accurate SEMS deployment across the stricture on the first attempt. Clinical success was defined as complete relief of a bowel obstruction as judged by clinical symptoms and radiographic observations, without the occurrence of complications. Initial clinical success was evaluated in all patients. In the group that received stents for palliation, maintenance of clinical success continued to be assessed until death or the last follow-up. Bridging to surgery denoted the performance of elective one-stage surgery in SEMS recipients with resectable disease.
Statistical analysis Figure 1. WallFlex colonic stent. A, Stent mounted in deployment system. B, Fully expanded stent.
was conducted for both clinical and investigational purposes.
SEMS placement Patients received the TTS WallFlex colonic stent with either a 22-mm or 25-mm stent body and 27-mm or 30-mm proximal flare, respectively (Fig. 1). Available lengths of this SEMS are 6, 9, and 12 cm, and working lengths of the delivery system are either 135 or 230 cm. These indicated SEMS lengths correspond to the fully expanded state. The SEMSs undergo partial foreshortening during deployment, which the endoscopist must take into account during positioning.17 The delivery system is designed to permit recapture and repositioning of the stent until deployment is up to 70% complete. Prophylactic antibiotics were not administered before stent placement. Sedation was accomplished through use of midazolam in 40 patients and propofol in two. SEMS placement was performed under both endoscopic and fluoroscopic guidance, as previously described.15,16 Briefly, a guidewire and a standard ERCP catheter were introduced to cannulate the stricture; the guidewire was then withdrawn, and contrast material was injected to delineate the location, length, and anatomy of the stricture. A 0.035-inch super-stiff guidewire was then inserted, and the catheter was withdrawn. SEMSs were selected of a length sufficient to cover the entire stricture, with an www.giejournal.org
Continuous data distributions were characterized by the median and interquartile range. The percentages of patients with technical and initial clinical success were calculated with exact binomial 95% CI. Time to clinical failure and death in recipients of SEMSs for palliation and to elective surgery in the bridge-to-surgery group were estimated by the Kaplan-Meier product limit method. Differences in times to event related to baseline characteristics were evaluated by two-sided exact log-rank test. Data were analyzed by using R version 2.5.0 (The R Foundation for Statistical Computing, Vienna, Austria), StatXact 7.0 (Cytel Software Corp, Cambridge, Mass) and SPSS 11.5 (SPSS Inc, Chicago, Ill) statistical software.
RESULTS Forty-two consecutive patients were enrolled in the study. Baseline data for these patients are summarized in Table 1. Nearly two thirds of the patients (64%) were 70 years of age or older. The strictures in 35 of 42 patients (83%) were situated distal to the splenic flexure.
Technical success SEMSs were placed with palliative intent in 23 patients and as a bridge to surgery in 19 (Table 2). Thirty-six patients received a single SEMS. Two SEMSs each were placed in 6 patients, of whom 5 required a second stent because of long strictures and in one patient because of malpositioning of the first stent, as detailed below. No patient underwent balloon dilation, either before or after stent placement. Volume 67, No. 1 : 2008 GASTROINTESTINAL ENDOSCOPY 79
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TABLE 1. Baseline patient data (n Z 42) Characteristic
N
%
50-59
6
14
60-69
9
21
70-79
15
36
R80
12
29
Women
18
43
Men
24
57
Bologna, Italy
16
38
Milan, Italy
26
62
Colonic adenocarcinoma
41
98
Gastric adenocarcinoma infiltrating hepatic flexure
1
2
13
31
Descending colon
9
21
Rectum
7
17
Rectosigmoid junction
6
14
Splenic flexure
3
7
Hepatic flexure
2
5
Transverse colon
2
5
Complete
31
74
Subtotal
11
26
Age (y)*
Sex
Patients per center
Malignancy
Stricture location Sigmoid
Occlusive syndrome
*Mean 72 y.
Figure 2. A to C, Radiographic views of stent placement.
Spanning of the strictures by accurate SEMSs placement was accomplished in 39 of 42 patients; thus, the rate of technical success was 93%, 95% CI, 81%-99%. The SEMSs could not be passed through a hepatic flexure stricture in one patient, who then proceeded to palliative surgery. 80 GASTROINTESTINAL ENDOSCOPY Volume 67, No. 1 : 2008
In another patient, a stent failed to expand after placement within a severe angulation of the rectosigmoid junction, which was compressed by a large neoplastic mass. The third technical failure was because of malpositioning of the stent proximal to the stricture. With the guidewire remaining in situ, a second overlapping SEMSs was placed forthwith during the same procedure, and, on this second attempt, spanning of the stricture succeeded.
Clinical success The proportion of patients with prompt decompression and relief of obstructive symptoms was 40 of 42, corresponding to a 95% initial clinical success rate, 95% CI, 84%-99%. In the cases with clinical success, the relief of www.giejournal.org
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symptoms was apparent within 24 hours of stent placement. The two initial clinical failures were the result of technical failure in stent placement. As described above, a third patient’s stent placement was declared a technical failure because of stent malpositioning, but a second stent was successfully placed and complete relief of obstruction was achieved. Consequently, that patient was considered an initial clinical success. During follow-up after SEMS placement in the group that received a SEMSs for palliation, complications resulted in 8 additional clinical failures (Table 3). The median time at risk for clinical failure in the palliative group was 99 days (range 42-212 days). At 6 months, their rate of clinical success was 58% (Fig. 3). Among these recipients of stents for palliation, no difference could be detected in maintenance of clinical success over the time between when patients presented with complete versus subtotal occlusion (P Z .12) or between those with strictures distal to the splenic flexure versus more proximal sites (P Z .80). In the palliative group, 3 complications were encountered within 30 days of stent placement. Perforation was diagnosed in an 85-year-old woman the day after stent placement. With conservative medical therapy, which consisted of nasogastric tube insertion, antibiotics, and total parenteral nutrition, the perforation spontaneously resolved, and, within several days, the patient was able to pass stool through the anus uneventfully. A SEMSs migrated distally from the rectum at 7 days in another patient, who developed tenesmus. The stent could be grasped digitally and was removed through the anus with no further clinical measures. The patient then received an over-the-wire stent (Ultraflex Precision Colonic Stent; Microvasive) and remained free of obstructive symptoms thereafter until death 3 months later. The third patient developed minor rectal bleeding after 8 days that did not necessitate a blood transfusion and resolved under medical therapy within 3 weeks. This patient was also among those who developed a late occlusion, as described below. Six patients in the palliative group were affected by late complications (O30 days). Four of these patients experienced an occlusion attributable to tumor ingrowth in two cases and tumor overgrowth and stool impaction in one case each. The stool impaction was corrected by endoscopic mechanical recanalization, and the occlusion in two patients was successfully relieved by a second stent and that of one patient by 3 sessions of argon plasma coagulation. The remaining late complications in the palliative group were two cases of tumor ingrowth with subocclusive symptoms, one managed by two sessions of argon plasma coagulation and one without procedural intervention.
Survival All patients with operable tumors survived until elective surgery and throughout postoperative follow-up. Their www.giejournal.org
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TABLE 2. SEMS placement data Parameter
No. patients
%
Palliation
23
55
Bridge to surgery
19
45
1
36
86
2
6
14
6
15
36
9
26
62
1
2
22
17
40
25
25
60
Indication for stent placement
No. stents placed per patient
Stent length (cm)
One 6 and one 9 Stent diameter (mm)
total median follow-up time after stent placement was 528 days (range 445-634 days). In the palliative group, 7 of 23 patients (30%) were still alive at the end of the follow-up period (January 2007). The median survival of the group was 208 days, 95% CI, 93-323 days. Because of censoring, the median time at risk for death (179 days, range 98-267 days) was slightly shorter. At the time of death, 7 of the 16 nonsurvivors (44%) remained clinical successes, and, for those patients, stent placement had fulfilled its palliative purpose over their entire remaining life span. No difference in survival was evident between patients with complete versus subtotal occlusion at baseline (P Z .31).
Bridging to surgery All 19 patients who received a SEMSs as a bridge to surgery proceeded to elective one-stage surgery. Thus, the rate of successful bridging to surgery was 100%, 95% CI, 85%-100%. The median time from SEMS placement to elective surgery was 5.0 days, 95% CI, 4.4-5.6 days. A single early complication occurred in the bridge-to-surgery group, namely, stent occlusion because of stool impaction two days after stent placement. The occlusion was promptly and completely alleviated by multiple passages of an endoscope through the stent and lavage, without balloon dilation, and the patient underwent elective surgery 4 days after SEMSs placement. Among all patients in the bridge-to-surgery group, stents were removed en bloc with the tumor, without any surgical complications. Two patients in the bridge-to-surgery group experienced one postoperative complication each, ie, pulmonary embolism and wound infection. The patient with Volume 67, No. 1 : 2008 GASTROINTESTINAL ENDOSCOPY 81
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Palliative Stent Placement TABLE 3. Complications Complication type
100
No.
% 80
Perforation
1
2.4
Stent occlusion
1
2.4
Stent migration
1
2.4
Rectal bleeding
1
2.4
Stent occlusion
4
9.6
Tumor ingrowth
2
4.8
Late (O30 d after stent placement)
Clinical Success (%)
Early (%30 d after stent placement)
60
40
20
Clinical Success at 6 mo = 58% (95% CI, 40-84 %)
0
Postoperative after bridging to surgery
At Risk
Pulmonary embolism
1
2.4
Wound infection
1
2.4
the pulmonary embolism was admitted to the intensive care unit and received medical therapy. After 3 weeks, the patient was discharged. The wound infection was treated with local and systemic antibiotics and resolved within 20 days. In both of these patients, the clinical course after stent placement, including preoperative bowel preparation, was otherwise uneventful, and no clear relationship between the SEMS and the postoperative complications could be discerned.
DISCUSSION In the present prospective study, placement of the newly introduced WallFlex colonic stent obviated emergency surgery in nearly all cases. The rates of technical (93%) and initial clinical success (95%) with the evaluated TTS stent were comparable with those reported in earlier studies, which ranged from percentages in the high 80s to mid 90s.5-7,18 There was no procedure-related mortality in this study, and all complications could be managed without surgical intervention. Comparative studies indicated advantages of stents versus emergency surgery.9-11,19 In a recent meta-analysis of colonic stenting versus open surgery for malignant bowel obstruction, which encompassed 10 studies with a total of 451 patients, the length of hospital stay was shorter by 7.72 days in the stent group (P!.001), which also enjoyed lower mortality (P Z.03) and fewer medical complications (P ! .001). Stoma formation at any point during management was significantly less frequent in the stent group (odds ratio 0.02; P ! .001), and bridging to surgery did not adversely influence survival. All 19 patients who received SEMS as a bridge to surgery successfully proceeded to single-stage tumor resection and primary end-to-end anastomosis. The only 82 GASTROINTESTINAL ENDOSCOPY Volume 67, No. 1 : 2008
23
19
17
14
11
11
11
11
0
30
60
90
120
150
180
210
Time after SEMS Placement (days) Figure 3. Kaplan-Meier estimated fractions with clinical success (solid line) and 95% CI (dashed line) among recipients of SEMS for palliation. Patients at risk for clinical failure enumerated above the abscissa for the indicated time points.
preoperative complication in this group was rectified by minimally invasive endoscopic intervention. After the elective resection, two patients developed complications, which were successfully treated medically. All 19 of these patients survived throughout a median follow-up period of almost 18 months. A recent case-matched study that compared stent placement with emergency resection demonstrated a higher rate of primary anastomosis as well as reduced intensive care unit and hospital stays in the stent group.20 In the emergency setting, morbidity and mortality rates for primary resection of the tumor with a colostomy have fallen into the range of 9% to 40% and 8% to 20%, respectively.21 About 40% of these patients ultimately undergo permanent colostomy, because metastatic disease is found on subsequent staging.21 Previous evidence on the utility of stents is more limited for bridging to surgery than palliation. Nevertheless, two systematic reviews concluded that SEMS placement is safe and effective as a bridge to surgery and is useful as an option to avoid colostomy.5,7 The first of these systematic reviews documented a clinical success rate of 85% among 262 patients undergoing colorectal SEMS placement as a bridge to surgery.5 Of those patients, 95% underwent one-stage colonic resection within a mean of 9 days (range 2-115 days). In the second systematic review of 21 reports that involved a total of 407 patients, the pooled rates of technical and clinical success were 92 and 72%, respectively, for SEMS placement as a bridge to surgery.7 In a recent prospective study, placement of uncovered Wallstents was successful in 84% of 45 patients.22 Single-stage tumor resection and primary end-to-end anastomosis without complications was possible in 31 of 36 operative cases (86%). www.giejournal.org
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The estimated median survival in patients with incurable colorectal cancer is 8 months.23 A central goal of SEMS placement for palliation is continuing relief of obstruction, with minimum adverse impact on the quality of life. In the present study, the benefits of stent placement proved to be long lasting in the majority of the palliation group patients, as indicated by the continuing success rate of 58% after 6 months. It should be noted that, as defined for this study, the clinical success rate was penalized by the occurrence of any complication, regardless of its type or the remedial measures needed. Occlusion is one complication type of particular importance and potential urgency. Eleven of the 15 nonsurvivors in the palliation group (73%) remained free of recurrent obstruction until death. Moreover, in all 8 patients of the palliative group who experienced complications, unobstructed bowel function could be preserved through minimally invasive measures. Reported complications associated with SEMS use include stent dislocation and migration, stent obstruction because of tumor ingrowth or overgrowth, perforation, fecal impaction, bleeding, abdominal pain, and tenesmus. In systematic reviews, migration was reported to occur in approximately 10% to 12% of patients.5,7 In this study, a single migration (2%) occurred in a patient with obstruction of the rectum, a site especially prone to this type of complication. Design features of dedicated colorectal SEMS, such as the large diameter and flared ends of the WallFlex stent, might have helped to minimize migration risk. Perforation is the complication of greatest clinical concern in SEMS placement. Perforation has been described in approximately 4% of patients with a colorectal SEMS.5,7 Anatomical sites of comparatively high perforation risk are in the rectosigmoid area, especially the rectosigmoid junction.7 Perforation risk also appears to be heightened by balloon predilation5 and sharp wire tips of stents.24 The looped ends of the WallFlex stent serve to reduce the risk of perforation, and, in the present study, only one patient had a perforation, which occurred one day after stent placement and spontaneously resolved with medical treatment. By contrast, in a recent Dutch study that compared WallFlex stent placement with palliative surgery, late perforations were reported in 4 of 10 stent recipients.25 At present, the high incidence of late perforation in the Dutch study remains unexplained. The risks attending chemoradiotherapy before or after SEMS placement, such as migration, perforation, and acute tissue reactions remain poorly defined. In a retrospective study of 58 patients with malignant colonic obstruction who received a SEMS for palliation or bridging to surgery, stent migration occurred after chemoradiotherapy in 7 patients.14 In case reports, migration was described in the presence26 but not the absence27 of evidence indicating chemoradiotherapy-induced tumor shrinkage. www.giejournal.org
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One limitation of the present study was the absence of a control group. Consequently, any ostensive advantages of a larger-diameter versus smaller-diameter SEMSs could not be directly assessed. In addition, the number of patients in the study limited the precision with which the incidence of clinically important complications, such as migration and perforation, could be estimated. As concluded in a recent systematic review, ‘‘palliative colorectal stenting has the potential to be the first choice modality in patients with advanced colorectal cancer presenting with obstruction.’’7 This study provides further support for that conclusion and also further confirms the value of SEMS placement as a bridge to surgery in patients with colonic adenocarcinoma. Based on the present findings, highly effective relief of malignant colonic obstruction can now be furnished by a large-diameter TTS SEMSs.
ACKNOWLEDGMENT We thank Roberta J. Navickis, PhD, and Mahlon M. Wilkes, PhD, who contributed to the statistical analysis of the study data and preparation of the manuscript. DISCLOSURE The authors report that there are no disclosures relevant to this publication.
REFERENCES 1. Deans GT, Krukowski ZH, Irwin ST. Malignant obstruction of the left colon. Br J Surg 1994;81:1270-6. 2. Adler DG, Merwat SN. Endoscopic approaches for palliation of luminal gastrointestinal obstruction. Gastroenterol Clin North Am 2006;35: 65-82. 3. Dohmoto M. New method: endoscopic implantation of rectal stent in palliative treatment of malignant stenosis. Endosc Digest 1991;3: 1507-12. 4. Harris GJ, Senagore AJ, Lavery IC, et al. The management of neoplastic colorectal obstruction with colonic endolumenal stenting devices. Am J Surg 2001;181:499-506. 5. Khot UP, Lang AW, Murali K, et al. Systematic review of the efficacy and safety of colorectal stents. Br J Surg 2002;89:1096-102. 6. Keymling M. Colorectal stenting. Endoscopy 2003;35:234-8. 7. Sebastian S, Johnston S, Geoghegan T, et al. Pooled analysis of the efficacy and safety of self-expanding metal stenting in malignant colorectal obstruction. Am J Gastroenterol 2004;99:2051-7. 8. Martinez-Santos C, Lobato RF, Fradejas JM, et al. Self-expandable stent before elective surgery vs. emergency surgery for the treatment of malignant colorectal obstructions: comparison of primary anastomosis and morbidity rates. Dis Colon Rectum 2002;45:401-6. 9. Law WL, Choi HK, Chu KW. Comparison of stenting with emergency surgery as palliative treatment for obstructing primary left-sided colorectal cancer. Br J Surg 2003;90:1429-33. 10. Fiori E, Lamazza A, de Cesare A, et al. Palliative management of malignant rectosigmoidal obstruction. Colostomy vs. endoscopic stenting. A randomized prospective trial. Anticancer Res 2004;24:265-8.
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Stents for colonic obstruction 11. Tomiki Y, Watanabe T, Ishibiki Y, et al. Comparison of stent placement and colostomy as palliative treatment for inoperable malignant colorectal obstruction. Surg Endosc 2004;18:1572-7. 12. Targownik LE, Spiegel BM, Sack J, et al. Colonic stent vs. emergency surgery for management of acute left-sided malignant colonic obstruction: a decision analysis. Gastrointest Endosc 2004;60:865-74. 13. Garcı´a-Cano J, Gonza´lez-Huix F, Juzgado D, et al. Use of self-expanding metal stents to treat malignant colorectal obstruction in general endoscopic practice. Gastrointest Endosc 2006;64:914-20. 14. Soto S, Lo´pez-Rose´s L, Gonza´lez-Ramı´rez A, et al. Endoscopic treatment of acute colorectal obstruction with self-expandable metallic stents: experience in a community hospital. Surg Endosc 2006;20: 1072-6. 15. Repici A, Fregonese D, Costamagna G, et al. Ultraflex precision colonic stent placement for palliation of malignant colonic obstruction: a prospective multicenter study. Gastrointest Endosc 2007;66:920-7. 16. Fregonese D, Naspetti R, Ferrer S, et al. Ultraflex precision colonic stent placement as a bridge to surgery in patients with malignant colonic obstruction. Gastrointest Endosc 2007 Oct 29 [Epub ahead of print]. 17. Tierney W, Chuttani R, Croffie J, et al. Enteral stents. Gastrointest Endosc 2006;63:920-6. 18. Tilney HS, Lovegrove RE, Purkayastha S, et al. Comparison of colonic stenting and open surgery for malignant large bowel obstruction. Surg Endosc 2007;21:225-33. 19. Xinopoulos D, Dimitroulopoulos D, Theodosopoulos T, et al. Stenting or stoma creation for patients with inoperable malignant colonic obstructions? Results of a study and cost-effectiveness analysis. Surg Endosc 2004;18:421-6. 20. Ng KC, Law WL, Lee YM, et al. Self-expanding metallic stent as a bridge to surgery versus emergency resection for obstructing left-sided colorectal cancer: a case-matched study. J Gastrointest Surg 2006;10:798-803.
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Repici et al 21. Vandervoort J, Tham TC. Colonic stents for malignant obstruction: not a bridge too far? Gastrointest Endosc 2006;64:921-4. 22. Jost RS, Jost R, Schoch E, et al. Colorectal stenting: an effective therapy for preoperative and palliative treatment. Cardiovasc Intervent Radiol 2007;30:433-40. 23. Simmonds PC. Palliative chemotherapy for advanced colorectal cancer: systematic review and meta-analysis. Colorectal Cancer Collaborative Group. BMJ 2000;321:531-5. 24. Low DE, Panto PN, Hastings AG, et al. An unusual complication of a colonic Wallstent. Cardiovasc Intervent Radiol 2004;27:377-8. 25. van Hooft JE, Fockens P, Marinelli AW, et al. Premature closure of the Dutch Stent-in I study. Lancet 2006;368:1573-4. 26. Vrazas JI, Ferris S, Bau S, et al. Stenting for obstructing colorectal malignancy: an interim or definitive procedure. ANZ J Surg 2002;72:392-6. 27. Adler DG, Young-Fadok TM, Smyrk T, et al. Preoperative chemoradiation therapy after placement of a self-expanding metal stent in a patient with an obstructing rectal cancer: clinical and pathologic findings. Gastrointest Endosc 2002;55:435-7.
Received June 12, 2007. Accepted August 9, 2007. Current affiliations: Digestive Endoscopy Unit (A.R., G.D.C., C.L., N.P., P.P., S.D., P.C., A.M.), IRCCS Istituto Clinico Humanitas, Rozzano (Milano), Gastroenterology Unit (C.F., L.F., N.D., V.C.), Ospedale Bellaria, Bologna, Italy. Presented at the Digestive Disease Week, May 20-23, 2007, Washington, DC (Gastrointest Endosc 2007;65:AB283). Reprint requests: Alessandro Repici, MD, Digestive Endoscopy Unit, IRCCS Istituto Clinico Humanitas, Via Manzoni 56, Rozzano (MI), 20089 Italy.
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WallFlex colonic stent placement for management of malignant colonic obstruction: a prospective study at two centers Alessandro Repici, MD, Giuseppe De Caro, MD, Carmelo Luigiano, MD, Carlo Fabbri, MD, Nico Pagano, MD, Paoletta Preatoni, MD, Silvio Danese, MD, Lorenzo Fucci, MD, Pierluigi Consolo, MD, Alberto Malesci, MD, Nicola D’Imperio, MD, Vincenzo Cennamo, MD Milano, Bologna, Italy
Background: Self-expanding metal stents (SEMSs) can alleviate malignant colonic obstruction and avoid emergency decompressive surgery. The use of colonic larger-diameter SEMSs may improve bowel function and reduce migration risk. Objective: To evaluate the effectiveness and safety of a novel large-diameter SEMS (WallFlex) designed for delivery through the endoscope in treating malignant colonic obstruction. Design: Prospective clinical cohort study. Setting: Two Italian study centers. Patients: Forty-two consecutive patients with malignant colonic obstruction: 23 requiring palliation and 19 bridging to surgery. Interventions: Colorectal SEMS placement. Main Outcome Measurements: Technical success, defined as accurate SEMS deployment across the stricture on the first attempt; clinical success, ie, complete relief of bowel obstruction without complications; and bridging to surgery, denoting the performance of elective one-stage surgery. Results: The rate of technical success was 93% (95% CI, 81%-99%) and of initial clinical success was 95% (95% CI, 84%-99%). In 58% (95% CI, 40%-84%) of the palliation group, clinical success was maintained after 6 months. All 19 patients with operable tumors were successfully bridged to one-stage elective surgery within a median of 5 days. One perforation and one stent migration occurred. All complications could be resolved nonsurgically. Limitations: No control group was included. Conclusions: In a prospective study of through-the-scope WallFlex stent placement for malignant colonic obstruction, high rates of technical and initial clinical success, and bridging to surgery were achieved. Complications could be readily managed. (Gastrointest Endosc 2008;67:77-84.)
Primary or recurrent adenocarcinoma, pelvic malignancies, and metastatic diseases can lead to the development of malignant colorectal strictures. Acute complete or partial obstruction occurs in 8% to 29% of patients with colorectal cancer.1 Although colorectal obstruction needs to be relieved as quickly as possible, patients with acute or chronic large-bowel obstruction are challenging to manage because they are often in poor general health; present with a painful, distended abdomen and with dehydration; Abbreviations: SEMS, self-expanding metal stent; TTS, through the scope. Copyright ª 2008 by the American Society for Gastrointestinal Endoscopy 0016-5107/$32.00 doi:10.1016/j.gie.2007.08.019
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and face relatively high risks as surgical candidates. The dilated bowel wall proximal to the obstruction is often friable, which complicates emergency surgical interventions.2 Self-expanding metallic stents (SEMSs) were developed as a minimally invasive modality for rapid decompression of colonic occlusion. Since the first report on the use of SEMSs for palliation in colorectal cancer in 1991,3 a growing number of reports and reviews have demonstrated the effectiveness of SEMSs for both palliation in patients with advanced, nonresectable carcinoma and as a bridge to surgery in those patients with resectable disease.4-7 A high success rate has been reported in accurate stent deployment and clinical relief of obstruction, with a low rate of morbidity and mortality. The SEMS placement procedure, typically Volume 67, No. 1 : 2008 GASTROINTESTINAL ENDOSCOPY 77
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performed with the patient under conscious sedation, entails less-acute debilitation, more rapid recovery, and a shorter hospital stay compared with surgical alternatives.8-11 According to a decision model of colonic-stent placement versus emergency surgery for obstructing cancer of the left side of the colon, preoperative colonic SEMS placement would decrease operative procedures by an estimated 23% and reduce the need for a stoma from 43% to 7%.12 Complications of SEMS placement include perforation and migration. In some cases, accurate SEMS positioning may be hampered by inadequate fluoroscopic visualization. Initially, the stents used for relief of a colorectal obstruction were designed for esophageal or tracheobronchial indications, and their internal diameters were smaller than would be ideal for colorectal strictures. A number of dedicated colonic stents and delivery systems have now been introduced. The attributes of the ideal stent have been described as compatibility with a smalldiameter delivery system, which allows passage through the endoscope, high flexibility, and strong expansile force.6 In addition, a large internal stent diameter is a desirable property for colonic stenting, to minimize the likelihood of stool impaction or other stent occlusion and to decrease the likelihood of stent migration. Among the advantages of endoscopic colorectal stent placement, compared with radiologic techniques, are greater accessibility to obstructions proximal to the sigmoid colon and better control of stent delivery in patients with extremely angulated strictures.13 The endoscope provides better fixation of the sigmoid colon than a guidewire alone, which can be very valuable in patients with a twisted sigmoid colon.6 Endoscopic placement also allows biopsy specimens to be collected and facilitates the passage of the guidewire through the stenosis.14 The most frequently used through-the-scope (TTS) colorectal stent to date is the enteral Wallstent (Microvasive Endoscopy, Boston Scientific Corp, Natick, Mass), with an 18-mm to 22-mm internal diameter. Larger internal diameter colorectal stents have been placed over a guidewire.15,16 A newly developed noncovered nitinol stent, the WallFlex colonic stent (Microvasive), with either a 22-mm or 25-mm mid diameter is suitable for placement through the endoscope, because of its narrow-profile delivery system. The present study evaluated the effectiveness and safety of this new nitinol stent in patients with malignant colonic obstruction that requires either palliation or bridging to surgery.
PATIENTS AND METHODS Patients This prospective study was conducted at two Italian centers between May 2004 and January 2007. Approval of the study protocol was granted by the institutional 78 GASTROINTESTINAL ENDOSCOPY Volume 67, No. 1 : 2008
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Capsule Summary What is already known on this topic d
Emergency surgery for malignant colonic obstruction can be avoided by placement of self-expanding, large-diameter stents, which improve bowel function and reduce the likelihood of migration.
What this study adds to our knowledge d
d
In a prospective study of 42 patients with malignant colonic obstruction, large-diameter stents placed by through-the-scope procedures had a 93% rate of technical success and 95% rate of initial clinical success, with only one perforation and one stent migration. All operable tumors were successfully bridged to one-stage elective surgery.
ethics committees of the participating centers, and all patients rendered their informed consent in writing. Eligibility was predicated on the presence of largebowel obstruction secondary to malignancy as confirmed by erect and supine abdominal radiograph imaging and CT. Consecutive patients of age R18 years old who required stents for palliation or a bridge to surgery were enrolled. Exclusion criteria were composed of the following: benign stricture, perforated colon, concurrent radiotherapy for the colorectal stricture, treatment with an investigational drug or device within the preceding 4 weeks, placement of another metal stent for the same stricture, and a terminal condition. The assignment of patients to palliation rather than surgery was based on an unacceptable surgical risk because of advanced age or comorbidities or because of the presence of locally advanced disease or distant metastases.
Patient assessments Baseline assessment encompassed patient demographics and medical history, the type of malignancy, the stricture location, and the degree of occlusion. Patients were assessed at the time of SEMS placement and, in those patients who received stents for palliation, at follow-up evaluations approximately 1 month after stent placement. Additional observation of the palliation group was conducted every 3 months by telephone and communications with the primary care physicians of the patients. The follow-up of patients with resectable disease continued until elective surgery and periodically thereafter to document postoperative complications. For all patients, obstructivebowel symptoms, any therapeutic interventions, and the occurrence of adverse events were recorded at each follow-up evaluation. Obstructive-bowel symptoms were defined as the inability to pass flatus or stool through the anus for more than 24 hours, in conjunction with bowel distension and radiographic evidence of ileus. Observation www.giejournal.org
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extension 1 to 2 cm beyond both stricture margins. The selected SEMSs were then deployed through the endoscope. At the end of the procedure, contrast material was injected through the endoscope to rule out the occurrence of a perforation (Fig. 2A to C). Patients attaining clinical relief of obstruction were allowed to resume an oral diet after 2 days.
Outcomes The primary study outcome measures were technical and clinical success and bridging to surgery. The definition of technical success was accurate SEMS deployment across the stricture on the first attempt. Clinical success was defined as complete relief of a bowel obstruction as judged by clinical symptoms and radiographic observations, without the occurrence of complications. Initial clinical success was evaluated in all patients. In the group that received stents for palliation, maintenance of clinical success continued to be assessed until death or the last follow-up. Bridging to surgery denoted the performance of elective one-stage surgery in SEMS recipients with resectable disease.
Statistical analysis Figure 1. WallFlex colonic stent. A, Stent mounted in deployment system. B, Fully expanded stent.
was conducted for both clinical and investigational purposes.
SEMS placement Patients received the TTS WallFlex colonic stent with either a 22-mm or 25-mm stent body and 27-mm or 30-mm proximal flare, respectively (Fig. 1). Available lengths of this SEMS are 6, 9, and 12 cm, and working lengths of the delivery system are either 135 or 230 cm. These indicated SEMS lengths correspond to the fully expanded state. The SEMSs undergo partial foreshortening during deployment, which the endoscopist must take into account during positioning.17 The delivery system is designed to permit recapture and repositioning of the stent until deployment is up to 70% complete. Prophylactic antibiotics were not administered before stent placement. Sedation was accomplished through use of midazolam in 40 patients and propofol in two. SEMS placement was performed under both endoscopic and fluoroscopic guidance, as previously described.15,16 Briefly, a guidewire and a standard ERCP catheter were introduced to cannulate the stricture; the guidewire was then withdrawn, and contrast material was injected to delineate the location, length, and anatomy of the stricture. A 0.035-inch super-stiff guidewire was then inserted, and the catheter was withdrawn. SEMSs were selected of a length sufficient to cover the entire stricture, with an www.giejournal.org
Continuous data distributions were characterized by the median and interquartile range. The percentages of patients with technical and initial clinical success were calculated with exact binomial 95% CI. Time to clinical failure and death in recipients of SEMSs for palliation and to elective surgery in the bridge-to-surgery group were estimated by the Kaplan-Meier product limit method. Differences in times to event related to baseline characteristics were evaluated by two-sided exact log-rank test. Data were analyzed by using R version 2.5.0 (The R Foundation for Statistical Computing, Vienna, Austria), StatXact 7.0 (Cytel Software Corp, Cambridge, Mass) and SPSS 11.5 (SPSS Inc, Chicago, Ill) statistical software.
RESULTS Forty-two consecutive patients were enrolled in the study. Baseline data for these patients are summarized in Table 1. Nearly two thirds of the patients (64%) were 70 years of age or older. The strictures in 35 of 42 patients (83%) were situated distal to the splenic flexure.
Technical success SEMSs were placed with palliative intent in 23 patients and as a bridge to surgery in 19 (Table 2). Thirty-six patients received a single SEMS. Two SEMSs each were placed in 6 patients, of whom 5 required a second stent because of long strictures and in one patient because of malpositioning of the first stent, as detailed below. No patient underwent balloon dilation, either before or after stent placement. Volume 67, No. 1 : 2008 GASTROINTESTINAL ENDOSCOPY 79
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TABLE 1. Baseline patient data (n Z 42) Characteristic
N
%
50-59
6
14
60-69
9
21
70-79
15
36
R80
12
29
Women
18
43
Men
24
57
Bologna, Italy
16
38
Milan, Italy
26
62
Colonic adenocarcinoma
41
98
Gastric adenocarcinoma infiltrating hepatic flexure
1
2
13
31
Descending colon
9
21
Rectum
7
17
Rectosigmoid junction
6
14
Splenic flexure
3
7
Hepatic flexure
2
5
Transverse colon
2
5
Complete
31
74
Subtotal
11
26
Age (y)*
Sex
Patients per center
Malignancy
Stricture location Sigmoid
Occlusive syndrome
*Mean 72 y.
Figure 2. A to C, Radiographic views of stent placement.
Spanning of the strictures by accurate SEMSs placement was accomplished in 39 of 42 patients; thus, the rate of technical success was 93%, 95% CI, 81%-99%. The SEMSs could not be passed through a hepatic flexure stricture in one patient, who then proceeded to palliative surgery. 80 GASTROINTESTINAL ENDOSCOPY Volume 67, No. 1 : 2008
In another patient, a stent failed to expand after placement within a severe angulation of the rectosigmoid junction, which was compressed by a large neoplastic mass. The third technical failure was because of malpositioning of the stent proximal to the stricture. With the guidewire remaining in situ, a second overlapping SEMSs was placed forthwith during the same procedure, and, on this second attempt, spanning of the stricture succeeded.
Clinical success The proportion of patients with prompt decompression and relief of obstructive symptoms was 40 of 42, corresponding to a 95% initial clinical success rate, 95% CI, 84%-99%. In the cases with clinical success, the relief of www.giejournal.org
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symptoms was apparent within 24 hours of stent placement. The two initial clinical failures were the result of technical failure in stent placement. As described above, a third patient’s stent placement was declared a technical failure because of stent malpositioning, but a second stent was successfully placed and complete relief of obstruction was achieved. Consequently, that patient was considered an initial clinical success. During follow-up after SEMS placement in the group that received a SEMSs for palliation, complications resulted in 8 additional clinical failures (Table 3). The median time at risk for clinical failure in the palliative group was 99 days (range 42-212 days). At 6 months, their rate of clinical success was 58% (Fig. 3). Among these recipients of stents for palliation, no difference could be detected in maintenance of clinical success over the time between when patients presented with complete versus subtotal occlusion (P Z .12) or between those with strictures distal to the splenic flexure versus more proximal sites (P Z .80). In the palliative group, 3 complications were encountered within 30 days of stent placement. Perforation was diagnosed in an 85-year-old woman the day after stent placement. With conservative medical therapy, which consisted of nasogastric tube insertion, antibiotics, and total parenteral nutrition, the perforation spontaneously resolved, and, within several days, the patient was able to pass stool through the anus uneventfully. A SEMSs migrated distally from the rectum at 7 days in another patient, who developed tenesmus. The stent could be grasped digitally and was removed through the anus with no further clinical measures. The patient then received an over-the-wire stent (Ultraflex Precision Colonic Stent; Microvasive) and remained free of obstructive symptoms thereafter until death 3 months later. The third patient developed minor rectal bleeding after 8 days that did not necessitate a blood transfusion and resolved under medical therapy within 3 weeks. This patient was also among those who developed a late occlusion, as described below. Six patients in the palliative group were affected by late complications (O30 days). Four of these patients experienced an occlusion attributable to tumor ingrowth in two cases and tumor overgrowth and stool impaction in one case each. The stool impaction was corrected by endoscopic mechanical recanalization, and the occlusion in two patients was successfully relieved by a second stent and that of one patient by 3 sessions of argon plasma coagulation. The remaining late complications in the palliative group were two cases of tumor ingrowth with subocclusive symptoms, one managed by two sessions of argon plasma coagulation and one without procedural intervention.
Survival All patients with operable tumors survived until elective surgery and throughout postoperative follow-up. Their www.giejournal.org
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TABLE 2. SEMS placement data Parameter
No. patients
%
Palliation
23
55
Bridge to surgery
19
45
1
36
86
2
6
14
6
15
36
9
26
62
1
2
22
17
40
25
25
60
Indication for stent placement
No. stents placed per patient
Stent length (cm)
One 6 and one 9 Stent diameter (mm)
total median follow-up time after stent placement was 528 days (range 445-634 days). In the palliative group, 7 of 23 patients (30%) were still alive at the end of the follow-up period (January 2007). The median survival of the group was 208 days, 95% CI, 93-323 days. Because of censoring, the median time at risk for death (179 days, range 98-267 days) was slightly shorter. At the time of death, 7 of the 16 nonsurvivors (44%) remained clinical successes, and, for those patients, stent placement had fulfilled its palliative purpose over their entire remaining life span. No difference in survival was evident between patients with complete versus subtotal occlusion at baseline (P Z .31).
Bridging to surgery All 19 patients who received a SEMSs as a bridge to surgery proceeded to elective one-stage surgery. Thus, the rate of successful bridging to surgery was 100%, 95% CI, 85%-100%. The median time from SEMS placement to elective surgery was 5.0 days, 95% CI, 4.4-5.6 days. A single early complication occurred in the bridge-to-surgery group, namely, stent occlusion because of stool impaction two days after stent placement. The occlusion was promptly and completely alleviated by multiple passages of an endoscope through the stent and lavage, without balloon dilation, and the patient underwent elective surgery 4 days after SEMSs placement. Among all patients in the bridge-to-surgery group, stents were removed en bloc with the tumor, without any surgical complications. Two patients in the bridge-to-surgery group experienced one postoperative complication each, ie, pulmonary embolism and wound infection. The patient with Volume 67, No. 1 : 2008 GASTROINTESTINAL ENDOSCOPY 81
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Palliative Stent Placement TABLE 3. Complications Complication type
100
No.
% 80
Perforation
1
2.4
Stent occlusion
1
2.4
Stent migration
1
2.4
Rectal bleeding
1
2.4
Stent occlusion
4
9.6
Tumor ingrowth
2
4.8
Late (O30 d after stent placement)
Clinical Success (%)
Early (%30 d after stent placement)
60
40
20
Clinical Success at 6 mo = 58% (95% CI, 40-84 %)
0
Postoperative after bridging to surgery
At Risk
Pulmonary embolism
1
2.4
Wound infection
1
2.4
the pulmonary embolism was admitted to the intensive care unit and received medical therapy. After 3 weeks, the patient was discharged. The wound infection was treated with local and systemic antibiotics and resolved within 20 days. In both of these patients, the clinical course after stent placement, including preoperative bowel preparation, was otherwise uneventful, and no clear relationship between the SEMS and the postoperative complications could be discerned.
DISCUSSION In the present prospective study, placement of the newly introduced WallFlex colonic stent obviated emergency surgery in nearly all cases. The rates of technical (93%) and initial clinical success (95%) with the evaluated TTS stent were comparable with those reported in earlier studies, which ranged from percentages in the high 80s to mid 90s.5-7,18 There was no procedure-related mortality in this study, and all complications could be managed without surgical intervention. Comparative studies indicated advantages of stents versus emergency surgery.9-11,19 In a recent meta-analysis of colonic stenting versus open surgery for malignant bowel obstruction, which encompassed 10 studies with a total of 451 patients, the length of hospital stay was shorter by 7.72 days in the stent group (P!.001), which also enjoyed lower mortality (P Z.03) and fewer medical complications (P ! .001). Stoma formation at any point during management was significantly less frequent in the stent group (odds ratio 0.02; P ! .001), and bridging to surgery did not adversely influence survival. All 19 patients who received SEMS as a bridge to surgery successfully proceeded to single-stage tumor resection and primary end-to-end anastomosis. The only 82 GASTROINTESTINAL ENDOSCOPY Volume 67, No. 1 : 2008
23
19
17
14
11
11
11
11
0
30
60
90
120
150
180
210
Time after SEMS Placement (days) Figure 3. Kaplan-Meier estimated fractions with clinical success (solid line) and 95% CI (dashed line) among recipients of SEMS for palliation. Patients at risk for clinical failure enumerated above the abscissa for the indicated time points.
preoperative complication in this group was rectified by minimally invasive endoscopic intervention. After the elective resection, two patients developed complications, which were successfully treated medically. All 19 of these patients survived throughout a median follow-up period of almost 18 months. A recent case-matched study that compared stent placement with emergency resection demonstrated a higher rate of primary anastomosis as well as reduced intensive care unit and hospital stays in the stent group.20 In the emergency setting, morbidity and mortality rates for primary resection of the tumor with a colostomy have fallen into the range of 9% to 40% and 8% to 20%, respectively.21 About 40% of these patients ultimately undergo permanent colostomy, because metastatic disease is found on subsequent staging.21 Previous evidence on the utility of stents is more limited for bridging to surgery than palliation. Nevertheless, two systematic reviews concluded that SEMS placement is safe and effective as a bridge to surgery and is useful as an option to avoid colostomy.5,7 The first of these systematic reviews documented a clinical success rate of 85% among 262 patients undergoing colorectal SEMS placement as a bridge to surgery.5 Of those patients, 95% underwent one-stage colonic resection within a mean of 9 days (range 2-115 days). In the second systematic review of 21 reports that involved a total of 407 patients, the pooled rates of technical and clinical success were 92 and 72%, respectively, for SEMS placement as a bridge to surgery.7 In a recent prospective study, placement of uncovered Wallstents was successful in 84% of 45 patients.22 Single-stage tumor resection and primary end-to-end anastomosis without complications was possible in 31 of 36 operative cases (86%). www.giejournal.org
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The estimated median survival in patients with incurable colorectal cancer is 8 months.23 A central goal of SEMS placement for palliation is continuing relief of obstruction, with minimum adverse impact on the quality of life. In the present study, the benefits of stent placement proved to be long lasting in the majority of the palliation group patients, as indicated by the continuing success rate of 58% after 6 months. It should be noted that, as defined for this study, the clinical success rate was penalized by the occurrence of any complication, regardless of its type or the remedial measures needed. Occlusion is one complication type of particular importance and potential urgency. Eleven of the 15 nonsurvivors in the palliation group (73%) remained free of recurrent obstruction until death. Moreover, in all 8 patients of the palliative group who experienced complications, unobstructed bowel function could be preserved through minimally invasive measures. Reported complications associated with SEMS use include stent dislocation and migration, stent obstruction because of tumor ingrowth or overgrowth, perforation, fecal impaction, bleeding, abdominal pain, and tenesmus. In systematic reviews, migration was reported to occur in approximately 10% to 12% of patients.5,7 In this study, a single migration (2%) occurred in a patient with obstruction of the rectum, a site especially prone to this type of complication. Design features of dedicated colorectal SEMS, such as the large diameter and flared ends of the WallFlex stent, might have helped to minimize migration risk. Perforation is the complication of greatest clinical concern in SEMS placement. Perforation has been described in approximately 4% of patients with a colorectal SEMS.5,7 Anatomical sites of comparatively high perforation risk are in the rectosigmoid area, especially the rectosigmoid junction.7 Perforation risk also appears to be heightened by balloon predilation5 and sharp wire tips of stents.24 The looped ends of the WallFlex stent serve to reduce the risk of perforation, and, in the present study, only one patient had a perforation, which occurred one day after stent placement and spontaneously resolved with medical treatment. By contrast, in a recent Dutch study that compared WallFlex stent placement with palliative surgery, late perforations were reported in 4 of 10 stent recipients.25 At present, the high incidence of late perforation in the Dutch study remains unexplained. The risks attending chemoradiotherapy before or after SEMS placement, such as migration, perforation, and acute tissue reactions remain poorly defined. In a retrospective study of 58 patients with malignant colonic obstruction who received a SEMS for palliation or bridging to surgery, stent migration occurred after chemoradiotherapy in 7 patients.14 In case reports, migration was described in the presence26 but not the absence27 of evidence indicating chemoradiotherapy-induced tumor shrinkage. www.giejournal.org
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One limitation of the present study was the absence of a control group. Consequently, any ostensive advantages of a larger-diameter versus smaller-diameter SEMSs could not be directly assessed. In addition, the number of patients in the study limited the precision with which the incidence of clinically important complications, such as migration and perforation, could be estimated. As concluded in a recent systematic review, ‘‘palliative colorectal stenting has the potential to be the first choice modality in patients with advanced colorectal cancer presenting with obstruction.’’7 This study provides further support for that conclusion and also further confirms the value of SEMS placement as a bridge to surgery in patients with colonic adenocarcinoma. Based on the present findings, highly effective relief of malignant colonic obstruction can now be furnished by a large-diameter TTS SEMSs.
ACKNOWLEDGMENT We thank Roberta J. Navickis, PhD, and Mahlon M. Wilkes, PhD, who contributed to the statistical analysis of the study data and preparation of the manuscript. DISCLOSURE The authors report that there are no disclosures relevant to this publication.
REFERENCES 1. Deans GT, Krukowski ZH, Irwin ST. Malignant obstruction of the left colon. Br J Surg 1994;81:1270-6. 2. Adler DG, Merwat SN. Endoscopic approaches for palliation of luminal gastrointestinal obstruction. Gastroenterol Clin North Am 2006;35: 65-82. 3. Dohmoto M. New method: endoscopic implantation of rectal stent in palliative treatment of malignant stenosis. Endosc Digest 1991;3: 1507-12. 4. Harris GJ, Senagore AJ, Lavery IC, et al. The management of neoplastic colorectal obstruction with colonic endolumenal stenting devices. Am J Surg 2001;181:499-506. 5. Khot UP, Lang AW, Murali K, et al. Systematic review of the efficacy and safety of colorectal stents. Br J Surg 2002;89:1096-102. 6. Keymling M. Colorectal stenting. Endoscopy 2003;35:234-8. 7. Sebastian S, Johnston S, Geoghegan T, et al. Pooled analysis of the efficacy and safety of self-expanding metal stenting in malignant colorectal obstruction. Am J Gastroenterol 2004;99:2051-7. 8. Martinez-Santos C, Lobato RF, Fradejas JM, et al. Self-expandable stent before elective surgery vs. emergency surgery for the treatment of malignant colorectal obstructions: comparison of primary anastomosis and morbidity rates. Dis Colon Rectum 2002;45:401-6. 9. Law WL, Choi HK, Chu KW. Comparison of stenting with emergency surgery as palliative treatment for obstructing primary left-sided colorectal cancer. Br J Surg 2003;90:1429-33. 10. Fiori E, Lamazza A, de Cesare A, et al. Palliative management of malignant rectosigmoidal obstruction. Colostomy vs. endoscopic stenting. A randomized prospective trial. Anticancer Res 2004;24:265-8.
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Stents for colonic obstruction 11. Tomiki Y, Watanabe T, Ishibiki Y, et al. Comparison of stent placement and colostomy as palliative treatment for inoperable malignant colorectal obstruction. Surg Endosc 2004;18:1572-7. 12. Targownik LE, Spiegel BM, Sack J, et al. Colonic stent vs. emergency surgery for management of acute left-sided malignant colonic obstruction: a decision analysis. Gastrointest Endosc 2004;60:865-74. 13. Garcı´a-Cano J, Gonza´lez-Huix F, Juzgado D, et al. Use of self-expanding metal stents to treat malignant colorectal obstruction in general endoscopic practice. Gastrointest Endosc 2006;64:914-20. 14. Soto S, Lo´pez-Rose´s L, Gonza´lez-Ramı´rez A, et al. Endoscopic treatment of acute colorectal obstruction with self-expandable metallic stents: experience in a community hospital. Surg Endosc 2006;20: 1072-6. 15. Repici A, Fregonese D, Costamagna G, et al. Ultraflex precision colonic stent placement for palliation of malignant colonic obstruction: a prospective multicenter study. Gastrointest Endosc 2007;66:920-7. 16. Fregonese D, Naspetti R, Ferrer S, et al. Ultraflex precision colonic stent placement as a bridge to surgery in patients with malignant colonic obstruction. Gastrointest Endosc 2007 Oct 29 [Epub ahead of print]. 17. Tierney W, Chuttani R, Croffie J, et al. Enteral stents. Gastrointest Endosc 2006;63:920-6. 18. Tilney HS, Lovegrove RE, Purkayastha S, et al. Comparison of colonic stenting and open surgery for malignant large bowel obstruction. Surg Endosc 2007;21:225-33. 19. Xinopoulos D, Dimitroulopoulos D, Theodosopoulos T, et al. Stenting or stoma creation for patients with inoperable malignant colonic obstructions? Results of a study and cost-effectiveness analysis. Surg Endosc 2004;18:421-6. 20. Ng KC, Law WL, Lee YM, et al. Self-expanding metallic stent as a bridge to surgery versus emergency resection for obstructing left-sided colorectal cancer: a case-matched study. J Gastrointest Surg 2006;10:798-803.
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Repici et al 21. Vandervoort J, Tham TC. Colonic stents for malignant obstruction: not a bridge too far? Gastrointest Endosc 2006;64:921-4. 22. Jost RS, Jost R, Schoch E, et al. Colorectal stenting: an effective therapy for preoperative and palliative treatment. Cardiovasc Intervent Radiol 2007;30:433-40. 23. Simmonds PC. Palliative chemotherapy for advanced colorectal cancer: systematic review and meta-analysis. Colorectal Cancer Collaborative Group. BMJ 2000;321:531-5. 24. Low DE, Panto PN, Hastings AG, et al. An unusual complication of a colonic Wallstent. Cardiovasc Intervent Radiol 2004;27:377-8. 25. van Hooft JE, Fockens P, Marinelli AW, et al. Premature closure of the Dutch Stent-in I study. Lancet 2006;368:1573-4. 26. Vrazas JI, Ferris S, Bau S, et al. Stenting for obstructing colorectal malignancy: an interim or definitive procedure. ANZ J Surg 2002;72:392-6. 27. Adler DG, Young-Fadok TM, Smyrk T, et al. Preoperative chemoradiation therapy after placement of a self-expanding metal stent in a patient with an obstructing rectal cancer: clinical and pathologic findings. Gastrointest Endosc 2002;55:435-7.
Received June 12, 2007. Accepted August 9, 2007. Current affiliations: Digestive Endoscopy Unit (A.R., G.D.C., C.L., N.P., P.P., S.D., P.C., A.M.), IRCCS Istituto Clinico Humanitas, Rozzano (Milano), Gastroenterology Unit (C.F., L.F., N.D., V.C.), Ospedale Bellaria, Bologna, Italy. Presented at the Digestive Disease Week, May 20-23, 2007, Washington, DC (Gastrointest Endosc 2007;65:AB283). Reprint requests: Alessandro Repici, MD, Digestive Endoscopy Unit, IRCCS Istituto Clinico Humanitas, Via Manzoni 56, Rozzano (MI), 20089 Italy.
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