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Plastic prosthesis versus expandable metal stents for palliation of inoperable esophageal thoracic carcinoma: a controlled prospective study
0016-5107/96/4305-047855.00 + 0 GASTROINTESTINAL ENDOSCOPY Copyright © 1996 by the American Society for Gastrointestinal Endoscopy
Plastic prosthesis versus expandable metal stents for palliation of inoperable esophageal thoracic carcinoma: a controlled prospective study Giovanni D, De Palma, MD, Elio di Matteo, MD, Giovanni Romano, MD Antonio Fimmano, MD, Gennaro Rondinone, MD, Carlo Catanzano, MD Naples, Italy
Background: Rapid palliation of malignant dysphagia is usually possible with endoscopic implantation of a plastic prosthesis, but this device has a high rate of complications. Recently, expandable metal stents, a new class of endoprosthesis, have become available and may reduce complication rates. Methods: Thirty nine patients affected by esophageal thoracic cancer were randomly assigned to treatment with either a plastic stent (20 patients) or expandable metal stent (19 patients). The degree of palliation (expressed as dysphagia score) and incidence of complications (short- and long-term) were compared in both treatment groups. Results: Technical success, as a percentage of successful intubation, was similar in both treatment groups (90% vs 94.7%, p = NS) and dysphagia scores improved significantly and similarly in both treatment groups. Nevertheless, complications and mortality related to implantation were significantly less frequent with metal stents than with plastic prostheses (complications: 0% vs 21%, p < 0.001; mortality: 0% vs. 15.8%, p < 0.001). Late complications included obstruction by food in both treatment groups (four cases with plastic stents vs four cases with metal stents), tube migration only with plastic prostheses (two cases) and tumor ingrowth only with metal stents (two cases). Conclusions: Expandable metal stents can be considered an effective and safer alternative to conventional plastic prostheses in the treatment of esophageal obstruction caused by inoperable cancer. (Gastrointest Endosc 1996; 43:478-82.) Endoscopic intubation is well established as an inexpensive, quick, and long-lasting palliation of malignant dysphagia. Whereas intubation has been successful in more than 90% of cases, acute procedure-related complications occur in about 20% of patients and death related to such complications occurs in as much
Received December 9, 1994. For revision April 6, 1995. Accepted August 7, 1995. From the Servizio Centralizzato di Endoscopia Digestiva Operatoria, Universit& Federico II di Napoli, Facolth di Medicina e Chirurgia, Naples, Italy. Reprint requests: Giovanni De Palma, MD, Via De Gasperi n. 7, 80033 Cicciano (Napoli), Italy. 37/1/68425 478
GASTROINTESTINAL ENDOSCOPY
as 8% of patients. Moreover, over the long term, frequent dysfunction of the prosthesis is caused by migration and obstruction by food or tumor. 1-3 Recently a new class ofendoprostheses (expandable metal stents) t h a t has become available may reduce complication rates. 4-s In contrast to conventional prostheses, expandable metal stents can theoretically be inserted without significant tumor dilation. As such, acute placement-related complications, such as perforation or major hemorrhage, are potentially minimized, and placement success rates remain high. Over the past 18 months we conducted a trial comparing traditional prostheses with self-expanding metal stents in palliative treatment of esophageal cancer. VOLUME 43, NO. 5, 1996
PATIENTS AND METHODS Study design This study was prospective and controlled (plastic stents versus self-expanding metal stents). Criteria of inclusion were as follows: (1) esophageal thoracic carcinoma or (2) recurrent malignant stricture after surgery or laser therapy in (3) patients with contraindications for radical surgery because of locally advanced extension or wide dissemination of tumor or a tumor that is inoperable due to medical illness. Patients with cervical or cardial cancers and patients with esophagorespiratory fistulas were excluded from this study. The evaluation of the results was based on the following parameters: (1) technical success (as percentage of successful intubations); (2) functional success (as improvement of dysphagia graded according to the following criteria9: grade 0, normal swallowing; grade 1, able to swallow some but not all solids; grade 2, able to swallow semi-solids; grade 3, able to swallow fluids only; grade 4, complete dysphagia); (3) incidence of acute complications; and (4) long-term results (as incidence of late complications, recurrence of dysphagia due to prosthesis malfunction, and survival).
Evaluation of results The results were expressed as means. Differences between the two treatment groups were tested by the MannWhitney U test or Fisher's exact probability test, as appropriate. The results of the two treatments were compared by chi-squared test. Differences in survival rates were tested with life-table analysis (Kaplan-Meir).
Patients Between January 1993 and June 1994, 39 patients affected by esophageal carcinoma were referred to our service for endoscopic palliation of dysphagia. The patients were allocated by the random number table of Fisher and Yates to traditional stent (group A, 20 patients) or expandable metal stent (group B, 19 patients). The groups were similar in age range (group A, 58 to 89 years; group B, 60 to 86 years), tumor length (group A mean, 7.9 cm; group B mean, 7.8 cm) and grade of dysphagia (group A mean, 3; group B mean, 2.9). The patient details are included in Table 1.
Prosthesis and implantation technique In group A we utilized a Wilson-Cook prosthesis (WilsonCook, Winston-Salem, N.C.) constructed of plastic material and reinforced with a metallic core, allowing a 12 mm channel. Our placement method utilized a Savary system. Following dilation to 18 to 20 mm, the 10.5 mm dilator, stent, and pusher tube were fluoroscopically passed over a guide wire (Eder-Puestow, Key Medical Inc., Essex, U.K.) until the stent funnel was at the level of the proximal tumor shoulder. The dilator was then removed, followed by the pusher and the guide wire. In group B we utilized an Ultraflex esophageal prosthesis (Microvasive, Boston Scientific Corp., Watertown, Mass.). The prosthesis is constructed ofElastalloy, a titanium-based alloy that exhibits cross-sectional elasticity, thus allowing compression of the prosthesis into a small (8 mm) delivery system. The compressed prosthesis is encased in a gelatin VOLUME 43, NO. 5, 1996
Table 1. Characteristics of 39 patients affected by inoperable esophageal thoracic cancer Plastic prosthesis (n = 20)
Metal stent (n = 19)
15/5 69.4 7.9 16
16/3 67.8 7.8 16
3 1 3
1 2 2.9
Sex (M/F) Mean age (yr) Mean tumor length (cm) Primary esophageal cancer Recurrence after Surgery Laser therapy Median dysphagia score before treatment
cover, which, upon exposure to body temperature and moisture, dissolves and allows the stent to expand to its full 18 mm diameter. The stents were fluoroscopically placed over a guide wire with predilation to 10 to 12 mm. A prosthesis 4 to 6 cm longer than the stricture was chosen and advanced until the distal inner radiopaque marker was 2 to 3 cm beyond the distal margin of the tumor. An Olympus GIF Q 20 endoscope (Olympus Corp., Hamburg, Germany) was inserted for control of the proximal end of the prosthesis. After the proximal and distal ends of the prosthesis were expanded the delivery system was removed and a 12 mm diameter ballon (Rigiflex, Microvasive) was inflated within the prosthesis to provide adequate esophageal lumen size for endoscopic examination. In both treatment groups an esophagogram with meglumine diatrizoate (Gastrografin) was performed 24 hours after placement to evaluate stent functioning and to exclude a perforation. No subsequent treatments, such as chemotherapy or radiation therapy, were performed in either group.
RESULTS Immediate results and acute complications I n group A technical success was achieved in 18 of 20 p a t i e n t s (90%). I n two p a t i e n t s it proved impossible to position the endoprosthesis because of inadeq u a t e dilation of the stenosis. I n 12 of 20 p a t i e n t s the prosthesis h a d to be inserted u n d e r general anesthesia because of considerable p a t i e n t pain caused by p r e l i m i n a r y dilation. Acute complications occurred in four patients (22.2%) d u r i n g i m p l a n t a t i o n of the tube. Perforation of the e s o p h a g u s was observed in t h r e e patients (16.6%) a n d in two (11.1%) cases it proved fatal. Acute bleeding was observed in one patient, who died two days after s t e n t implantation. I m m e d i a t e l y after stent imp l a n t a t i o n the d y s p h a g i a g r a d e dropped significantly, from 3 to 1. I n group B technical success was achieved in 18 of 19 p a t i e n t s (94.7%). I n one p a t i e n t we observed incomplete expansion of the prosthesis because of severe t u m o r compression a n d m a r k e d l u m e n a l angulaGASTROINTESTINAL ENDOSCOPY
479
Table 2. Plastic stents versus metal stents in palliative treatment of esophageal thoracic cancer: immediate results Plastic prosthesis (n = 20) Technical success (%) Median dysphagia score after t r e a t m e n t Complications* Perforation Hemorrhage Seven-day mortality*
18 (90) 1 4 (22.2%) 3 1 3 (16.6%)
Metal stent (n = 19) 18 (94.7) 0.5 0 0 0 0
*p = 0.001.
tion; the patient underwent surgical gastrostomy. In another case the complete bridging of stenoses required the use of two stents because of proximal dislocation of the stent during delivery system removal. In all cases the prosthesis was inserted without general anesthesia and under intravenous sedation (diazepam 5 to 10 mg). No treatment complications were noted and all patients were discharged from the hospital. Immediately after stent implantation, the dysphagia grade dropped significantly, from 2.9 to 0.5. Table 2 shows the comparison of immediate results of the treatment groups. Long-term results, late complications, and survival Long-term results (follow-up at least 30 days after stent implantation) were obtained in 13 patients from group A. Two patients were lost to follow-up. We observed migration of the prosthesis in two cases 3 and 7 weeks after stenting, and repositioned the stents. Obstruction of the tube occurred in five cases: in four because of food and in one because of progressive tumor growth. In each case it proved possible to restore patency by endoscopic removal of the food remnants or, in the case of tumor obstruction, by laser therapy. The median survival time was 6.2 months. In group B two patients were lost to follow-up but long-term results were obtained in 16 patients. Four patients had episodes of acute dysphagia 2, 3, 5, and 7 weeks, respectively, after stenting. Endoscopy revealed food impaction of the prosthesis and recannalization could be achieved by means of endoscopic irrigation. Dysphagia recurred in two additional patients because of tumor infiltration of the stent lumen 96 and 115 days, respectively, after insertion. In one patient recannalization could be achieved by endoscopic laser therapy; the second patient underwent surgical gastrostomy. No dislocations of prostheses were observed during the follow-up period. The median survival time was 6.6 months. Table 3 shows the comparison of long-term results in the treatment groups. 480
GASTROINTESTINAL ENDOSCOPY
Table 3. Plastic stents versus metal stents in palliative treatment of esophageal thoracic cancer: long-term results Plastic prosthesis (n 13)
Metal stent (n 16)
2 4 1 0 6.2
0 4 0 2 6.6
=
Migration of prosthesis Obstruction by food Tumor overgrowth Tumor ingrowth Median survival time (mo)
=
DISCUSSION Less than half the patients diagnosed as having carcinoma of the esophagus will be resectable and only a small percentage of these will be cured by surgery. Thus, for the majority of patients, good quality palliation is the management of choice. The major goal of palliative treatment is to relieve dysphagia quickly and permanently with minimal 'invasiveness and maximal patient comfort. Rapid palliation is usually possible with endoscopic placement of a plastic prosthesis, but this device has a high incidence of acute and long-term complications and high mortality rates. 1-3 A new alternative is a metal stent that promises reduced complications. There are various types of expandable metal stents including a Z configuration in the Gianturco model; a knitted mesh of tantalium or various alloys such as cobalt, iron, or nickel and titanium; or a spring in nickel-titanium alloy. Expansion after positioning is ensured by various procedures: balloon dilation, mechanical releases by pull-through catheter dislocation of a constraining membrane, and dissolution of a gelatin encasement so the memory of the alloy causes the stent to expand progressively in the stenoses. The insertion procedure with plastic stents, which necessitates prior dilation, is not only traumatic for the patient but also is associated with a considerable rate of acute complications--from 5% to 30%. 1-3 The risk of complications appears to be higher in patients who have previously undergone radiotherapy. In contrast to placement of conventional esophageal stents, placement of expandable metal stents does not require a large-bore bougienage, thereby minimizing t h e risk of perforation and facilitating the insertion procedure. A further advantage of the metal stent is that when fully expanded the luminal diameter is 18 mm, compared with 10 to 12 mm for most commercially available plastic stents. This allows the patient to enjoy a more normal diet. Major disadvantages of metal stents are tumor ingrowth, food impaction, and esophagobronchial fistula VOLUME 43, NO. 5, 1996
formation. Moreover, these devices are not removable once deployed. There have been several uncontrolled studies of successful implantation of metal stents for malignant esophageal obstruction, 4-s and only one controlled trial 1° (Wallstent vs plastic stents). In this study we compared a conventional prosthesis with a metal stent in a randomized prospective trial. The rate of technical success (as a percentage of successful intubation) was similar in both treatment groups (90% vs 94.7%, p = NS). Nevertheless, in contrast to the plastic prosthesis, the implantation procedure of metal stents is well-tolerated because of the smaller diameter of the delivery catheter, which can be inserted without significant tumor dilation. In our experience and according to other studies, 1-3 intubation with a conventional prosthesis is often a painful procedure and frequently requires general anesthesia (60%, in our experience). However, expandable metal stents can be inserted under intravenous sedation because the implantation procedure is less painful. Moreover, acute procedure-related complications and mortality were significantly less frequent with metal stents than with plastic stents (complications 0% vs 22%, p < 0.001). These results are remarkable for the absence of acute procedure-related complications in patients who received the expandable metal stents; this is unusual for placement of conventional stents. In our series, major complications such as perforation or hemorrhage occurred in more than 20% of patients who received plastic stents, a proportion slightly higher than in other reports 1, 2 and lower than in another, 3 but higher than in our previous report. 11 This was probably due to the aggressive policy of dilation of the tumor to the diameter required for stent insertion over a single session as performed in these patients. We generally perform a gradual dilation of the stenoses over several sessions before the day of stent placement, which certainly reduces the perforation rates. 12 In the short run, the functional success, as judged by improvement of dysphagia score, was similar in both treatment groups. In the long run, late complications included tube obstruction by food in both treatment groups (4 of 13 cases with plastic stents vs 4 of 16 cases with metal stents), tube migration only with plastic stents (2 cases) and tumor ingrowth only with metal prostheses (2 cases). Displacement is a problem with plastic stents that may require extraction and, if possible, replacement of the prosthesis. In contrast, when released, the uncoated metal mesh stents remain permanently in situ, which appears to be a considerable advantage. However, removal of uncoated metal stents may prove technically impossible, so accurate positioning of the prosthesis is essential. Tumor ingrowth is a problem VOLUME 43, NO. 5, 1996
that is peculiar to uncovered metal stents. The incidence of tumor ingrowth in our study is comparable to the incidence reported in other studies 4s, 10 and appears related to the length of survival. Treatment of ingrowth can usually be performed by laser, electrocoagulation, or photodynamic therapy, 13 or sometimes by insertion of a plastic prosthesis within the metal stent. 4 In one patient we successfully used laser therapy, but in another the laser beam could not be sufficiently directed toward the axis of the obstructed stent. Because the stent was not removable, it was necessary to perform surgical gastrostomy. In general, the results of our study are very similar to the only other controlled trial 10 of expandable metal stents versus plastic stents for palliation of esophageal obstruction caused by inoperable cancer. Moreover, in that study Knyrim et al. 1° demonstrated that the period of hospitalization after placement of a prosthesis was significantly longer in the group given plastic prostheses than in the group given metal stents and that, despite their higher initial cost, they were cost-effective because of the absence of fatal complications and the decrease in length of hospital stay. The results of these studies suggest that expandable metal stents are an effective and safe alternative to conventional prostheses in the management of malignant esophageal obstruction. However, uncovered metal stents are not appropriate for bronchoesophageal fistulas, and tumor ingrowth is a significant problem with these devices. Covered stents are highly effective in treating malignant esophagorespiratory fistulas and are associated with much lower rates of tumor ingrowth, 14, 15 but reported cases of stent migration may indicate that fixation of a covered metal stent is inferior to an uncovered device. Because of the irreversibility of stent implantation, misplacement may induce significant complications. We conclude that prospective controlled studies are needed to compare different types of expandable stents and evaluate which patients can effectively benefit from palliation of dysphagia with these new devices. REFERENCES 1. Parker CH, Peura DA. Palliative treatment of esophageal carcinoma using esophageal dilation and prosthesis. Gastroentero] C]in North Am 1991;20:719-29. 2. Tytgat GNJ, Huibregtse K. Endoscopic palliative therapy of gastrointestinal and biliary tumors with prosthesis. Clin Gastroenterol 1986;15:249-71. 3. Fugger R, Niederle B, Jantasch H. Endoscopic tube implantation of malignant esophageal stenoses. Endoscopy 1990;22: 101-4. 4. Neuhaus H, Hoffmann W, Dittler HJ, Classen M. Implantation of self-expanding esophageal metal stents for palliation of malignant dysphagia. Endoscopy 1992;24:405-10. 5. Kozarek RA, Ball TJ, Pattersen DJ. Metallic self-expanding stent application in the upper gastrointestinal tract: caveats and concerns. Gastrointest Endosc 1992;36:1-6.
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6. Schaer J, Katon RM, Naucev K, Achida B. Treatment of malignant esophageal obstruction with silicone-coated metallic selfexpanding stent. Gastrointest Endosc 1992;38:7-11. 7. Lightdale CJ. Self-expanding metal stents for esophageal and gastric cancer: a new opening. Gastrointest Endosc 1992;38: 86-8. 8. F]eischer DE, Bull-Henry K. A new coated self-expanding metal stent for malignant esophageal stricture. Gastrointest Endosc 1992;38:494-6. 9. Mellow MH, Pinkas H. Endoscopic laser therapy for malignancies affecting the esophagus and gastroesophageal junction: analysis of technical and functional efficacy. Ann Intern Med 1985;145:1443-6. 10. Knyrim K, Wagner HJ, Betge N, Vakil N..A controlled trial of an expandable metal stent for palliation of esophageal obstruction due to inoperable cancer. N Engl J Med 1993;329:1302-7.
11. Catanzano C, De Palma GD, Manguso L, et al. Endoscopic treatment of esophageal malignancies: personal experience. Giornale Italiano di Endoscopia Digestiva 1989;12:177-84. 12. Boyce HW Jr. Palliation of advanced esophageal cancer. Semin Oncol 1984;11:186-94. 13. Raijman I, Lalor E, Marcon NE. Photodynamic therapy for tumor ingrowth through an expandable esophageal stent. Gastrointest Endosc 1995;41:73-4. 14. Wu WC, Katon RM, Saxon RR, et al. Silicone-covered self-expanding metallic stents for the palliation of malignant esophageal obstruction and esophagorespiratory fistulas: experience in 32 patients and a review of the literature. Gastrointest Endosc 1994;40:22-34. 15. Song HY, Choi KC, Kwon HC, et al. Esophageal strictures: treatment with a new design of modified Gianturco stent. Radiology 1992;184:729-34.
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482 GASTROINTESTINAL ENDOSCOPY
VOLUME 43, NO. 5, 1996
Plastic prosthesis versus expandable metal stents for palliation of inoperable esophageal thoracic carcinoma: a controlled prospective study Giovanni D, De Palma, MD, Elio di Matteo, MD, Giovanni Romano, MD Antonio Fimmano, MD, Gennaro Rondinone, MD, Carlo Catanzano, MD Naples, Italy
Background: Rapid palliation of malignant dysphagia is usually possible with endoscopic implantation of a plastic prosthesis, but this device has a high rate of complications. Recently, expandable metal stents, a new class of endoprosthesis, have become available and may reduce complication rates. Methods: Thirty nine patients affected by esophageal thoracic cancer were randomly assigned to treatment with either a plastic stent (20 patients) or expandable metal stent (19 patients). The degree of palliation (expressed as dysphagia score) and incidence of complications (short- and long-term) were compared in both treatment groups. Results: Technical success, as a percentage of successful intubation, was similar in both treatment groups (90% vs 94.7%, p = NS) and dysphagia scores improved significantly and similarly in both treatment groups. Nevertheless, complications and mortality related to implantation were significantly less frequent with metal stents than with plastic prostheses (complications: 0% vs 21%, p < 0.001; mortality: 0% vs. 15.8%, p < 0.001). Late complications included obstruction by food in both treatment groups (four cases with plastic stents vs four cases with metal stents), tube migration only with plastic prostheses (two cases) and tumor ingrowth only with metal stents (two cases). Conclusions: Expandable metal stents can be considered an effective and safer alternative to conventional plastic prostheses in the treatment of esophageal obstruction caused by inoperable cancer. (Gastrointest Endosc 1996; 43:478-82.) Endoscopic intubation is well established as an inexpensive, quick, and long-lasting palliation of malignant dysphagia. Whereas intubation has been successful in more than 90% of cases, acute procedure-related complications occur in about 20% of patients and death related to such complications occurs in as much
Received December 9, 1994. For revision April 6, 1995. Accepted August 7, 1995. From the Servizio Centralizzato di Endoscopia Digestiva Operatoria, Universit& Federico II di Napoli, Facolth di Medicina e Chirurgia, Naples, Italy. Reprint requests: Giovanni De Palma, MD, Via De Gasperi n. 7, 80033 Cicciano (Napoli), Italy. 37/1/68425 478
GASTROINTESTINAL ENDOSCOPY
as 8% of patients. Moreover, over the long term, frequent dysfunction of the prosthesis is caused by migration and obstruction by food or tumor. 1-3 Recently a new class ofendoprostheses (expandable metal stents) t h a t has become available may reduce complication rates. 4-s In contrast to conventional prostheses, expandable metal stents can theoretically be inserted without significant tumor dilation. As such, acute placement-related complications, such as perforation or major hemorrhage, are potentially minimized, and placement success rates remain high. Over the past 18 months we conducted a trial comparing traditional prostheses with self-expanding metal stents in palliative treatment of esophageal cancer. VOLUME 43, NO. 5, 1996
PATIENTS AND METHODS Study design This study was prospective and controlled (plastic stents versus self-expanding metal stents). Criteria of inclusion were as follows: (1) esophageal thoracic carcinoma or (2) recurrent malignant stricture after surgery or laser therapy in (3) patients with contraindications for radical surgery because of locally advanced extension or wide dissemination of tumor or a tumor that is inoperable due to medical illness. Patients with cervical or cardial cancers and patients with esophagorespiratory fistulas were excluded from this study. The evaluation of the results was based on the following parameters: (1) technical success (as percentage of successful intubations); (2) functional success (as improvement of dysphagia graded according to the following criteria9: grade 0, normal swallowing; grade 1, able to swallow some but not all solids; grade 2, able to swallow semi-solids; grade 3, able to swallow fluids only; grade 4, complete dysphagia); (3) incidence of acute complications; and (4) long-term results (as incidence of late complications, recurrence of dysphagia due to prosthesis malfunction, and survival).
Evaluation of results The results were expressed as means. Differences between the two treatment groups were tested by the MannWhitney U test or Fisher's exact probability test, as appropriate. The results of the two treatments were compared by chi-squared test. Differences in survival rates were tested with life-table analysis (Kaplan-Meir).
Patients Between January 1993 and June 1994, 39 patients affected by esophageal carcinoma were referred to our service for endoscopic palliation of dysphagia. The patients were allocated by the random number table of Fisher and Yates to traditional stent (group A, 20 patients) or expandable metal stent (group B, 19 patients). The groups were similar in age range (group A, 58 to 89 years; group B, 60 to 86 years), tumor length (group A mean, 7.9 cm; group B mean, 7.8 cm) and grade of dysphagia (group A mean, 3; group B mean, 2.9). The patient details are included in Table 1.
Prosthesis and implantation technique In group A we utilized a Wilson-Cook prosthesis (WilsonCook, Winston-Salem, N.C.) constructed of plastic material and reinforced with a metallic core, allowing a 12 mm channel. Our placement method utilized a Savary system. Following dilation to 18 to 20 mm, the 10.5 mm dilator, stent, and pusher tube were fluoroscopically passed over a guide wire (Eder-Puestow, Key Medical Inc., Essex, U.K.) until the stent funnel was at the level of the proximal tumor shoulder. The dilator was then removed, followed by the pusher and the guide wire. In group B we utilized an Ultraflex esophageal prosthesis (Microvasive, Boston Scientific Corp., Watertown, Mass.). The prosthesis is constructed ofElastalloy, a titanium-based alloy that exhibits cross-sectional elasticity, thus allowing compression of the prosthesis into a small (8 mm) delivery system. The compressed prosthesis is encased in a gelatin VOLUME 43, NO. 5, 1996
Table 1. Characteristics of 39 patients affected by inoperable esophageal thoracic cancer Plastic prosthesis (n = 20)
Metal stent (n = 19)
15/5 69.4 7.9 16
16/3 67.8 7.8 16
3 1 3
1 2 2.9
Sex (M/F) Mean age (yr) Mean tumor length (cm) Primary esophageal cancer Recurrence after Surgery Laser therapy Median dysphagia score before treatment
cover, which, upon exposure to body temperature and moisture, dissolves and allows the stent to expand to its full 18 mm diameter. The stents were fluoroscopically placed over a guide wire with predilation to 10 to 12 mm. A prosthesis 4 to 6 cm longer than the stricture was chosen and advanced until the distal inner radiopaque marker was 2 to 3 cm beyond the distal margin of the tumor. An Olympus GIF Q 20 endoscope (Olympus Corp., Hamburg, Germany) was inserted for control of the proximal end of the prosthesis. After the proximal and distal ends of the prosthesis were expanded the delivery system was removed and a 12 mm diameter ballon (Rigiflex, Microvasive) was inflated within the prosthesis to provide adequate esophageal lumen size for endoscopic examination. In both treatment groups an esophagogram with meglumine diatrizoate (Gastrografin) was performed 24 hours after placement to evaluate stent functioning and to exclude a perforation. No subsequent treatments, such as chemotherapy or radiation therapy, were performed in either group.
RESULTS Immediate results and acute complications I n group A technical success was achieved in 18 of 20 p a t i e n t s (90%). I n two p a t i e n t s it proved impossible to position the endoprosthesis because of inadeq u a t e dilation of the stenosis. I n 12 of 20 p a t i e n t s the prosthesis h a d to be inserted u n d e r general anesthesia because of considerable p a t i e n t pain caused by p r e l i m i n a r y dilation. Acute complications occurred in four patients (22.2%) d u r i n g i m p l a n t a t i o n of the tube. Perforation of the e s o p h a g u s was observed in t h r e e patients (16.6%) a n d in two (11.1%) cases it proved fatal. Acute bleeding was observed in one patient, who died two days after s t e n t implantation. I m m e d i a t e l y after stent imp l a n t a t i o n the d y s p h a g i a g r a d e dropped significantly, from 3 to 1. I n group B technical success was achieved in 18 of 19 p a t i e n t s (94.7%). I n one p a t i e n t we observed incomplete expansion of the prosthesis because of severe t u m o r compression a n d m a r k e d l u m e n a l angulaGASTROINTESTINAL ENDOSCOPY
479
Table 2. Plastic stents versus metal stents in palliative treatment of esophageal thoracic cancer: immediate results Plastic prosthesis (n = 20) Technical success (%) Median dysphagia score after t r e a t m e n t Complications* Perforation Hemorrhage Seven-day mortality*
18 (90) 1 4 (22.2%) 3 1 3 (16.6%)
Metal stent (n = 19) 18 (94.7) 0.5 0 0 0 0
*p = 0.001.
tion; the patient underwent surgical gastrostomy. In another case the complete bridging of stenoses required the use of two stents because of proximal dislocation of the stent during delivery system removal. In all cases the prosthesis was inserted without general anesthesia and under intravenous sedation (diazepam 5 to 10 mg). No treatment complications were noted and all patients were discharged from the hospital. Immediately after stent implantation, the dysphagia grade dropped significantly, from 2.9 to 0.5. Table 2 shows the comparison of immediate results of the treatment groups. Long-term results, late complications, and survival Long-term results (follow-up at least 30 days after stent implantation) were obtained in 13 patients from group A. Two patients were lost to follow-up. We observed migration of the prosthesis in two cases 3 and 7 weeks after stenting, and repositioned the stents. Obstruction of the tube occurred in five cases: in four because of food and in one because of progressive tumor growth. In each case it proved possible to restore patency by endoscopic removal of the food remnants or, in the case of tumor obstruction, by laser therapy. The median survival time was 6.2 months. In group B two patients were lost to follow-up but long-term results were obtained in 16 patients. Four patients had episodes of acute dysphagia 2, 3, 5, and 7 weeks, respectively, after stenting. Endoscopy revealed food impaction of the prosthesis and recannalization could be achieved by means of endoscopic irrigation. Dysphagia recurred in two additional patients because of tumor infiltration of the stent lumen 96 and 115 days, respectively, after insertion. In one patient recannalization could be achieved by endoscopic laser therapy; the second patient underwent surgical gastrostomy. No dislocations of prostheses were observed during the follow-up period. The median survival time was 6.6 months. Table 3 shows the comparison of long-term results in the treatment groups. 480
GASTROINTESTINAL ENDOSCOPY
Table 3. Plastic stents versus metal stents in palliative treatment of esophageal thoracic cancer: long-term results Plastic prosthesis (n 13)
Metal stent (n 16)
2 4 1 0 6.2
0 4 0 2 6.6
=
Migration of prosthesis Obstruction by food Tumor overgrowth Tumor ingrowth Median survival time (mo)
=
DISCUSSION Less than half the patients diagnosed as having carcinoma of the esophagus will be resectable and only a small percentage of these will be cured by surgery. Thus, for the majority of patients, good quality palliation is the management of choice. The major goal of palliative treatment is to relieve dysphagia quickly and permanently with minimal 'invasiveness and maximal patient comfort. Rapid palliation is usually possible with endoscopic placement of a plastic prosthesis, but this device has a high incidence of acute and long-term complications and high mortality rates. 1-3 A new alternative is a metal stent that promises reduced complications. There are various types of expandable metal stents including a Z configuration in the Gianturco model; a knitted mesh of tantalium or various alloys such as cobalt, iron, or nickel and titanium; or a spring in nickel-titanium alloy. Expansion after positioning is ensured by various procedures: balloon dilation, mechanical releases by pull-through catheter dislocation of a constraining membrane, and dissolution of a gelatin encasement so the memory of the alloy causes the stent to expand progressively in the stenoses. The insertion procedure with plastic stents, which necessitates prior dilation, is not only traumatic for the patient but also is associated with a considerable rate of acute complications--from 5% to 30%. 1-3 The risk of complications appears to be higher in patients who have previously undergone radiotherapy. In contrast to placement of conventional esophageal stents, placement of expandable metal stents does not require a large-bore bougienage, thereby minimizing t h e risk of perforation and facilitating the insertion procedure. A further advantage of the metal stent is that when fully expanded the luminal diameter is 18 mm, compared with 10 to 12 mm for most commercially available plastic stents. This allows the patient to enjoy a more normal diet. Major disadvantages of metal stents are tumor ingrowth, food impaction, and esophagobronchial fistula VOLUME 43, NO. 5, 1996
formation. Moreover, these devices are not removable once deployed. There have been several uncontrolled studies of successful implantation of metal stents for malignant esophageal obstruction, 4-s and only one controlled trial 1° (Wallstent vs plastic stents). In this study we compared a conventional prosthesis with a metal stent in a randomized prospective trial. The rate of technical success (as a percentage of successful intubation) was similar in both treatment groups (90% vs 94.7%, p = NS). Nevertheless, in contrast to the plastic prosthesis, the implantation procedure of metal stents is well-tolerated because of the smaller diameter of the delivery catheter, which can be inserted without significant tumor dilation. In our experience and according to other studies, 1-3 intubation with a conventional prosthesis is often a painful procedure and frequently requires general anesthesia (60%, in our experience). However, expandable metal stents can be inserted under intravenous sedation because the implantation procedure is less painful. Moreover, acute procedure-related complications and mortality were significantly less frequent with metal stents than with plastic stents (complications 0% vs 22%, p < 0.001). These results are remarkable for the absence of acute procedure-related complications in patients who received the expandable metal stents; this is unusual for placement of conventional stents. In our series, major complications such as perforation or hemorrhage occurred in more than 20% of patients who received plastic stents, a proportion slightly higher than in other reports 1, 2 and lower than in another, 3 but higher than in our previous report. 11 This was probably due to the aggressive policy of dilation of the tumor to the diameter required for stent insertion over a single session as performed in these patients. We generally perform a gradual dilation of the stenoses over several sessions before the day of stent placement, which certainly reduces the perforation rates. 12 In the short run, the functional success, as judged by improvement of dysphagia score, was similar in both treatment groups. In the long run, late complications included tube obstruction by food in both treatment groups (4 of 13 cases with plastic stents vs 4 of 16 cases with metal stents), tube migration only with plastic stents (2 cases) and tumor ingrowth only with metal prostheses (2 cases). Displacement is a problem with plastic stents that may require extraction and, if possible, replacement of the prosthesis. In contrast, when released, the uncoated metal mesh stents remain permanently in situ, which appears to be a considerable advantage. However, removal of uncoated metal stents may prove technically impossible, so accurate positioning of the prosthesis is essential. Tumor ingrowth is a problem VOLUME 43, NO. 5, 1996
that is peculiar to uncovered metal stents. The incidence of tumor ingrowth in our study is comparable to the incidence reported in other studies 4s, 10 and appears related to the length of survival. Treatment of ingrowth can usually be performed by laser, electrocoagulation, or photodynamic therapy, 13 or sometimes by insertion of a plastic prosthesis within the metal stent. 4 In one patient we successfully used laser therapy, but in another the laser beam could not be sufficiently directed toward the axis of the obstructed stent. Because the stent was not removable, it was necessary to perform surgical gastrostomy. In general, the results of our study are very similar to the only other controlled trial 10 of expandable metal stents versus plastic stents for palliation of esophageal obstruction caused by inoperable cancer. Moreover, in that study Knyrim et al. 1° demonstrated that the period of hospitalization after placement of a prosthesis was significantly longer in the group given plastic prostheses than in the group given metal stents and that, despite their higher initial cost, they were cost-effective because of the absence of fatal complications and the decrease in length of hospital stay. The results of these studies suggest that expandable metal stents are an effective and safe alternative to conventional prostheses in the management of malignant esophageal obstruction. However, uncovered metal stents are not appropriate for bronchoesophageal fistulas, and tumor ingrowth is a significant problem with these devices. Covered stents are highly effective in treating malignant esophagorespiratory fistulas and are associated with much lower rates of tumor ingrowth, 14, 15 but reported cases of stent migration may indicate that fixation of a covered metal stent is inferior to an uncovered device. Because of the irreversibility of stent implantation, misplacement may induce significant complications. We conclude that prospective controlled studies are needed to compare different types of expandable stents and evaluate which patients can effectively benefit from palliation of dysphagia with these new devices. REFERENCES 1. Parker CH, Peura DA. Palliative treatment of esophageal carcinoma using esophageal dilation and prosthesis. Gastroentero] C]in North Am 1991;20:719-29. 2. Tytgat GNJ, Huibregtse K. Endoscopic palliative therapy of gastrointestinal and biliary tumors with prosthesis. Clin Gastroenterol 1986;15:249-71. 3. Fugger R, Niederle B, Jantasch H. Endoscopic tube implantation of malignant esophageal stenoses. Endoscopy 1990;22: 101-4. 4. Neuhaus H, Hoffmann W, Dittler HJ, Classen M. Implantation of self-expanding esophageal metal stents for palliation of malignant dysphagia. Endoscopy 1992;24:405-10. 5. Kozarek RA, Ball TJ, Pattersen DJ. Metallic self-expanding stent application in the upper gastrointestinal tract: caveats and concerns. Gastrointest Endosc 1992;36:1-6.
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6. Schaer J, Katon RM, Naucev K, Achida B. Treatment of malignant esophageal obstruction with silicone-coated metallic selfexpanding stent. Gastrointest Endosc 1992;38:7-11. 7. Lightdale CJ. Self-expanding metal stents for esophageal and gastric cancer: a new opening. Gastrointest Endosc 1992;38: 86-8. 8. F]eischer DE, Bull-Henry K. A new coated self-expanding metal stent for malignant esophageal stricture. Gastrointest Endosc 1992;38:494-6. 9. Mellow MH, Pinkas H. Endoscopic laser therapy for malignancies affecting the esophagus and gastroesophageal junction: analysis of technical and functional efficacy. Ann Intern Med 1985;145:1443-6. 10. Knyrim K, Wagner HJ, Betge N, Vakil N..A controlled trial of an expandable metal stent for palliation of esophageal obstruction due to inoperable cancer. N Engl J Med 1993;329:1302-7.
11. Catanzano C, De Palma GD, Manguso L, et al. Endoscopic treatment of esophageal malignancies: personal experience. Giornale Italiano di Endoscopia Digestiva 1989;12:177-84. 12. Boyce HW Jr. Palliation of advanced esophageal cancer. Semin Oncol 1984;11:186-94. 13. Raijman I, Lalor E, Marcon NE. Photodynamic therapy for tumor ingrowth through an expandable esophageal stent. Gastrointest Endosc 1995;41:73-4. 14. Wu WC, Katon RM, Saxon RR, et al. Silicone-covered self-expanding metallic stents for the palliation of malignant esophageal obstruction and esophagorespiratory fistulas: experience in 32 patients and a review of the literature. Gastrointest Endosc 1994;40:22-34. 15. Song HY, Choi KC, Kwon HC, et al. Esophageal strictures: treatment with a new design of modified Gianturco stent. Radiology 1992;184:729-34.
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