Argon plasma coagulation in Barrett's esophagus

Gastrointest Endoscopy Clin N Am 13 (2003) 457 – 466

Argon plasma coagulation in Barrett’s esophagus Denis Franchimont, MD, PhD, Jean-Luc Van Laethem, MD, PhD, Jacques Devie`re, MD, PhD* Gastroenterology Department, Hoˆpital Erasme – Universite´ Libre de Bruxelles, Brussels, Belgium

Barrett’s esophagus is defined by the replacement of squamous esophageal epithelium by intestinal metaplasia in the distal esophagus. Barrett’s esophagus is a fairly frequent complication of gastroesophageal reflux disease (GERD); 5% to 10% of patients with GERD suffer from Barrett’s esophagus. GERD is essential for the development of Barrett’s esophagus [1]. Intestinal metaplasia is a premalignant lesion that may develop further into dysplasia and lead to adenocarcinoma of the esophagus [2]. The latter accounts for almost 50% of esophageal cancer cases in western countries; the largest increase in its incidence was recorded during the past two decades [3]. Patients with Barrett’s esophagus have a 2% to 25% risk of developing mild-to-severe dysplasia and a 2% to 5% risk of having adenocarcinoma, namely 30 to 150 times higher than the risk of the general population. Forty percent to 50% of Patients who have Barrett’s esophagus with high-grade dysplasia can develop adenocarcinoma within 5 years [4,5]. Esophageal adenocarcinoma is associated with a poor prognosis because of its delayed diagnosis. Endoscopy screening and surveillance programs therefore may recognize earlier adenocarcinoma that can be treated adequately. It remains controversial, however, whether such screening and surveillance in the general population will decrease the incidence of adenocarcinoma and improve the survival of these patients. Furthermore, whether screening and surveillance are cost-effective remains a matter of considerable debate [6 –8]. Medical therapies using high doses of proton pump inhibitors (PPIs) or surgical therapies (eg, fundoplication) have been proposed to reverse Barrett’s esophagus and abrogate the trigger event in the cascade of the metaplasia –dysplasia – cancer sequence, namely GERD. On the one hand, retrospective surgical therapies have however failed to demonstrate a significant benefit in BE regression and on * Corresponding author. E-mail address: [email protected] (J. Devie`re). 1052-5157/03/$ – see front matter D 2003 Elsevier Inc. All rights reserved. doi:10.1016/S1052-5157(03)00040-0

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the development of adenocarcinoma [9– 11]. Similarly, high doses of PPIs offer only a modest remission, with partial restoration of squamous islands within the intestinal metaplasia [12 – 18]. With therapeutic endoscopy, ablation of Barrett’s esophagus stands as an attractive alternative treatment that could impact directly on the risk of tumor development. Recent studies using laser therapy (Nd:YAG), photodynamic therapy (PDT), and multipolar electrocoagulation (MPEC) could demonstrate, combined with profound acid suppression, significant Barrett’s esophagus regression with eradication of intestinal metaplasia and squamous re-epithelialization of the targeted lesions. These techniques are expensive [19 –22], however. Moreover, PDT is associated with significant complications (eg, esophageal strictures occur in one-third of patients treated with PDT).

Argon plasma therapy technology Argon plasma coagulation is a thermal coagulation technique that is inexpensive, easy to use, effective, safe, and allows treatment of large surface areas. The argon plasma coagulation device consists of a contact-free monopolar highfrequency probe that delivers electrical energy through an ionized plasma of argon gas to the target tissue, engendering tissue surface coagulation. The APC system (Argon beemer II, ERBE Elektromedizin, Tubingen, Germany) includes the argon gas source with gas flow meter, a high-frequency electrosurgical generator, and flexible Teflon delivery catheters that can be passed through the operator channel of the endoscope. Different diameters and lengths exist for the APC probes that can deliver the plasma parallel or perpendicular to the axis of the catheter. The coagulation depth is approximately controlled to 1 to 3 mm because of the physical properties of the electrically insulating zone of tissue desiccation, which confers increased electrical resistance and contributes to limit depth of coagulation. Depth of injury is dependent on generator power setting (0 –155 W, ie, 30 –90 W for Barrett’s esophagus ablation), argon gas flow rate (0.5 –7 L per minute, ie, 1 –2 L for Barrett’s esophagus ablation), probe – tissue distance (2– 8 mm), and duration of application (0.5 – 2 seconds) [23]. When applied in Barrett esophagus, APC generates a white coagulum either circumferentially, point-by-point for a short segment, or by achieving longitudinal strips in a backward direction during withdrawal of the endoscope.

Studies on argon plasma coagulation in nondysplastic Barrett’s esophagus Short-term results Several groups of investigators have evaluated the effectiveness of APC in Barrett’s esophagus ablation associated with PPI treatment for patients having nondysplastic Barrett’s esophagus [24 – 32]. After one to eight APC sessions, a success rate of complete (histological) Barrett’s esophagus eradication ranging from 68%

Authors

Patients

APC sessions (median, range)

APC power setting (W)

Length of Barrett’s esophagus (cm) (range)

PPI doses during treatment

Endoscopic ablation (%)

Residual intestinal metaplasia (%)

Mork et al [27] Van Laethem et al [31] Byrne et al [25] Grade et al [26]

15 31

4 (1 – 8) 2.4 (1 – 4)

60 60

Median 4 (2 – 8) Mean 4.5 (3 – 11)

Omeprazole 60 mg/day Omeprazole 40 mg/day

86.7% 81%

0% 24%

30 9

60 60

Median 5 (3 – 17) Mean 3.5 (UK)

Omeprazole 20 – 40 mg/day Lansoprazole 60 – 90 mg/day

100% 100%

30% 22%

Pereira-Lima et al [29] Schultz et al [30] Morris et al [28] Basu et al [24] Kahaleh et al [32]

33

4 (2 – 7) Mean 1.7 (1 – 3) Mean 1.96 (1 – 4) 2 (1 – 4) Mean 3 (?) 4 (1 – 8) 3 (1 – 4)

65 – 70

Median 4 (0.5 – 7)

Omeprazole 60 mg/day

100%

0%

90 UK 30 60

Median 4 (1 – 12) Mean 6 (3 – 15) Mean 5.9 (3 – 19) Mean 4.7 (2 – 11)

Omeprazole Omeprazole Omeprazole Omeprazole

98.6% UK 68% 70%

0% 30% 44% 18%

73 53 50 39

Abbreviation: UK, unknown.

120 mg/day 20 – 60 mg/day 20 mg/day 40 mg/day

D. Franchimont et al / Gastrointest Endoscopy Clin N Am 13 (2003) 457–466

Table 1 Studies on argon plasma coagulation in nondysplastic Barrett’s esophagus: short-term results

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to 100% was achieved (Table 1). Partial regression also could be observed in some patients with a significant Barrett’s esophagus length reduction. Highest success rates seemed to be observed by upgrading the APC power setting 30 to 90 W, with increased incidence of strictures, however [29,30]. Endoscopic ablation of Barrett’s esophagus (68% to 100%) was not always associated with histological eradication of intestinal metaplasia (55% to 100%). In fact, remaining buried glands and persisting intestinal metaplasia under the squamous re-epithelialization were reported with a frequency of 0% to 44% in areas where Barrett’s esophagus was eliminated endoscopically (see Table 1). Again, the use of higher power setting of APC resulting in a deeper injury and higher PPI doses may account for the very low incidence of residual buried glands observed in more recent clinical trials. Complications Chest discomfort and odynophagia were very frequent after APC sessions and easily managed by antacids and simple analgesia. Severe complications were unusual, although non-negligible, because they include strictures [29 –31], fever [29], bleeding [31], or even perforation and death (Table 2) [25,29]. Perforations and strictures occurred early during the trial at the beginning of the learning curve. Strictures were associated with higher APC power setting and required one to three balloon dilatations. One blood transfusion was necessary for an upper gastrointestinal (GI) bleeding occurring 1 week after an APC session, probably because of the detachment of a scar [31]. Fever with pleural effusions was frequent in one study and may have been related to micro-perforations [29]. Perforations (n = 5) were the most serious complications; two perforations

Table 2 Complications of argon plasma coagulation in Barrett’s esophagus Authors

Patients

Retrosternal pain

Odynophagia

Fever

Strictures

Perforation

Mork et al [27] Van Laethem et al [31] Byrne et al [25] Grade et al [26] Pereira-Lima et al [29] Schultz et al [30] Morris et al [28] Basu et al [24]

15

7(46%)

1(6.7%)

0 (0%)

0 (0%)

0 (0%)

0 (0%)

2 (6.4%)

0 (0%)

31 30 9

2 (6.4%) UK

UK

0 (0%)

0 (0%)

2 (6.7%)

6(66%)

1 (11%)

0 (0%)

0 (0%)

0 (0%)

5 (15%)

3 (9%)

1 (3%)

0 (0%)

3 (4.3%)

0 (0%)

33

18 (54.5%) 28 (38.4%)

73 53

UK

UK

0 (0%)

0 (0%)

2 (4%)

50

UK

UK

UK

UK

UK

Abbreviation: UK, unknown.

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resolved with conservative medical treatment and parenteral nutrition; three were addressed for thoracotomy and drainage, two of which died postoperatively [25,28,29]. That is difficult to justify in patients with nondysplastic Barrett’s for whom endoscopic surveillance is very effective, and this is a major concern to rule out the use of APC in routine for this indication. Long-term results The encouraging results in terms of re-epithelialization turned out to be, however, disappointing in the long-term, with relapses of intestinal metaplasia with positive biopsies ranging from 0% to 68% when performing endoscopic follow-up (at an average of 12 months) in patients successfully treated (Table 3) [24 – 31]. Follow-up in these studies was short and averaged 12 months. Recently, Kahaleh et al examined 39 patients, with median follow-up of 36 months [12 – 46] to identify the predictive factors of Barrett’s esophagus reversal [32]. According to univariate analysis, significant predictors were female gender, short length of Barrett’s esophagus segment, and normalization of esophageal exposure to acid under PPI treatment as shown on 24 hour pH monitoring. Multivariate analysis revealed that short Barrett’s esophagus and normalization of acid exposure were the only independent predictive factors for sustained long-term re-epithelialization. That length of Barrett’s esophagus is a predictive factor already reported in previous studies is obvious; short intestinal metaplasia areas are easier to eradicate than larger areas. Adequate and optimal acid suppression should have been suspected when recent clinical trials demonstrated almost no Barrett’s esophagus relapse with very high Table 3 Studies on argon plasma coagulation in nondysplastic Barrett’s esophagus: long-term results

Authors

Patients

APC power setting (W)

PPI dose maintenance

Mork et al [27]

15

60

Van Laethem et al [31] Byrne et al [25]

31

60

30

60

Omeprazole 20 – 60 mg/day Omeprazole 10 or 40 mg/day Omeprazole 20 mg/day Omeprazole 30 mg/day Omeprazole 20 or 40 mg/day Omeprazole 20 – 60 mg/day Omeprazole 20 – 60 mg/day Omeprazole 20 or 40 mg/day

Pereira-Lima et al [29] Schultz et al [30]

33

65 – 70

73

90

Morris et al [28]

53

UK

Basu et al [24]

50

30

Kahaleh et al [32]

39

60

Abbreviation: UK, unknown.

Median follow-up (months) 6 – 13

Intestinal metaplasia on follow-up (%) 7.6%

12

47%

9

30%

10.6

3%

12

0%

38.5

UK

14

68%

36

62%

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doses of PPI (omeprazole 60 – 120 mg) [30]. In the Kahaleh study, patients with normal pH monitoring relapsed less than patients with abnormal monitoring results (12.5% versus 83%) while receiving PPIs. Basu et al observed a higher rate of Barrett’s recurrence in patients who had reduced their PPI use [24]. This suggests that, once the eradication is obtained, patients should receive prolonged high doses PPI therapy to avoid recurrence. Patients taking PPIs with normal pH monitoring still may relapse, however. Indeed, acid and biliary refluxes are significantly higher in patients with Barrett’s esophagus than in controls or patients with GERD [33,34]. A trend for more severe biliary reflux was observed among patients with persistent Barrett’s esophagus at the end of treatment in the Basu study [24]. This emphasizes that acid reflux is not the only factor to be considered when looking after the mechanisms affecting outcome of such therapy [35]. Another concern with this technique is the description of two cases of adenocarcinoma arising under the squamous re-epithelialization [36,37]. These adenocarcinomas may have progressed during follow-up from residual buried glands and may have been missed by routine surveillance biopsies. Such discovery is frightening when considering the high percentage of residual buried glands after treatment and the relapse rates of intestinal metaplasia on longer follow-up. In the long term follow-up of the authors cases, two cases of adenocarcinoma were observed, representing an incidence of adenocarcinoma very similar to the one observed in the general Barrett’s esophagus population [32]. This not only suggests that surveillance (and biopsies targeting) could become more difficult after treatment completion but also questions the final objective of such ablative therapy, that is cancer prevention. Cost-effectiveness Cost-effectiveness studies are not available for ablative therapies. If successful in all patients, the cost of a median of three endoscopic therapy sessions is not minor. Moreover, the cost of potential complication management must be taken into account, and this may be significant, especially when using higher power rate. Furthermore, life-long maintenance therapy with high doses of PPI also will increase the price of this ablative therapy dramatically. APC treatment would be justified if no further follow-up were needed. Considering that fewer than 50% of the patients are cleared from BE and, hence, surveillance could not be avoided, APC in nondysplastic Barrett’s esophagus increases the cost of managing patients without evidence of clinical benefit. Therefore, not only should it not be performed outside of rigorous clinical trials, but the potential usefulness of new trials should be analyzed carefully.

Studies on argon plasma coagulation in dysplastic Barrett’s esophagus There are two major ablative therapies that appear to be useful for Barrett’s esophagus patients with high-grade dysplasia or early carcinoma: namely PDT

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Table 4 Argon plasma coagulation in dysplastic Barrett’s esophagus Authors

LGD

HGD

TIS

Ablation

Relapse

Mork et al [27] Van Laethem et al [31] Byrne et al [25] Pereira-Lima et al [29] Schultz et al [30] Morris et al [28] Basu et al [24] Van Laethem et al [45] Kahaleh et al [32]

2 5 4 14 0 9 0 0 7

0 0 3 1 0 9 0 7 0

0 0 0 0 0 0 0 3 0

100% 100% 100% 100% —— 100% —— 80% (8/10) 57% (4/7)

0% 0% 0% 0% —— 0% —— 20% (2/10) 100% (4/4)

Abbreviations: HGD, high-grade dysplasia; LGD, low-grade dysplasia; TIS, tumor in situ.

and mucosectomy [20,22,38 – 44]. They provide interesting results for selected esophageal lesions, especially in the elderly, in patients at higher risk of surgery, or in nonoperable patients [40]. They have some limitations, however, including, for PDT, the need of expensive equipment and a significant rate of complications. For mucosectomy, they include the need for endoscopic expertise (which also means a large case volume). APC therefore could represent a low cost and relatively easier alternative to these techniques. Few data are available on the use of APC in this indication (Table 4). Success rates of 57% to 100% [45] were reported in eradicating high-grade dysplasia or intramucosal adenocarcinoma, with a limited follow-up. These data suggested that APC could be advocated in the absence of endoscopically recognizable mucosal lesions (ie, mucosal thickening or nodules) and in the absence of abnormalities detected at endoultrasonography [45]. Additionally, it might be promising in short dysplastic Barrett’s segments [46]. Unfortunately, this latter indication also represents an ideal case for mucosectomy, which provides histological material and allows assessment of treatment completion.

Summary Despite the availability of many clinical trials, there is no evidence that APC has any role in the management of Barrett’s esophagus. Ablation therapy is not indicated for nondysplastic Barrett’s esophagus (and this is true, whatever the technique used), and it should not be performed outside of a carefully designed and approved clinical trial. Indeed, these patients have a low risk of cancer, and there is no evidence that Barrett’s esophagus ablation will be of any benefit for these patients. In some cases, APC could be of some help, especially for treating short segments of dysplastic Barrett’s esophagus. In this field, however, it competes with the growing indication of mucosectomy, which clearly offers advantages in terms of treatment’s quality control assessment.

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