INTRODUCTION — Barrett's esophagus (BE) is thought to be a complication of longstanding gastroesophageal reflux, resulting in the replacement of the normal squamous lining of the distal esophagus by columnar epithelium containing specialized intestinal metaplasia. (See "Epidemiology, clinical manifestations, and diagnosis of Barrett's esophagus".)
Endoscopic surveillance is recommended for patients with Barrett's esophagus because of its malignant potential in the hope of detecting dysplasia before it progresses to adenocarcinoma. Esophagectomy has traditionally been recommended for patients found to have high-grade dysplasia or early cancer. (See "Management of Barrett's esophagus".)
Endoscopic therapy has been proven to be a safe, effective, and less invasive alternative to surgery for treating such patients.
Endoscopic resection (ER) is an endoscopic approach in which the neoplastic epithelium is excised, thus allowing for a definitive histologic diagnosis, while also potentially being curative. ER has been applied not only to Barrett's esophagus with high-grade dysplasia but also to early cancer in which the risk of lymph node involvement or hematogenous dissemination is low enough to justify a relatively conservative approach compared with esophagectomy [1-8].
In Europe and Japan, ER is considered the mainstay of endoscopic management and ablative techniques are mainly used as an adjunct to ER. By contrast, in the United States, ablative techniques are more commonly used.
The experience with ER in patients with Barrett's esophagus who have high-grade dysplasia (HGD) or early cancer (EC) is discussed here. Photodynamic therapy, radiofrequency ablation, a general approach to Barrett's esophagus, and other treatment options for superficial esophageal cancer are presented separately. (See "Photodynamic therapy for ablation of Barrett's esophagus" and "Radiofrequency ablation for Barrett's esophagus" and "Management of Barrett's esophagus" and "Management of superficial esophageal cancer".)
EVALUATION FOR ELIGIBILITY — There are three major considerations in the evaluation of patients with Barrett's esophagus who have high-grade dysplasia or early cancer: histopathologic evaluation, the endoscopic work-up, and staging of the lesions.
Histopathologic evaluation — Esophageal neoplasia is usually classified according to the internationally accepted Vienna classification [13]. The Vienna classification is based upon the histopathologic evaluation of endoscopically acquired biopsies:
The distinction between categories 4 and 5 can be difficult since it depends in part upon the size, location, depth, and number of biopsies. In category 4, there is no obvious invasion beyond the epithelial basal membrane. Category 5 is subdivided based upon whether there is invasion into the lamina propria or muscularis mucosa (category 5.1, also referred to as intramucosal cancer) or into the submucosa (category 5.2, also referred to as submucosal cancer).
Another problem with the diagnosis of dysplasia in Barrett's epithelium is the interobserver reliability among pathologists. As a result, it is helpful to achieve a consensus (ie, from more than one pathologist) in categorizing such specimens. A consensus diagnosis has better predictive value regarding prognosis and may revise the original diagnosis, which can have implications for subsequent management [14,15]. These observations underlie the recommendation that a second, experienced pathologist should confirm the diagnosis of high-grade dysplasia. (See "Management of Barrett's esophagus".)
Endoscopic evaluation — Patients diagnosed with HGD or EC in Barrett's esophagus should undergo an endoscopic work-up in a center with expertise in evaluating such patients. The reasons for this are threefold:
Early neoplastic lesions in Barrett's esophagus are often difficult to detect with standard video endoscopy. Although a number of techniques have been proposed to increase the accuracy of endoscopic imaging (such as chromoendoscopy, magnification endoscopy, and optical coherence tomography), none is used routinely in clinical practice. (See "Chromoendoscopy" and "Magnification endoscopy" and "Narrow band imaging in Barrett's esophagus" and "Autofluorescence endoscopy for Barrett's esophagus" and "Confocal laser endomicroscopy and endocytoscopy" and "Optical coherence tomography in the gastrointestinal tract".)
Three general rules should be followed in the endoscopic evaluation of patients being considered for ER:
Use the best endoscope available — High-resolution endoscopy may have higher sensitivity for the detection of early BE neoplasia compared with standard video endoscopy systems [17,18]. Because early BE neoplasia often presents as flat lesions with only subtle mucosal abnormalities, most experts agree that high-resolution endoscopy is the preferred method for the endoscopic evaluation of BE.
Have a vigilant eye — Up to 80 percent of patients referred for evaluation of HGD or EC without visible abnormalities will have at least one visible abnormality detected in their BE upon endoscopic inspection by expert endoscopists [17,19]. Although early BE neoplasia generally presents as subtle flat lesions that can be difficult to detect, most state-of-the-art endoscopes are capable of revealing these abnormalities when viewed by highly experienced endoscopists. Thus, familiarity with the endoscopic appearance of early Barrett's neoplasia is essential for its diagnosis.
Perform a systematic endoscopic inspection — The detection of gross mucosal abnormalities such as elevations, ulcerations, and nodularities is relatively easy. By comparison, the detection of subtle abnormalities requires a more careful and thorough inspection, making a systematic approach imperative.
After intubation of the esophagus, the esophagus should be carefully cleaned to remove any mucus or saliva. Simple water flushes usually are sufficient but spraying acetylcysteine (1 percent) can be helpful if there is excessive or viscous mucus. It is important to suction all gastric secretions to prevent reflux into the esophagus that could interfere with inspection.
The endoscope should be gradually withdrawn to examine the BE segment for mucosal irregularities and to describe the extent of BE. One system for doing so uses the validated Prague C & M criteria, which assess the circumferential and maximum extent of the visualized BE segment [20]. After initial inspection, the inflated esophagus should be gradually deflated to reveal any irregularities that may have flattened during inflation, making them more difficult to see. Special attention should be paid to the area between 12 and 6 o'clock in the endoscopic view, where the majority of neoplastic lesions are found [21]. In addition, if a hiatal hernia is present, it is important to inspect the transition of the BE into the hiatal hernia in the retroflexed position, since abnormalities in this area are easily overlooked in the antegrade view.
The Seattle biopsy protocol is recommended for mapping Barrett's esophagus with HGD [22]. Targeted biopsies are obtained from all visible abnormalities and random four-quadrant biopsies are taken every 1 cm starting from the top of the gastric folds up to the most proximal extent of the BE (squamocolumnar junction).
Based upon the above observations, inspection and classification of all visible lesions should be followed by biopsies from each visible abnormality and then random four-quadrant biopsies. The biopsies should always start distally, working upwards to minimize bleeding that obscures visualization. We follow the rule "look longer, biopsy less" since, in our experience, the diagnosis of HGD or EC can be made in 80 to 90 percent of patients with these lesions by targeted biopsies after a thorough inspection [23]. However, random four-quadrant biopsies are still required, since 10 to 20 percent of lesions are missed with targeted biopsies alone.
Staging procedures — Among patients diagnosed with HGD or EC, other imaging techniques should be considered to evaluate tumor infiltration depth, local lymph node status, and metastatic spread. Endoscopic ultrasonography (EUS) and computerized tomography (CT scan) are the most widely used techniques.
Endoscopic ultrasound — EUS is the most accurate technique for locoregional staging of esophageal cancer. However, EUS is less reliable for T- and N-staging in patients with HGD and EC than in patients with more advanced esophageal cancer. In addition, accuracy is influenced by the experience of the endosonographer [24,25]. (See "Endoscopic ultrasound in esophageal carcinoma" and "Diagnosis and staging of esophageal cancer".)
High frequency miniprobes may improve the accuracy of T-staging compared with standard EUS, but the accuracy of N-staging appears to be inferior to standard EUS because, while it is higher resolution, the visualization is more superficial [24]. (See "High frequency catheter endoscopic ultrasonography".)
There appears to be limited added value of EUS for determining T-staging once tumor depth has been estimated by endoscopic inspection of the lesion of interest by an expert endoscopist [26,28].
CT scanning — The value of computed tomography (CT) scanning lies mainly in the detection of distant metastases. The risk for distant metastases is very low in patients with HGD or EC who show no signs of deep submucosal infiltration or suspicious lymph nodes on EUS. Thus, the value of CT is limited in such patients.
Other radiographic modalities — Other imaging techniques, such as positron emission tomography (PET) scanning and magnetic resonance imaging (MRI), do NOT have a role in the work-up of patients with esophageal HGD or EC.
Value of endoscopic resection for staging — We consider ER to be both a reasonable treatment option and also the final step in the diagnostic work-up of patients with HGD or EC in BE [29-31]. In one study, interobserver agreement about the presence of neoplasia was significantly better on ER specimens than biopsy specimens [30].
The most important predictor of lymph node metastasis is the penetration depth of the tumor [32]. Endoscopic resection of the most suspicious area in the Barrett's segment, followed by histopathologic evaluation of the endoscopic resection-specimen, permits assessment of infiltration depth and estimation of the risk for local lymph node metastasis.
ENDOSCOPIC RESECTION TECHNIQUES — A variety of endoscopic resection techniques have been described for the esophagus, primarily for esophageal squamous neoplasia.
Established techniques
Endoscopic resection-cap — The most widely practiced endoscopic resection technique for the treatment of Barrett's neoplasia is the endoscopic resection-cap technique after submucosal lifting (figure 1 and figure 2) [33,34]. The target lesion is first lifted by injection of a fluid, which may be saline or diluted epinephrine (1:100,000), into the submucosal layer. Subsequently, a transparent cap is attached to the endoscope. The cap has a distal ridge that allows positioning of a crescent-shaped endoscopic resection-snare. The lesion is sucked into the cap, thus creating a pseudopolyp that is immediately captured by forcefully closing the pre-positioned endoscopic resection-snare. The lesion is then removed using electrocoagulation. (See "Overview of endoscopic resection of gastrointestinal tumors".)
Endoscopic resection-caps are available with different diameters and have either a straight or an oblique shape. The largest en bloc resections are achieved with a large caliber flexible cap that, despite its large outer diameter of 18 mm, can be relatively easily introduced into the esophagus due to its flexibility. Using this technique, lesions with a diameter of more than 2 cm can be removed en bloc.
An alternative approach (the "suck-band-and-ligate" technique) does not require submucosal injection (figure 2) [9]. A reusable variceal ligation device is used to suck the lesion into the ligation cap, allowing it to be captured with a rubber band. The endoscope is then removed, the ligation device is disassembled, and the endoscope is reintroduced to remove the created pseudopolyp with a standard polypectomy snare.
These two techniques were compared in a prospective randomized trial of 100 consecutive endoscopic resections in 72 patients with early stage esophageal cancer [35]. Fifty endoscopic resections were performed with the "suck-band-and-ligate technique" without prior submucosal injection and 50 resections were done with the endoscopic resection-cap technique after submucosal injection of a diluted epinephrine solution. No significant differences were observed between the two groups with regard to size of the resected specimens (ligation group: 16.4 x 11 mm versus cap group: 15.5 x 10.7 mm). There was one minor episode of bleeding in each group and no severe complications occurred.
Multiband mucosectomy — Multiband mucosectomy (MBM) uses a modified variceal band ligator with six bands and a handle that allows passage of a hexagonal snare alongside the releasing wires for the bands. Suction is used to draw the lesion into the cap, a rubber band is deployed, and a polypoid lesion is created. The "polyp" can then be removed using a snare that is inserted through the biopsy channel during the procedure, thereby eliminating the need to remove the scope between banding and snare polypectomy. Multiple specimens can be removed during the procedure using this device (figure 3). A multiband mucosectomy device is now commercially available (Duette™; Cook Medical, Limerick, Ireland).
This MBM technique has several advantages:
A prospective registration of 243 MBM procedures in patients with BE demonstrated that the technique is safe and effective. Complications occurring during the procedure (acute complications) were observed in 3 percent. Bleeding was the only acute complication, and in all cases it was managed endoscopically. No perforations occurred. Complications within 30 days of the procedure (early complications) included delayed bleeding (2 percent of procedures) that was managed endoscopically and stenosis (48 percent). Endoscopic complete resection was achieved in 91 percent of focal lesions [34].
In a case control study, 80 MBM procedures were compared with 86 endoscopic resection-cap procedures [36]. The study showed that MBM was safe and effective for widespread endoscopic resection in Barrett's esophagus. MBM appeared to be quicker than endoscopic resection-cap, but the specimens removed with MBM were significantly smaller than with the endoscopic resection-cap technique.
Following this case-control study, a multicenter randomized controlled trial was initiated to compare the endoscopic resection-cap technique and MBM for piecemeal resection of early neoplasia in Barrett's esophagus [37]. The trial included 84 patients (42 assigned to MBM and 42 to ER -cap) and found that procedure times and costs were significantly less with MBM versus endoscopic resection-cap (34 versus 50 minutes and 240 versus 322 euro, respectively). MBM resulted in smaller specimens than endoscopic resection-cap (18 versus 20 mm in longest dimension). There were no significant differences in maximum specimen thickness or the amount of submucosa resected. There were three perforations in the endoscopic resection-cap group and one perforation in the MBM group. The perforations in the endoscopic resection-cap group were treated endoscopically, whereas the perforation in the MBM group required surgical repair because of periesophageal scarring that prevented endoscopic closure.
MBM appears to be safe and fast for widespread ER in Barrett's esophagus. Time and costs appear to be saved compared to endoscopic resection-cap, since submucosal lifting is not required and a single snare can be used for all resections. MBM does not appear to be associated with more complications than endoscopic resection-cap, despite lack of submucosal lifting. MBM results in significantly smaller sized resections, but the clinical relevance of this finding may be questioned, since there was no significant difference in the depth of resection between the two techniques.
New techniques — New endoscopic resection techniques continue to be explored. Japanese endoscopists have used specially designed needle-knives for en bloc dissection of large esophageal lesions, a technique known as endoscopic submucosal dissection [38-41]. These dissection techniques are usually performed after submucosal injection with viscous substances such as hyaluronidate, which provide prolonged submucosal lifting [38-40]. Experience is limited and a high level of endoscopic expertise appears to be required for their safe application. (See "Overview of endoscopic resection of gastrointestinal tumors", section on 'ESD techniques'.)
In the future, different ER techniques may be combined. The endoscopic resection-cap technique or the needle-knife endoscopic dissection technique may be preferred for en bloc removal of focal lesions, while the other approaches may be used for removal of residual mucosa.
ACID SUPPRESSION FOLLOWING ENDOSCOPIC RESECTION — Patients should be treated with adequate acid suppression to allow the endoscopic resection wounds to heal with neosquamous epithelium and probably also to reduce local scarring. Most centers treat patients with high dose proton pump inhibitors (we use esomeprazole 40 mg twice daily).
The wounds generally heal in three to six weeks depending upon the size of the resected area. No studies have evaluated the mucosal regenerative pattern after ER. In our experience, healing proceeds from proximal to distal with regeneration starting from the edges.
PATHOLOGIC ASSESSMENT — Interpreting ER specimens of Barrett's neoplasia may be more difficult than specimens obtained from squamous lesions. The tissue architecture with crypts and villi differs from the layered architecture in squamous mucosa, making it more difficult to discern a clear transition between wall layers. This problem is further increased by the presence of a double muscularis mucosae in many patients with BE [42]. Because the deeper muscle layer represents the true muscularis mucosae, lesions infiltrating through the superficial muscularis mucosae should NOT be considered as submucosal invading cancers.
To further complicate matters, complete histologic assessment is generally not available during the procedure. As a result, the endoscopist cannot make real-time decisions regarding the adequacy of tissue resection. A pilot study suggested that real-time frozen sections can provide histologic assessment that correlates well with permanent sections, but experience is limited [43].
Many early lesions in BE are associated with severe inflammation that is due to the accompanying reflux disease and may hamper histological assessment. Similarly, because endoscopic resection involves the use of electrocoagulation, the deep and especially the lateral resection margins often have extensive coagulation artifacts, complicating histologic evaluation compared with surgical resection specimens [44].
The ability to treat EC with ER underscores the important nuances of histopathologic assessment. However, making important distinctions between HGD and invasive cancer (and its depth of invasion) may not be straightforward. In an illustrative report, the interobserver reliability for distinguishing Barrett's esophagus with HGD from intramucosal cancer in surgical specimens was poor (kappa statistic 0.42) [45]. It was somewhat better for distinguishing intramucosal and submucosal cancer (kappa statistic of 0.71).
Pathologic subclassification — The terminology and classification of early esophageal cancers have evolved and are outlined in the 2010 TNM staging system of the AJCC (American Joint Committee on Cancer)/UICC (International Union Against Cancer) [46].
Early esophageal cancers are those that are classified as Tis (high-grade dysplasia, which includes all noninvasive neoplastic epithelial that was formerly called carcinoma in situ) or T1 tumors. T1 tumors are further split into T1a and T1b subcategories, depending upon the depth of invasion (table 1) [45]. However, this classification by itself is inadequate to distinguish differences in lymph node involvement among T1a and T1b esophageal cancers. (See "Diagnosis and staging of esophageal cancer".)
A more comprehensive subclassification scheme has been proposed for early esophageal cancers and is useful for determining prognosis and selecting treatment (figure 4) [46]. According to this classification, mucosal tumors are divided into three types based upon the depth of invasion:
M1 tumors correspond to the Tis stage in the AJCC stage definition, while both M2 and M3 tumors would be considered T1a lesions.
Tumors invading the submucosa are subclassified as follows [46]:
All of these subcategories would be considered T1b disease according to the AJCC stage definitions [45].
For Barrett's neoplasia, ER is considered appropriate therapy for lesions limited to the superficial mucosal layers (M1 and M2 tumors) because these tumors have low rates of lymph node metastasis (<3 percent). There is less consensus, however, with regard to lesions that extend to the muscularis mucosa (M3 tumors), yet most centers consider this an accepted indication for endoscopic treatment of early Barrett's neoplasia, whereas for squamous neoplasia M3 lesions are a relative indication.
Esophagectomy is generally preferred for lesions that invade the submucosa (SM1, SM2, and SM3 tumors) given the significantly higher rates of lymph node metastasis associated with these lesions (table 2). Some groups have suggested that ER may be appropriate for lesions that penetrate into the superficial submucosal (SM1 tumors with submucosal penetration <500 microns). The reason ER may be an option is that these lesions may have a low risk of positive lymph nodes, provided that they do not show poorly differentiated cancer or lymphovascular invasion [47,48]. However, most centers consider SM1 tumors to be an indication for surgery and reserve ER for patients who are considered to be at high surgical risk. More studies are required before strong management advice can be given with regard to these lesions.
The above considerations underscore the importance of specialized referral centers where expert pathologists are available [11,15]. This topic is discussed in detail elsewhere. (See "Management of superficial esophageal cancer".)
EFFICACY — An understanding of the efficacy of ER for management of high-grade dysplasia (HGD) or early cancer (EC) in BE is evolving. The available evidence suggests that ER for these conditions has an initial success rate comparable to surgical treatment, but with fewer complications [9,12,49-56].
Larger lesions are less suitable for ER since piecemeal resection is often necessary, which requires a higher level of endoscopic expertise, increases the chances of complications, and often makes it impossible to be conclusive about the completeness of the resection at the lateral margins.
The rate of complete remission (ie, successful removal of the HGD or EC with ER) is variable, ranging from 59 to 99 percent in different studies [9,12,49-54,56,57]. Higher degrees of success are seen in patients with lower risk lesions, which are defined as macroscopic types I (protruded type), IIa (flat elevated type), IIb (flat type), and IIc (flat depressed type); a lesion diameter up to 20 mm that is limited to the mucosa; and histologically well to moderately well differentiated tumors.
Recurrence of carcinoma or the development of metachronous malignancies has been described in 7 to 30 percent of patients [9,12,49-53,55,56]. Multiple factors have been associated with recurrence [12,50,53]:
In most cases, recurrences were successfully managed endoscopically.
The ideal candidate for ER has a solitary, small (ie, <2 cm diameter), flat type lesion (usually a combination of types IIa, IIb, and IIc) that is limited to the mucosa. Histopathologic differentiation may be less important for most cases, since the vast majority of these early lesions will be classified as high-grade dysplasia or well differentiated cancers [11]. Poor or undifferentiated tumor differentiation is a predictor of adverse outcomes in studies using univariate analysis, but these studies usually included patients with more advanced lesions [11].
In multivariate analyses, tumor differentiation has NOT been identified as an independent risk factor for lymph node metastasis or tumor recurrence [32]. This finding may be related to the fact that most undifferentiated tumors have already invaded the submucosa at the time of diagnosis [11]. However, reliable data on the relevance of histopathologic differentiation are sparse, especially given the small number of early, undifferentiated lesions in the available studies.
An important drawback of ER monotherapy for HGD or EC in BE is the high recurrence rate of 30 percent within five years during follow-up. Endoscopic ablative therapy with photodynamic therapy (PDT) or radiofrequency ablation (RFA) permits treatment of the whole Barrett's segment in one session, which may permit treatment of larger lesions and/or be associated with a lower recurrence rate.
PDT has been investigated as monotherapy for HGD and EC in BE as well as an adjuvant treatment after ER. Studies of RFA have reported impressive success rates when used in combination with ER for removal of visible abnormalities [58,59]. (See "Photodynamic therapy for ablation of Barrett's esophagus" and "Radiofrequency ablation for Barrett's esophagus".)
Because of the risk for recurrence, patients treated with endoscopic resection require regular endoscopic follow-up to detect recurrent lesions. In most studies, patients are followed every three months during the first year and annually thereafter.
COMPLICATIONS — Serious complications with the ER techniques described above are rare, though complications such as stricture formation are common if large areas of Barrett's mucosa are resected [9,57,60,61]. Studies have shown that the risk of complications increases with piecemeal resection and the degree of involvement of the mucosa [60,62]:
FUTURE PROSPECTS — Complete ER of the whole Barrett's segment (figure 5) offers the potential to remove the entire area of dysplastic and metaplastic tissue, an approach that we believe has several advantages.
Several series have demonstrated the feasibility and safety in experienced hands of ER of the entire Barrett's segment, even in patients with a long segment of BE [57,68-71]. As examples:
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