RESUMO
BACKGROUND & AIMS: It is important to identify superficial (T1) gastroesophageal adenocarcinomas (EAC) that are most or least likely to metastasize to lymph nodes, to select appropriate therapy. We aimed to develop a risk stratification model for metastasis of superficial EAC to lymph nodes using pathologic features of the primary tumor. METHODS: We collected pathology data from 210 patients with T1 EAC who underwent esophagectomy from 1996 through 2012 on factors associated with metastasis to lymph nodes (tumor size, grade, angiolymphatic invasion, and submucosal invasion). Using these variables, we developed a multivariable logistic model to generate 4 categories for estimated risk of metastasis (<5% risk, 5%-10% risk, 15%-20% risk, or >20% risk). The model was validated in a separate cohort of 39 patients who underwent endoscopic resection of superficial EAC and subsequent esophagectomy, with node stage analysis. RESULTS: We developed a model based on 4 pathologic factors that determined risk of metastasis to range from 2.9% to 60% for patients in the first cohort. In the endoscopic resection validation cohort, higher risk scores were associated with increased detection of lymph node metastases at esophagectomy (P = .021). Among patients in the first cohort who did not have lymph node metastases detected before surgery (cN0), those with high risk scores (>20% risk) had 11-fold greater odds for having lymph node metastases at esophagectomy compared with patients with low risk scores (95% confidence interval, 2.3-52 fold). Increasing risk scores were associated with reduced patient survival time (P < .001) and shorter time to tumor recurrence (P < .001). Patients without lymph node metastases (pT1N0) but high risk scores had reduced times of survival (P < .001) and time to tumor recurrence (P = .001) after esophagectomy than patients with pT1N0 tumors and lower risk scores. CONCLUSIONS: Pathologic features of primary superficial EACs can be used, along with the conventional node staging system, to identify patients at low risk for metastasis, who can undergo endoscopic resection, or at high risk, who may benefit from induction or adjuvant therapy.
Assuntos
Adenocarcinoma/patologia , Adenocarcinoma/secundário , Técnicas de Apoio para a Decisão , Neoplasias Esofágicas/patologia , Neoplasias Esofágicas/secundário , Linfonodos/patologia , Patologia/métodos , Idoso , Estudos de Coortes , Feminino , Humanos , Masculino , Modelos Estatísticos , Metástase Neoplásica , Medição de RiscoRESUMO
The treatment approach for superficial (stage T1) esophageal adenocarcinoma critically depends on the pre-operative assessment of metastatic risk. Part of that assessment involves evaluation of the primary tumor for pathologic characteristics known to predict nodal metastasis: depth of invasion (intramucosal vs submucosal), angiolymphatic invasion, tumor grade, and tumor size. Tumor budding is a histologic pattern that is associated with poor prognosis in early-stage colorectal adenocarcinoma and a predictor of nodal metastasis in T1 colorectal adenocarcinoma. In a retrospective study, we used a semi-quantitative histologic scoring system to categorize 210 surgically resected, superficial (stage T1) esophageal adenocarcinomas according to the extent of tumor budding (none, focal, and extensive) and also evaluated other known risk factors for nodal metastasis, including depth of invasion, angiolymphatic invasion, tumor grade, and tumor size. We assessed the risk of nodal metastasis associated with tumor budding in univariate analyses and controlled for other risk factors in a multivariate logistic regression model. In all, 41% (24 out of 59) of tumors with extensive tumor budding (tumor budding in ≥3 20X microscopic fields) were metastatic to regional lymph nodes, compared with 10% (12 out of 117) of tumors with no tumor budding, and 15% (5 out of 34) of tumors with focal tumor budding (P<0.001). When controlling for all pathologic risk factors in a multivariate analysis, extensive tumor budding remains an independent risk factor for lymph node metastasis in superficial esophageal adenocarcinoma associated with a 2.5-fold increase (95% CI=1.1-6.3, P=0.039) in the risk of nodal metastasis. Extensive tumor budding is also a poor prognostic factor with respect to overall survival and time to recurrence in univariate and multivariate analyses. As an independent risk factor for nodal metastasis and poor prognosis after esophagectomy, tumor budding should be evaluated in superficial (T1) esophageal adenocarcinoma as a part of a comprehensive pathologic risk assessment.
Assuntos
Adenocarcinoma/patologia , Neoplasias Esofágicas/patologia , Metástase Linfática/patologia , Adenocarcinoma/mortalidade , Idoso , Neoplasias Esofágicas/mortalidade , Feminino , Humanos , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , Prognóstico , Modelos de Riscos Proporcionais , Estudos Retrospectivos , Fatores de RiscoRESUMO
BACKGROUND: Activated hedgehog (Hh) pathway is associated with development of both Barrett esophagus (BE) and esophageal adenocarcinoma (EAC). We hypothesize that blockade of the Hh pathway with smoothened (Smo) inhibitor can prevent the development of BE/EAC in the Levrat model, in which induced gastroduodenoesophageal reflux (GDER) leads to esophageal carcinogenesis. METHODS: GDER was induced in 6- to 8-week-old male Sprague-Dawley rats. The Smo inhibitor (10 mg/kg/d) was given orally on postoperative weeks 10 to 16, 18 to 22, and 24 to 28, and rats were killed on week 28. The primary outcome measure was the incidence of BE and EAC. To examine potential therapeutic effects of Smo inhibition on tumor tissue, semiquantitative immunohistochemistry for Ki-67 and caspase 3 was performed. In treated animals that developed cancer, gene expression was analyzed. RESULTS: Thirty-eight of 48 controls and 32 of 46 treated animals survived to 28 weeks. messenger ribonucleic acid (mRNA) expression of Indian Hh, a ligand of transmembrane receptor patched 1, was 184× higher in BE and 99× higher in EAC compared with normal esophageal tissue (P = 0.0239 and P = 0.0004, respectively). Compared with controls, the incidence of BE and EAC was decreased in treated animals by 35.7% (relative risk reduction, 36%; P = 0.0015) and 36% (relative risk reduction, 62%; P = 0.0033), respectively. Compared with untreated EAC, Ki-67 was downregulated (P = 0.04) and cleaved caspase 3 was no different in treated EAC (P = 0.398). Of the 84 well-known genes involved in cancer drug resistance, 50 were dysregulated in treated EAC (P < 0.05 for each gene). CONCLUSIONS: Smo inhibitor prevents the development of BE and EAC in an in vivo model of GDER.
Assuntos
Adenocarcinoma/etiologia , Adenocarcinoma/prevenção & controle , Esôfago de Barrett/etiologia , Esôfago de Barrett/prevenção & controle , Neoplasias Esofágicas/etiologia , Neoplasias Esofágicas/prevenção & controle , Refluxo Gastroesofágico/complicações , Receptores Acoplados a Proteínas G/antagonistas & inibidores , Animais , Benzamidas/farmacologia , Caspase 3/metabolismo , Modelos Animais de Doenças , Expressão Gênica , Proteínas Hedgehog/metabolismo , Técnicas Imunoenzimáticas , Antígeno Ki-67/metabolismo , Masculino , Quinazolinas/farmacologia , RNA Mensageiro/análise , Ratos , Ratos Sprague-Dawley , Reação em Cadeia da Polimerase em Tempo Real , Receptor SmoothenedRESUMO
BACKGROUND: There is a need for improved tools to detect high-grade dysplasia (HGD) and esophageal adenocarcinoma (EAC) in patients with Barrett's esophagus. In previous work, we demonstrated that a 3-tier classifier predicted risk of incident progression in Barrett's esophagus. Our aim was to determine whether this risk classifier could detect a field effect in nondysplastic (ND), indefinite for dysplasia (IND), or low-grade dysplasia (LGD) biopsies from Barrett's esophagus patients with prevalent HGD/EAC. METHODS: We performed a multi-institutional case-control study to evaluate a previously developed risk classifier that is based upon quantitative image features derived from 9 biomarkers and morphology, and predicts risk for HGD/EAC in Barrett's esophagus patients. The risk classifier was evaluated in ND, IND, and LGD biopsies from Barrett's esophagus patients diagnosed with HGD/EAC on repeat endoscopy (prevalent cases, n = 30, median time to HGD/EAC diagnosis 140.5 days) and nonprogressors (controls, n = 145, median HGD/EAC-free surveillance time 2,015 days). RESULTS: The risk classifier stratified prevalent cases and non-progressor patients into low-, intermediate-, and high-risk classes [OR, 46.0; 95% confidence interval, 14.86-169 (high-risk vs. low-risk); P < 0.0001]. The classifier also provided independent prognostic information that outperformed the subspecialist and generalist diagnosis. CONCLUSIONS: A tissue systems pathology test better predicts prevalent HGD/EAC in Barrett's esophagus patients than pathologic variables. The results indicate that molecular and cellular changes associated with malignant transformation in Barrett's esophagus may be detectable as a field effect using the test. IMPACT: A tissue systems pathology test may provide an objective method to facilitate earlier identification of Barrett's esophagus patients requiring therapeutic intervention. Cancer Epidemiol Biomarkers Prev; 26(2); 240-8. ©2016 AACR.
Assuntos
Adenocarcinoma/patologia , Esôfago de Barrett/patologia , Transformação Celular Neoplásica/patologia , Neoplasias Esofágicas/patologia , Esôfago/patologia , Lesões Pré-Cancerosas , Medição de Risco , Adenocarcinoma/epidemiologia , Esôfago de Barrett/epidemiologia , Biópsia , Estudos de Casos e Controles , Progressão da Doença , Neoplasias Esofágicas/epidemiologia , Esofagoscopia , Feminino , Seguimentos , Humanos , Incidência , Masculino , Microscopia de Fluorescência , Pessoa de Meia-Idade , Países Baixos/epidemiologia , Pennsylvania/epidemiologia , Prevalência , Prognóstico , Fatores de Risco , Fatores de TempoRESUMO
BACKGROUND: Better methods are needed to predict risk of progression for Barrett's esophagus. We aimed to determine whether a tissue systems pathology approach could predict progression in patients with nondysplastic Barrett's esophagus, indefinite for dysplasia, or low-grade dysplasia. METHODS: We performed a nested case-control study to develop and validate a test that predicts progression of Barrett's esophagus to high-grade dysplasia (HGD) or esophageal adenocarcinoma (EAC), based upon quantification of epithelial and stromal variables in baseline biopsies. Data were collected from Barrett's esophagus patients at four institutions. Patients who progressed to HGD or EAC in ≥1 year (n = 79) were matched with patients who did not progress (n = 287). Biopsies were assigned randomly to training or validation sets. Immunofluorescence analyses were performed for 14 biomarkers and quantitative biomarker and morphometric features were analyzed. Prognostic features were selected in the training set and combined into classifiers. The top-performing classifier was assessed in the validation set. RESULTS: A 3-tier, 15-feature classifier was selected in the training set and tested in the validation set. The classifier stratified patients into low-, intermediate-, and high-risk classes [HR, 9.42; 95% confidence interval, 4.6-19.24 (high-risk vs. low-risk); P < 0.0001]. It also provided independent prognostic information that outperformed predictions based on pathology analysis, segment length, age, sex, or p53 overexpression. CONCLUSION: We developed a tissue systems pathology test that better predicts risk of progression in Barrett's esophagus than clinicopathologic variables. IMPACT: The test has the potential to improve upon histologic analysis as an objective method to risk stratify Barrett's esophagus patients. Cancer Epidemiol Biomarkers Prev; 25(6); 958-68. ©2016 AACR.
Assuntos
Esôfago de Barrett/diagnóstico , Biomarcadores Tumorais/análise , Progressão da Doença , Esôfago/patologia , Imunofluorescência/métodos , Adenocarcinoma/diagnóstico , Adenocarcinoma/metabolismo , Adulto , Idoso , Esôfago de Barrett/metabolismo , Esôfago de Barrett/patologia , Biópsia , Estudos de Casos e Controles , Neoplasias Esofágicas/diagnóstico , Neoplasias Esofágicas/metabolismo , Esôfago/metabolismo , Reações Falso-Positivas , Feminino , Humanos , Masculino , Microscopia de Fluorescência , Pessoa de Meia-Idade , PrognósticoRESUMO
Development of a tracheopharyngeal fistula after pharyngeal perforation is an uncommon occurrence. As a result, published guidance for management of this rare type of aerodigestive tract fistula is limited. We describe the workup and management of a traumatic tracheopharyngeal fistula caused by foreign body impaction. A conservative, endoscopic treatment strategy with broad-spectrum antibiotics, transnasal drainage, and covered tracheal stent placement was used. The stent was removed after 4 weeks, and complete closure of the fistula tract was confirmed by endoscopy and contrast esophagram. Although tracheopharyngeal fistulae are rare and operative treatment can be complex, this case demonstrates that conservative management with antibiotics, drainage, and endoscopic stenting can be successful in select patients.
Assuntos
Corpos Estranhos/complicações , Doenças Faríngeas/etiologia , Faringe/lesões , Fístula do Sistema Respiratório/etiologia , Doenças da Traqueia/etiologia , Humanos , Masculino , Pessoa de Meia-IdadeRESUMO
Undifferentiated carcinoma of the esophagus is a rare histologic variant of esophageal carcinoma. Using criteria based on studies of undifferentiated carcinomas arising at other sites, we have collected 16 cases of resected esophageal undifferentiated carcinomas. Patients ranged in age from 39 to 84 years (mean, 65.5 years) and were predominantly male (94%). The tumors were characterized by an expansile growth pattern of neoplastic cells organized in solid sheets and without significant glandular, squamous, or neuroendocrine differentiation. The neoplastic cells had a syncytial-like appearance, little intervening stroma, and patchy tumor necrosis. In a subset of cases, the tumor cells adopted a sarcomatoid (n = 2), rhabdoid (n = 1), or minor component (<5%) of glandular morphology (n = 3). In 1 case, reactive osteoclast-like giant cells were found interspersed among the neoplastic cells. Lymphovascular invasion, perineural invasion, and lymph node metastases were identified in 88%, 56%, and 81% of cases, respectively. In 12 (75%) specimens, the background esophageal mucosa was notable for Barrett esophagus. Consistent with the epithelial nature of these neoplasms, cytokeratin positivity was identified in all cases. In addition, SALL4 expression was present in 8 (67%) of 12 cases. Follow-up information was available for 15 (94%) of 16 patients, all of whom were deceased. Survival after surgery ranged from 1 to 50 months (mean, 11.9 months). Before death, 67% patients had documented locoregional recurrence and/or distant organ metastases. In summary, esophageal undifferentiated carcinomas are aggressive neoplasms and associated with a high incidence of recurrence and/or metastases and a dismal prognosis.
Assuntos
Carcinoma de Células Escamosas/patologia , Carcinoma/patologia , Neoplasias Esofágicas/patologia , Invasividade Neoplásica/patologia , Recidiva Local de Neoplasia/patologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Consumo de Bebidas Alcoólicas/epidemiologia , Anemia/epidemiologia , Esôfago de Barrett/epidemiologia , Biomarcadores Tumorais/análise , Carcinoma/química , Carcinoma/epidemiologia , Carcinoma/secundário , Carcinoma de Células Escamosas/química , Carcinoma de Células Escamosas/epidemiologia , Carcinoma de Células Escamosas/secundário , Comorbidade , Transtornos de Deglutição/epidemiologia , Neoplasias Esofágicas/química , Neoplasias Esofágicas/epidemiologia , Neoplasias Esofágicas/secundário , Carcinoma de Células Escamosas do Esôfago , Feminino , Seguimentos , Refluxo Gastroesofágico/epidemiologia , Humanos , Imuno-Histoquímica , Hibridização In Situ , Queratinas/análise , Metástase Linfática , Masculino , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Segunda Neoplasia Primária/patologia , Prognóstico , Fumar/epidemiologia , Taxa de Sobrevida , Fatores de Transcrição/análise , Resultado do TratamentoRESUMO
Previously regarded as a rare neoplasm, the incidence of esophageal adenocarcinoma has risen rapidly in recent decades. It is often discovered late in the disease process and has a dismal prognosis. Current prognostic markers including clinical, radiographic, and histopathologic findings have limited utility and do not consider the biology of this deadly disease. Genome-wide analyses have identified SMAD4 inactivation in a subset of tumors. Although Smad4 has been extensively studied in other gastrointestinal malignancies, its role in esophageal adenocarcinoma remains to be defined. Herein, we show, in a large cohort of esophageal adenocarcinomas, Smad4 loss by immunohistochemistry in 21 of 205 (10%) tumors and that Smad4 loss correlated with increased postoperative recurrence (P=0.040). Further, patients whose tumors lacked Smad4 had shorter time to recurrence (TTR) (P=0.007) and poor overall survival (OS) (P=0.011). The median TTR and OS of patients with Smad4-negative tumors was 13 and 16 months, respectively, as compared with 23 and 22 months, respectively, among patients with Smad4-positive tumors. In multivariate analyses, Smad4 loss was a prognostic factor for both TTR and OS, independent of histologic grade, lymphovascular invasion, perineural invasion, tumor stage, and lymph node status. Considering Smad4 loss correlated with postoperative locoregional and/or distant metastases, Smad4 was also assessed in a separate cohort of 5 locoregional recurrences and 43 metastatic esophageal adenocarcinomas. In contrast to primary tumors, a higher prevalence of Smad4 loss was observed in metastatic disease (44% vs. 10%). In summary, loss of Smad4 protein expression is an independent prognostic factor for TTR and OS that correlates with increased propensity for disease recurrence and poor survival in patients with esophageal adenocarcinoma after surgical resection.
Assuntos
Adenocarcinoma/química , Biomarcadores Tumorais/análise , Neoplasias Esofágicas/química , Recidiva Local de Neoplasia , Proteína Smad4/análise , Adenocarcinoma/mortalidade , Adenocarcinoma/secundário , Adenocarcinoma/cirurgia , Adulto , Idoso , Idoso de 80 Anos ou mais , Distribuição de Qui-Quadrado , Intervalo Livre de Doença , Regulação para Baixo , Neoplasias Esofágicas/mortalidade , Neoplasias Esofágicas/patologia , Neoplasias Esofágicas/cirurgia , Feminino , Humanos , Imuno-Histoquímica , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Modelos de Riscos Proporcionais , Estudos Retrospectivos , Fatores de Risco , Fatores de Tempo , Análise Serial de Tecidos , Resultado do Tratamento , Adulto JovemRESUMO
BACKGROUND: Current histologic methods for diagnosis are limited by intra- and inter-observer variability. Immunohistochemistry (IHC) methods are frequently used to assess biomarkers to aid diagnoses, however, IHC staining is variable and nonlinear and the manual interpretation is subjective. Furthermore, the biomarkers assessed clinically are typically biomarkers of epithelial cell processes. Tumors and premalignant tissues are not composed only of epithelial cells but are interacting systems of multiple cell types, including various stromal cell types that are involved in cancer development. The complex network of the tissue system highlights the need for a systems biology approach to anatomic pathology, in which quantification of system processes is combined with informatics tools to produce actionable scores to aid clinical decision-making. AIMS: Here, we describe a quantitative, multiplexed biomarker imaging approach termed TissueCypher™ that applies systems biology to anatomic pathology. Applications of TissueCypher™ in understanding the tissue system of Barrett's esophagus (BE) and the potential use as an adjunctive tool in the diagnosis of BE are described. PATIENTS AND METHODS: The TissueCypher™ Image Analysis Platform was used to assess 14 epithelial and stromal biomarkers with known diagnostic significance in BE in a set of BE biopsies with nondysplastic BE with reactive atypia (RA, n = 22) and Barrett's with high-grade dysplasia (HGD, n = 17). Biomarker and morphology features were extracted and evaluated in the confirmed BE HGD cases versus the nondysplastic BE cases with RA. RESULTS: Multiple image analysis features derived from epithelial and stromal biomarkers, including immune biomarkers and morphology, showed significant differences between HGD and RA. CONCLUSIONS: The assessment of epithelial cell abnormalities combined with an assessment of cellular changes in the lamina propria may serve as an adjunct to conventional pathology in the assessment of BE.
RESUMO
Mucin core proteins (MUCs) are expressed in tissue-specific patterns in the gastrointestinal tract and expression is deregulated in Barrett's metaplasia. Based on differential expression, MUCs have been used to classify adenocarcinomas into distinct phenotypes (eg, intestinal, gastric, pancreaticobiliary, etc). Because MUC expression patterns carry prognostic significance in other tumors, we evaluated MUC expression in superficial adenocarcinomas of the gastroesophageal junction and esophagus (EAC) to determine whether there are differences in outcome associated with MUC subtype in this potentially curable subset of EAC. We classified 142 resected, superficial (T1) EAC based on their pattern of expression of MUC2, MUC5AC, MUC6 and MUC1. The association between survival and MUC expression pattern was determined in univariate and multivariate analyses. The MUC2 positive "intestinal" phenotype was associated with significantly worse prognosis in submucosal EAC (hazard ratio 2.2, 95% confidence interval 1.2-4.2), independent of node stage and other prognostic factors. MUC2 expression in submucosal EAC also showed significantly accelerated time to recurrence (hazard ratio 2.8, 95% confidence interval 1.2-6.8) after adjusting for node stage. The classification of superficial EAC by MUC protein expression has prognostic significance. MUC2 expression is an adverse prognostic indicator in submucosal EAC, independent of node stage and other prognostic factors.
Assuntos
Adenocarcinoma/metabolismo , Neoplasias Esofágicas/metabolismo , Mucina-2/metabolismo , Adenocarcinoma/mortalidade , Adenocarcinoma/patologia , Idoso , Biomarcadores Tumorais/metabolismo , Neoplasias Esofágicas/mortalidade , Neoplasias Esofágicas/patologia , Junção Esofagogástrica/metabolismo , Junção Esofagogástrica/patologia , Esôfago/metabolismo , Esôfago/patologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Mucina-5AC/metabolismo , Mucina-1/metabolismo , Mucina-6/metabolismo , Prognóstico , Taxa de SobrevidaRESUMO
We assessed 103 resected gastroesophageal adenocarcinomas for HER2 amplification by fluorescence in situ hybridization (FISH) and 2 commercial immunohistochemical assays. Of 103, 30 (29%) were FISH-amplified. Both immunohistochemical assays had greater than 95% concordance with FISH. However, as a screening test for FISH amplification, the Ventana Medical Systems (Tucson, AZ) 4B5 antibody demonstrated superior sensitivity (87%) compared with the DAKO (Carpinteria, CA) A0485 (70%). Of the cases, 28 were immunohistochemically 3+ or immunohistochemically 2+/FISH-amplified with the 4B5 assay compared with only 22 cases with the A0485 assay, representing a large potential difference in patient eligibility for anti-HER2 therapy. Cases with low-level FISH amplification (HER2/CEP17, 2.2-4.0) express lower levels of HER2 protein compared with cases with high-level amplification (HER2/CEP17, ≥4.0), raising the possibility of a differential response to anti-HER2 therapy. The H score and digital image analysis may have a limited role in improving HER2 test performance.
Assuntos
Adenocarcinoma/metabolismo , Neoplasias Esofágicas/metabolismo , Hibridização in Situ Fluorescente/métodos , Receptor ErbB-2/metabolismo , Neoplasias Gástricas/metabolismo , Adenocarcinoma/genética , Adenocarcinoma/patologia , Idoso , Idoso de 80 Anos ou mais , Neoplasias Esofágicas/genética , Neoplasias Esofágicas/patologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Receptor ErbB-2/genética , Neoplasias Gástricas/genética , Neoplasias Gástricas/patologiaRESUMO
The following on Barrett's esophagus (BE) and animal models contains commentaries on the factors of BE carcinogenesis; a duodenoesophageal reflux model; translation of targeted therapies for esophageal adenocarcinoma; and novel target regimens selected through a proteomics screen.
Assuntos
Esôfago de Barrett/patologia , Modelos Animais de Doenças , Adenocarcinoma/patologia , Animais , Neoplasias Esofágicas/patologia , HumanosRESUMO
INTRODUCTION: Limitations of endoscopic therapies for Barrett's esophagus and superficial cancer include a compromised histological assessment, the need for surveillance, subsequent procedures, and stricture formation. Circumferential en bloc resection of the mucosa-submucosa complex followed by deployment of a biologic scaffold onto the remaining muscularis propria may address these concerns. The objective of this study was to determine technical feasibility of transoral resection of the esophageal lining. MATERIALS AND METHODS: Transoral endoscopic inner layer esophagectomy was performed in ten swine. Endpoints included procedure duration, hemorrhage, number of perforations, and adequacy of resection length and depth. RESULTS: Procedures were successfully completed in all animals without perioperative mortality. Procedure times averaged 179 min (range 125-320). No perforations were found, and a mean of 1.7 (0-4) interventions for hemorrhage was required. Complete longitudinal resection was achieved in nine of ten animals. Resection depth included all mucosal layers in 100% of tissue sections, the submucosal layers, SM1 in 100%, and SM2 in 96%. A portion of SM3 was adherent to the muscularis propria in 70%. CONCLUSION: Transoral endoscopic resection of the inner esophageal layers was feasible and reproducible. This technique may facilitate a single-step definitive treatment and staging tool for early neoplastic lesions, obviating the need for esophagectomy.