Lack of EGFR gene mutations in exons 19 and 21 in esophageal (Barrett's) adenocarcinomas

Epidermal growth factor receptor is over-expressed in several tumors and is the target for the tyrosine kinase inhibitor gefitinib. This receptor is also over-expressed in esophageal adenocarcinomas. In non-small cell lung cancer, specific somatic mutations residing in the epidermal growth factor receptor tyrosine kinase in the activation loop and the glycine-rich P-loop, are responsible for an enhanced sensitivity toward gefitinib. We analyzed exons 19 and 21 coding for the receptor tyrosine kinase of the epidermal growth factor gene in 105 samples of esophageal (Barrett's) adenocarcinoma by denaturing high-pressure liquid chromatography. We found only one silent mutation in exon 19 of adenine to guanine in codon 754 leading to a substitution of K to K, the rest of the sample being wild-type genotype. In conclusion, mutations within the tyrosine kinase domain of EGFR associated with sensitivity of non-small cell lung cancer patients to gefitinib are not present in esophageal (Barrett's) adenocarcinoma.

Squamous cell carcinoma and Zenker diverticulum

Squamous cell carcinoma in a Zenker diverticulum is a very rare condition. We report a case of a patient with a Zenker carcinoma, who was primarily functionally inoperable and therefore received neoadjuvant radiochemotherapy before cardiac bypass surgery. After a complicated course with cardiogenic shock and myocardial infarction, a re-evaluation of functional risk analysis and the tumor situation revealed operability. Subsequently, partial hypopharyngectomy and partial cervical esophageal resection with lymphadenectomy was performed. Reconstruction of the gastrointestinal continuity was made by interposition of a free small bowel graft and microvascular anastomosis. The postoperative course showed a small anastomotic leakage of the hypopharyngeal-small bowel anastomosis, which was successfully treated conservatively.

Expression of cyclo-oxygenase 1 and 2, prostaglandin E synthase and transforming growth factor beta1, and their relationship with vascular endothelial growth factors A and C, in primary adenocarcinoma of the small intestine

BACKGROUND

Primary adenocarcinomas of the small intestine are rare. The prostaglandin biosynthetic pathway plays a major role in carcinogenesis and is linked with angiogenesis in various tumours. Promotion of tumour growth by transforming growth factor (TGF) beta may be mediated through the prostaglandin pathway.

METHODS

Expression of cyclo-oxygenase (COX) 1 and 2, prostaglandin E synthase (PGES), TGF-beta1 and vascular endothelial growth factor (VEGF) A and C genes was analysed in 54 primary adenocarcinomas of the small intestine and corresponding normal intestinal mucosa. All patients had undergone surgical resection without previous antineoplastic therapy. Target gene expression was analysed at the mRNA level by reverse transcriptase-polymerase chain reaction and correlated with clinicopathological parameters as well as survival. COX-2 protein expression was examined by immunohistochemistry.

RESULTS

Expression of COX-2 protein was detected immunohistochemically in 98 per cent of the carcinomas. COX-1, COX-2, VEGF-A, VEGF-C, PGES and TGF-beta1 mRNA expression varied markedly in different tumours, but all were overexpressed compared with levels in normal intestinal mucosa. There were significant associations between levels of COX-1, COX-2, TGF-beta1 and PGES mRNAs and those of VEGF-A and VEGF-C.

CONCLUSION

Correlations between levels of mRNA for COX-1, COX-2, TGF-beta1 and PGES and those for proangiogenic factors VEGF-A and VEGF-C suggest a role for these factors in the propagation of primary adenocarcinomas of the small intestine.

Adenocarcinoma of the esophagogastric junction: surgical therapy based on 1602 consecutive resected patients

Because of the borderline location between the esophagus and stomach, many discrepancies exist in the current literature regarding the etiology, classification, and surgical treatment of adenocarcinoma arising at the esophagogastric junction. The classification of adenocarcinomas into three types, AGE type I, type II, and type III, shows marked differences between the tumor entities and is recommended for selection of a proper surgical approach. Complete tumor resection and adequate lymphadenectomy are recommended for a good, long-term prognosis. With better surgical management and standardized procedures, even the results in patients with more radical surgical approaches, the abdomino-thoracic esophagectomy improved.

c-myc amplification is frequent in esophageal adenocarcinoma and correlated with the upregulation of VEGF-A expression

BACKGROUND

Deregulation of c-myc plays a major role in the carcinogenesis of human malignancies. We investigated the amplification of the c-myc gene in a surgical series of Barrett cancers.

METHODS

Primary resected esophageal (Barrett) adenocarcinomas (n = 84) were investigated for c-myc amplification using chromogene in situ hybridization. Tumor samples were assembled in a tissue microarray. c-myc gene dosage was correlated with clinicopathologic parameters, including the survival and gene expression of cyclooxygenases (COX-1 and COX-2) and proangiogenic growth factors (VEGF-A and VEGF-C).

RESULTS

The majority (70 of 84; 83.3%) exhibited amplification of the c-myc gene. There were low-level amplifications in 63 (75.0%) cases and high-level amplifications in 7 (8.3%) cases. No amplification was found in 14 (16.7%) cases. Tumors without c-myc amplification had lower VEGF-A, VEGF-C, and COX-2 expression levels than tumors with low-level and high-level c-myc amplification (statistically significant for VEGF-A; P = .0348). c-myc amplification was not correlated with clinicopathological parameters or survival. Only diffuse and mixed-type tumors, according to Lauren classification, exhibited c-myc amplifications more frequently (P = .0466).

CONCLUSIONS

Amplifications of the c-myc gene are frequent in Barrett cancer. c-myc may be involved in the regulation of angiogenesis.

Surgical management of esophagogastric junction tumors

Surgical resection with lymphadenectomy is the mainstay of treatment for all resectable esophagogastric junction tumors, prior to systemic generalization of the disease. This makes accurate pre-treatment staging and classification of the tumors most demanding. A well-established and internationally accepted classification for adenocarcinomas of the esophagogastric junction (AEG) helps to choose the appropriate surgical approach and to make results from different institutions comparable. Distal esophageal adenocarcinomas (AEGI) are distinguished from true cardia carcinomas (AEG II) and subcardiac gastric cancers (AEG III). Substantial advancements in this surgical field during the preceding decades have clearly revealed that individualization of the surgical strategy is the key to successfully approaching these entities. In this review we discuss the surgical management of esophagogastric junction tumors with a tailored surgical strategy.

Overexpression of TGF-beta1 in esophageal (Barrett's) adenocarcinoma is associated with advanced stage of disease and poor prognosis

Expression of TGF-beta1, a major member of the TGF-beta superfamily and important promoter of tumor growth, was investigated in a series of primary resected esophageal (Barrett's) adenocarcinomas to establish its potential clinical significance and prognostic relevance in this entity. A series of 123 primary resected adenocarcinomas of the distal esophagus, arising in association with Barrett's esophagus, and corresponding normal squamous epithelium (n = 12) and non-malignant Barrett's mucosa (n = 11), were investigated by means of quantitative RT-PCR for expression of TGF-beta1, using paraffin embedded tissue samples. Gene expression levels were correlated with clinical parameters and overall survival. TGF-beta1 mRNA was expressed in all tumors, but relative gene expression levels varied largely among different tumors. The relative gene expression was significantly higher in tumor tissue compared to squamous epithelium (P = 0.005) and Barrett's mucosa (P=0.002), expressing only low amounts of TGF-beta1. Relative overexpression of the TGF-beta1 gene was associated with advanced UICC stage (III/IV vs. I/II; P = 0.009), depth of tumor infiltration (pT3 vs. pT1/2; P < 0.001), nodal involvement (pN1 vs. pN0; P = 0.006), and lymphatic vessel invasion (L1 vs. L0; P = 0.011). On univariate survival analysis, TGF-beta1 overexpression had a significant negative impact on survival (log rank test; P = 0.0255). However, the prognostic impact was not independent from other strong predictors of survival (pT, pN) on multivariate survival analysis. Our data show that TGF-beta1 overexpression is associated with advanced stage of esophageal adenocarcinoma and implies a negative impact on survival. The TGF-beta pathway may be a potential target for molecular therapies of advanced tumors of this entity.

Precision measurement of the quasifree pn-->dvarphi reaction close to threshold

The quasifree pn-->dvarphi reaction has been studied at the Cooler Synchrotron COSY-Jülich, using the internal proton beam incident on a deuterium cluster-jet target and detecting a fast deuteron in coincidence with the K+K- decay of the varphi meson. The energy dependence of the total and differential cross sections are extracted for excess energies up to 80 MeV by determining the Fermi momentum of the target neutron on an event-by-event basis. Though these cross sections are consistent with s-wave production, the kaon angular distributions show the presence of p waves at quite a low energy. Production on the neutron is found to be stronger than on the proton but not by as much as for the eta meson.

Prognostic significance of expression patterns of c-erbB-2, p53, p16INK4A, p27KIP1, cyclin D1 and epidermal growth factor receptor in oesophageal adenocarcinoma: a tissue microarray study

AIMS

To correlate immunohistochemical expression patterns and prognosis in oesophageal adenocarcinoma.

METHODS

The expression of c-erbB-2, p53, p16INK4A, p27KIP1, cyclin D1 and epidermal growth factor receptor (EGFR) was studied in a series of 137 primarily resected oesophageal adenocarcinoma samples. The expression analysis on protein level was performed on routine paraffin wax-embedded material, with immunohistochemical staining of the samples, assembled on a tissue microarray. The results were correlated with clinicopathological features (pT, pN and G) and survival.

RESULTS

22 (16%) tumours showed an overexpression of the c-erbB-2 oncoprotein. Expression of EGFR was observed in 72 (55%) cases, accumulation of p53 in 68 (52%) cases and of cyclin D1 in 102 (77%) cases. Loss of p16INK4A expression was observed in 101 (76%) cases and low expression of p27KIP1 in 91 (71%) cases. Expression of these proteins did not correlate with tumour stage, grade, Lauren's or World Health Organization classification or lymph node status. On univariate survival analysis, more advanced tumour stage (p = 0.002), lymph node involvement (p = 0.003), high tumour grade (p = 0.017) and lack of EGFR expression (p = 0.034) were found to be associated with poorer survival. On multiple regression analysis, only tumour stage (p = 0.03) and lymph node involvement (p = 0.004) were shown to have an association with the survival of the patient.

CONCLUSION

The immunohistochemical expression of c-erbB-2 oncoprotein, cylin D1, p16INK4A, p27KIP1, p53 and EGFR in most oesophageal adenocarcinomas suggests their implication in the pathogenesis of this entity. None of the molecular markers assessed, however, was of prognostic value. Identification of any marker superior to or even approaching the prognostic value of conventional histopathological markers (pT and pN) was therefore not possible.

Giant Pulmonary Hamartoma—A Rare Presentation of a Common Tumor

Hamartomata, the most common benign tumors of the lung, are rarely symptomatic and usually come to clinical attention as coin-shaped lesions on a routine plain chest roentgenogram. We report a case of a 63-year-old woman presenting with reduced endurance on exercise. The plain chest roentgenogram showed a tumor in the left chest. After clinical work-up, the patient underwent radical tumor resection through a lateral thoracotomy. The resected tumor, with two separate nodules, measured 26 x 25 cm and weighed 3.2 kg. The histopathology work-up showed pulmonary hamartoma.

The prognostic impact of O6-Methylguanine-DNA Methyltransferase (MGMT) promotor hypermethylation in esophageal adenocarcinoma

Promotor hypermethylation is a common event in human cancer. O6-Methylguanine-DNA Methyltransferase (MGMT) is a gene involved in DNA repair, which is methylated in a variety of cancer types. In colorectal cancer and lung cancer, hypermethylation of MGMT has been correlated with p53 mutation. In the present study, 132 samples of esophageal adenocarcinoma and 58 samples of normal esophageal tissue were investigated for MGMT hypermethylation status by methylation-specific real-time PCR and results were correlated to clinicopathological parameters, patient's survival, p53 mutation and expression of p53 protein and MGMT protein. In the carcinomas, hypermethylation of MGMT was found in 63.6% of cases and loss of MGMT protein expression in 48.5% of cases. Furthermore, MGMT hypermethylation was found in 5.7% of normal esophageal smooth muscle tissue, in 20.0% of esophageal squamous epithelium and in 61.5% of nonneoplastic Barrett's mucosa. In the carcinomas, hypermethylation of the MGMT gene was correlated with loss MGMT protein expression (p < 0.0001) and with high tumor differentiation (p = 0.0079). In contrast, no correlation between MGMT hypermethylation, Lauren's classification, WHO classification, tumor size, gender, age, pT category and pN category, and p53 status was found. Neither MGMT hypermethylation nor loss of MGMT protein expression was correlated with patient's survival. In conclusion, MGMT hypermethylation in esophageal adenocarcinoma is a frequent event that is associated with loss of MGMT protein expression but not with patient's outcome.

Near-threshold production of phi mesons in pp collisions

The pp-->ppphi reaction has been studied at the Cooler Synchrotron COSY-Jülich, using the internal beam and ANKE facility. Total cross sections have been determined at three excess energies epsilon near the production threshold. The differential cross section closest to threshold at epsilon=18.5 MeV exhibits a clear S wave dominance as well as a noticeable effect due to the proton-proton final-state interaction. Taken together with data for ppomega production, a significant enhancement of the phi/omega ratio of a factor 8 is found compared to predictions based on the Okubo-Zweig-Iizuka rule.

No association of primary adenocarcinomas of the small bowel with Epstein-Barr virus infection

Epstein-Barr Virus (EBV) infection is considered to play an etiologic role in human malignancies, including a subset of gastric and cardiac cancers. Adenocarcinomas of the small bowel comprise a very rare entity, with little knowledge about molecular properties and etiological aspects. We have investigated the prevalence of EBER expression (EBV-encoded small RNAs) in a series of small bowel adenocarcinomas (n=56) utilizing RNA in situ hybridization (EBER-RISH). The patients had undergone primary surgical resection at either the Technical University of Munich or at the University of Graz. A surgical series of 82 primary resected gastric (n=36) or cardiac (n=46) adenocarcinomas (TU Munich) was used as control group. None of the 56 small bowel carcinomas exhibited EBER expression whereas in the control group the rate of EBER expression accounted for 4.4% in the group of cardia carcinomas and 8.6% in the group of gastric cancers. These results indicate that EBV infection plays no etiologic role in primary small bowel adenocarcinomas.

Distribution of p53 mutations in esophageal and gastric carcinomas and the relationship with p53 expression

Mutations of p53, a tumor suppressor gene, are known to be involved in the pathogenesis of a number of neoplasms. This study investigated the distribution of p53 mutations within both esophageal and gastric adenocarcinomas. The correlation between p53 mutations and an overexpression of p53, which has been reported by other researchers, was also explored. Samples were taken from 17 patients following a surgical resection of the tumor. The patients included 8 cases of adenocarcinoma from the cardia (esophagogastric junction) and 9 cases of gastric carcinoma. Two or three samples were taken from each tumor, plus samples of normal tissue from the patient. Denaturing high pressure liquid chromatography (DHPLC) was employed to detect p53 mutations, and samples found to have mutations were then sequenced. The expression of p53 was determined by immunohistochemistry. DHPLC demonstrated that 37.5% (3/8) of esophageal carcinomas and 44.4% (4/9) of gastric carcinomas have p53 mutations. DNA sequencing showed the same mutation to be present in all of the samples from each tumor, while the corresponding normal tissue was free from mutations (except for 2 cases of polymorphism). The results of immunohistochemistry did not demonstrate a relationship between p53 mutations and the expression of p53 protein, and only 4 of the 7 tumors with p53 mutations showed a positive result. These findings support the hypothesis that p53 mutations are homogeneous throughout a tumor and may thus be a more useful diagnostic and prognostic indicator than the expression of p53, which does not reliably correlate with p53 mutations.

Limitierte chirurgische Resektion versus lokale endoskopische Therapie beim Frühkarzinom des ösophagogastralen Übergangs

BACKGROUND

Adenocarcinomas of the esophagogastric junction (especially Barrett's cancers) are increasingly diagnosed at early stages. The current standard treatment - radical resection with extensive lymphadenectomy - has been challenged. Limited resection or endoscopic mucosal ablation have been proposed as less invasive alternatives.

METHODS

Available data regarding limited surgical resections and endoscopic interventional procedures are evaluated with respect to short- and long-term results (mortality, morbidity, oncologic adequacy, quality of life).

RESULTS

Limited resection of the esophagogastric junction has been proven as safe (low morbidity and mortality) and oncologically adequate procedure (low rate of recurrence/excellent long-term survival) with good quality of life. The procedure meets the oncological requirements (R0-resection, complete resection of potentially tumor-infiltrated lymph nodes and the entire precancerous Barrett's esophagus). Reconstruction with interposition of a pedicled isoperistaltic jejunal loop prevents reflux and is crucial for achieving good postoperative quality of life. In contrast, endoscopic mucosal resection (EMR) carries the risk of high recurrence rates (at least 30 %). This has to be regarded as an effect of the frequent incomplete resection, multicentric tumor growth, the persistence of precancerous Barrett's mucosa and persistence of gastroesophageal reflux. Consequently, from the oncological view point, EMR is only suited for unicentric mucosal tumors (T1a) in short segments of Barrett's esophagus. Reliable preoperative identification of such tumors is, however, currently not possible.

CONCLUSION

For adequately selected patients with early Barrett's cancer, limited resection of the esophagogastric junction is an appropriate procedure. Endoscopic mucosa resection (EMR) might gain importance as staging tool.

Association of pretherapeutic expression of chemotherapy-related genes with response to neoadjuvant chemotherapy in Barrett carcinoma

PURPOSE

We analyzed pretherapeutic gene expression patterns of patients with locally advanced adenocarcinomas of the esophagus with regard to response to neoadjuvant chemotherapy.

EXPERIMENTAL DESIGN

Pretherapeutic, paraffin-embedded, formalin-fixed endoscopic esophageal tumor biopsies of 38 patients with locally advanced esophageal adenocarcinomas (Barrett adenocarcinoma) were included. All patients underwent two cycles of cisplatin and 5-fluorouracil (5-FU) therapy with or without additional paclitaxel followed by abdominothoracal esophagectomy. RNA expression levels of 5-FU metabolism-associated genes thymidylate synthase, thymidine phosphorylase, dihydropyrimidine dehydrogenase, methylenetetrahydrofolate reductase, MAP7, and ELF3, of platinum- and taxane-related genes caldesmon, ERCC1, ERCC4, HER-2/neu, and GADD45, and of multidrug resistance gene MRP1 were determined using real-time reverse transcriptase-PCR. Expression levels were correlated with response to chemotherapy, histopathologically assessed in surgically resected specimens.

RESULTS

Responding patients showed significantly higher pretherapeutic expression levels of MTHFR (P = 0.012), caldesmon (P = 0.016), and MRP1 (P = 0.007). In addition, patients with high pretherapeutic MTHFR and MRP1 levels had a survival benefit after surgery (P = 0.013 and P = 0.015, respectively). Additionally, investigation of intratumoral heterogeneity of gene expression of relevant genes (MTHFR, caldesmon, HER-2/neu, ERCC4, and MRP1), verified in nine untreated Barrett adenocarcinomas by examination of five distinct tumor areas, revealed no significant heterogeneity in gene expression indicating that expression profiles obtained from biopsy material may yield a representative genetic expression profile of total tumor tissue.

CONCLUSIONS

Our results indicate that determination of mRNA levels of few genes may be useful for the prediction of the success of neoadjuvant chemotherapy in individual cancer patients with locally advanced Barrett adenocarcinoma.

Preferred location for the development of esophageal adenocarcinoma within a segment of intestinal metaplasia

BACKGROUND

Barrett's metaplasia is the predominant precursor for the development of esophageal adenocarcinoma. This precancerous lesion has become the focus of various surveillance programs aimed at detecting earlier and therefore potentially curable lesions. However, sampling error by missing invasive cancer lesions is a common problem. This study aimed to identify preferred locations within a segment of Barrett's mucosa for the development of esophageal adenocarcinoma.

METHODS

The study group consisted of 213 patients with histologically proven esophageal adenocarcinoma. Of those, there were 134 cases of early cancer and 79 cases of locally advanced lesions. These patients received neoadjuvant chemotherapy. The frequency of intestinal metaplasia and the location of the tumor occurrence within the segment of intestinal metaplasia were assessed.

RESULTS

Intestinal metaplasia was found in 83% of the early lesions and in 98% of the advanced tumors after neoadjuvant chemotherapy. In 82.2% of the cases, the tumor was located at the distal margin of the intestinal metaplasia in patients with early tumor manifestations. The remaining tumor mass after neoadjuvant therapy also was located predominantly at the distal margin of the segment of intestinal metaplasia (85% of the cases).

CONCLUSIONS

The results demonstrate that almost all adenocarcinomas of the esophagus are based on the development of a segment of intestinal metaplasia. The distal margin of Barrett's mucosa seems to be the most vulnerable location for the development of invasive cancer.

Surgical strategies for early esophageal adenocarcinoma

The need for extensive surgical resection for early-stage esophageal adenocarcinoma has been challenged by the increasing frequency of early detection in patients with Barrett's esophagus undergoing surveillance endoscopy. Limited endoscopic or surgical procedures are promoted as alternatives to radical esophagectomy and lymphadenectomy in such patients. Currently available data show that limited surgical resection of the distal esophagus with regional lymphadenectomy and interposition of an isoperistaltic jejunal segment is a safe and oncologically adequate procedure in this situation and provides good quality of life. This is in contrast to endoscopic ablation or endoscopic mucosal resection, which are associated with high tumour recurrence rates and persistence of premalignant Barrett esophagus. New technologies for accurate prediction of the presence and pattern of lymphatic spread-e.g. sentinel node techniques and artificial neural networks-may allow a further reduction of the invasiveness of surgical resection without compromising cure rates.

Multimodal treatment of gastrointestinal tract tumors: consequences for surgery

Formerly an exclusive business of surgery, gastrointestinal (GI) tumors are nowadays increasingly approached with multimodal strategies. Neoadjuvant concepts have had a particularly far-reaching impact on surgery and have contributed to improved survival. Modern pre-treatment staging and risk assessment provide the basis for decision on one of three general treatment concepts (1) Early cancers, confined to the mucosal/submucosal layers, are approached with primary surgery, without prior antineoplastic therapy. (2) Systemically metastasized tumors receive merely palliative treatment. (3) Locally advanced cancers are increasingly approached with neoadjuvant strategies. The benefit from these preoperative protocols is proven for diverse entities, but is evidently confined to a specific subgroup patients, i.e., the responders to neoadjuvant treatment. These are the ones benefiting most from subsequent surgical resection, which is required to ensure complete removal of the residual tumor tissue, as complete tumor regression occurs very rarely and cannot be proven without a specimen. The fact that responders will benefit and non-responders will not benefit or will even deteriorate during the neoadjuvant treatment makes early response prediction most demanding. An amazing new approach is the use of position emission tomography with fluro-desoxyglucose (FDG-PET) to assess the "metabolic response," which is possible as early as 14 days after initiation of the neoadjuvant protocol. This strategy offers the chance for modulating the surgical approach in accord i.e., with such metrobolic response termination of the protocol and proceeding to resection in the case of nonresponse. The future of GI cancer surgery is multimodal therapy in a response-based fashion and requires reponse-based trials for further evaluation.

Early esophageal cancer: pattern of lymphatic spread and prognostic factors for long-term survival after surgical resection

OBJECTIVE

The objective of this study was to assess the prevalence and pattern of lymphatic spread in patients with early squamous cell and adenocarcinoma and identify prognostic factors for long-term survival after resection and lymphadenectomy.

SUMMARY BACKGROUND DATA

Limited endoscopic approaches without lymphadenectomy are increasingly applied in patients with early esophageal cancer.

MATERIAL AND METHODS

A total of 290 patients with early esophageal cancer (157 adenocarcinoma, 133 squamous cell cancer) had surgical resection with systematic lymphadenectomy. Specimens were assessed for prevalence and pattern of lymphatic spread. Prognostic factors were determined by multivariate analysis.

RESULTS

None of the 70 patients with adenocarcinoma limited to themucosa had lymphatic spread, as compared with 2 of 26 with mucosal squamous cell cancer. Lymphatic spread was more common in patients with submucosal squamous cell cancer as compared with submucosal adenocarcinoma (36.4% versus 20.7%). Although lymph node metastases were usually limited to locoregional lymph node stations in early adenocarcinoma, distant lymphatic spread was frequent in early squamous cell cancer. On multivariate analysis, only histologic tumor type and the presence of lymph node metastases were independent predictors of long-term survival. Five-year survival rate was 83.4% for early adenocarcinoma versus 62.9% for early squamous cell cancer and 48.2% versus 79.5% for patients with/without lymphatic spread.

DISCUSSION

Prevalence and pattern of lymphatic spread as well as long-term prognosis differ markedly between early esophageal squamous cell and adenocarcinoma. Limited resection techniques and individualized lymphadenectomy strategies appear applicable in patients with early adenocarcinoma.