Jan Johansson

Telomerase reverse transcriptase expression is increased early in the Barrett’s metaplasia, dysplasia, adenocarcinoma sequence

Barrett’s esophagus is a multistage polyclonal disease that is associated with the development of adenocarcinoma of the esophagus and csophagogastric junction. Telomerase activation is associated with cellular immortality and carcinogenesis, and increased expression of the telomerase reverse transcriptase catalytic subunit (hTERT) has been used for the early detection of malignant diseases. To identify’ biomarkers associated with each stage of the Barrett’s process, relative mRNA expression levels of hTERT were measured using a quantitative reverse transcription-polymerase chain reaction method (ABI 7700 Sequence Detector (TaqMan system) in Barrett’s intestinal metaplasia (n —14), Barrett’s dysplasia (n =10), Barrett’s adenocarcinoma (n = 14), and matching normal squamous esophagus tissues (n = 32). hTERT expression was significantly increased at all stages of Barren’s esophagus, including the intestinal metaplasia stage, compared to normal tissues from patients without cancer (intestinal metaplasia vs. normal esophagus, P <0.0001; dysplasia, P = 0.001; adenocarcinoma, P = 0.007; all Alann-Whitney U test). hTERT expression levels were significantly higher in adenocarcinoma tissues than in intestinal metaplasia tissues (P = 0.003), and were higher in dysplasia compared with intestinal metaplasia tissues (P = 0.056). hTERT levels were also significantly higher in histologically normal squamous esophagus tissues from cancer panents than in normal esophagus tissues from patients vrith no cancer (P = 0.013). Very high expression levels ([hTERT × 100: β-actin] >20) were found only in patients with cancer. These findings suggest that telomerase activation is an important early event in the development of Barrett’s esophagus and esophageal adenocarcinoma, that very high telomerase levels may be a clinically useful biomarker for the detection of occult adenocarcinoma, and that a widespread cancer ‘field’ effect is present in the esophagus of patients with Barrett’s cancer.

Suppression of gastric acid secretion in patients with gastroesophageal reflux disease results in gastric bacterial overgrowth and deconjugation of bile acids

The aim of this study was to test the hypothesis that gastric bacterial overgrowth is a side effect of acid suppression therapy in patients with gastroesophageal reflux disease (GERD) and that the bacteria-contaminated gastric milieu is responsible for an increased amount of deconjugated bile acids. Thirty patients with GERD who were treated with 40 mg of omeprazole for at least 3 months and 10 patients with GERD who were off medication for at least 2 weeks were studied. At the time of upper endoscopy, 10 ml of gastric fluid was aspirated and analyzed for bacterial growth and bile acids. Bacterial over-growth was defined by the presence of more than 1000 bacteria/ml. Bile acids were quantified via high-performance liquid chromatography. Eleven of the 30 patients taking omeprazole had bacterial over-growth compared to one of the 10 control patients. The median pH in the bacteria-positive patients was 5.3 compared to 2.6 in those who were free of bacteria and 3.5 in the control patients who were off medication. Bacterial overgrowth only occurred when the pH was >3.8. The ratio of conjugated to unconjugated bile acids changed from 4:1 in the patients without bacterial overgrowth to 1:3 in those with bacterial growth greater than 1000/ml. Proton pump inhibitor therapy in patients with GERD results in a high prevalence of gastric bacterial overgrowth. The presence of bacterial overgrowth markedly increases the concentration of unconjugated bile acids. These findings may have implications in the pathophysiology of gastroesophageal mucosal injury.

Cervical or Thoracic Anastomosis After Esophageal Resection and Gastric Tube Reconstruction: A Prospective Randomized Trial Comparing Sutured Neck Anastomosis With Stapled Intrathoracic Anastomosis

Objective: The purpose of the study was to compare in prospective randomized fashion a manually sutured esophagogastric anastomosis in the neck and a stapled in the chest after esophageal resection and gastric tube reconstruction. Summary Background Data: Despite the fact that all reconstructions after esophagectomy will result in a cervical or a thoracic anastomosis, controversy still exists as to the optimal site for the anastomosis. In uncontrolled studies, both neck and chest anastomoses have been advocated. The only reported randomized study is difficult to evaluate because of varying routes of the substitute and different anastomotic techniques within the groups. The reported high failure rate of stapled anastomoses in the neck and the fact that most surgeons prefer to suture cervical anastomoses made us choose this technique for anastomosis in the neck. Our routine and the preference of most surgeons to staple high thoracic anastomoses became decisive for type of thoracic anastomoses. Methods: Between May 9, 1990 and February 5, 1996, 83 patients undergoing esophageal resection were prospectively randomized to receive an esophagogastric anastomosis in the neck (41 patients) or an esophagogastric anastomosis in the chest (42 patients). To evaluate selection bias, patients undergoing esophageal resection during the same period but not randomized (n = 29) were also followed and compared with those in the study (n = 83). Objective measurements of anastomotic level and diameter were assessed with an endoscope and balloon catheter 3, 6, and 12 months after surgery. The long-term survival rates were compared with the log-rank test. Results: Two patients (1.8%) died in hospital, and the remaining 110 patients were followed until death or for a minimum of 60 months. The genuine 5-year survival rate was 29% for chest anastomoses and 30% for neck anastomoses. The overall leakage rate was 1.8% (2 cases of 112) with no relation to mortality or anastomotic method. All patients in the randomized group had tumor-free proximal and distal resection lines, but 1 patient in the nonrandomized group had tumor infiltrates in the proximal resection margin. At 3, 6, and 12 months after operation, there was no difference in anastomotic diameter between the esophagogastric anastomosis in the neck and in the thorax (P = 0.771), and both increased with time (P = 0.004, ANOVA repeated measures). Body weight development was the same in the two groups. With similar results in randomized and nonrandomized patients, study bias was eliminated. Conclusions: When performed in a standardized way, neck and chest anastomoses after esophageal resection are equally safe. The additional esophageal resection of 5 cm in the neck group did not increase tumor removal and survival; on the other hand, it did not adversely influence morbidity, anastomotic diameter, or eating as reflected by body weight development.

Endoscopic surveillance of columnar-lined esophagus - Frequency of intestinal metaplasia detection and impact of antireflux surgery

ObjectiveTo quantify the occurrence of intestinal metaplasia in columnar-lined esophagus (CLE) during endoscopic surveillance and to evaluate the impact of antireflux surgery on the development of intestinal metaplasia. Summary Background DataThe malignant potential in segments of CLE is mainly restricted to those containing intestinal metaplasia. Patients with segments of CLE in which no intestinal metaplasia can be detected are rarely enrolled in a surveillance program but may still be at increased risk of developing esophageal adenocarcinoma because intestinal metaplasia may be missed or may develop with time. MethodsThe occurrence of intestinal metaplasia on biopsy samples was determined on repeated endoscopies in 177 patients enrolled in a surveillance program for CLE. The incidence of intestinal metaplasia in patients with no evidence of intestinal metaplasia on the two first endoscopies was evaluated on the subsequent endoscopies and compared in patients with medically and surgically treated gastroesophageal reflux disease. ResultsIntestinal metaplasia was found in 53% of the patients (94/177) on their first surveillance endoscopy and was more prevalent in long segments of CLE. The prevalence of intestinal metaplasia increased markedly with increasing number of surveillance endoscopies. Intestinal metaplasia tended to be detected early in patients with long segments of CLE; in patients with shorter segments, intestinal metaplasia was also detected late in the course of endoscopic surveillance. Patients with surgically treated reflux disease were 10.3 times less likely to develop intestinal metaplasia compared with a group receiving standard medical therapy. ConclusionBiopsy samples from a single endoscopy, despite an adequate biopsy protocol, are insufficient to rule out the presence of intestinal metaplasia. Patients in whom biopsy specimens from a segment of CLE show no intestinal metaplasia have a significant risk of having undetected intestinal metaplasia or of developing intestinal metaplasia with time. Sampling error is probably the reason for the absence of intestinal metaplasia in segments of CLE longer than 4 cm, whereas development of intestinal metaplasia is common in patients with shorter segments of CLE. Antireflux surgery protects against the development of intestinal metaplasia, possibly by better control of reflux of gastric contents.

Metaplastic columnar mucosa in the cervical esophagus after esophagectomy

ObjectiveTo evaluate the pathogenesis of metaplastic processes within the esophagus using a human model in which the exact duration of reflux was known. Summary Background DataThe pathogenesis of Barrett’s esophagus (BE) is incompletely understood. Patients undergoing esophagectomy and gastric tube reconstruction represent a good model for studying the pathophysiology of columnar cell metaplasia of the human esophagus because the cervical esophagus is rarely or never exposed to gastric contents before the surgical procedure. MethodsThirty-two patients underwent manometry, simultaneous 24-hour pH and bilirubin monitoring, and endoscopy with biopsy 3 to 10.4 years after esophagectomy. The presence of columnar mucosa in the cervical esophagus was confirmed on histologic examination. The findings on endoscopy and histology were related to clinical data and the results of pH and bilirubin monitoring 1 cm proximal to the esophagogastrostomy. ResultsFifteen (46.9%) of the 32 patients had metaplastic columnar mucosa within their cervical esophagus. Metaplasia was significantly more common in patients with a preoperative diagnosis of BE. The length of metaplastic mucosa correlated significantly with the degree of esophageal acid exposure, but the presence of abnormal bilirubin exposure was unrelated to the presence of metaplasia. The prevalence of metaplasia did not change with increasing time. Intestinal metaplasia was found within the columnar-lined segment in three patients 8.5, 9.5, and 10.4 years after esophagectomy. All patients with intestinal metaplasia had abnormal exposure of both acid and bilirubin, but the presence of combined reflux was not significantly higher in these patients compared with patients with nonintestinalized segments of columnar mucosa. ConclusionsEsophageal columnar metaplasia is a common complication after gastric pull-up esophagectomy. Metaplasia is more likely to develop in patients with previous BE than other patients. Metaplasia develops in response to squamous epithelial injury in predisposed individuals.

Barrett Esophagus: Risk Factors for Progression to Dysplasia and Adenocarcinoma

Objective:To evaluate risk factors for dysplasia and adenocarcinoma development in nondysplastic Barrett mucosa. Summary Background Data:The risk for patients with Barrett esophagus to develop esophageal adenocarcinoma is low, and most patients undergoing surveillance will not develop malignancy. Identification of risk factors may allow for more rational surveillance programs in which patients are stratified according to their individual risk of progressing to dysplasia and invasive adenocarcinoma. Methods:The development of dysplasia and esophageal adenocarcinoma was studied during long-term endoscopic and histologic surveillance in 140 patients with Barrett esophagus free from dysplasia. Risk factors for progression to dysplasia and adenocarcinoma were evaluated. Results:Median follow-up was 5.8 years. Forty-four patients (31.4%) developed low-grade dysplasia and 7 patients (5%) developed high-grade dysplasia or esophageal adenocarcinoma. Dysplasia development was significantly less common after antireflux surgery compared with conventional medical therapy. Low-grade dysplasia (relative risk = 5.5; 95% confidence interval, 1.1–28.6) and long duration of reflux symptoms (relative risk = 1.3; 95% confidence interval, 1.2–1.7) were independently associated with an increased risk of developing high-grade dysplasia or esophageal adenocarcinoma. Conclusions:Successful antireflux surgery protects the Barrett mucosa from developing high-grade dysplasia and esophageal adenocarcinoma, possibly by better control of reflux of gastric contents. Low-grade dysplasia is the only clinically useful risk factor that permits stratification of the surveillance intervals according to the risk of the individual patient.