Search

Background: In the early stage esophageal cancer, changes in the mucosa are subtle and pass unnoticed in endoscopic examinations using white light. To increase sensitivity, chromoscopy with Lugol's solution has been used. Technological advancements have led to the emergence of virtual methods of endoscopic chromoscopy, including narrow band imaging (NBI). NBI enhances the relief of the mucosa and the underlying vascular pattern, providing greater convenience without the risks inherent to the use of vital dye. The purpose of this systematic review and meta-analysis was to evaluate the ability of NBI to diagnose squamous cell carcinoma of the esophagus and to compare it to chromoscopy with Lugol's solution., Methods: This systematic review included all studies comparing the diagnostic accuracy of NBI and Lugol chromoendoscopy performed to identify high-grade dysplasia and/or squamous cell carcinoma in the esophagus. In the meta-analysis, we calculated and demonstrated sensitivity, specificity, and positive and negative likelihood values in forest plots. We also determined summary receiver operating characteristic (sROC) curves and estimates of the areas under the curves for both per-patient and per-lesion analysis., Results: The initial search identified 7079 articles. Of these, 18 studies were included in the systematic review and 12 were used in the meta-analysis, for a total of 1911 patients. In per-patient and per-lesion analysis, the sensitivity, specificity, and positive and negative likelihood values for Lugol chromoendoscopy were 92% and 98, 82 and 37%, 5.42 and 1.4, and 0.13 and 0.39, respectively, and for NBI were 88 and 94%, 88 and 65%, 8.32 and 2.62, and 0.16 and 0.12, respectively. There was a statistically significant difference in only specificity values, in which case NBI was superior to Lugol chromoendoscopy in both analyses. In the per-patient analysis, the area under the sROC curve for Lugol chromoendoscopy was 0.9559. In the case of NBI, this value was 0.9611; in the per-lesion analysis, this number was 0.9685 and 0.9587, respectively., Conclusions: NBI was adequate in evaluating the esophagus in order to diagnose high-grade dysplasia and squamous cell carcinoma. In the differentiation of those disorders from other esophageal mucosa alterations, the NBI was shown to be superior than Lugol.

Background: H. pylori seroprevalence in Brazilians varies and is dependent on socioeconomic status, sanitation conditions and ethnicity; furthermore, H. pylori is not always associated with the incidence of gastric cancer, suggesting the role of more virulent strains. The purpose of this study was to analyze the association of more virulent H. pylori strains with gastric cancer., Methods: DNA was extracted from gastric biopsies of thirty-four cases of gastric cancer (11 intestinal-type, 23 diffuse-type), and thirty-four of patients with endoscopic gastritis. The presence of cagPAI genes (cagA, cagA promoter, cagE, cagM, tnpB, tnpA, cagT and the left end of the cagII (LEC)) and babA were analyzed by PCR., Results: Comparison of H. pylori isolates from gastric cancer and gastritis patients showed significant associations of tnpA and LEC with gastric cancer (73.5% [OR, 6.66; 95% CI, 2.30-19.25] and 58.8% [OR, 10.71; 95% CI, 3.07-37.28] of cases, respectively). Other cagPAI genes were detected in both groups at similar frequencies., Conclusions: tnpA and LEC of H. pylori cagPAI were associated with gastric cancer; nonetheless, these results were restricted within this group of patients and further studies are needed to confirm these results in a larger sample and determine their role in gastric carcinogenesis.