Hypermethylation of the CDKN2/p16 promoter during neoplastic progression in Barrett's esophagus

Background & Aims: Inactivation of the CDKN2/p16^INK4A tumor-suppressor gene is one of the most frequent genetic alterations in human malignancies. In esophageal adenocarcinomas, mutations of the p16 gene or homozygous deletions of the gene locus 9p21 are rare. This study investigated whether p16 promoter hypermethylation is an alternative mechanism for p16 gene inactivation during neoplastic progression in Barrett's esophagus. Methods: A methylation-specific polymerase chain reaction protocol was applied. A total of 95 specimens from 14 patients with Barrett's esophagus were analyzed longitudinally. The p16 promoter status was compared with histomorphological findings. Results: p16 promoter hypermethylation was detected in 9 of the 10 patients who had displayed dysplasia at some time during surveillance, whereas none of the patients who had not displayed dysplasia during surveillance had p16 promoter hypermethylation. p16 promoter hypermethylation was detected in 3% (2 of 67) of the samples without dysplasia, 60% (3 of 5) of the samples with lesions indefinite for dysplasia, 55.6% (10 of 18) of the specimens with low-grade dysplasia, and 75% (3 of 4) of the specimens with high-grade dysplasia. Conclusions: These data suggest that p16 promoter hypermethylation is a common mechanism of p16 gene inactivation during neoplastic progression in Barrett's esophagus.GASTROENTEROLOGY 1998;115:1381-1386     

EMR for Barrett's esophagus-related superficial neoplasms offers better diagnostic reproducibility than mucosal biopsy

BACKGROUND: EMR of Barrett's esophagus (BE)-related superficial neoplasms represents an efficacious staging modality. It also allows for better pathologic grading compared with mucosal biopsy specimens. However, the interobserver variation in the interpretation of EMR specimens has not been tested. OBJECTIVE: To evaluate consistency in the diagnosis of BE-related neoplasia on EMR specimens. DESIGN: Nine pathologists reviewed 25 esophageal EMR specimens and corresponding biopsy specimens independently. Each pathologist classified the cases as either non-neoplastic BE, low-grade dysplasia, high-grade dysplasia, intramucosal adenocarcinoma, or invasive adenocarcinoma. Interobserver concordance for both specimens from EMRs and biopsies was measured by intraclass correlation and Kendall's coefficient of concordance. The proportion of agreement was also calculated for each specimen and compared for EMR and biopsy by using the Wilcoxon signed rank test. SETTING: Teaching hospitals. PATIENTS: Twenty-five patients who underwent EMR for BE-related neoplasia. RESULTS: The intraclass correlation and the Kendall's coefficient for the 25 biopsy specimens was 0.938 (95% CI 0.880-0.965) and 0.677, respectively; for the 25 EMRs, these were significantly improved, at 0.977 (95% CI 0.957-0.987) and 0.831, respectively. In addition, the proportion of agreement for EMR specimens was significantly better compared with biopsy specimens (P = .015). CONCLUSIONS: Interobserver agreement of BE-related neoplasia on EMR specimens is significantly higher compared with biopsy specimens. The results may relate to the larger tissue sampling compared with biopsy specimens and the ability to evaluate mucosal landmarks, such as double muscularis mucosae. Thus, we suggest that EMRs, in addition to being a staging and therapeutic procedure, improve diagnostic consistency.     

Five-year efficacy and safety of photodynamic therapy with Photofrin in Barrett's high-grade dysplasia

BACKGROUND: Barrett's esophagus (BE) with high-grade dysplasia (HGD) is a risk factor for development of esophageal carcinoma. Photodynamic therapy (PDT) with Photofrin (PHO) has been used to eliminate HGD in BE. OBJECTIVE: Our purpose was to compare PHOPDT plus omeprazole with omeprazole only (OM). DESIGN: Five-year follow-up of a randomized, multicenter, multinational, pathology-blinded HGD trial. SETTING: 30 sites in 4 countries. PATIENTS: 208. INTERVENTIONS: Patients with BE and HGD were randomized (2:1) to PHOPDT (n=138) or OM (n=70) into a 2-year trial followed up for 3 more years. PHOPDT patients received 2 mg/kg PHO intravenously followed by endoscopic laser light exposure of Barrett's mucosa at a wavelength of 630 nm within 40 to 50 hours to a maximum of 3 courses at least 90 days apart. Both groups received 20 mg of OM twice daily. Pathologists at one center assessed biopsy specimens in a blinded fashion. MAIN OUTCOME MEASUREMENT: HGD ablation status over 5 years of follow-up. RESULTS: At 5 years PHOPDT was significantly more effective than OM in eliminating HGD (77% [106/138] vs 39% [27/70], P<.0001). A secondary outcome measure preventing progression to cancer showed a significant difference (P=.027) with about half the likelihood of cancer occurring in PHOPDT (21/138 [15%]) compared with OM (20/70 [29%]), with a significantly (P=.004) longer time to progression to cancer favoring PHOPDT. LIMITATIONS: Not all patients were available for follow-up. CONCLUSIONS: This 5-year randomized trial of BE patients with HGD demonstrates that PHOPDT is a clinically and statistically effective therapy in producing long-term ablation of HGD and reducing the potential impact of cancer compared with OM.