Oesophageal mucosa in a population at risk of oesophageal cancer: post-mortem studies

Esophageal Squamous Dysplasia is Common in Asymptomatic Kenyans: A Prospective, Community-Based, Cross-Sectional Study

OBJECTIVES

Esophageal squamous cell carcinoma (ESCC) is endemic in east Africa and is a leading cause of cancer death among Kenyans. The asymptomatic precursor lesion of ESCC is esophageal squamous dysplasia (ESD). We aimed to determine the prevalence of ESD in asymptomatic adult residents of southwestern Kenya.

METHODS

In this prospective, community-based, cross-sectional study, 305 asymptomatic adult residents completed questionnaires and underwent video endoscopy with Lugol's iodine chromoendoscopy and mucosal biopsy for detection of ESD.

RESULTS

Study procedures were well tolerated, and there were no adverse events. The overall prevalence of ESD was 14.4% (95% confidence interval (CI): 10-19%), including 11.5% with low-grade dysplasia and 2.9% with high-grade dysplasia. The prevalence of ESD was >20% among men aged >50 years and women aged >60 years. Residence location was significantly associated with ESD (Zone A adjusted odds ratio (OR) 2.37, 95% CI: 1.06-5.30 and Zone B adjusted OR 2.72, 95% CI: 1.12-6.57, compared with Zone C). Iodine chromoendoscopy with biopsy of unstained lesions was more sensitive than white-light endoscopy or random mucosal biopsy for detection of ESD and had 67% sensitivity and 70% specificity.

CONCLUSIONS

ESD is common among asymptomatic residents of southwestern Kenya and is especially prevalent in persons aged >50 years and those living in particular local regions. Lugol's iodine chromoendoscopy is necessary for detection of most ESD but has only moderate sensitivity and specificity in this setting. Screening for ESD is warranted in this high-risk population, and endoscopic screening of Kenyans is feasible, safe, and acceptable, but more accurate and less invasive screening tests are needed.

Diagnosis and staging of cancer of the esophagus and esophagogastric junction

Esophageal/esophagogastric junction cancer staging in the 7th edition of the AJCC staging manual is data driven and harmonized with gastric staging. New definitions are Tis, T4, regional lymph node, N, and M. Nonanatomic characteristics (histopathologic cell type, histologic grade, cancer location) and TNM classifications determine stage groupings. Classifications before treatment define clinical stage (cTNM or ycTNM). Current best clinical staging modalities include endoscopic ultrasonography for T and N and CT/PET for M. Classifications at resection define pathologic stage (pTNM or ypTNM). Accurate pathologic stage requires communication/cooperation between surgeon and pathologist. Classifications are defined at retreatment (rTNM) and autopsy (aTNM).

Low prevalence of incidentally discovered and early-stage esophageal cancers in a 30-year autopsy study

Autopsy studies provide information that may guide future patient management. This study analyzed autopsy findings in patients with esophageal cancers, with emphasis on the prevalence of incidentally diagnosed esophageal cancer, histologic subtypes, early-stage lesions, and any associated pathology. Autopsies detected 346 patients (306 men; 40 women) with esophageal carcinomas during a 30-year period, constituting an overall prevalence of 3.4%. Out of these patients, 30 (8.7%) were incidentally discovered at autopsy. Squamous cell cancers were found in 336 (97.1%) patients, small cell cancers in nine (2.7%), and adenocarcinomas in one (0.3%). Stage distributions were stage I in seven patients (2%), stage II in 49 (14%), stage III in 121 (35%), and stage IV in 169 (49%). Isolated dysplasia or carcinoma-in-situ were not found. Comparing with symptomatic patients, patients with incidental cancers were older, had higher frequency of small cell carcinomas, and lower T-stage. The prevalence of incidentally diagnosed esophageal carcinomas and early-stage carcinomas were low. Unusual histologic subtypes may be found.

p53 overexpression in squamous cell carcinoma of the esophagus

BACKGROUND

Coastal South Carolina has a high incidence of squamous cell carcinoma of the esophagus (SCCE) among black residents. Overexpression and mutations of the p53 tumor suppressor gene have been noted in SCCE from other high-incidence regions. The purpose of this study was to determine the frequency of p53 overexpression in this region both in patients with SCCE and in normal subjects.

METHODS

Normal and malignant tissue obtained at esophagoscopy and normal esophageal mucosa (NEM) from random autopsies were studied with monoclonal antibodies to the p53 gene product. Total cellular RNA was extracted from SCCE, reverse transcribed to complementary DNA, and a portion of the p53 gene was amplified via polymerase chain reaction and sequenced.

RESULTS

Immunohistochemical studies on SCCE from nine patients showed that six (67%) were positive, two (22%) were negative, and one was indeterminate for p53 overexpression. The corresponding normal samples showed that three (33%) had p53-positive cells in the basal epithelial layer, whereas six did not. NEM from 18 random forensic cases displayed p53 overexpression in seven (39%). Eight of the nine tumors had p53 mutations.

CONCLUSIONS

p53 overexpression and mutations are frequently found in SCCE from patients in coastal South Carolina. Overexpression in normal epithelium from random autopsy cases may indicate an inherited or acquired predisposition in this geographic region.