Cytologic screening for esophageal cancer in a high-risk population in Anyang County, China.

Anyang County, China, is one of the areas with the highest incidence of esophageal cancer in the world. Esophageal cancer has a poor prognosis because most tumors are unresectable at the time of diagnosis. We launched a screening study for early esophageal carcinoma in western Anyang County in 1997. The scope was to identify patients with in situ and early invasive carcinoma, applying esophageal balloon cytology and treating with photodynamic therapy (PDT).The study cohort consisted of all inhabitants over 35 years of age in 10 communes. Screening was performed by balloon cytology. Grade 2 dysplasia and more advanced lesions were examined with endoscopy, including biopsy and brush cytology, followed by PDT for early cancer.In total, 20,049 persons participated in the screening program, and 1,018 were diagnosed with a grade 2 dysplasia or higher, including 164 invasive cancers and 169 near-cancers. Ninety-four percent of atypical lesions were of squamous cell type. Seventy-two percent of cases showing severe dysplasia and cancer were located to the middle esophageal segment. The prevalence of dysplasia and cancer increased significantly with age. The balloon cytology results were confirmed by brush cytology and histology.Balloon cytology is a reliable method for esophageal cancer screening. Positive cytology must be verified by endoscopy and biopsy.