Efficacy of Endoscopy Screening on Esophageal Cancer in China (ESECC)

"1. Upper G.I. endoscopic examination with Lugols Iodine in esophagus~2. Biopsy at the visually abnormal sites~3. Pathologic examination of all biopsy tissue specimens~4. Subsequent re-examination and further medical services among individuals who already have high-grade lesions found at screening.~5. Advises of endoscopic or surgical treatment will be given to participants who are diagnosed of high grade upper G.I. lesions."