Cytological screening and 15 years’ follow-up (1986-2001) for early esophageal cancer and precancerous lesions in a high-risk population in Anyang County, Henan Province, northern China

LD Wang MD^a, ZM Fan MS^a, HH Yang MD^b, YJ Li MD^a, JX Li MD^a, XDLÃ

^aLaboratory for Cancer Research, College of Medicine, Zhengzhou University, Zhengzhou, China and, ^bDepartment of Pathology, Anyang Tumor Hospital, Anyang, Henan, China

Anyang County nearby Linzhou (formerly Linxian) in northern China has been well recognized as the highest incidence area for esophageal squamous cell carcinoma (SCC) in the world. SCC remains the leading cause of cancer related death in this area and its natural history is not clear. Balloon cytology has been applied in this area since late 50’s for early detection of SCC. In the present study, to determine the significance of cytological examination and natural history for SCC, balloon cytological screening and follow-up studies have been performed on 2894 symptom-free subjects in Anyang County since 1986. The study cohort consisted of all inhabitants over 35 years of age in 10 natural villages. Based on cellular morphological changes, esophageal epithelial cells were divided as normal (NOR), chronic esophagitis (CE), hyperplasia (HYP), dysplasia (grade 1 and 2) (DYS1, and 2), near cancer (NSCC) and SCC. At the entry of follow-up, 112 cases (3.9%, 112/2894) with early SCC (83%, 93/112) and gastric cardia adenocarcinoma (GCA) (17%, 19/112) were identified cytologically and confirmed by late biopsy and surgery. The prevalence of NOR, HYP, DYS1 and 2 and NSCC was 31.6%, 33.9%, 18.9%, 8.8% and 2.9%, respectively. No difference was observed between the male and female (p>0.05). Of the 2894 subjects examined, 2260 subjects entered the final follow-up analysis (78.6%). During the 15 years’ follow-up on these subjects, 94 new cases (4.2%, 94/2260) including 91 with SCC (97%, 91/94, 58 males and 33 females) and 3 with GCA (3%, 3/94, 1 male and 2 females) were identified with a mean time of 8±4.6 years after the entry of follow-up. The incidence for SCC in males was higher than in females (p<0.05). Of the 91 new cases with SCC, 13 occurred in the group of NOR (2.4%), 3 occurred in the group of IN (2.9%), 23 occurred in the group of HYP (3%), 23 occurred in the group of DYS1 (5%), 20 occurred in the group of DYS2 (8.3%), 9 occurred in the group of NSCC (10.3%). The rate for SCC development increased apparently from the groups of NOR to DYS1 and DYS2 and NSCC (p<0.001); IN to NSCC (p<0.05); HYP to DYS2 and NSCC (p<0.005). DYS1 occurred more frequently in the age group of 40-49 in males and 50-59 in females; DYS2 in the age group of 60+ in males and 40-60 in females; NSCC in the age group of 60+. The prevalence of DYS and NSCC increased significantly with age. The present results indicate that Balloon cytology is a reliable method for early esophageal cancer and precancerous lesions screening, that HYP and DYS are important biomarkers for high-risk subjects with predisposition to SCC and that exact follow-up to the subjects with HYP, DYS and NSCC may shed light on exploring the natural history for human esophageal carcinogenesis. (Supported by Chinese National Outstanding Young Scientists Foundation 30025016 and NCI CA65871; Correspondence to: Dr. Li Dong Wang, Lab. for Cancer Res., College of Medicine, Zhengzhou University, Zhengzhou, Henan, 450052, China. E-mail: lidong0823@sina.com).

Paper presented at the International Symposium on Predictive Oncology and Intervention Strategies; Nice, France; February 7 - 10, 2004; in oral session 992 (Screening & detection - Part I).