The Endoscopic Diagnosis of Anal Intra-Epithelial Neoplasia

The possible association between anal cancer and a sexually transmissible agent was first suggested from epidemiological data by Cooper in 1979 [1]. Other studies have supported this hypothesis; Austin [2] demonstrated an association between male homosexuality and anal cancer. Subsequently Dating [3] has demonstrated that receptive anal intercourse and genital warts are closely correlated with the subsequent development of anal cancer in males. Epidemiological studies of the aetiology of carcinoma of the uterine cervix have also suggested an association with a sexually transmissible agent. Common aetiological factors in tumours at these sites may reflect the common embfyological origins of the anal and endocervical canals (both are derived from the cloacogenic membrane) [4]. Both the anal canal and the endocervical canal have squamous epithelium in their lower part and columnar epithelium above, with an area of transitional epithelium in between.