Classification of Cervical Cancer

The naming and classification of cervical carcinoma percursor lesions has changed many times over the 20th century. The World Health Organization classification system was descriptive of the lesions, naming them mild, moderate or severe dysplasia or carcinoma in situ (CIS). The term, Cervical Intraepithelial Neoplasia (CIN) was developed to place emphasis on the spectrum of abnormality in these lesions, and to help standardise treatment. It classifies mild dysplasia as CIN1, moderate dysplasia as CIN2, and severe dysplasia and CIS as CIN3. The most recent classification is the Bethesda System, which divides all cervical epithelial presursor lesions into 2 groups: Low-grade Squamous Intraepithelial Lesion (LSIL) and High-grade Squamous Intraepithelial Lesion (HSIL). LSIL corresponds to CIN1, and HSIL includes CIN2 and CIN3. More recently, CIN2 and CIN3 have been combined into CIN2/3.