CIN stands for cervical intraepithelial neoplasia, which is the abnormal growth of cells on the surface of the cervix that could potentially lead to cervical cancer. CIN is not cancer, but if the abnormal cells are not treated, over time they may develop into cancer of the cervix. CIN is graded on a 1-3 scale, with 3 being the most abnormal. CIN-1 involves the lower 1/3 or less of the epithelium, whereas CIN-2 and CIN-3 progress to include the entire thickness of the epithelium. Cervical dysplasia was once classified as mild, moderate, or severe, based on how likely abnormal cells would become cancerous. A more recent system classifies disease severity based on how much epithelial tissue in the cervix has abnormal cells. Cervical intraepithelial neoplasia (CIN) is classified on a scale from one to three.

CIN does not cause any symptoms, and you are not likely to find out you have it unless you have cervical screening. If CIN is persistent after two years or progresses within that time, treatment is recommended. There are different types of treatment that can be used to remove CIN, and your doctor will explain what treatment they suggest for you. They will only offer treatment if they are sure the cells are very abnormal and there is a risk of cancer developing. You usually only need one treatment to remove the abnormal cells completely.