Cervical Intraepithelial Neoplasia or CIN for short is called the pre-cancerous changes of the outer (squamous) cells of the cervix which have the potential to turn into cancer if left untreated for some time. There are different grades of CIN according to how severe the changes are, from CIN1 (minor change) to CIN3 (the most severe change). The risk of developing cancer is related to the grade of CIN. Most of the cases of CIN1 will go back to normal without any treatment as the risk of CIN1 developing into cancer is very small. The CIN2 and CIN3 cases can also revert to normality or stay unchanged for many years but they may also develop into cancer if left untreated in a small but significant fraction. We don’t really know the exact risk of CIN2 and CIN3 turning into cancer as it would be unacceptable to watch this happen without offering treatment.
Cervical Glandular Intraepithelial Neoplasia or cGIN is the pre-cancerous changes involving the inner glandular cells of the cervix. Treatment of cGIN is usually the same as CIN. CIN and cervical cancer is caused by a viral infection with human papillomavirus (HPV) which is acquired or caught in almost all cases through close intimate or sexual contact. These are in fact a large family of over 150 viruses, only a few of which are involved in causing abnormalities of the cervix and lower genital tract. The main types responsible for changes to the cervix are types 16,18,31,33 and 45. About 4 out of 5 adult men and women have had HPV infection at some time in their lives, but only a small minority of women with an HPV infection ultimately have an abnormal smear and a tiny fraction of these get cervical cancer.