Cervical cancer and
pre-cancer are classified by their appearance under microscope. There are two
main types of cervical cancer:
i.
squamous cell carcinoma
ii.
adenocarcinoma.
About
80% to 90% of cervical cancers are squamous cell carcinomas. The cancer starts
in the squamous cells that cover the surface of the exocervix. Under
microscope, the cancer cells are squamous cell-like. The rest of the cervical
cancers are adenocarcinomas. Cervical adenocarcinoma becomes more common in the
last 20-30 years. Cervical adenocarcinoma develops from the mucus-producing
gland cells of the endocervix. Cervical cancers also have features of both
squamous cell carcinomas and adenocarcinomas which known as adenosquamous
carcinomas (mixed carcinomas).
Although
cervical cancers start from cells with pre-cancerous changes, only some women
with pre-cancers of the cervix will develop cancer. The change from pre-cancer
to cancer usually takes several years; however, it can be happen in less than a
year. For majority, pre-cancerous cells will remain unchanged and go away
without any treatment. Still, in some women, pre-cancers have turned into true
(invasive) cancers.