What is cervical cancer?

Cervical cancer is cancer of the cervix, the lower part of the uterus that connects to the vagina. The cervix is divided in endocervix, which is closer to the body of the uterus and exocervix, which is closer to the vagina. The endocervix contains squamous cells and the exocervix contains glandular cells. Most cancers start in the area where these two cell types meet: the transformation zone. The cells lining the cervix develop pre-cancerous changes that are called cervical intraepithelial neoplasia (CIN), human squamous intraepithelial lesion (HSIL), and dysplasia, and can be detected under the microscope. Cervical Cancer is separated into squamous cell carcinoma, which affects the endocervix and makes up 80-90%, and adenocarcinoma, which develops in the exocervix. It can take several years before these changes can develop into invasive cancer, and not all pre-cancerous cells develop cancer as some go away on their own without any treatment. Once the cancer invades deep tissue and the cancerous cells break away from the main cell it spreads to other cells via the bloodstream or lymph vessels (American Cancer Society 2011).

Illustration of female reproductive system

93% of cervical cancer are caused by humanpapillomaviruses (HPV) (Bosch, et al. 1995). HPVs are the most common sexually transmitted infection and can cause genital warts as well as cervical cancer. However, the ones that cause cancer are different from those that cause warts (CDC). Even though the infection rate of HPV is 60%, most people clear the virus before the pre-cancerous HSIL can progress to a carcinoma and end in invasive cancer (Baseman and Koutsky 2005). There are about 15 out of 100 different HPVs associated with cervical cancer. And infection with oncogenic papillomavirus is considered a necessary but not sufficient cause for the development of cervix cancer (Burk, Chen, and Van Doorslaer 2009).