Cervical cancer refers to cancers that originate in the cervix. The cervix is the part of the reproductive system that connects the upper uterus (where fetuses grow and develop) with the birth canal (through which the fetus travels during the birthing process). The cervix is made up of three distinct parts: the first, the endocervix, is located next to the uterus. The second, the exocervix, is located next to the vagina. The third, the transformation zone, connects the two parts of the cervix. The majority of cervical cancers originate in the transformation zone.
Most cervical cancers begin with precancerous cell changes. These precancerous cell changes are often caused by the human papillomavirus, or HPV. HPV is a disease transmitted through genital contact with an infected person. HPV can be diagnosed by a simple blood test, and there is now a vaccine for the virus. The precancerous changes can also be detected at a very early stage by annual pap smears, and generally treated before cervical cancer progresses. Cervical cancer is considered to be a slow-growing cancer.
Stages of Cervical Cancer
Like all cancers, the prognosis depends on the stage of the cancer. Stage I cervical cancer has a much higher survival rate than Stage IV cervical cancer. Cervical cancer is staged using a system created by the International Federation of Gynecology and Obstetrics, called the FIGO system. Staging is based on a physical examination of the cervix by a physician, as well as other tests including a proctoscopy and cystoscopy to evaluate the extent of the growth of cancer cells within the cervix.
Stage 0
Cervical cancer classified as Stage 0 is generally considered to be very easily treatable. Stage 0 cervical cancer is diagnosed when cancer cells are found on only the surface outer layer of cells lining the cervix. The cancer cells have not yet grown into deeper tissue on the cervix. The survival rate for stage 0 cervical cancer is above 95 percent, based on five-year survival rates provided by the American Cancer Society.
Stage 1 Cervical Cancer
There are two types of cervical cancer that are classified as stage I: stage IA, and stage IB. Both stage IA and stage IB have 2 levels: stage IA1, Stage IA2 and stage IB1, and stage IB2.
The five-year survival rates for those with stage IA cervical cancer are higher than 95 percent. Stage IA is characterized by cancer that has actually grown beyond the outer layer of the cervix's lining into the tissues of the cervix. However, the amount of growth is very small, and the cancer cells can only be seen under a microscope. In stage I, the cancer cells have invaded an area less than 3mm deep and 7mm wide. In Stage IA2, the cancer cells have invaded an area between 3 and 5mm deep, and less than 7mm wide.
In stage IB1 and IB2, the cancer cells have grown large enough to be seen without the help of a microscope. Stage IB1, which has a 90 percent five-year survival rate, describes tumors less than 4cm large. Stage IB2, which has between an 80 to 85 percent five-year survival rate, is characterized by tumors that can be seen without the aid of a microscope, that are larger than 4cm.
Stage II Cervical Cancer
Cervical cancer that has progressed beyond the cervix and uterus but not yet spread to the pelvis wall or lower vagina is considered to be Stage II. Stage II Cervical Cancer also has an A and a B stage, but the survival rates for both are between 70 to 75 percent. Stage IIA describes cancer that has spread beyond the cervix but not yet invaded the parametria (the tissues adjacent to the cervix). The cancer may have spread into the upper vagina, but not the lower vagina. Stage IIB describes cancers that have spread into the tissue adjacent to the cervix.
Stage III Cervical Cancer
Stage III cervical cancer also has an A and a B stage, although the survival rates for both Stage IIIA and IIIB are between 47 and 50 percent. In Stage IIIA, the cancer has invaded the lower 1/3 of the vagina. It has not spread to the pelvic wall or blocked the ureters. If the cancer has blocked the ureters or spread to the walls of the pelvis, the cancer is characterized as Stage IIIB.
Stage IV Cervical Cancer
Stage IV cervical cancer indicates the cancer has spread, or metastasized, to parts of the body distinct from the cervix. In Stage IVA, the cancer has spread to the closest organs to the cervix, including the bladder or rectum. In Stage IVB, the cancer has spread to organs outside the pelvic area, including the lungs. Stage IV cervical cancer is not curable. Radiotherapy is the only method of extending survival, but even with radiotherapy the five-year survival rate is around 20 to 30 percent of patients.
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