Cervical cancer is a malignant neoplasm of the cervix. Cervical cancer stages begin at 0 and go to 4, with several sub-stages in between. Stage 0 is the earliest of the cervical cancer stages and is characterized by abnormal cells have yet to progress to full blown cancer. Stages 1, 2, and 3 encompass cancer that has not yet spread to the rest of the body. Stage 4 cervical cancers are the most serious and include cancer that has spread to other portions of the body.
Carcinoma in situ is the clinical term that describes the earliest stage. This occurs when abnormal cells that will eventually turn into cancer are found in the cervix, i.e., the area between the uterus and vagina. The cells are usually only found in the innermost tissue of the cervix, and are typically tested for following an abnormal pap smear that indicates a HPV infection may be present.
Stage 1 is when the abnormal cells become cancerous yet remain inside the cervix. This level is further classified into four different subgroups: A1, A2, B1, and B2. Stage A1 is when the cancer can only be seen with a microscope and the cells are less than 3 millimeters deep and 7 millimeters wide; stage A2 is when the cancer is between 3 and 5 millimeters deep and less than 7 millimeters wide. In the B cervical cancer stages, the cells can be seen without a microscope: the first level of this subgroup has cancerous cells less than 4 centimeters. Anything over 4 centimeters is classified as Stage B2 cervical cancer.
The second stage of this type of cancer has two subgroups: A and B. In stage 2 cervical cancer, the cells are outside of the cervix yet have not traveled past the pelvis or into the lower part of the vagina. Stage A is when the cancer has not yet made it to the tissue surrounding the uterus and stage B is when the cancer has spread to this area.
The third of the cervical cancer stages also has two A and B sub-stages. In this stage, the cancerous cells have made it to the lower portion of the vagina or into the pelvic wall; depending on the spread, this level of cancer may cause issues with kidney function. In sub-stage A, the cancer is still outside of the pelvic wall; in B, the cancer has entered the pelvis.
Stage 4 A cervical cancer is when the cancer is in the cervix, pelvic wall, and lower vagina. Stage 4 B, the final level of the cervical cancer stages, is when the cells have spread beyond the pelvis into other areas of the body. At this point, the cancer could spread anywhere.