The stage of cervical cancer refers to the extent to which it has spread. Stage 0 means that the cancer cells are found on the surface of the cervix, and stage I means the cancer is localized to the cervix. Spread to the upper part of the vagina signals a stage II cancer. Stage III tumors extent to the lower vagina, and in Stage IV, the tumor has spread to the bladder or rectum, or to distant sites in the body.