Stage 0 (Papillary Carcinoma and Carcinoma in Situ)
In stage 0, abnormal cells are found in tissue lining the inside of the bladder. These abnormal cells may become cancer and spread into nearby normal tissue. Stage 0 is divided into stage 0a and stage 0is, depending on the type of the tumor:
Stage 0a is also called papillary carcinoma, which may look like tiny mushrooms growing from the lining of the bladder.
Stage 0is is also called carcinoma in situ, which is a flat tumor on the tissue lining the inside of the bladder.
In stage I, cancer has formed and spread to the layer of tissue under the inner lining of the bladder.
In stage II, cancer has spread to either the inner half or outer half of the muscle wall of the bladder.
In stage III, cancer has spread from the bladder to the fatty layer of tissue surrounding it, and may have spread to the reproductive organs (prostate, uterus, vagina).
In stage IV, cancer has spread from the bladder to the wall of the abdomen or pelvis. Cancer may have spread to one or more lymph nodes or to other parts of the body.