Definition

Stage 0 bladder cancer refers to noninvasive bladder cancer. This means that cancer cells are found in tissue lining the inside of the bladder but have not invaded the bladder wall. Stage 0 is divided into stages 0a and 0is, depending on the type of tumor. Stage 0a is also called noninvasive papillary carcinoma, which may look like long, thin growths extending into the bladder lumen (the space where urine collects). Stage 0is is also called carcinoma in situ, which is a flat tumor on the tissue lining the inside of the bladder.