Types of Bladder Cancer

The bladder is made up of several different types of cells. Bladder cancer is usually made up of one type of these cells, although it is not uncommon for a mixed cell type to occur. The common forms of bladder cancer include transitional cell carcinoma, squamous cell carcinoma, and adenocarcinoma.

Transitional cell carcinoma: This is by far the most common form and accounts for more than 90% of bladder cancers. The cells of transitional cell carcinoma are a cancerous version of the transitional cells that normally line the bladder.

Squamous cell carcinoma: This type accounts for only about 3% to 8% of bladder cancers. Under a microscope, the cells look much like cells from skin cancers. Nearly all squamous cell carcinomas are invasive cancers (have spread beyond the layer of cells where it first developed to involve adjacent tissues).

Adenocarcinoma: This form accounts for only about 1% to 2% of bladder cancers. The cells have a lot in common with gland-forming cells of intestinal cancers. Nearly all adenocarcinomas of the bladder are invasive cancers.

These same types of cancer can also develop in the lining of the center part of the kidney where urine collects and is funneled into the ureter (called the renal pelvis), the ureters, and the urethra. In fact, patients with bladder cancer sometimes have a similar type of cancer in the lining of the kidneys, ureters, or urethra. Therefore, a complete evaluation of the urinary system is recommended.

Bladder cancers are described further according to whether they are noninvasive, invasive, or metastatic, and solid or papillary.

Noninvasive or carcinoma in situ (CIS) transitional cell tumors: In noninvasive bladder cancer, the cancer cells are found only in the innermost layer of the bladder, called the urothelium. They have not spread to deeper layers of the bladder. This type is also called carcinoma in situ (CIS) when the tumor is in the very superficial lining of the bladder but does not invade surrounding tissues.

Invasive transitional tumors: Invasive cancers have spread from the urothelium to the deeper layers of the bladder wall. Invasion of the thick, deep muscle layer of the bladder is much more serious than invasion that is limited to the lamina propria (superficial connective tissue layer) or the muscularis mucosa (superficial, thin, muscle layer). The treatment depends on how deeply the cancer invades the bladder wall. This will influence the decision to remove the bladder or to keep it in place. This choice depends on whether there is a high risk that the cancer will spread, which means other approaches will be needed to improve the chances of cure.

Metastatic tumors: Metastatic bladder cancers have spread elsewhere in the body. The goal of therapy in this group is to prolong life, function, and comfort. Cancer chemotherapy and newer drugs are usually used to achieve the best possible outcome.

Solid (sessile) tumors: Solid bladder cancers are generally flat and do not grow toward the hollow part of the bladder. Some of these only affect the layer of cells closest to the inside or the hollow part of the bladder.

Papillary tumors: Papillary tumors have slender finger-like projections that grow into the hollow center of the bladder. They are sometimes said to look like a branching type of cactus plant.

There are other, rare forms of bladder cancer, such as rhabdomyosarcoma or small cell carcinoma. These cancers are not discussed in this document. For information on these types of bladder cancers, call the American Cancer Society at 1-800-ACS-2345 or visit the ACS Web site at www.cancer.org.

INTRODUCTION

BLADDER CANCER WORK-UP

For more information on these treatment guidelines, or on cancer in general, call the NCCN at 1-888-909-NCCN or the American Cancer Society at 1-800-ACS-2345. Or you can visit these organizations’ web sites at www.cancer.org (ACS) and www.nccn.org (NCCN).

© 2005 by the National Comprehensive Cancer Network (NCCN) and the American Cancer Society (ACS). All rights reserved. The information herein may not be reproduced in any form for commercial purposes or downloaded and stored in any information-retrieval system without the express written permission of the NCCN and the ACS. Single copies of each page may be printed out for personal, noncommercial use only.