What is bladder cancer?
The bladder, a hollow organ in the lower part of the abdomen, serves as a reservoir for urine until it is discharged out of the body through the urethra.
There are different types of bladder cancer. The cancer can be transitional cell carcinoma, squamous cell carcinoma, or adenocarcinoma -- each named for the types of cells that line the wall of the bladder where the cancer originates.
- Most bladder cancers (more than 90%) start from the transitional cells, which occupy the innermost lining of the bladder wall. The cancers, which originate in these cells lining the bladder, can, in some instances, invade into the deeper layers of the bladder (called the lamina propria), the thick muscle layer of the bladder, or through the bladder wall into the fatty tissues that surround the bladder.
- Squamous cells are thin flat cells that can form in the bladder after long bouts of bladder inflammation or irritation. Squamous cell carcinoma makes up about 5% of bladder cancers.
- Adenocarcinoma is a very rare type of bladder cancer that begins in glandular (secretory) cells in the lining of the bladder. Only 1% to 2% of bladder cancers are adenocarcinoma.
What are the stages of bladder cancer?
Bladder cancer can be either early stage (confined to the lining of the bladder) or invasive (penetrating the bladder wall and possibly spreading to nearby organs or lymph nodes).
The stages range from TA (confined to the internal lining of the bladder) to IV (most invasive). In the earliest stages (TA, T1, or CIS), the cancer is confined to the lining of the bladder or in the connective tissue just below the lining, but has not invaded into the main muscle wall of the bladder.
Stages II to IV denote invasive cancer:
- In Stage II, cancer has spread to the muscle wall of the bladder.
- In Stage III, the cancer has spread to the fatty tissue outside the bladder muscle.
- In Stage IV, the cancer has metastasized from the bladder to the lymph nodes or to other organs or bones.
A more sophisticated and preferred staging system is known as TNM, which stands for tumor, node involvement, and metastases. In this system:
- Invasive bladder tumors can range from T2 (spread to the main muscle wall below the lining) all the way to T4 (tumor spreads beyond the bladder to nearby organs or the pelvic side wall).
- Lymph node involvement ranges from N0 (no cancer in lymph nodes) to N3 (cancer in many lymph nodes, or in one or more bulky lymph nodes larger than 5 cm).
- M0 means that there is no metastasis outside of the pelvis. M1 means that it has metastasized outside of the pelvis.
What are the warning signs of bladder cancer?
Some symptoms of bladder cancer are also symptoms of other conditions, and should prompt a visit to your physician. Blood in the urine is the most important warning sign. Pain during urination, frequent urination, or difficulty urinating are other symptoms.