Each year, almost 71,000 new cases of bladder cancer are diagnosed in this country. Men, Caucasians and smokers have twice the risk of bladder cancer as the general population. Almost all the people who develop bladder cancer are over 55 years old. When it is diagnosed and treated in the early stages, bladder cancer is usually highly treatable.
The bladder is a hollow organ in the lower abdomen. It stores urine, the waste that is produced when the kidneys filter the blood. The bladder has an elastic and muscular wall that allows it to get larger and smaller as urine is stored or emptied.
Urine passes from the two kidneys into the bladder through tubes called ureters. Urine leaves the bladder through another tube called the urethra. The urethra is longer in men than women.
Bladder cancer begins in the inside layer of the bladder and grows into the walls, becoming more difficult to treat.
Bladder Cancer Types
Bladder cancer is classified based on the type of cells it contains. The main types of bladder cancer are:
Transitional cell bladder cancer: About 90% of bladder cancers are transitional cell carcinomas – cancers that begin in the urothelial cells, which line the inside of the bladder. Cancer that is confined to the lining of the bladder is called non-invasive bladder cancer.
Squamous cell bladder cancer: This type of bladder cancer begins in squamous cells, which are thin, flat cells that may form in the bladder after long-term infection or irritation. These cancers occur less often than transitional cell cancers, but they may be more aggressive.
Adenocarcinoma: Bladder cancer that develops in the inner lining of the bladder as a result of chronic irritation and inflammation. This type of bladder cancer tends to be aggressive.
The most frequent bladder cancer symptom is blood in the urine (hematuria), which causes the urine to appear rusty or deep red in color. However, hematuria cannot always be detected by the naked eye, and it can be a symptom of other conditions such as kidney or bladder stones or urinary tract infection.
Other bladder cancer symptoms may include:
- Changes in bladder habits
- Painful urination
- Frequent urination
- Having the urge to urinate
These symptoms do not always mean you have bladder cancer. However, it is important to discuss any symptoms with your doctor, since they may signal other health problems.
How is bladder cancer staged?
The stage of a bladder cancer is a standard summary of how far the cancer has spread. It is one of the most important factors in choosing treatment options and predicting a person’s prognosis (outlook). If you have bladder cancer, ask your cancer care team to explain its stage. This can help you make informed choices about your treatment.
There are actually 2 types of stages for bladder cancer.
The clinical stage of the cancer is the doctor’s best estimate of the extent of the cancer, based on the results of physical exams, cystoscopy, biopsies, and any imaging tests that are done (such as CT scans). These exams and tests are described in the section, “How is bladder cancer diagnosed?” Doctors looking at biopsy samples are especially interested in whether any cancer cells have spread into the bladder’s muscle layers.
If surgery is done, the pathologic stage can be determined using the same test results used for the clinical stage, plus what is found during surgery to remove the bladder and nearby lymph nodes.
The clinical stage is used to help plan treatment. Sometimes, though, the cancer has spread further than the clinical stage estimates. Because the pathologic stage is based on what was found at surgery, it can more accurately predict the patient’s outlook.
AJCC TNM staging system for bladder cancer
A staging system is a standard way for members of the cancer care team to describe the extent of cancer spread. The staging system most often used for bladder cancer is that of the American Joint Committee on Cancer (AJCC). This is also called the TNM system.
The TNM staging system classifies bladder cancers based on 3 key pieces of information:
- The letter T is followed by numbers and/or letters to describe how far the main (primary) tumor has grown through the bladder wall and whether it has grown into nearby tissues. Higher T numbers mean more extensive growth.
- The letter N is followed by a number from 0 to 3 to indicate any cancer spread to lymph nodes near the bladder. Lymph nodes are bean-sized collections of immune system cells, to which cancers often spread first.
- The letter M is followed by 0 or 1 to indicate whether or not the cancer has spread (metastasized) to distant sites, such as other organs or lymph nodes that are not near the bladder.
T categories for bladder cancer
The T category describes the main tumor. (See “What is bladder cancer?” for a description of papillary and flat carcinomas and the different layers of the bladder.)
TX: Main tumor cannot be assessed due to lack of information
T0: No evidence of a primary tumor
Ta: Non-invasive papillary carcinoma
Tis: Non-invasive flat carcinoma (flat carcinoma in situ, or CIS)
T1: The tumor has grown from the layer of cells lining the bladder into the connective tissue below. It has not grown into the muscle layer of the bladder.
T2: The tumor has grown into the muscle layer.
- T2a: The tumor has grown only into the inner half of the muscle layer.
- T2b: The tumor has grown into the outer half of the muscle layer.
T3: The tumor has grown through the muscle layer of the bladder and into the fatty tissue layer that surrounds it.
- T3a: The spread to fatty tissue can only be seen by using a microscope.
- T3b: The spread to fatty tissue is large enough to be seen on imaging tests or to be seen or felt by the surgeon.
T4: The tumor has spread beyond the fatty tissue and into nearby organs or structures. It may be growing into any of the following: the stroma (main tissue) of the prostate, the seminal vesicles, uterus, vagina, pelvic wall, or abdominal wall.
- T4a: The tumor has spread to the stroma of the prostate (in men), or to the uterus and/or vagina (in women).
- T4b: The tumor has spread to the pelvic wall or the abdominal wall.
Bladder cancer can sometimes affect many areas of the bladder at the same time. If more than one tumor is found, the letter m is added to the appropriate T category.
N categories for bladder cancer
The N category describes spread only to the lymph nodes near the bladder (in the true pelvis) and those along the blood vessel called the common iliac artery. These lymph nodes are called regional lymph nodes. Any other lymph nodes are considered distant lymph nodes. Spread to distant nodes is considered metastasis (described in the M category). Surgery is usually needed to find cancer spread to lymph nodes, since it is not often seen on imaging tests.
NX: Regional lymph nodes cannot be assessed due to lack of information.
N0: There is no regional lymph node spread.
N1: The cancer has spread to a single lymph node in the true pelvis.
N2: The cancer has spread to 2 or more lymph nodes in the true pelvis.
N3: The cancer has spread to lymph nodes along the common iliac artery.
M categories for bladder cancer
M0: There are no signs of distant spread.
M1: The cancer has spread to distant parts of the body. (The most common sites are distant lymph nodes, the bones, the lungs, and the liver).
Stages of bladder cancer
Once the T, N, and M categories have been determined, this information is combined to find the overall cancer stage. Bladder cancer stages are defined using 0 and the Roman numerals I to IV (1 to 4). Stage 0 is the earliest stage, while stage IV is the most advanced.
Stage 0a (Ta, N0, M0)
The cancer is a non-invasive papillary carcinoma (Ta). It has grown toward the hollow center of the bladder but has not grown into the connective tissue or muscle of the bladder wall. It has not spread to lymph nodes or distant sites.
Stage 0is (Tis, N0, M0)
The cancer is a flat, non-invasive carcinoma (Tis), also known as flat carcinoma in situ (CIS). The cancer is growing in the inner lining layer of the bladder only. It has neither grown inward toward the hollow part of the bladder nor has it invaded the connective tissue or muscle of the bladder wall. It has not spread to lymph nodes or distant sites.
Stage I (T1, N0, M0)
The cancer has grown into the layer of connective tissue under the lining layer of the bladder but has not reached the layer of muscle in the bladder wall (T1). The cancer has not spread to lymph nodes or to distant sites.
Stage II (T2a or T2b, N0, M0)
The cancer has grown into the thick muscle layer of the bladder wall, but it has not passed completely through the muscle to reach the layer of fatty tissue that surrounds the bladder (T2). The cancer has not spread to lymph nodes or to distant sites.
Stage III (T3a, T3b, or T4a, N0, M0)
The cancer has grown into the layer of fatty tissue that surrounds the bladder (T3a or T3b). It might have spread into the prostate, uterus, or vagina, but it is not growing into the pelvic or abdominal wall (T4a). The cancer has not spread to lymph nodes or to distant sites.
One of the following applies:
T4b, N0, M0: The cancer has grown through the bladder wall and into the pelvic or abdominal wall (T4b). The cancer has not spread to lymph nodes or to distant sites.
Any T, N1 to N3, M0: The cancer has spread to nearby lymph nodes (N1-N3) but not to distant sites.
Any T, any N, M1: The cancer has spread to distant lymph nodes or to sites such as the bones, liver, or lungs (M1).