Bladder Cancer Stages

After a person is diagnosed with bladder cancer, doctors will try to figure out if it has spread, and if so, how far. This process is called staging. The stage of a cancer describes the extent (amount) of cancer in the body.

Staging bladder cancer

The stage of a bladder cancer is one of the most important factors in deciding how best to treat it and in determining how successful treatment might be.

To find the cancer’s stage, doctors try to answer these questions:

• How far has the cancer grown into the wall of the bladder?
• Has the cancer reached nearby tissues or organs?
• Has the cancer spread to the nearby lymph nodes or to distant organs?

The stage of a bladder cancer is based on the results of physical exams, biopsies (from a cystoscopy or TURBT), and imaging tests (CT or MRI scan, x-rays, etc.), which are described in Tests for Bladder Cancer. The results of surgery (a partial or radical cystectomy), if it has been done, can also be used to help determine the stage of the cancer.

Understanding your bladder cancer stage

A staging system is a standard way for the cancer care team to describe how far a cancer has spread. The staging system most often used for bladder cancer is the American Joint Committee on Cancer (AJCC) TNM system, which is based on 3 key pieces of information:

• T describes how far the main (primary) tumor has grown through the bladder wall and whether it has grown into nearby tissues.
• N indicates 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.
• M indicates if the cancer has spread (metastasized) to distant parts of the body, such as other organs, like the lungs or liver, or lymph nodes that are not near the bladder.

Numbers or letters after T, N, and M provide more details about each of these factors. Higher numbers mean the cancer is more advanced.

Once a person’s T, N, and M categories have been determined, usually after surgery, this information is combined in a process called stage grouping to assign an overall stage. The earliest stage (non-invasive) cancers are stage 0, and then range from stages I (1) through IV (4).

As a rule, the lower the number, the less the cancer has spread. A higher number, such as stage IV, means a more advanced cancer. And within a stage, an earlier letter means a lower stage (for example, stage IIIA is less advanced than stage IIIB).

Cancers with similar stages tend to have a similar outlook and are often treated in much the same way.

There are 2 types of staging for bladder cancer:

• The clinical stage is your doctor’s best estimate of the extent of your cancer, based on the results of physical exams, any biopsies that have been done (during a cystoscopy or TURBT), and any imaging tests you’ve had. The clinical stage is used to help determine which treatments are likely to be best.
• If you’ve had surgery to remove your cancer (a partial or radical cystectomy), your doctors can also determine the pathological stage. The pathological stage is likely to be more accurate than the clinical stage, as it’s done after the surgical specimen has been examined in the lab.

The staging system in the table below describes the pathological stages for bladder cancer. (More information about the TNM categories follows the stage table.) 

Bladder cancer staging can be complex. If you have any questions about your stage, please ask your doctor to explain it to you in a way you understand.

Stage	Stage grouping	Stage description
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 deeper into the connective tissue or muscle of the bladder wall (see image below). It has not spread to nearby lymph nodes (N0) or distant parts of the body (M0).
0is	Tis N0 M0	The cancer is a flat, non-invasive carcinoma (Tis), also known as carcinoma in situ (CIS). The cancer is growing in the inner lining layer of the bladder only. It has not grown inward toward the hollow part of the bladder, nor has it invaded deeper into the connective tissue or muscle of the bladder wall. It has not spread to nearby lymph nodes (N0) or distant parts of the body (M0).
I	T1 N0 M0	The cancer has grown into the layer of connective tissue under the lining layer of the bladder, but it has not reached the layer of muscle in the bladder wall (T1). The cancer has not spread to nearby lymph nodes (N0) or to distant parts of the body (M0).
II	T2a or T2b N0 M0	The cancer has grown into the inner (T2a) or outer (T2b) 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. The cancer has not spread to nearby lymph nodes (N0) or to distant parts of the body (M0).
IIIA	T3a, T3b or T4a N0 M0	The cancer has grown through the muscle layer of the bladder and into the layer of fatty tissue that surrounds the bladder (T3a or T3b). It might have spread into the prostate, seminal vesicles, uterus, or vagina, but it's not growing into the pelvic or abdominal wall (T4a). The cancer has not spread to nearby lymph nodes (N0) or to distant parts of the body (M0).
	OR
	T1-4a N1 M0	The cancer has at least grown into the layer of connective tissue under the lining of the bladder wall (and may have grown farther), but it's not growing into the pelvic or abdominal wall (T1-T4a), AND the cancer has spread to 1 nearby lymph node in the true pelvis (N1). It has not spread to distant parts of the body (M0).
IIIB	T1-T4a N2 or N3 M0	The cancer has at least grown into the layer of connective tissue under the lining of the bladder wall (and may have grown farther), but it's not growing into the pelvic or abdominal wall (T1-T4a), AND the cancer has spread to 2 or more lymph nodes in the true pelvis (N2) or to lymph nodes along the common iliac arteries (N3). It has not spread to distant parts of the body (M0).
IVA	T4b Any N M0	The cancer has grown through the bladder wall into the pelvic or abdominal wall (T4b).   It might or might not have spread to nearby lymph nodes (Any N). It has not spread to distant parts of the body (M0).
	OR
	Any T Any N M1a	The cancer might or might not have grown through the wall of the bladder and into nearby organs (Any T). It might or might not have spread to nearby lymph nodes (Any N). It has spread to distant lymph nodes (M1a).
IVB	Any T Any N  M1b	The cancer might or might not have grown through the wall of the bladder and into nearby organs (Any T). It might or might not have spread to nearby lymph nodes (Any N). It has spread to 1 or more distant organs, such as the bones, liver, or lungs (M1b).

T categories for bladder cancer

The T category describes how far the main tumor has grown into the wall of the bladder (or beyond).

The wall of the bladder has 4 main layers.

• The innermost lining is called the urothelium or transitional epithelium.
• Beneath the urothelium is a thin layer of connective tissue, blood vessels, and nerves.
• Next is a thick layer of muscle.
• Outside of this muscle, a layer of fatty connective tissue separates the bladder from other nearby organs.

Nearly all bladder cancers start in the lining or urothelium. As the cancer grows into or through the other layers in the bladder, it becomes more advanced (the stage goes up).

The T categories are described in the table above, except for:

TX: Main tumor cannot be assessed due to lack of information

T0: No evidence of a primary tumor

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 this is seldom seen on imaging tests.

The N categories are described in the table above, except for:

NX: Regional lymph nodes cannot be assessed due to lack of information.

N0: There's no regional lymph node spread.

M categories for bladder cancer

The M categories are described in the table above.

Risk groups for non-muscle invasive bladder cancer

For treatment purposes, bladder cancers are typically divided into 2 main groups:

• Non-muscle invasive bladder cancer (NMIBC) has not yet grown deep enough into the bladder wall to reach the muscle layer.
• Muscle invasive bladder cancer (MIBC) has grown into the muscle layer of the bladder wall (and possibly deeper). These cancers typically require more extensive treatment.

NMIBC is often further divided into low-, intermediate-, and high-risk groups. This is based on factors such as:

• The size and depth of the tumor(s)
• The grade of the tumor(s)
• How many tumors there are
• Whether a tumor is new or if it has recurred (come back)
• If the tumor has certain other high-risk features

Doctors use these risk groups to get an idea of how likely it is that a bladder cancer will come back or progress further, which in turn might affect a person’s treatment options.

The risk groups for NMIBC can be complex. If you have NMIBC and want to know more, ask your doctor to explain your risk group to you in a way you understand.