Stage and grade of bladder cancer

The stages for bladder cancer depend on the size of the cancer, its growth in the bladder wall, any lymph node involvement, and any spread to other areas of the body (metastasis). The grade of bladder cancer refers to how the cancer cells look under a microscope. Stage and grade of bladder cancer has been classified by the American Joint Committee on Cancer (AJCC).¹

The primary tumor (T) is staged in the following way:

Superficial bladder cancer

• TX: A primary tumor cannot be assessed.
• T0: No primary tumor seen.
• Ta: Superficial cancer is found only in polyps (papillary) on the surface of the inner lining of the bladder.
• Tis: Carcinoma in situ. Tumor is found only in flat lesions on the surface of the inner lining of the bladder.
• T1: Tumor is found in the connective tissue below the lining of the bladder but has not spread to the bladder muscle.

Invasive bladder cancer

• T2a: Tumor has spread to the inner half of the smooth muscle layer (superficial layer) below the lining of the bladder.
• T2b: Tumor has spread to the outer half of the smooth muscle layer (deep layer) of the bladder.
• T3a: Tumor has spread through the muscular wall of the bladder into the fatty tissue layer as identified under a microscope.
• T3b: Tumor has spread through the muscular wall of the bladder into the fatty tissue layer and a mass is visible to the eye.
• T4a: Tumor has spread to the prostate in men and to the uterus or vagina in women.
• T4b: Tumor has spread to the pelvic or abdominal wall.

After the tumor (T) is staged, the TNM system stages lymph node involvement (N) to help determine the treatment options at each stage. Lymph node involvement is staged in the following way:

• NX: Lymph nodes in the pelvis cannot be assessed.
• N0: No bladder cancer is found in lymph nodes.
• N1: Bladder cancer is found in one lymph node, 2cm or less in size.
• N2: Bladder cancer is found in one lymph node and is more than 2cm but less than 5cm in size, or cancer is found in multiple lymph nodes but none are more than 5cm in size.
• N3: Bladder cancer is found in one or more lymph nodes and is more than 5cm in size.

The last part of staging bladder cancer is to determine whether cancer has spread to other parts of the body (metastasized). The TNM system stages metastasis (M) in the following way:

• MX: Spread of cancer to other organs cannot be evaluated.
• M0: No evidence of bladder cancer exists elsewhere in the body.
• M1: Bladder cancer cells are found somewhere else in the body.

The TNM staging system allows a health professional to recommend the most effective treatment options and discuss the long-term outcome (prognosis) based on the type of tumor, the stage of the cancer, and the person's age and overall health condition.

Classification of bladder cancer

Stage	TNM Classification
0(a)	TaN0M0
0(is)	TisN0M0
I	T1N0M0
II	T2aN0M0
	T2bN0M0
III	T3aN0M0
	T3bN0M0
	T4aN0M0
IV	T4bN0M0
	Any T, N1, M0
	Any T, N2, M0
	Any T, N3, M0
	Any T, any N, M1

The grade of bladder cancer refers to how the cancer cells look under a microscope. Bladder cancer cells are described as well differentiated, moderately differentiated, or poorly differentiated. Differentiation is a term used to describe how clearly the cancer cells can be distinguished from the surrounding normal tissues and how normal or abnormal the cells look.

• GX: Grade cannot be assessed.
• G1: Well-differentiated cancers have very clear boundaries and cells that look relatively normal. They usually do not grow and spread rapidly.
• G2: Moderately differentiated cancer has more abnormal looking cells and cell boundaries.
• G3-4: Poorly differentiated cancers have less-clearly defined boundaries and cells that look very abnormal. They often grow and spread rapidly.

Citations

1. American Joint Committee on Cancer (2002). Urinary bladder. In AJCC Cancer Staging Manual, 6th ed., pp. 335–340. New York: Springer-Verlag.