Staging is the process of finding out how far a cancer hasspread. The stage of gallbladder cancer is one of the most important factors in selecting treatment options and estimating a patient's outlook for recovery and survival (prognosis).

A staging system is a standardized way for members of the cancer care team to summarize the extent of a cancer's spread. The stage of a cancer can be determined by the results of the physical exam, imaging tests (ultrasound, CT or MRI scan, etc.) and other tests, which are described in the section "How is gallbladder cancer diagnosed?" and by the results of surgery if it has been done.

The American Joint Committee on Cancer (AJCC) TNM system

The major system used to describe the stages of gallbladder cancer is the American Joint Committee on Cancer (AJCC) TNM system. This system contains 3 key pieces of information:

• T describes how far the primary tumor has grown into the wall of the gallbladder and whether it has grown into other nearby organs or tissues.

• N describes whether the cancer has metastasized (spread) to nearby (regional) lymph nodes (bean-sized collections of immune system cells located throughout the body).

• M indicates whether the cancer has metastasized (spread) to other organs of the body. (The most common sites of gallbladder cancer spread are the liver, peritoneum [the lining of the abdominal cavity], and the lungs.)

Numbers or letters appear after T, N, and M to provide more details about each of these factors:

• The numbers 0 through 4 indicate increasing severity.
• The letter X means "cannot be assessed" because the information is not available.

Nearly all gallbladder cancers begin in the tissue on the inside of the gallbladder. Over time they grow deeper into the gallbladder, pushing through the various layers toward the outside of the gallbladder.

The gallbladder wall has several layers. From the inside out, these are:

• the epithelium, a thin sheet of cells closest to the inside of the gallbladder

• the lamina propria, a thin layer of loose connective tissue (the epithelium plus the lamina propria form the mucosa)

• the muscularis, a layer of muscular tissue that helps the gallbladder contract, squirting its bile into the bile duct

• the perimuscular ("around the muscle") fibrous tissue, another layer of connective tissue

• the serosa, the outer covering of the gallbladder that comes from the peritoneum, which is the lining of the abdominal cavity

The tumor may grow to fill some or all of the space inside the gallbladder at the same time that it grows through the various layers of gallbladder in the opposite direction. If it continues to grow, the tumor may invade nearby organs, such as the liver, by growing directly into those organs, or it may enter the lymphatic or blood vessels within the gallbladder wall and spread to lymph nodes, the liver, and other parts of the body.

T groups

TX: No description of the tumor's extent is possible because of incomplete information.

T0: No evidence of primary tumor

Tis (carcinoma in situ): Cancer cells are only found in the epithelium (the innermost layer of the gallbladder) and have not grown into (invaded) deeper layers of the gallbladder.

T1: The tumor grows into the lamina propria or the muscle layer (muscularis).

• T1a: Tumor grows into lamina propria.
• T1b: Tumor grows into the muscle layer below the mucosa and lamina propria.

T2: The tumor grows into perimuscular fibrous tissue.

T3: The tumor has grown through the serosa (the outermost covering of the gallbladder) and/or it has grown from the gallbladder directly into the liver and/or a nearby structure such as the stomach, duodenum (first part of the small intestine), colon, pancreas, or bile ducts outside the liver.

T4: The tumor has grown into one of the main blood vessels leading into the liver (portal vein or hepatic artery) or it has grown into 2 or more organs outside of the liver. Generally speaking, most doctors think T3 tumors are potentially resectable (removable by surgery), while T4 tumors are not. However, there may be other factors that affect whether surgery is a good treatment option in any given case.

N groups

NX: Regional (nearby) lymph nodes cannot be assessed.
N0: The cancer has not spread to regional lymph nodes.
N1: The cancer has spread to nearby lymph nodes.

M groups

MX: Distant spread (metastasis) cannot be assessed.
M0: The cancer has not spread to tissues or organs far away from the gallbladder.
M1: The cancer has spread to tissues or organs far away from the gallbladder.

TNM stage grouping

Once the T, N, and M categories have been determined, this information is combined in a process called stage grouping. The stage is expressed in Roman numerals from stage 0 (the least advanced) to stage IV (the most advanced). Some stages are subdivided with letters.

Stage 0: Tis, N0, M0: There is a small cancer only in the epithelial layer of the gallbladder. It has not spread outside of the gallbladder.

Stage IA: T1(a or b), N0, M0: The tumor grows into the lamina propria (T1a) or the muscle layer (T1b). It has not spread outside of the gallbladder.

Stage IB: T2, N0, M0: The tumor grows into the perimuscular fibrous tissue. It has not spread outside of the gallbladder.

Stage IIA: T3, N0, M0: The tumor extends through the serosa layer and/or directly grows into the liver and/or one other nearby structure. It has not spread to lymph nodes or to tissues or organs far away from the gallbladder.

Stage IIB: T1 to T3, N1, M0: In addition to any growth in the gallbladder, the tumor has spread to nearby lymph nodes (N1). It has not spread to tissues or organs far away from the gallbladder.

Stage III: T4, any N, M0: Tumor invades the main blood vessels leading into the liver or has reached more than one nearby organ other than the liver. It may or may not have spread to lymph nodes. It has not spread to tissues or organs far away from the gallbladder.

Stage IV: Any T, any N, M1: The tumor has spread to tissues or organs far away from the gallbladder.

Survival statistics by stage

Survival rates are a way for doctors to discuss and compare the prognosis (outlook) for patients, based on the stage of the cancer or other traits. The numbers below come from the American College of Surgeons National Cancer Data Base and are based on more than 10,000 patients diagnosed with gallbladder cancer from 1989 to 1996. There are some important points to note about these numbers:

• The 5-year survival rate refers to the percentage of patients who live at least 5 years after being diagnosed. Of course, some of these patients live much longer than 5 years after diagnosis.

• Although these numbers are among the most current we have available, they represent people who were first diagnosed and treated several years ago. Because of improvements in treatment since then, survival rates for people now being diagnosed with these cancers may be higher.

• Survival statistics can sometimes be useful as a general guide, but they may not accurately represent any one person's prognosis. A number of other factors, including other tumor characteristics, how the cancer was treated, and a person's age and general health, can also affect outlook. Your doctor is likely to be a good source as to whether these numbers may apply to you, as he or she is familiar with the aspects of your particular situation.

Grading gallbladder cancer

Another factor that can affect the patient's outlook (prognosis) is the grade of the cancer. The cancer's grade describes of how closely a cancer resembles normal gallbladder tissue when looked at under a microscope.

The scale used for grading gallbladder cancers goes from G1 (where the cancer looks much like normal gallbladder tissue) to G4 (where the cancer looks very abnormal). The grades G2 and G3 fall somewhere in between.

Typically, low-grade cancers are less likely to spread outside the gallbladder than high-grade cancers, and have a more favorable outlook. Intermediate grade cancers have an appearance and prognosis between that of low- and high-grade cancers.

Last Medical Review: 11/02/2009
Last Revised: 11/02/2009