What is staging?

Staging describes the extent or severity of an individual's cancer based on the extent of the original (primary) tumor and the extent of spread in the body. Staging is important:

• Staging helps the doctor plan a person's treatment.
• The stage can be used to estimate the person's prognosis (likely outcome or course of the disease).
• Knowing the stage is important in identifying clinical trials (research studies) that may be suitable for a particular patient.
• Staging helps researchers and health care providers exchange information about patients. It also gives them a common language for evaluating the results of clinical trials and comparing the results of different trials.

What is the basis for staging?

What are the common elements of staging systems?

Staging systems for cancer have evolved over time. They continue to change as scientists learn more about cancer. Some staging systems cover many types of cancer; others focus on a particular type. The common elements considered in most staging systems are:

• Location of the primary tumor,
• Tumor size and number of tumors,
• Lymph node involvement (spread of cancer into lymph nodes),
• Cell type and tumor grade* (how closely the cancer cells resemble normal tissue), and
• Presence or absence of metastasis.

What is the TNM system?

The TNM system is one of the most commonly used staging systems. This system has been accepted by the International Union Against Cancer (UICC) and the American Joint Committee on Cancer (AJCC). Most medical facilities use the TNM system as their main method for cancer reporting. PDQ®, the NCI's comprehensive cancer database, also uses the TNM system.

The TNM system is based on the extent of the tumor (T), the extent of spread to the lymph nodes (N), and the presence of metastasis (M). A number is added to each letter to indicate the size or extent of the tumor and the extent of spread.

What types of tests are used to determine stage?

The types of tests used for staging depend on the type of cancer. Tests include the following:

Physical exams are used to gather information about the cancer. The doctor examines the body by looking, feeling, and listening for anything unusual. The physical exam may show the location and size of the tumor(s) and the spread of the cancer to the lymph nodes and/or to other organs.

Imaging studies produce pictures of areas inside the body. These studies are important tools in determining stage. Procedures such as x-rays, computed tomography (CT) scans, magnetic resonance imaging (MRI) scans, and positron emission tomography (PET) scans can show the location of the cancer, the size of the tumor, and whether the cancer has spread.

Laboratory tests are studies of blood, urine, other fluids, and tissues taken from the body. For example, tests for liver function and tumor markers (substances sometimes found in increased amounts if cancer is present) can provide information about the cancer.

Pathology reports may include information about the size of the tumor, the growth of the tumor into other tissues and organs, the type of cancer cells, and the grade of the tumor (how closely the cancer cells resemble normal tissue). A biopsy (the removal of cells or tissues for examination under a microscope) may be performed to provide information for the pathology report. Cytology reports also describe findings from the examination of cells in body fluids.

Surgical reports tell what is found during surgery. These reports describe the size and appearance of the tumor and often include observations about lymph nodes and nearby organs.

How can a patient find more information about staging?

The doctor most familiar with a patient's situation is in the best position to provide staging information for that individual.