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Staging: Questions and Answers 

1. 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. 

Key Points 

• Staging describes the extent or severity of an individual’s cancer. Knowing the 

stage of the disease helps the doctor plan a person’s treatment and estimate 

prognosis (see Question 1).

• Staging systems for cancer have evolved over time and continue to change as 

scientists learn more about cancer (see Question 3). 

• The TNM staging system is based on the extent of the tumor (T), spread to lymph 

nodes (N), and metastasis (spread to other parts of the body) (M) (see Question 4).

• Most cancers can be described as stage 0, stage I, stage II, stage III, or stage IV 

(see Question 4).

• Physical exams, imaging procedures, laboratory tests, pathology reports, and 

surgical reports provide information to determine the stage of the cancer (see 

Question 6).
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2. What is the basis for staging? 

Staging is based on knowledge of the way cancer develops. Cancer cells divide and grow 

without control or order to form a mass of tissue, called a growth or tumor. As the tumor 

grows, it can invade nearby organs and tissues. Cancer cells can also break away from 

the tumor and enter the bloodstream or lymphatic system. By moving through the 

bloodstream or lymphatic system, cancer can spread from the primary site to form new 

tumors in other organs. The spread of cancer is called metastasis. 

3. 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. 

*Information about tumor grade is available in the NCI fact sheet Tumor Grade: 

Questions and Answers, which can be found at 

http://www.cancer.gov/cancertopics/factsheet/Detection/tumor-grade on the Internet. 

4. 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. 

Primary Tumor (T) 

TX Primary tumor cannot be evaluated 

T0 No evidence of primary tumor 

Tis Carcinoma in situ (early cancer that has not spread to neighboring 

tissue) 

T1, T2, T3, T4 Size and/or extent of the primary tumor 
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Regional Lymph Nodes (N) 

NX Regional lymph nodes cannot be evaluated 

N0 No regional lymph node involvement (no cancer found in the lymph 

nodes) 

N1, N2, N3 Involvement of regional lymph nodes (number and/or extent of spread) 

Distant Metastasis (M) 

MX Distant metastasis cannot be evaluated 

M0 No distant metastasis (cancer has not spread to other parts of the body) 

M1 Distant metastasis (cancer has spread to distant parts of the body) 

For example, breast cancer T3 N2 M0 refers to a large tumor that has spread outside the 

breast to nearby lymph nodes, but not to other parts of the body. Prostate cancer 

T2 N0 M0 means that the tumor is located only in the prostate and has not spread to the 

lymph nodes or any other part of the body. 

For many cancers, TNM combinations correspond to one of five stages. Criteria for 

stages differ for different types of cancer. For example, bladder cancer T3 N0 M0 is 

stage III; however, colon cancer T3 N0 M0 is stage II. 

Stage Definition 

Stage 0 Carcinoma in situ (early cancer that 

is present only in the layer of cells in 

which it began). 

Stage I, Stage II, and Stage III Higher numbers indicate more 

extensive disease: greater tumor 

size, and/or spread of the cancer to 

nearby lymph nodes and/or organs 

adjacent to the primary tumor. 

Stage IV The cancer has spread to another 

organ. 

Question 7 describes sources of additional information about staging for specific types of 

cancer. 

5. Are all cancers staged with TNM classifications? 

Most types of cancer have TNM designations, but some do not. For example, cancers of 

the brain and spinal cord are classified according to their cell type and grade. Different 

staging systems are also used for many cancers of the blood or bone marrow, such as 

lymphoma. The Ann Arbor staging classification is commonly used to stage lymphomas 

and has been adopted by both the AJCC and the UICC. However, other cancers of the 

blood or bone marrow, including most types of leukemia, do not have a clear-cut staging 

system. Another staging system, developed by the International Federation of 

Gynecology and Obstetrics, is used to stage cancers of the cervix, uterus, ovary, vagina, 
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and vulva. This system uses the TNM format. Additionally, childhood cancers are 

staged using either the TNM system or the staging criteria of the Children’s Oncology 

Group, a group that conducts pediatric clinical trials. 

Many cancer registries, such as the NCI’s Surveillance, Epidemiology, and End Results 

Program (SEER), use summary staging. This system is used for all types of cancer. It 

groups cancer cases into five main categories: 

• In situ is early cancer that is present only in the layer of cells in which it began. 

• Localized is cancer that is limited to the organ in which it began, without evidence of 

spread. 

• Regional is cancer that has spread beyond the original (primary) site to nearby lymph 

nodes or organs and tissues. 

• Distant is cancer that has spread from the primary site to distant organs or distant 

lymph nodes. 

• Unknown is used to describe cases for which there is not enough information to 

indicate a stage. 

6. 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. 
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• 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. 

7. 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. For background information, PDQ, the NCI’s 

cancer information database, contains cancer treatment summaries that describe the 

staging of each type of cancer. PDQ treatment summaries are available at 

http://www.cancer.gov/cancerinfo/pdq/ on the NCI’s Web site. 

Staging information can also be obtained by calling the NCI’s Cancer Information 

Service (CIS) toll-free at 1–800–4–CANCER (1–800–422–6237). For deaf and hard of 

hearing callers with TTY equipment, the toll-free number is 1–800–332–8615. CIS 

information specialists also offer immediate online assistance through the Help link at 

http://www.cancer.gov/ on the Internet. 

# # # 

Related Resources

Publications (available at http://www.cancer.gov/publications) 

• National Cancer Institute Fact Sheet 5.9, Tumor Grade: Questions and Answers

• National Cancer Institute Fact Sheet 5.18, Tumor Markers

• National Cancer Institute Fact Sheet 5.27, Interpreting Laboratory Test Results

• National Cancer Institute Fact Sheet 6.20, Metastatic Cancer: Questions and 

Answers

• What You Need To Know AboutTM Cancer 

National Cancer Institute (NCI) Resources

Cancer Information Service (toll-free)

 Telephone: 1–800–4–CANCER (1–800–422–6237) 

 TTY: 1–800–332–8615 

Online 

NCI’s Web site: http://www.cancer.gov 

LiveHelp, NCI’s live online assistance: 

https://cissecure.nci.nih.gov/livehelp/welcome.asp 

This fact sheet was reviewed on 1/6/04