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

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 nasopharyngeal cancer diagnosed?", and by the results of surgery if it has been done.

If you have NPC, ask your cancer care team to explain staging in a way you can understand. By knowing all you can about staging, you can take a more active role in making informed decisions about your treatment.

The American Joint Committee on Cancer (AJCC) TNM system

A staging system is a standardized way for members of the cancer care team to summarize the extent of a cancer's spread. The most common system used to describe the spread of NPC is the TNM system created by the American Joint Committee on Cancer (AJCC). This system contains 3 key pieces of information:

• T describes whether the primary tumor has invaded other organs or tissues near the nasopharynx.

• N describes whether the cancer 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 distant nasopharyngeal cancer spread are the lungs, liver, and bones.)

The numbers or letters that appear after T, N, and M 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.

• The letters "is" after the T stand for "in situ," which means the tumor is still only in the layer of cells where it started and has not yet invaded deeper.

T groups for nasopharyngeal cancer

TX: Primary tumor cannot be assessed due to incomplete information.

T0: No evidence of a primary tumor.

Tis: Carcinoma in situ (cancer cells are present only in the surface layer of the nasopharynx but have not invaded into deeper layers).

T1: Tumor is in the nasopharynx. The cancer may also extend to the oropharynx (the back of the mouth, where the throat begins) and/or nasal cavity but no farther.

T2: The cancer has grown into the tissues of left or right sides of the upper part of the throat (but not bone)

T3: Tumor extends to the sinuses and/or the bones near the nasopharynx.

T4: Tumor extends into the skull and/or cranial nerves (nerves in the head that lie near the nasopharynx and have special functions such as vision, smell, and eye movement), the hypopharynx (lower part of the throat), or the eye or its nearby tissues.

N groups for nasopharyngeal cancer

NX: Nearby lymph nodes cannot be assessed due to incomplete information.

N0: No spread to nearby lymph nodes.

N1: Spread to 1 or more lymph nodes, not larger than 6 cm (about 2½ inches) across, on one side of the neck; OR spread to lymph nodes behind the throat (called retropharyngeal lymph nodes) on either side, with no lymph node larger than 6 cm.

N2: Spread to lymph nodes not larger than 6 cm across, on both sides of the neck.

N3: Spread to 1 or more lymph nodes that are either:

M groups for nasopharyngeal cancer

MX: Distant spread (metastasis) cannot be assessed.

M0: The cancer has not spread to tissues or organs far away from the nasopharynx.

M1: The cancer has spread to tissues or organs far away from the nasopharynx.

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: The cancer is "in situ." It has not yet invaded into deeper layers of nasopharyngeal tissue (Tis) and has not spread to nearby lymph nodes (N0) or distant sites (M0).

Stage I

T1, N0, M0: The tumor is in the nasopharynx and may have spread to soft tissues of the nasal cavity and/or the oropharynx (T1). It has not spread to nearby lymph nodes (N0) or distant sites (M0).

Stage II: Either:

T2, N0, M0: The tumor has grown into the tissues of the left or right sides of the upper part of the throat (T2). It has not spread to nearby lymph nodes (N0) or distant sites (M0).

OR

T1 or T2, N1, M0: The tumor may still be confined to the nasopharynx (T1), or it may have extended to the soft tissues of the nasal cavity and the oropharynx (T1) and/or the left or right sides of the upper part of the throat (T2). It has spread to one or more nearby ymph nodes, not larger than 6 cm (about 2½ inches) across. Either neck lymph nodes on one side or lymph nodes behind the throat (retropharyngeal lymph nodes) on either side (N1). The cancer has not spread to distant sites (M0).

Stage III: Either:

T3, N0 to N2, M0: The tumor has spread to the sinuses or the bones near the nasopharynx (T3). It may or may not have spread to lymph nodes in the neck or behind the throat, none of which are larger than 6 cm across (N0 to N2)). It has not spread to distant sites (M0).

OR

T1 or T2, N2, M0: The tumor may still be confined to the nasopharynx (T1), or it may have extended to the soft tissues of the nasal cavity (T1), the oropharynx (T1), or the left or right sides of the upper part of the throat (T2). The tumor has spread nearby neck lymph nodes on both sides, and none are larger than 6 cm across (T2). The cancer has not spread to distant sites. (M0).

Stage IVA

T4, N0 to N2, M0: The tumor has extended to the skull and/or cranial nerves, the hypopharynx, the eye, or its nearby tissues (T4). It may or may not have spread to nearby lymph nodes in the neck, none of which are larger than 6 cm across (N0 to N2). It has not spread to distant sites (M0).

Stage IVB

Any T, N3, M0: The tumor may or may not have extended into nearby soft tissues or bones (any T). It has spread to lymph nodes that are larger than 6 cm across and/or are located in the shoulder area above the collarbone (N3). The cancer has not spread to distant sites (M0).

Stage IVC

Any T, any N, M1: The tumor may or may not have extended into nearby soft tissues or bones (any T). It may or may not have spread to nearby lymph nodes (any N). It has spread to distant sites (M1).

Survival rates by stage

Survival rates are often used by doctors as a standard way of discussing a person's prognosis (outlook). Some patients with cancer may want to know the survival statistics for people in similar situations, while others may not find the numbers helpful, or may even not want to know them. Whether or not you want to read about the survival statistics below for nasopharyngeal cancer is up to you.

The 5-year survival rate refers to the percentage of patients who live at least 5 years after their cancer is diagnosed. Of course, many people live much longer than 5 years (and many are cured).

Relative survival rates (such as the numbers below) adjust for patients with nasopharyngeal cancer who die from other causes, such as heart disease. They are considered to be a more accurate way to describe the outlook for patients with a particular type and stage of cancer.

In order to get 5-year survival rates, doctors have to look at people who were treated at least 5 years ago. Improvements in treatment since then may result in a more favorable outlook for people now being diagnosed with nasopharyngeal cancer.

Survival rates are often based on previous outcomes of large numbers of people who had the disease, but they cannot predict what will happen in any particular person's case. Many other factors may affect a person's outlook, such as their age, overall health, and how well the cancer responds to treatment. Your doctor can tell you how the numbers below may apply to you, as he or she is familiar with the aspects of your particular situation.

The numbers below come from the American Joint Committee on Cancer, and are based on people diagnosed between 1998 and 1999.

Last Medical Review: 01/21/2009
Last Revised: 01/21/2009