understanding nose cancer : staging

When the MRI results came out, my oncologist told me the tumour was Stage "T2N0" NPC. Do you know what it means? At that time, I didn't quite understand the staging process for NPC. I will share what I've learned from the internet library. What is staging & why is staging necessary?

Staging is the process used to find out whether cancer has spread within the nasopharynx or to other parts of the body. The information gathered from the staging process determines the stage of the disease. The results of the tests used to diagnose NPC are often used to stage the disease. It is important to know the stage in order for your oncologist to plan your treatment. (http://www.medicinenet.com/)

I believe that in Singapore, we use the AJCC TNM staging system. I obtain information about this system from the American Cancer Society website. (http://www.cancer.org/)

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 has 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 limited to the nasopharynx.
T2: Tumor extends to tissues (but not bone) near the nasopharynx.

• T2a: Cancer extends to the oropharynx (the back of the mouth, where the throat begins) and/or nasal cavity but no farther.
• T2b: Cancer has also extended to the left or right sides of the upper part of the throat.

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.
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 :

• larger than 6 cm across (N3a), or
• are located just above the collarbone (N3b)

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 and has not spread to nearby lymph nodes or distant sites.

Stage I
T1, N0, M0 : The tumor is only in the nasopharynx and has not spread to nearby lymph nodes or distant sites.

Stage IIA
T2a, N0, M0: The tumor has spread to soft tissues of the nasal cavity and/or the oropharynx but no farther. It has not spread to nearby lymph nodes or distant sites.

Stage IIB
There are 2 combinations of categories that make up this stage.

T2b, N0, M0 : The tumor has extended to the soft tissues of the nasal cavity and/or the oropharynx and has also extended to the left or right sides of the upper part of the throat. It has not spread to nearby lymph nodes or distant sites.

T1-T2b, N1, M0: The tumor may still be confined to the nasopharynx, or it may have extended to the soft tissues of the nasal cavity and the oropharynx and/or the left or right sides of the upper part of the throat. It has spread to one or more nearby lymph nodes, not larger than 6 cm (about 2½ inches) across, on only one side of the neck. The cancer has not spread to distant sites.

Stage III
There are 2 combinations of categories that make up this stage.

T3, N0-N1, M0 : The tumor has spread to the sinuses or the bones near the nasopharynx. It may or may not have spread to nearby lymph nodes (not larger than 6 cm across and on only one side of the neck). It has not spread to distant sites.

T1-T3, N2, M0 : The tumor may still be confined to the nasopharynx, or it may have extended to the soft tissues of the nasal cavity, the oropharynx, the left or right sides of the upper part of the throat, the sinuses, or the bones near the nasopharynx. The tumor has spread nearby lymph nodes on both sides of the neck, and none are larger than 6 cm across. The cancer has not spread to distant sites.

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

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

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

References :
American Cancer Society
http://www.cancer.org/docroot/CRI/content/CRI_2_4_3X_How_is_nasopharyngeal_cancer_staged_17.asp