What is the stage of my tumor?

Determining if your tumor has spread — and if so, how much it has spread — is known as staging. The lower the number, the less the cancer has spread. Although each person’s cancer experience is unique, cancers in the same stages often have a similar outlook, and are treated in similar ways.

For example, the best treatment for an early-stage cancer might be surgery or radiation, while later stages may require chemotherapy, targeted drug therapy, or immunotherapy.

Staging is determined by testing, including physical exams, imaging, endoscopies (such as a colonoscopy), biopsies and sometimes surgery. It’s important to know that cancer can be staged more than once. You might get a stage when you’re first diagnosed, but often staging is updated after treatment has started. This is known as restaging.

Stages are determined by three key pieces of information:

• How far the cancer has grown into the wall of the colon or rectum
• If the cancer has spread to any lymph nodes
• If the cancer has metastasized, which means spread to distant organs

Take a look at what the wall of the colon looks like:

TNM system

The most common and useful staging is the TNM system.

In this system, the overall stage from I (one) to IV (four) is determined after the cancer is assigned a letter or number to describe the T (tumor), N (node) and M (metastasis) categories. 

Confusing, right? Let’s go over it again:

• T describes the original tumor
• N says whether the cancer has spread to any lymph nodes
• M shows whether the cancer has spread (metastasized) to any other parts of the body

T: The primary tumor

When determining how much the cancer has spread, doctors first take a look at the primary tumor. This is where the cancer originated. The size, location, and growth into other areas are important to look at.

The T category is assigned a letter or a number:

• TX means there is no information about the primary tumor, or it can’t be measured
• T0 means there is no evidence of a primary tumor, and it can’t be found
• Tis means that the cancer cells are only growing in the layer they started in, without spreading into deeper layers. This might also be referred to as in situ cancer or pre-cancer
• T1, T2, T3 and T4 describe the tumor size and/or amount of spread into nearby areas. The higher the T number, the larger the tumor and/or the more it has grown

N: The lymph nodes

Many types of cancer spread into nearby lymph nodes before they reach other parts of the body. Your doctor will check to see if cancer has spread to them.

The N category is assigned a letter or a number:

• NX means there’s no information about the lymph nodes near the tumor, or they can’t be assessed
• N0 means nearby lymph nodes do not contain cancer
• N1, N2 and N3 describe the size, location and/or number of lymph nodes affected by cancer. The higher the N number, the greater the spread

M: Metastasis

Cancer that has spread to body parts far away from the primary tumor is known as metastasis. 

The M category is assigned a number:

• M0 means that no distant cancer spread has been found
• M1 means that cancer has spread to other organs

Putting it all together

Adding these TMN categories together can give you your stage, broadly classified into stage I, II, III, and IV. 

You can use the chart below to determine which stage your cancer is:

For example, if your tumor is T3 N1 M0, you have stage III cancer.