Understanding cancer stages

What is staging?

No two cases of cancer are exactly alike. Some cancers are found early, and others aren’t noticed until the cancer has metastasized (spread past the place in the body where it first started). Staging is the system doctors use to learn how much a cancer has spread. Once doctors know the cancer’s stage, they can come up with the best possible treatment plan for that cancer.

You’ll learn the stage of your cancer from your doctor, who will help you to understand the system, and give you a better idea of what to expect. A cancer “stage” puts all of the information that is known about a tumor into a few letters and numbers, almost like a short-hand system for doctors. In most cases, as the numbers get higher, it means that your treatment will need to become stronger. You might have more side effects from these stronger treatments, with more pain and tiredness. However, these extra problems can be treated.

Before doctors can stage your cancer, they need to find out:

  • Where the primary (original) tumor is located in your body
  • The size of the tumor
  • How quickly the tumor is growing or spreading
  • The type of cancer cells in the tumor
  • Whether the tumor has spread to your lymph nodes
  • Whether the tumor has metastasized (spread) to other parts of your body

Types of staging systems

There are a few different ways to stage cancer. The system that’s used most often is called “TNM.” “T” stands for the size of the original tumor, “N” lets doctors know if the tumor has spread to the lymph nodes, and “M” shows whether there has been any metastasis (spread) of the tumor to other parts of the body. Not all cancers use the TNM system, though. Cancers of the blood or lymph system — leukemia, lymphoma, and brain cancers, for example — are handled differently.

The most common system for cancer uses five different levels (stages) that range from 0 (zero) through the Roman numerals I, II, III, and IV. When two or more doctors talk about a person’s cancer, this system of letters and numbers lets them all know that they’re on the same page: They understand what type of cancer they’re dealing with, and how hard (or easy) it should be to treat.

Tests and exams that help doctors decide on a cancer’s stage

Oncologists (doctors who diagnose and treat cancer) have many different ways to figure out a cancer’s stage. Their methods include:

  • Physical examinations: By touching, looking, and listening for signs of anything that’s out of the ordinary, a doctor can sometimes figure out where a tumor is located, its size, and whether it has spread to the lymph nodes. In many cases, though, the doctor may need to take a small bit of tissue from the problem area and look at it under a microscope, to know for sure if cancer is involved.
  • Imaging tests: These tests — such as X-rays, CT (computed tomography) scans, MRI (magnetic resonance imaging) and PET (positron emission tomography) studies — can help doctors find out where cancer is hiding in the body. The scans can also show a tumor’s size and whether or not it has spread.
  • Sometimes an endoscope (a thin, lighted, flexible telescope) will be used to take a close-up look at the bladder, intestines, lungs, or other organs inside the body.
  • Laboratory tests: The doctor may need to get samples of blood, urine, or other body fluids to see if there are any cancerous cells.
  • biopsy is when a small piece of a tumor is removed; these cells are looked at under a microscope to find out if they’re cancerous. Sometimes a biopsy can be done by putting a needle into the tissue instead, without having to do any surgery.
  • Surgery in the area around the tumor may give information about whether or not the cells are cancerous. The doctor will also be able to see if the cancer has spread to the lymph nodes or other organs.

Staging and treatment

Oncologists use staging to help them come up with a treatment plan. Cancer that’s not too serious – at a low stage, in other words — may only need surgery to take care of it; this step could be followed by radiation therapy. Higher stages of cancer may need to have a few different kinds of treatments, including surgery, chemotherapy, and radiation.

The staging system is a good way to get information for diagnosing and treating cancer. But a person’s medical history and health at the time of the cancer diagnosis can have a big effect on how the illness turns out — no matter what the stage.


National Cancer Institute Fact Sheet. (2004). Staging: questions and answers. Retrieved 6/30/08 from www.cancer.gov.

American Cancer Society. (n.d.) What is staging. Retrieved 6/30/08 from www.cancer.org.