The Steps to Cancer Staging

When you hear about someone being diagnosed with cancer, people usually say something like, "She has stage 1 cancer." But what is the significance of that "stage 1" part?

Staging(STAY-JING) — The process of clearly defining a cancer using several measurable characteristics is the process of clearly defining a cancer using many measurable characteristics. These characteristics describe how advanced a cancer is, helping doctors estimate a patient's overall outcome and make treatment(TREET-MINT) — Techniques to help eliminate or control a disease recommendations. The stages of cancer are numbered from least severe, 0, to most advanced, 4.

Your doctor will use all the information they have collected to help determine the stage. This information can include things like imaging test results (CT scans(C-T SCANS) — An imaging technique that uses x-rays to see the inside of the body, Pet scans(PET SCANS) — An imaging technique that measures how fast lymphoma cells are growing by taking pictures of the inside of the body using a special dye, MRIsA loud banging machine that uses magnets to obtain pictures of the inside of the body; magnetic resonance imaging), biopsy(BYE-OP-SEE) — Removal of a sample or piece of tissue to identify abnormalities results, and pathology(PATH-ALL-O-GEE) — Looking closely at removed tissue samples to identify if the tissue is abnormal.

Wondering what pathology is? Read this.

Some types of cancer have very complicated staging processes, while others are simpler. We'll start with the guiding principles and basic steps to help explain the main concepts.

Step 1 – TMN Staging

To stage the cancer, doctors start with the AJCC Staging System(A-J-C-C STAY-JING SIS-TEM) — The most commonly used method to categorize cancer. This system relies on defining three very important qualities of the cancer—T, N, and M.

Keep in mind: Each type of cancer has a very specific, exact definition for each of these letters, and they can vary greatly. Many doctors have to look up the different values for each component even for common cancers like lung, breast, colon, or prostate.

Let's figure out what these random letters mean and how they fit together.

T Component – Size and location of the primary tumor(TOO-MER) — Abnormal growth in the body. This usually includes characteristics like the size of the tumor, the number of tumors nearby, and what the tumor is touching or invading. (How big is the original dandelion? Is it invading or touching other areas of the flowerbed? Is there more than one dandelion in the flowerbed?)
N Component – The degree of lymph node involvement(LIMFF NODE IN-VOLV-MINT) — Cancer that has spread to the lymph nodes. (Did the dandelion spread to other flowerbeds close by?)
M Component – Whether or not the disease has metastasized—spread to other sites in the body beyond the nearby lymph nodes(LIMFF NODES) — Glands that filter bodily fluid and react to infections. (Did the dandelion spread to far-away flowerbeds? Did it spread to the other parts of the yard?)

An easier way to remember what the N and M components mean is to think of the "N" standing for "nearby" and "M" for "moved."

Check out How Does Cancer Grow and Spread? for a better understanding of how doctors classify the spread of cancer.

Step 2 – The Complex Table

The next step of the system is to reference a very complex table and match up a patient's specific combination of T, N, and M. The results provide the doctor with the stage of the disease.

But nothing ever stays that simple in medicine! Doctors have recently updated the process (AJCC version 8) and added a new step (step 3) for some cancers. And, to be honest, the changes can be a little confusing.

Step 3 – The Biology of the Tumor

*This step is currently only used for a few types of cancer (like breast cancer). However, we expect it to be added to the staging process for other types of cancers in the future.

While your doctor will still use the TNM staging(T-N-M STAY-JING) — Categories that are used to determine the stage of the disease; T – Tumor, N – Node, M – Metastatic components (for most cancers), he or she may also need to look at additional information. Doctors call this information the "biology of the tumorTumor characteristics used to determine best treatment options and predict outcome."

Doctors use the biology of the tumor to understand the unique characteristics of each cancer to better predict outcomes and help choose the best treatment.

So, what are a couple of the cancer characteristics your doctor might look at?

Tumor grade(TOO-MER GRADE) — How different a tumor is from normal tissue; an indication of how quickly a tumor may grow. The higher the grade, the more aggressive the cancer is.
Presence of receptors. Some receptors(REE-SEP-TORS) — A protein in or on a cell that may control some functions of the cell can be targeted with treatment, making the cancer a bit easier to kill or control. There is a growing list of important receptors that medications can target across many types of cancer.

Step 4 – Updating the Stage

It's important to keep in mind that your stage may change throughout your journey, like when your doctor obtains new information about your cancer or when the staging system is updated. These changes can cause some confusion, but the goal is always to better understand a patient's cancer so they can receive the best treatment possible.

Doctors use staging to determine your prognosis and best treatment options. Get started by learning the basics: Prognosis for Curable Patients & Types of Cancer Treatments.