When you're first diagnosed with cancer, your doctor will give you an idea of how advanced the cancer is. This is generally called the ‘stage’ and helps determine what kind of treatment you may need. The five stages range from 0 (when the cancer cells are still located in the place they started but haven't spread to nearby tissues ) to IV (when cancer has spread to other organs or parts of the body; this is also referred to as "advanced" or "metastatic" cancer).
Cancer staging is often based on where the cancer is located and where it has spread. By staging cancer, doctors get a better idea of what treatment to use. While this information helps guide your plan of care, it's important to know that a stage doesn't necessarily predict how easy or hard it will be to treat.
For many, the idea of staging is overwhelming. Just know that the staging process will help give you and your medical team vital information on how to determine your treatment plan.
How is Cancer Stage Determined?
Your doctor may order multiple tests to help determine the stage of your cancer.
Common tests used to stage cancer:
- Blood tests help determine the overall health of your body, organ function, and can give clues about some kinds of cancer.
- Imaging tests like MRI, CT scan, PET scan, and/or ultrasound are used to help visualize the internal structures and organs.
- Endoscopy lets doctors get a closer look at internal structures like the esophagus, stomach, and colon.
- Biopsies help determine whether cells are cancerous, what kind of cancer it may be, and how aggressive it is. Samples are sent to a laboratory for pathological staging.
- Bone marrow aspiration/biopsy looks for changes in the blood cells. This is done by making a small incision in the hip and aspirating (removing) bone marrow fluid. These samples are sent to a lab for testing.
What Do the 5 Stages of Cancer Mean?
The most common way to think about cancer staging is on a scale from stage 0 to stage IV.
Stage 0
Stage 0 is used for very early forms of cancer. At this stage, the cancer cells are "in situ" ("in place"), meaning they are still located in the place they started growing and have not spread to nearby tissues. This stage of cancer is often curable. In most cases, stage 0 cancers can be surgically removed.
Stage I
Cancer is called Stage I when it has begun to invade local tissues but has not yet spread to any nearby lymph nodes or other parts of the body.
Stage II
When cancer has spread to regional tissue or into the nearby lymph nodes, it is often referred to as Stage II.
Stage III
Stage III is very similar to Stage II but it refers to a deeper level of regional spread.
Stage IV
Stage IV is the most advanced stage of cancer. You may also hear it referred to as metastatic cancer, which signifies the cancer has spread to distant areas of the body, away from its original site.
Other Cancer Staging Systems
While the above refers to a more general way to stage cancer, there are several methods doctors use for more detailed staging.
The TNM staging system is one of the most commonly used staging methods and can be used for most forms of cancer. This system uses letters and numbers to describe the size of your tumor and how far it has spread in your body.
The letters T, N, and M refer to:
- T: Tumor size and location
- N: Lymph node involvement
- M: Metastasis to other organs
Each letter is followed by additional letters or numbers which give a more detailed description of the cancer.
T: Primary tumor
- TX: It is not possible to determine the size of the primary tumor
- T0: The primary tumor cannot be found
- T1, T2, T3, T4: How big the primary tumor is/how far it has spread. The higher the number, the bigger the tumor or the more it has invaded surrounding tissues.
N: Regional lymph nodes
- NX: Unable to measure cancer in nearby lymph nodes
- N0: No cancer cells found in nearby lymph nodes
- N1, N2, N3: Number and location of cancer-containing lymph nodes found. A higher number signifies a higher amount of diseased lymph nodes.
M: Distant metastasis
- MX: Unable to measure for metastasis
- M0: The cancer has not spread
- M1: Cancer has spread to distant areas
Staging is Crucial
There are many different ways to stage cancer. Understanding the different stages is essential in helping you understand your diagnosis and treatment options. It's important to remember that a higher stage doesn't always mean your cancer treatment will be more difficult—it just means it could be more extensive.
Getting a thorough diagnosis of your cancer is key, and having a solid understanding of the stage will help you prepare for future treatment.
