Doctors use physical exams, imaging tests, endoscopy exams, biopsies, and other procedures to find out a cancer’s stage. The staging information helps your team plan your treatment.
Staging may also include a description of the cancer’s grade, which describes how much the cancer cells look like healthy cells. This is called pathological staging.
TNM Stages
Staging describes how far a cancer has grown and spread. It is one of the most important factors that doctors use to predict how a person will do with treatment. It tells them how large the tumor is, if it has spread to nearby tissues and lymph nodes, and if it has metastasized or spread to other parts of the body. Different types of cancer have different staging systems. A few have very specific staging systems that are used only for them.
For most cancers, doctors use the TNM (Tumor, Node, Metastasis) system of staging. The T, N, and M stages use letters and numbers to describe how big the tumor is, if it has spread, and how many lymph nodes have cancer in them. The numbers 1 to 4 indicate how advanced the cancer is. Each stage has substages that help doctors understand it better.
Doctors will use physical exams, x-rays, scans, and biopsies to determine the stage of your cancer. They will also look at the results of any previous treatments you had. This information helps them plan your care and decide what type of surgery you need, if any. It also helps them choose other treatments like radiation or drugs.
Some cancers are treated before they are fully diagnosed. This is called pre-therapy staging. This may be done to shrink a tumor or make it easier to remove during surgery. It can also be done to learn how well a treatment works for the cancer. Doctors will use the same tests to find out the stage of your cancer after your first treatment. This is known as post-therapy staging. The cancer might be the same as before, but doctors will change the stage if it has grown or spread.
When a doctor changes the stage of your cancer, they will write it down on your medical report. They will usually add a lowercase “c” or “p” before the T, N, and M stages. Doctors might also use the word “nodal” before the N stage to explain if there is cancer in the lymph nodes.
TNM Grades
For many types of cancer, doctors use two different ways to describe how abnormal the cancer cells look. These descriptions are called grading and staging. Grading and staging help doctors understand how serious a cancer is and plan its treatment.
The most common way to stage cancer is to combine information about the size of the main tumor (T), whether nearby lymph nodes contain cancer cells (N) and if the cancer has spread beyond the original site of the tumor to other parts of the body (M). Doctors may also use a different numbering system for some types of cancer. If this is the case, your doctor will give you a description of how that cancer staging system works.
In the T part of the TNM classification, doctors use a number to describe how large the main tumor is. They may also add letters before the T to provide more information, such as c or p. This information tells them whether the cancer is based on what they know before surgery, or on what they find in the pathology report after surgery.
Most T categories have numbers from 1 to 4. The higher the number, the larger the main tumor and the more it has grown into nearby tissue. In some cancers, the T category can be further divided into subcategories, such as a or b, to provide more detail.
Using a microscope, a pathologist looks at the cells and tissues of the main tumor to see how abnormal they are. They then assign a grade to the tumor. The lower the grade, the less abnormal the cells and tissues are. Low-grade tumors are called well differentiated and tend to grow more slowly. High-grade tumors are more aggressive and have a worse prognosis.
In most cases, the cancer stage that a person gets at diagnosis will not change over time, even if the tumor grows or spreads. However, new information about how the cancer has changed can be added to the original stage to create a new one. For example, if the tumor has spread to other organs, it is given an M1 stage.
TNM Nodes
The cancer may spread into nearby tissues or lymph nodes. If it does, the doctor assigns a number to indicate how many lymph nodes are affected. The doctor then determines if the tumor has spread to other parts of the body. This information is called the pathological stage. If it has, the doctor assigns a letter to indicate where in the body the cancer has spread (metastasis).
There are two kinds of staging. The first, clinical staging, is based on the results of your physical exam and any x-rays, scans or other tests that are done when your doctor makes the diagnosis. Doctors may also use information from any biopsy that is done of the tumor or lymph nodes. Clinical staging is usually indicated by a lowercase “c” before the letters TNM on your medical reports.
A second kind of staging is pathologic staging, based on the results of a biopsy that is taken from your tumor or lymph nodes and then examined under a microscope. Occasionally, doctors use a lowercase letter a, b or c to further divide the T, N and M categories to make them more specific (for example, T2a). They may also use a number to indicate how far the cancer has spread (M1).
Both kinds of staging are important for your doctor to know so that they can plan your treatment. However, it is important to remember that different types of cancer have their own staging systems.
For some cancers, your doctor may use a different system that has 3 or 4 number stages. These systems may have very specific definitions for each of the stages, and they will tell your doctor more about the prognosis for your particular type of cancer.
For lung cancer, the TNM system is used to show how large a tumor is and whether it has spread into nearby tissue or lymph nodes. It also describes the number of metastases in the lungs or other areas of the body. In general, the smaller the primary tumor is and the fewer metastatic sites there are, the better the prognosis.
TNM Metastasis
The most common cancer staging system uses letters and numbers to describe the size of the tumor, whether it has spread to nearby tissue or lymph nodes, and if it has metastasized to other parts of the body. Healthcare providers use this information to determine your prognosis and plan your treatment. Some types of cancer have their own staging systems, such as brain and spinal cord tumors or blood cancers.
Doctors find out the stage of a cancer by examining the area around where the tumor is and using medical tests, such as x-rays or CT scans. They also may use other tests to learn about how the cancer has grown or spread.
A diagnosis of cancer can be very stressful. Healthcare providers are sensitive to this and will try to explain the staging system as clearly as possible.
For most solid cancers, doctors use the TNM (Tumor, Node, Metastasis) system. In TNM, the T describes the size of the main tumor. The N describes how many nearby lymph nodes have cancer cells. The M describes if the cancer has spread to other areas of the body, or if it has metastasized.
The stage of a cancer is important to your prognosis because it tells doctors how much of the cancer has spread when it is first diagnosed. In most cases, the more advanced a cancer is, the worse the prognosis will be.
TNM stages are numbered I-IV. A lowercase letter a, b or c is sometimes used to subdivide the T, N and M categories to make them more specific (for example, T2N1M0). A lowercase letter c is added after N to indicate carcinoma in situ or a non-invasive tumor.
A cancer’s stage may change after it has been treated. When this happens, it is called recurrence. Recurrences can be local, meaning they come back in the same place as the original cancer. They can also be regional, meaning they happen near the organ where the cancer started. They can also be distant, which means that the cancer has spread to other tissues or lymph nodes in the body.
