Staging of Cancer
Staging describes or classifies a cancer based on how much cancer is in the body and where it is when first diagnosed. This is often called the extent of cancer. The stage often includes the size of the tumour, which parts of the organ have cancer, whether the cancer has spread (metastasized) and where it has spread. Doctors use exams and tests to stage a cancer. The exams and tests show where the cancer is and approximately how much cancer is in the body. To stage a cancer, doctors may do a physical exam, blood tests, imaging tests or a biopsy. They may also look at the tissue with cancer during surgery or after the tissue is removed by surgery.
Why are Cancers Staged?
Doctors need to know the amount of cancer and where it is in the body to be able to choose the best treatment options. For example, the treatment for an early-stage cancer may be surgery or radiation, while a more advanced-stage cancer may need to be treated with chemotherapy. Doctors also use a cancer’s stage to help predict the course it will likely take.
In a larger sense, doctors use staging information when they’re studying cancer treatments. It allows researchers to make sure study groups are actually similar when they test cancer treatments against one another, measure outcomes, and more.
Not all cancers are staged. For example, leukemias are cancers of the blood cells and therefore spread throughout the body. Most types of leukemias aren’t staged the way cancers that form tumors are.
- Stage 0 means there’s no cancer, only abnormal cells with the potential to become cancer. This is also called carcinoma in situ.
- Stage 1 means the cancer is small and only in one area. This is also called early-stage cancer.
- Stage 2 and 3 mean the cancer is larger and has grown into nearby tissues or lymph nodes.
- Stage 4 means the cancer has spread to other parts of your body. It’s also called advanced or metastatic cancer.
Systems that Describe Stage…
There are many staging systems. Some, such as the TNM staging system, are used for many types of cancer. Others are specific to a particular type of cancer. Most staging systems include information about:
- Where the tumor is located in the body
- The cell type (such as, adenocarcinoma or squamous cell carcinoma)
- The size of the tumor
- Whether the cancer has spread to nearby lymph nodes
- Whether the cancer has spread to a different part of the body
- Tumor grade, which refers to how abnormal the cancer cells look and how likely the tumor is to grow and spread
The TNM Staging System
The TNM system is the most widely used cancer staging system. Most hospitals and medical centers use the TNM system as their main method for cancer reporting. You are likely to see your cancer described by this staging system in your pathology report, unless you have a cancer for which a different staging system is used. Examples of cancers with different staging systems include brain and spinal cord tumors and blood cancers.
In the TNM System:
- The T refers to the size and extent of the main tumor. The main tumor is usually called the primary tumor.
- The N refers to the the number of nearby lymph nodes that have cancer.
- The M refers to whether the cancer has metastasized. This means that the cancer has spread from the primary tumor to other parts of the body.
When your cancer is described by the TNM system, there will be numbers after each letter that give more details about the cancer—for example, T1N0MX or T3N1M0.
The Stage of Cancer Doesn’t Change
Once a person is told what stage the cancer is (either the clinical or pathologic stage), the stage of cancer doesn’t change. If a stage 2 cancer comes back (recurs) after it is treated, it is still stage 2 cancer that has recurred. And if the cancer has spread to a distant part of the body after it is treated, it is still stage 2 cancer but it is metastatic. This is important because the stage at diagnosis is used to study survival statistics and treatments for specific stages of cancer.
Cancer Stage: 5 Important Reasons to Know Yours
- Your cancer stage determines your treatment.
- Your cancer stage helps predict your chance of recovery.
- Your cancer stage sets expectations and starts discussions.
- Your cancer stage can help identify clinical trials that may be right for you.
- Cancer staging changes as we learn more.
Tumour grade describes a tumour in terms of how abnormal the tumour cells are when compared to normal cells. It also describes how abnormal the tissues look under a microscope.
The grade gives your doctor some idea of how the cancer might behave. A low grade cancer is likely to grow more slowly and be less likely to spread than a high grade one. Doctors can’t be certain exactly how the cells will behave. But the grade is a useful indicator.
What types of tests are used to determine stage?
The types of tests used for staging depend on the type of cancer. Tests include the following:
- Physical Exams
- Imaging Studies
- Laboratory Tests
- Pathology Reports
- Surgical Reports