What Does My Cancer Stage Mean?

Not all cancers are alike when they are first diagnosed. Sometimes there's just a small, single tumor that can be easily removed. Other times, a tumor might be dangerously large, or the cancer may have already spread to other parts of the body.

The size and extent of cancers when they are first diagnosed reveals a lot of important information about treatment options. Doctors have developed a system called cancer staging for describing the important details of each newly diagnosed case of cancer.

If you're a cancer patient or have a loved one facing a cancer diagnosis, becoming familiar with this code will help you understand your disease and your treatment options.

Starting Location Sets The Stage

The first thing to know about a cancer is where it started. There's a big difference in treatment for cancers that originate in different tissues (for example, those that started in the breast are very different from those cancers that started in the skin). doctors can take scans, X-rays, collect tissue samples, run blood tests, or conduct other medical tests to understand the size and scope of your condition, or confirm if it is cancer or not. This process is called staging.

“Staging implies the extent of the cancer, and it is normally diagnosed in three steps: Is it cancer? What kind of cancer is it, i.e. where did it originate? And how extensive is it?” explains Ajita Narayan, MD, PhD, a medical oncologist with Franciscan Health Lafayette East.

It's important to understand that staging only applies to the cancer when it's first diagnosed. Think of staging as a first impression. The stage doesn't usually change over the years, even if the disease gets better or worse.

The TNM System For Cancer Staging

Staging a solid tumor typically looks at three major factors: The size of the original tumor, whether the cancer has spread to the lymph nodes, and whether the cancer has spread to other parts of the body. Doctors call this approach the TNM system, and it's one of the most common cancer staging systems used around the world.

The T stands for Tumor size, the N stands for lymph Nodes, and the M stands for metastasis (the medical term for the spread of cancer throughout the body.)

T For Tumor Size

The size of a tumor is rated on a scale from 0 to 4. If your doctor says you have a T1 tumor, that means that the tumor is small for its type. A T4 tumor would have grown into other neighboring tissue and is often quite large for its type.

Codes following the T include:

• TX: The tumor size can't be measured
• T0: No primary tumor, or the tumor can't be found
• Tis: Tumor is "in situ," meaning it is small and completely contained in the tissue where it started
• T1-4: The tumor is increasing in size and is perhaps invading surrounding tissues and organs

N For Lymph Nodes

Lymph is the fluid between all the cells in the body. It collects and flows in lymphatic vessels, and along these vessels are small, rounded organs called lymph nodes.

Lymph nodes are reservoirs for cells called lymphocytes, the immune cells that produce targeted antibodies and give us long-term immunity against germs and other enemies, including cancer cells. Lymph nodes can intercept and destroy cancer cells that break free of a tumor and migrate to other areas of the body. If they fail to stop the cancer cells, the lymph nodes can end up serving as gateways to the whole body.

The nearby lymph nodes are rated on a scale of 0 to 3:

• A score of N0 means the lymph nodes are free of cancer.
• N1 means that a few cancer cells have reached one or more lymph nodes.
• N3 means that cancer in the lymph nodes is extensive and widespread.
• NX means nearby lymph nodes can't be tested or evaluated

M For Metastasis

Metastasis defines whether a cancer has spread to other parts of the body. An M0 cancer has not spread to other parts of the body, but an M1 cancer has. An MX cancer is unknown whether it has spread.

Putting Staging Together

So if your cancer is rated T1 N1 M0, you'll know your prospects look fairly good. The main tumor was small, and although a little bit of cancer was found in your lymph nodes, the disease hasn't reached other parts of the body. A T4 N3 M1 cancer would put a person at the opposite end of the spectrum.

Stage Grouping

For many types of cancer, each TNM rating also matches to a simple stage from one (zero) to four. Doctors often use this staging when talking to patients. In some types of blood cancers, there can be a stage 0 as well. Stages I though III include cancers that may have spread to nearby tissues, organs, or lymph nodes, with I being the lowest, least extensive and III being the largest and most extensive (without distant spread). Stage IV (4) includes all cancers that have spread to more distant parts of the body. For some cancers these stages might be broken down further, and so the Roman numerals would be followed by a letter, for example stage IIIB.

Dr. Narayan emphasizes that while staging is very precise, it’s not a determinant of how well a patient will do under cancer treatment.

“Stage 4 is not the end, especially in today’s world with so many treatment options,” she said. “Being a higher stage doesn’t necessarily mean things are bad, and it may mean the treatment options are different. Sometimes, having an advanced stage of cancer means there might be more therapy than just surgery. You may need chemotherapy and/or radiation therapy.”

Exceptions To TNM Staging

Most cancers fit into the staging system, but there are a few exceptions. Leukemia or other blood-cell cancers are staged differently (if at all). For example, lymphomas can also be staged from Stage I to IV but acute myelogenous leukemia is not staged as such. And staging isn’t very useful for brain cancer because even small tumors can be dangerous if they’re in a vital spot.

There are other staging systems used for these types of cancers, and sometimes childhood cancers and gynecological cancers are staged in different ways as well.

Regardless of cancer staging, a patient’s future depends on many other factors, including overall health and type of cancer.

“Medicine is equally a science as it is an art form and when we’re trying to figure out if a treatment is appropriate for someone, context matters,” Dr. Narayan said. “How a person does from a day-to-day perspective is very important. There’s a difference between a stage 4 colon cancer in a marathon runner and a stage 1 lung cancer in a patient who has very poor lung function and is already on oxygen. So stage is not everything in decision making regarding treatment of cancer.”

HealthDay News contributed information to this article.