Cancer Staging, How does it Work?

We all hear it on TV shows and in movies, read it in books, something along the lines of “I’m sorry, but the results are back from the lab, you have stage 4 cancer”. But do we really know what it mean? What is a stage 4 cancer? What is cancer staging? How many cancer stage are there? what does TMN stand for? So many questions. The cancer staging system is a beast and can get very complicated. So lets look at how cancer staging works.

The cancer staging system include information about the tumor location in the body, the type of cells that the tumor is made up off, the size and extend to the tumor, whether the tumor has spread to lymph nodes, and weather the cancer has spread to a different part of the body.

The staging of cancer is used mainly to describes the extent or severity of someone’s cancer. It is used to help doctors and physicians plan the extend of treatment that a patient may need. It also helps doctors and physicians estimate the prognosis of a patient’s outcome, along with the type of cancer. It also allows doctors to identify if there are any clinical trials that may benefit a patient. However, It is now being used more and more in general conversation discussing cancer, so we ought to know about it.

The Staging systems for cancer, like much of science and medicine, has evolved over time. It has become more complex and will continue to change as scientists learn more about cancer and its progression. There are now many staging systems and some are specifically tailored to certain cancer types.

Cancer Staging doesn’t change

One thing to note about the staging system is that a cancer will always be referred to by the stage it was given at diagnosis. Even if it responds to treatment and strings, of worse it grows and spreads. There will be new information added to the original staging about how a cancer has changed over. So, the stage doesn’t change, even though the cancer might.

The TNM staging system

One of the most know cancer staging systems is the TNM staging system. This is the system that is often quoted in all types of media, normally referring to a cancer as stage 1, 2, 3, or stage 4. This staging system was developed around 1940 to 1950. It has become one of the most accepted staging systems for solid tumors. It can’t be used for leukemia or blood cancers. So let’s learn more about this widely accepted staging system.

It has become widely accepted because can be used to stages nearly all tumors. TNM staging for lung cancer, TNM staging for Colon cancer, TNM staging for Oral cancer, TNM staging for Prostate Cancer, TNM for Breast cancer. They all use the same system, but It is much more complicated than just stage 1, 2, 3, and stage 4. When describing a cancer using this system TNM system there will be a number after each letter. For example, T1N0Mx, or T3N1M0. The following will explain what each number after TNM represents.

T is for Tumor

The T in the TNM staging system stands for tumor. It describes the size of the primary tumor, the tumor where the cancer started. And if the tumor is contained within an organ or tissue, or whether it has invaded nearby organs or tissues. There are 6 different stages for the tumor, they are x, is, 0, 1, 2, 3, and 4.

• Tx- is assigned to tumors that cannot be fully evaluated, not often assigned but could arise due to contradicting or poor diagnostic tests
• Tis- describes a carcinoma in situ. A carcinoma in situ is where the is not tumor present but some of the cells are abnormal and could possibly lead to a tumor in the future
• T0- is the most desirable stage of the tumor, that is there is no sign of a tumor being present
• T1- the tumor is small and localized it is only present in one tissue or organ
• T2- the tumor is medium and is localized it is only present in one tissue or organ
• T3- the tumor is large and is not localized to only one tissue or organ. It has spread into neighbouring tissues and organs
• T4- the tumor is large and has spread to a large number of other organs and tissues

N is for Lymph Nodes

The N in the TNM staging system stands for Lymph Nodes. It describe if there are any lymph nodes involved. An involvement basically means that the cancer cells have traveled to the lymph node. First of all we need to know what a lymph node is.

What are lymph nodes?

Lymph nodes are part of the body’s lymphatic system. The lymphatic system is a network throughout your body to help get rid of the toxins, waste and other unwanted material. The main flue that it transports is lymph, which contains infection fighting white blood cells throughout the body. This network has nodes, small oval structures which are an important part of the body’s immune system which produce and store cells which fight of infection.

The Lymph Nodes cancer stage can be classified into 5 different stages. These are X, 0, 1, 2, and 3 and are explained below.

• Nx- lymph nodes cannot be evaluated
• N0- is where tumor cells are absent from local lymph nodes. There is no cancer in the lymph nodes
• N1- is where local lymph nodes have been confirmed to have cancer present. The cancer has spread to closest local lymph nodes to the original cancer site
• N2- is where intermediate lymph nodes have also been confirmed to have cancer present. Normally this means both the local and intermediate lymph nodes have been diagnosed with cancer. Not all cancer sites can be staged into N2 as for these sites no intermediate lymph nodes exist
• N3- is where distance lymph nodes have also been confirmed to have cancer present. This normally means that both local and regional lymph nodes also have cancer present

M is for Metastasis

The M in TNM stands for metastasis. It describes if there are any metastasis involved.

What is a Metastasis?

A metastasis is where the cancer has spread to a new area in the body. This often happens through cancer cells traveling through the lymph system. A metastatic cancer or a metastatic tumor is a tumor that has spread from the main tumor site. Metastasis are different from lymph node involvement, as metastasis form tumors outside the lymph system.

There are three stages in metastasis. They are x, 0, and 1; as explained below.

• Mx- the metastasis cannot be measured
• M0- the cancer has not spread to other parts of the body
• M1- the cancer has spread to other parts of the body

Other TNM classifications

But wait, there is more. Other than the T, N, and M, there are other classifications that can be assigned to cancer staging as well. These include the following;

• G (1–4): the grade of the cancer cells. Low grade cancer cells score a 1 and they appear to be similar to normal cells, the highest grade, 4, is where the cells are easily distinguishable from normal cells
• S (0–3): elevation of serum tumor markers
• R (0–2): the completeness of a surgery in resecting the tumor. A higher R means that the resection boundaries may not be free of cancer cells
• L (0–1): invasion into lymphatic vessels, beyond the lymph nodes
• V (0–2): invasion into vein (0=no, 1= microscopic, 2=macroscopic)
• C (1–5): a modifier of the certainty (quality) of the last mentioned parameter. It estimates the certainty in the result of the diagnostic test.

How is the cancer stage determined?

A cancer stage is determined through a number of different diagnostic tests and examinations. Lab test can assess different fluids like blood, urine, to determine if certain cancer markers are present. Most of these test can help doctors make a diagnostic but cannot be used alone to diagnose a cancer. To form a more complete diagnostic an image is normally taken. There are several imaging modalities available to doctors, these include

• CT scans– A CT scan uses x-rays to create a 3D scan of a person. It is one of the most commonly used imaging machine in radiotherapy. It can take detailed images of a patient’s organs and contrast material can be used to enhance images for more accurate diagnoses.
• Nuclear Scans– A nuclear scan uses radioactive material that is injected into your bloodstream and tracked using a special camera. This type of scan can reveal a lot of information depending on where the tracer ends up. It can reliably tell you if the cancer has spread throughout the body. If Lymph nodes are involved, or if the cancer has metastasized into the bones. Once the scan is over you body will quickly get rid of the radioactive material quickly.
• Ultrasound. An ultrasound device produces an image by sending out sound waves that people cannot hear. The waves bounce off tissues inside your body like an echo. A computer uses these echoes to create a picture of areas inside your body. This picture is called a sonogram.
• MRI Scan. An MRI scan produces a 3D scan just like CT but it uses a strong magnet which aligns the cells in your body. A radio-frequency pulse is then used to excite some of these atoms and the response is measured using computers to form an image. MRI imaging is great for soft tissues, but bone do not show up well on images.
• PET Scan: PET scanning create 3D scans of the bodies functions through following a tracers path through the body. It basically shows how the body is working or functioning. For this scan you will need to be injected with the tracer before you undertake this scan.
• X-rays imaging: x-ray imaging uses low dose radiation to create a 2D projection of the body. These are similar to the x-rays taken for broken bones, ect.

And finally, a Biopsy can be done and in most cases is needed to make a diagnosis. A biopsy is where the doctor will remove a sample of tissue and send it to a pathologist to look at it. The pathologist will look at the cells inside the tissue using a microscope and determine if there are any cancer cells and what grade they are.

The sample of tissue can be removed in a number of different ways. IT can be collected using a needle to for both tissue and fluids. It can be removed using an endoscope, a device that can be placed inside the body through a natural opening, such as the mouth, and remove a sample of cells through a tube. A sample can also be collected using surgery, this is often done alongside surgical removal of the tumor. A surgeon removes the tumor and sends a sample to the pathologist for inspection.

The TNM staging system, for example, is used for lung cancer and is based on the extent of the tumor (T), its spread to lymph nodes (N) and its metastasis (spread to other parts of the body) (M). Most cancers can be described as stage 0, stage I, stage II, stage III or stage IV. Physical exams, imaging procedures, laboratory tests, pathology reports, and surgical reports provide information to determine the stage of each cancer.

Examples of How Cancer Stating Works?

So Here are some examples to give you an idea on how the TNM is used,

T1N0M0R0G1

This would be a Small, low-grade cancer, no metastasis, no spread to regional lymph nodes, cancer completely removed; this grouping of T, N, and M would be considered Stage I.

T2N0M1G2

This would be a localized medium tumor, medium grade cancer, with no spread to lymph nodes and metastasis present. This grouping of T,N,M would be considered a stage 2

T3N2M1R1G3

This would be a regionally localized large, high-grade cancer, with spread to regional lymph nodes and other organs, not completely removed. This grouping of T, N, and M would be considered Stage 3

Most Stage 1 tumors are curable either through chemotherapy, radiotherapy, surgery, or a combination of them; most Stage 4 tumors are inoperable, but radiotherapy and chemotherapy may be beneficial.

Cancer staging outside Medicine

As you can see the TNM staging system is complex and contains a lot of information, although it is all useful for doctors and health professionals. But when you want to quickly describe a cancer stage to someone the TNM system can be summarized to “stages” using the value of T. Again they use the same classifications. This staging system is a quick way of explaining how sever the cancer is, with larger numbers being worse.

• Stage 0 (T0/Tic)- Abnormal cells have been diagnosed, but have not spread to nearby tissue. Also called carcinoma in situ, is technically not cancer, but it may become cancer.
• Stage 1 (T1): Localize small Tumor
• Stage 2 (T2) Localized medium Tumor
• Stage 3 (T3) Regionally localized large tumor
• Stage 4 (T4) Non localized large tumor which is inoperable.

So I hope that has helped in deciphering cancer staging and shed some more light on the subject. As you can see there is a lot to the TNM staging system, and it gets complicated. But it does just boil down to “the higher the number the worst it is”. And you probably already knew that.

Thanks for reading, I hope you all your questions have been answered you learned something new about how the cancer staging system works. Please, if you have any feedback or question leave them in the comments section below! Or send me a message! I can’t wait to read them!

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Originally published at www.radicalradiationremedy.com on January 30, 2017.