Stages Of Cancer Made Simple – How The Cancer Grading System Works

​​Discover what the different stages of cancer ​mean. Learn ​the purpose of cancer staging and how doctors determine your cancer stage. Get an explanation of the TNM staging system and what every letter and number indicate.

​You have a greater chance of surviving cancer if you find it early. If you determine the stages of cancer development, you can treat it better.

In this video, you will learn how oncologists determine stages of cancer 1-4. First, you learn about the purpose of cancer staging.

Then you discover ways doctors determine the stages of cancer. And finally, you find out how the oncologists grade the cancer stages.

So let's start with the purpose of cancer staging.

​What Is The Purpose Of ​Cancer Staging? 

Cancer staging is the process of determining how much cancer is in the body and its location.

Understanding the stage of cancer helps doctors to:

​So how do doctors determine stages of cancer?

​How ​​Doctors ​​Stage Cancer

Doctors collect data about cancer to determine its stage. This information comes from the various tests.

Physical examinations can provide clues about the extent of the cancer. The physical exam may determine the location and size of the tumor(s).

Other things they look out for is if cancer has spread to the lymph nodes or other organs.

Imaging tests such as x-rays, CT scans, and MRI scans can show the location of the cancer. They reveal the size of the tumor, and whether the cancer has spread.

Laboratory tests from blood, urine and other fluids and tissues removed from the body can also reveal cancer.

Pathology reports provide information about the size, growth, and type of cancer. The reports often confirm the diagnosis of cancer, as well as the stage.

Surgical reports from samples removed during surgery can reveal valuable information. They can determine the size and appearance of a tumor or lymph node and organ involvement.

I’m now going to explain how oncologists grade different stages of cancer with the TNM-system.

​Different Cancer Staging Systems

There are different types of staging systems. The most common and useful one for most types of cancers is the TNM system. The TNM system describes cancers that form solid tumors, such as breast, colon, or lung cancers.

However, doctors use other staging systems to classify other types of cancer, such as:

Brain tumors since they do not often spread outside the brain and spinal cord.

Blood cancers such as leukemia, lymphoma, or multiple myeloma do not form solid tumors. Therefore they don't use the TNM system.

Doctors determine most childhood cancers according to other staging systems.

TNM Cancer Staging System

In the TNM system, each cancer has a letter or number to describe its spread.

Tumor (T)

The letter "T" plus a number (0-4) describes the size and location of the tumor. It includes how much the tumor has grown into nearby tissues. 

A larger tumor that grows deeper into the surrounding tissue receives a higher number.

For some types of cancer have lowercase letters, such as “a,” “b,” or "m" (for multiple), added to the “T.” The extra letters provide more detail about the tumor.

TX means that you can't measure the tumor.

T0 means there is no evidence of a primary tumor. 

TIS means that the cancer cells are only growing in the most superficial layer of tissue.

​Numbers after the T (such as T1-T4) describe the tumor size or the amount of spread into nearby structures. The higher the T number, the larger the tumor and the more it has grown into adjacent tissues.

Nodes (N)

The letter "N" plus a number (0-3) describes whether you can find cancer in the lymph nodes. It may also describe how many of the lymph nodes contain cancer.

Lymph nodes are tiny, bean-shaped organs that help fight infection.

NX means that you can't evaluate the nearby lymph nodes 

N0 means nearby lymph nodes do not contain cancer.

Numbers after the N (such as N1-N3) describe the size, location, or the number of lymph nodes affected by cancer. The higher the N number, the greater the cancer spread to nearby lymph nodes.

Metastasis (M)

The letter "M" indicates whether the cancer has metastasized, or spread, to other parts of the body.

M0 means that the cancer has not spread.

M1 Indicates that cancer has spread.

Differences Between TNM Classifications

Most cancer types have their own version of this classification system. So letters and numbers don’t always mean the same thing for every kind of cancer.

For example, in some types of cancer, the T-categories describe the size of the main tumor. In others, they represent how deep the tumor has grown into the organ it started in. Or they can indicate whether the tumor has grown into nearby structures.

Doctors combine the T,N,M results to determine the stages of cancer 1-4 for each person. Most cancers have four stages. Some cancers also have a stage 0 (zero).

Five Different Stages Of Cancer ​

Stage 0 Cancer

This stage describes cancer in situ, which means “in place.” Stage 0 cancers live in the place they started and have not spread to nearby tissues. This stage of cancer is often curable.

Stage I Cancer

This is a small tumor that has not grown deep into nearby tissues. It also has not spread to the lymph nodes or other parts of the body.

It is often called early-stage cancer.

Stage II ​& III Cancer 

These stages indicate larger cancers or tumors that survive deeper into nearby tissue.

They may also spread to lymph nodes but not to other parts of the body.

Stage IV Cancer 

This stage means that the cancer has reached other organs or parts of the body.

Some call it advanced or metastatic cancer.

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