The abcs and 123s of cancer stages

What is the Cancer staging? 

Cancer staging is a way used to determine the appearance and  the size of the cancer ,and how far it has spread from where it originated. The stage of a cancer provides information about the size of the tumor, which parts of the organ have the cancer, and whether it has metastasized or spread in the body.

Why is Cancer Staging important?

Cancer staging helps the therapists to determine the best treatment for the cancer that the patient has. Theses treatments are divided into two categories:

Doctors may recommend a local treatment, such as surgery or radiotherapy if your cancer is just in one place. This could be enough to get rid of the cancer completely. A local treatment treats only an area of the body. 

But you might need treatment that circulates throughout the whole body if your cancer has spread. These are called systemic treatments and include:

• Chemotherapy.
• Hormone Therapy.
• Targeted cancer drugs.

Cancer staging also helps physicians determine:

• A patient’s prognosis or outlook.
• How aggressive the cancer is.
• How well a treatment is likely to work. 

 So, We determine the cancer stage when we first recognize that there is a cancer.

Staging systems:

Different staging systems are used for different types of cancer, but the most common is the TNM system. This staging system is traditionally used for solid tumors, such as colon, lung or breast cancer. There are other systems used for staging other types of cancers, such as leukemias because we can not determine them by TNM system because they are liquid.

TNM stands for :

• Tumor (T). The letter "T" plus a number (0 to 4) describes the size and location of the tumor, including how much the tumor has grown into nearby tissues. 
• N represents lymph Nodes (small, bean-shaped organs that help the body fight infection) and describes whether the cancer has spread to lymph nodes around the tumor. N is also given a number, for instance N1 to N3, and the number increases to describe the number of lymph nodes that contain cancer. However, for some tumors, the location of the lymph nodes with cancer may determine the “N” category. Lymph nodes near where the cancer started are called regional lymph nodes. Lymph nodes in other parts of the body are called distant lymph nodes. 
• Metastasis (M). The letter "M" indicates whether the cancer has spread to other parts of the body, called distant metastasis. If the cancer has not spread, it is labeled M0. If the cancer has spread, it is considered M1. Sometimes doctors use the letters a, b or c to further divide the categories. For example, stage M1a lung cancer is a cancer that has spread to the other lung. Stage M1b lung cancer has spread to other parts of the body. M1c means that there is more than one area of cancer in one or several organs.

Cancer stage grouping:

Doctors use the TNM staging system to formulate the stage of a patient’s cancer. Stages 1-4 are described with the Roman numerals I, II, III, and IV.  As mentioned before ,Sometimes stages are further subdivided using the letters A, B and C that indicate certain characteristics found on work-up of the cancer.

• Stage 0. This stage describes cancer in situ, which means “in place.” Stage 0 cancers are still located in the place they started and have not spread to nearby tissues. This stage of cancer is often highly curable, usually by removing the entire tumor with surgery.

• Stage I. This stage is usually a small cancer or tumor that has not grown deeply 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 and Stage III. In general, these 2 stages indicate larger cancers or tumors that have grown more deeply into nearby tissue. They may have also spread to lymph nodes but not to other parts of the body.

• Stage IV. This stage means that the cancer has spread to other organs or parts of the body. It may also be called advanced or metastatic cancer.

Example : A small cancer that has spread to the lymph nodes but not to anywhere else in the body may be T2 N1 M0. Or a more advanced cancer that has spread may be T4 N3 M1

• Each stage and each type of cancers need a specific treatment.

Resources:

-Mary Bird Perkins , Cancer Center .

https://marybird.org/blog/olol/the-abcs-and-123s-of-cancer-stages/

-Cancer.Net

https://www.cancer.net/navigating-cancer-care/diagnosing-cancer/stages-cancer

-Cancer Research U.K

https://www.cancerresearchuk.org/about-cancer/what-is-cancer/stages-of-cancer

-NHS

https://www.nhs.uk/common-health-questions/operations-tests-and-procedures/what-do-cancer-stages-and-grades-mean/