It is no surprise that colon cancer is one of the most common types of cancer prevalent today.
Colon cancer is the cancer of the large intestine, one of the most important components of our digestive system.
The common symptoms include abnormal bowel movements, sudden and unplanned weight loss and altering diarrhea and constipation; thus, it is better to get yourself medically examined and tested upon doctor’s prescription for colon cancer.
There’s something you’d have to keep in mind that colon cancer is usually not what people get regular checkups for since there are no signs and symptoms apparent in the early stages. Thus, if you experience any of these symptoms, do not delay to get medical examination done.
The matter of stages is sometimes difficult to understand, but one thing is easy to comprehend that the earlier it is diagnosed the easier it is to be treated and controlled (just like any other type of cancer).
Why the Classification of Stages?
The classification of the stages of colon cancer is for the better understanding about the size of the tumor and also to determine how much it has spread in the body.
The screening tests and colonoscopy is a part of the medical examination to diagnose the stage of the cancer. This also helps in identifying the treatments needed according to the intensity of the disease and its stage.
There are three types of classifications pertaining to the staging of colon cancer:
- Number Stages
- TNM Stages
1. The Numbering Stage
The numbering stage is based on the detailed TNM stages of the bowel cancer (which is explained as you proceed with the article). This is the simpler form of staging system.
There is actually a ‘0’ stage prior to the first one in colon cancer. This actually defines the presence of the cancerous cell in the colon. If you are diagnosed with a stage 0 colon cancer, it means that there are cancerous cells present in the lining of the large intestine. However, the good part is that the disease had not spread through the lining and the risk is low too. If the cancer is caught at this stage, doctors can prevent any advancement of the disease by providing relevant treatment right away.
The first stage of bowel cancer is when the cancerous cells begin to spread themselves and start growing in the inner lining of the bowel (colon) and the muscle wall is also affected in this stage by the cancerous cells developing.
However, there is good news! The cells in this stage do not have a fast growth pace and if one is diagnosed with first stage cancer, it means that the lymph nodes are still unaffected by the cancer. Treatment in this stage could lead to a healthy life with cured intestine.
The second stage of colon cancer is further advanced from stage 1 and it has further been divided into two subdivisions.
- In the first case (Stage 2a), the cancer has grown into the outer layer of the intestinal wall (previously it was on the inside and growing), but the lymph nodes are clean.
- In the second case (Stage 2b), the cancer has went up the outer layer of the bowel and has affected the tissues nearby and have a tendency to affect the organs near it as well. The lymph nodes are still safe and any other body part remains unaffected in this stage.
It is better to get the treatment right away for cancer in this stage could be on a verge of spreading its wings.
The third stage of colon cancer gets more serious and detrimental. It is further divided into three stages.
- Stage 3a: The cancer is in the inner layer of the bowel and could have touched on the surface of the muscle layer too. But, 1 to 3 lymph nodes would have been affected by now.
- Stage 3b: The cancer has grown towards the outer lining of the large intestine and the tissues and organs surrounding it would be affected somehow as well. In this stage too, 1 to 3 lymph nodes would contain cancerous cells.
- Stage 3c: In this stage the cancer would have increased in its size (could grow enormously too) and more than 3 lymph nodes would contain the cancerous cells. The good part is, any other body part would not be affected by colon cancer, in this stage.
The most dangerous stage of colon cancer is the stage 4. In this stage, the treatment gets most complex and also difficult to cure completely for the cancer is not restricted to the large intestine anymore. In stage 4, the colon cancer would have spread to various other parts of the body such as lungs and the liver, thus impeding their functions too. The cancerous cells would also be present in the bloodstream.
2. TNM Stages
The TNM Staging system is used by doctors for a more intricate explanation of the spread of the disease. It is explained as follows:
- ‘T’ stands for the size of the tumor, as to how large it is.
- ‘N’ stands for the spread of the tumor/cancer, whether it has spread to the lymph nodes. If it has, how many have been affected?
- ‘M’ stands for Metastasis; which means if the tumor has spread to other body parts, and how much (the intensity).
The (T) is calculated in the following manner:
- TX: Tumor is unidentified
- T0: Absence of tumor in colon (or rectum)
- Tis: It refers to the stage 0 of cancer (numbering system). The cancerous cells are present in the linings of the colon.
- T1: The growth of tumor is in the upper layer of colon tissue.
- T2: The tumor has grown into muscle of intestine.
- T3: Growth is in the surrounding tissues (surrounding colon or rectum)
- T4a: Tumor has affected all layers of colon.
- T4b: The tumor has grown into other organs.
The Node (N)
The ‘N’ is calculated in the following manner:
- NX: The lymph nodes of colon cannot be evaluated
- N0: The lymph nodes aren’t affected
- N1a: One lymph node has been affected by the cancerous cells
- N1b: Two to three lymph nodes are affected
- N1c: The presence of nodules near colon which are made up of tumor cells (they don’t look like lymph nodes)
- N2a: Tumor is found in four to six lymph nodes
- N2b: The tumor is found in more than seven lymph nodes
The ‘M’ is defined in the following manner:
- MX: It cannot be evaluated that the tumor has spread to other organs or not
- M0: The cancer has not spread to any other organ
- M1a: One other body part (other than colon or rectum) has been affected
- M1b: More than one organ has been affected by the colon cancer
The grading system is yet another manner in which the colon cancer stages are defined. It is a technique used by doctors to compare the cancerous cells with the healthy ones and with the healthy tissues. If there is similarity, it would be a low grade tumor and it increases with differentiation, then the more the contrast, the higher the grade. It is explained in the following manner:
- GX: The grade of cancer is not identified.
- G1: The difference is very low, the cells are similar to healthy ones
- G2: There is moderate difference, still more inclination towards similarity with healthy cells
- G3: The difference is growing
- G4: The cells hardly look anything like the healthy ones
To prevent from reaching any of the last stages, be it in numbering, TNM or grade system, patients should get medical attention right away and don’t delay the treatment at all. It will be easier to cure the disease if it hasn’t affected the nearby organs or the lymph nodes and blood vessels (in advanced stage).
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