The staging of colon cancer is crucial for treatment. Most often the tumors do not reveal any symptoms. By the time the cancer is diagnosed, it could be many weeks or months. Hence, doctors would need the information to know how far the cancer has spread, so that they can plan accordingly. If the cancer is advanced, then doctors will pursue treatment aggressively. Not all stages of cancers are treated in the same way, and this information is necessary to ensure that the patient receives the right treatment at the right time. Read about the main stages of colon cancer.

What is metastasis?
Secondary growth of cancer away from the original site of the tumor is known as metastasis. The cancer cells dislodge and break away from the place they started and flow through the bloodstream, and/or enter the lymphatic system or affect any other organ. In a common example, breast cancer can spread to lungs and bones. In the case of colon cancer, if the tumor is not limited to the colon and has spread to any other organ that is far away from the colon, it is called as distant metastasis.

Metastasis is further classified into:

• M0 – The cancer is limited to the colon and has not spread to any other part of the body.
• M1a – Cancer has affected at least one organ, or distant lymph nodes, but has not yet reached the peritoneum.
• M1b – Cancer has affected more than one organ, or distant set of lymph nodes but has not yet reached the peritoneum.
• M1c – The peritoneum membrane covers all the organs in the abdomen. When the tumor affects the peritoneum membrane, the staging is termed as M1c. Cancer may or may not have reached or spread to lymph nodes.

Grading
Apart from the staging of cancer, doctors also conduct tests to find out how quickly the cancer is likely to spread. They do these tests by comparing the cancer cells to the normal cells in a patient’s body. These tests give the doctors hints about how quickly the cancer can spread. This information helps them to plan treatment. The cancers are then graded into low-grade- and high-grade cancers based on how they look under a microscope.

Low-grade colon cancers
If the cancer cells look more like normal cells, they are classified as well-differentiated tumors. This implies that cancer cells are not likely to grow very fast. This helps the doctors to plan treatment and prescribe medication and other protocols accordingly

High-grade colon cancers
If the tested cancer cells look highly disorganized and do not resemble the normal cell tissues in any way, the cancer is said to be poorly differentiated and is graded as high-grade colon cancer cells. These are likely to spread faster and this information helps the doctors to quickly start the treatment hastily.

Different grades of colon cancer:

• Grade X – Evaluation of grade is not possible.
• Grade 1 – Well-differentiated, low-grade cancer, and likely to spread very slowly.
• Grade 2 – Moderately differentiated and cancer might not spread either too quick or too slow.
• Grade 3 – Highly-differentiated and unorganized, and the cells are likely to spread rapidly.