Colon cancer is a form of tumor that begins in the large intestine of our digestive system. There are malignant cells that are initially benign polyps — these are a cluster of cells that slowly develop inside the colon and move on to becoming colon cancer cells. An individual’s health history does affect the chances of developing colon cancer.

Risk factors for developing colon cancer include a family history; having personal history of developing rectum, ovary, or colon cancer; being an alcoholic; smoking; obesity; old age; personal history of developing high risk adenomas or colorectal polyps that could be anywhere between 1 cm or more in size. Having a history of chronic colitis is another risk factor for colon cancer. After briefly looking at the risk factors, let us examine the main stages of colon cancer.

Stage 0: The abnormal cells are found in the mucosa, which is the innermost layer of the colon wall. These cells could get cancerous and sometimes spread to the connective tissue. This stage is also termed as carcinoma in situ.

Stage 1: Here, cancer is formed on the colon. It spreads to the submucosa, which is the layer next to the mucosa, or it could spread to the muscular layer of the colon wall.

Stage 2: In this stage, the cancer has spread through the colon’s muscle layer to the serosa, which is the connective tissue. There are subcategories under stage 2 cancer, like stage 2A where the cancer spreads through the colon wall’s layer of muscle; then comes stage 2B where cancer spreads through the outermost layer into the connective tissue, which is the abdomen lining. Stage 2C is where the cancer spreads to nearby organs.

Stage 3: Stage 3 has three subcategories: Stage 3A where the cancer spreads to the colon wall, submucosa layer, and the muscle layer. Tumor spreading to the lymph nodes and connective tissues is also included under stage 3A.

Malignant cells are formed near the lymph nodes which could be ranging from four to six lymph nodes. Stage 3B colon cancer is where the cancer has spread to serosa but not to the other organs. The tumor could spread to one or two lymph nodes and connective tissue. Stage 3C colon cancer is where the tumor spreads through the serosa and spreads to 4 or 6 lymph nodes but not to the nearby organs. Stage 3C could also see the cancer spread to seven or more lymph nodes and the connective tissues near the nodes.

Stage 4: This is the advanced stage of colon cancer where the cancer has spread quite far. It has moved to the bloodstream, lymph nodes, organs like liver, kidney, abdominal wall, ovary etc. This stage is further subcategorized to stage 4A, 4B, and 4C. Stage 4A is where the cancer spreads to one part of the organ like liver, kidney, ovary from the lymph nodes. 4B is where the cancer spreads to more than one part of the organs from the lymph nodes. 4C will have the cancer spread to connective tissues and wall lining of the abdomen.