Colorectal cancer is cancer that starts in the colon or the rectum. Like with other cancers in the body, they can be refereed to by the area in which the cancer is, or colon cancer or colorectal cancer.
Most colorectal cancers develop over the years starting with a growth of a tissue or tumor starting as a polyp. Generally these are in the inner linking and are not cancerous. Some polyps will turn into cancer, some will not. Polyps can be seen during colonoscopies. There are two kind of polyps, of which the and adenomatous polyps turn into cancer and the hyperplastic and inflammatory polyps do not.
Another kind of pre-cancerous condition is called dysplasia. Dysplasia is an area in the lining of the colon or rectum where the cells look abnormal. These cells can change into cancer over time. Dysplasia is usually found when in a person who has had other gastrointestinal issues for many years including ulcerative colitis and crohns.
The beginning and spreading of cancer
When cancer starts as a polyp, as it grows it will grow into the lining or wall of the colon. It is at this time that the cancer will be able to grow into the blood cells and/or lymph vessels. Once cancer has reached this stage it is able to travel through the body through the lymph or in the blood. This will allow it to spread to other organs of the body.
Types of cancer in the colon and rectum
- Adenocarcinomas: This cancer starts in cells that form glands that make mucus to lubricate the colon.
- Other, less common types of tumors may also start in the colon and rectum. These include:
- Carcinoid tumors: These tumors start from specialized hormone-producing cells in the intestine.
- Gastrointestinal stromal tumors (GISTs): These tumors start from specialized cells in the wall of the colon called the interstitial cells of Cajal. Some are benign (non-cancerous) and others are malignant (cancerous). These tumors are usually in the colon but can be found anywhere.
- Lymphomas: These are cancers of immune system cells that typically start in lymph nodes, but they may also start in the colon, rectum, or other organs.
- Sarcomas: These tumors can start in blood vessels as well as in muscle and connective tissue in the wall of the colon and rectum. Sarcomas of the colon or rectum are rare.
Symptoms of colorectal cancer are
- A change in bowel habits, such as diarrhea, constipation, or narrowing of the stool, that lasts for more than a few days.
- Feeling like you are not emptying your bowels after a movement.
- Rectal bleeding, dark stools, or blood in the stool (often, though, the stool will look normal)
- Cramping or abdominal pain
- Weakness and fatigue
- Unintended weight loss
These of course can be symptoms of other issues as well, but its best when present to see your doctor for an exam..