Most of the cancers which affect the colon and the rectum develop from the lining of these two large intestine elements and are known as adenocarcinomas. The cancer at first looks like a small swelling on the inside surface of the colon or rectum and then it develops forming a tumor, expanding to all the colon's layers and affecting the local lymph nodes. In its last stages the colorectal cancer spreads towards distant organs like liver or lungs affecting them too.

It seems that mostly the western population is affected by this disease. Women seem to develop colon cancer more frequently then men who develop rectal cancer more often. The persons aged more than 40 are at risk and those who are 60 or 70 are more likely to have this disease than others.

Scientists have not found out exactly why this disease occurs but they believe that if you follow a diet that is rich in proteins and fats and low in fiber you might develop cancer. Also, having a family history of colorectal cancer and breast or uterus cancer could be a risk for you. Drinking alcohol is also a factor that leads to cancer. If you have polyps on the inner wall of the intestine and you leave them untreated they can transform into malign tumors (meaning that cancer had occurred). Also, people who suffer of Crohn's disease or ulcerative colitis can develop this disease too.

There are some symptoms which could announce that cancer is installing, but they also appear in other diseases. Some of the symptoms are: seeing blood in your bowels, alternation of diarrhea with constipation, and low abdominal pains. Bloating can be present and feeling tiredness and vomiting can occur too. In most of the intestinal cancers, loosing weight is present. The loss of weight is made in a short period of time and even though for some people it might be considered a blessing, this is not a good thing, because it means that the tumor blocks the bowel somewhere inside the intestines. If the tumor is situated at the end of the colon or in the rectum it might give you the feeling that you still have to go to the bathroom even if you just went. Some people might even refuse to sit down as this act can be painful.

Diagnosing colon cancer is made by performing some tests. The stool is being tested to see if blood can be found in it. Sometimes a digital rectum examination can be performed by the doctor. The rectal and colon screening is made by sigmoidoscopy, which uses a tube with an optic camera to see what is inside the large intestine. Also, blood tests are needed to measure the level of carcinoembryonic antigen which might indicate the presence of a cancer.

As soon as the colon cancer is discovered the doctors will decide upon the best therapy measure for the patient. In early stages the cancer can be treated only by surgery which removes the tumor and the local lymph nodes. In more advanced stages of the cancer chemotherapy is needed after surgery to be sure the cancerous cells have been removed totally.
There are some cases in which the rectum and a part of the colon need to be removed and so the patient will remove the stool by an opening created in the abdominal wall which is connected to a colostomy bag.

For greater resources on colon cancer or especially about colon cancer symptoms please visit this link http://www.colon-cancer-center.com/colon-cancer-symptoms.htm