Colorectal cancer can cause different symptoms based on the location of the tumor. Cancers of the right colon often result in frequent blood in the stool, but usually do not block the colon. Cancers in the left colon may obstruct the bowel, causing a change in bowel habits, diarrhea or constipation and changes in stool size. A feeling that the bowel does not empty completely, and As in all cancers, fatigue, weight loss and loss of appetite are common symptoms. Surgery is the most common treatment.
Most patients have part of the colon or rectum removed in an operation called a colectomy.
Usually, the lymph nodes near the tumor are removed during surgery to help diagnose the stage of the cancer. Often, surgery is the only treatment necessary for early colorectal cancer. Chemotherapy sometimes is given after surgery to try to prevent the disease from spreading. Chemotherapy also may be given to relieve symptoms of the disease in patients whose primary tumor cannot be completely removed or to treat patients whose cancer has spread to other organs. Like surgery, radiation therapy is local, meaning that it can affect cancer only in the treated area.