Colon cancer is a leading cause of cancer-related deaths in the United States. It occurs in the colon, which is the longest part of the large intestine, or in the rectum, which is the last few inches of the colon closest to the anus. Most colon cancers originate from certain types of polyps, known as adenomatous polyps, which are small, noncancerous tumors and produce no symptoms. Colon cancer occurs as the transformation within adenomatous polyps, according to MayoClinic.com. Many people with colon cancer experience no symptoms in the early stages of the disease. When symptoms appear, it is likely the cancer in the late stages.
Bleeding
Blood in the stools normally indicates the cancer is in more advanced stages, and has spread into nearby tissues. Blood can change the color of the stools to black. Vomiting of blood can also occur. Additionally, the colon becomes narrower, which can cause constipation; the stools can become hard and difficult or painful to pass, resulting in anal tears, which can lead to additional bleeding.
Changes in Bowel Habits
Changes in bowel habits can vary depending on the individual and can run the gamut from diarrhea to constipation, or there can be changes in the consistency of the stool. Less than three bowel movements a week may indicate constipation. Diarrhea is loose, watery stools. A bout of diarrhea can contribute to excessive loss of electrolytes, which would subsequently cause dehydration.
Abdominal Pain
In the worst case symptoms of colon cancer, a tumor can perforate the inside walls of the colon and rectum, which would cause considerable pain, vomiting and other related symptoms. Patients may require immediate hospitalization for treatment. A perforated colon allows the bowel contents to leak into the abdominal cavity; this also may put patients at risk for infections.
