About Colon Cancer What is colorectal cancer? Colorectal cancer is malignant cells found in the colon or rectum. The colon and the rectum are parts of the large intestine, which is part of the digestive system. Because colon cancer and rectal cancers have many features in common, they are sometimes referred to together as colorectal cancer. Cancerous tumors found in the colon or rectum also may spread to other parts of the body. Watch the Colon Cancer episode from Second Opinion, featuring Dr. Monson What causes colorectal cancer? The exact cause of most colorectal cancer is unknown. A small percentage of colorectal cancers are caused by inherited gene mutations. People with a family history of colorectal cancer may wish to consider genetic testing. The American Cancer Society suggests that anyone undergoing such tests have access to a physician or geneticist qualified to explain the significance of these test results. What are the types of cancer in the colon and rectum? A type of cancer called adenocarcinoma accounts for more than 95 percent of the cancers in the colon and rectum and is usually what is meant by the term "colorectal cancer." There are other types of cancer that can be found in the colon and rectum, but they are rare. Adenocarcinoma. Adenocarcinomas are tumors that start in the lining of internal organs. "Adeno" means gland. These tumors start in cells with glandular properties, or cells that secrete. They can form in many different organs, such as the lung or the breast. In colorectal cancer, early tumors start as small adenomatous polyps that continue to grow and can then turn into malignant tumors. Gastrointestinal stromal tumors (GIST). These are tumors that start in the muscle tissue of the digestive tract, although they rarely appear in the colon. They can be benign (noncancerous) at first, but many do turn into cancer. When this happens, they are called sarcomas. Lymphoma. A lymphoma is a cancer that typically starts in a lymph node, which is part of the immune system. However, it can also start in the colon or rectum. Carcinoids. Carcinoids are tumors that start in special hormone-producing cells in the intestine. Often they cause no symptoms. What are the stages of colorectal cancer? When colorectal cancer is diagnosed, tests will be performed to determine how much cancer is present, and if the cancer has spread from the colon to other parts of the body. This is called staging, and is an important step toward planning a treatment program. The National Cancer Institute defines the following stages for colorectal cancer: Stage 0 The cancer is found in the innermost lining of the colon. Stage I The cancer has spread beyond the innermost lining of the colon to the second and third layers and the inside wall of the colon. The cancer has not spread to the outer wall of the colon or outside of the colon. Stage II The cancer has spread deeper into the wall or outside the colon to nearby tissue. However, the lymph nodes are not involved. Stage III The cancer has spread to nearby lymph nodes, but has not spread to other organs in the body. Stage IV The cancer has spread to other parts of the body, such as lungs. What are the symptoms of colorectal cancer? The following are the most common symptoms of colorectal cancer. However, each individual may experience symptoms differently. A change in bowel habits such as diarrhea, constipation, or narrowing of the stool that lasts for more than a few days Rectal bleeding or blood in the stool Cramping or gnawing stomach pain Decreased appetite Vomiting Weakness and fatigue Jaundice – yellowing of the skin and eyes The symptoms of colorectal cancer may resemble other conditions, such as infections, hemorrhoids, and inflammatory bowel disease. It is also possible to have colon cancer and not have any symptoms. Always consult your physician for a diagnosis. To make an appointment for a colorectal cancer screening, or to schedule a consult with one of our leading colorectal cancer experts, please call (585) 275-URMC (8762).