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Colorectal Cancer (Colon Cancer; Cancer of the Colon and Rectum) by Laurie LaRusso, MS, ELS Definition Colorectal cancer is a disease in which cancer cells grow in the colon and/or rectum. The colon and the rectum are parts of the large intestine, which is part of the digestive system. Cancer occurs when cells in the body (in this case colon or rectum cells) divide without control or order. Normally, cells divide in a regulated manner. If cells keep dividing uncontrollably when new cells are not needed, a mass of tissue forms, called a growth or tumor. The term cancer refers to malignant tumors, which can invade nearby tissues and can spread to other parts of the body. A benign tumor does not invade or spread. Causes The cause of colorectal cancer is unknown. However, research shows that certain risk factors are associated with the disease. Risk Factors A risk factor is something that increases your chance of getting a disease or condition. Age: 50 or older Diets high in fat and low in fiber Family history of colorectal cancer, especially a parent, sibling, or child Other risk factors include: obesity, physical inactivity, diabetes, smoking, alcohol intake, nightshift work, and ethnic background Personal history of colorectal cancer Polyps (benign growths) in the colon and rectum (especially due to familial polyposis, an inherited condition) Ulcerative colitis (inflammation of the lining of the colon) or Crohn’s Disease Symptoms Colorectal cancer often does not have any symptoms, but some symptoms associated with colorectal cancer include: A change in bowel habits such as diarrhea, constipation, or feeling that the bowel does not empty completely, lasting for more than a few days in people over age 50 Abdominal discomfort (frequent gas pains, bloating, fullness, and/or cramps) Blood (either bright red or very dark) in the stool Constant fatigue Stools that are narrower than usual Unexplained weight loss Note: These symptoms may also be caused by other, less serious health conditions. Anyone experiencing these symptoms should see a doctor. Diagnosis The doctor will ask about your symptoms and medical history, and perform a physical exam. Tests include: Digital Rectal Exam –use of a physician's gloved finger to examine the rectum for lumps, or growths Fecal Occult Blood Test – a test to check for hidden blood in the stool X-rays (using barium, called a barium enema) – pictures of the large intestine that show polyps or other changes Sigmoidoscopy – an examination of the rectum and lower colon using a lighted tube called a sigmoidoscope Colonoscopy – examination of the rectum and entire colon using a lighted tube called a colonoscope Polypectomy – the removal of a polyp during a sigmoidoscopy or colonoscopy Biopsy – the removal of colon or rectal tissue to be tested for cancer cells Treatment Once colon cancer is found, staging tests are performed to find out if the cancer has spread and, if so, to what extent. Treatment depends on the stage of the cancer. Treatments include: Surgery (the main treatment for colorectal cancer) –surgical removal of the cancerous tumor and nearby colon or rectum tissues, and possibly nearby lymph nodes. In most cases, the doctor reconnects the healthy portions of the colon or rectum. If they cannot be reconnected, a temporary or permanent colostomy is necessary. Colostomy is a surgical opening through the abdomen into the colon through which body waste is collected in a special bag that is worn on the outside of the body. Radiation Therapy (Radiotherapy) – the use of radiation to kill cancer cells and shrink tumors. Radiation is directed at the colon from a source outside the body. Chemotherapy – the use of drugs to kill cancer cells. Chemotherapy may be given in many forms including: pill, injection, and via a catheter. The drugs enter the bloodstream and travel through the body killing mostly cancer cells, but also some healthy cells. Biological therapy – the use of medications or substances made by the body to increase or restore the body's natural defenses against cancer. Also called biological response modifier (BRM) therapy. Prevention The cause of most colorectal cancer is not known. However, it is possible to prevent many colon cancers by finding and removing polyps that could become cancerous. Beginning at age 50, both men and women should follow one of the five screening options below: Colonoscopy every 10 years Double contrast barium enema (x-rays of the colon and rectum) every 5 years Flexible sigmoidoscopy every 5 years Yearly fecal occult blood test Yearly fecal occult blood test plus flexible sigmoidoscopy every 5 years People with any of the following risk factors should begin colorectal cancer screening earlier and/or undergo screening more often: A known family history of hereditary colorectal cancer syndromes A personal history of chronic inflammatory bowel disease A personal history of colorectal cancer or adenomatous polyps A strong family history of colorectal cancer or polyps Last reviewed: March 2004 by Judy Logan, MD.