According to the Centers for Disease Control and Prevention, colorectal cancer causes the third highest number of cancer cases in America. In 2006 alone, 68,857 women and 70,270 men were diagnosed with this cancer. The CDC recommends that all women and men who are 50 years old and older be screened. They estimate that screening could save 60 percent of the lives currently lost to this disease.
Risk Factors
The risk factors include a high-fat, low-fiber diet. But there is also increased risk in diseases such as adenomatous polyps, familial adenomatous polyps, or FAP, hereditary nonpolyposis colorectal cancer, or HNPCC, Gardner's syndrome, ulcerative colitis and Crohn's. A polyp is a mass inside the large intestine that sticks out inside the intestinal wall. Adenomatous polyps are usually benign growths; their structures have glandular tissue or resemble a gland. FAP is a hereditary disease caused by a mutation on chromosome 5, which results in a colon filled with hundreds or thousands of adenomatous polyps, as explained by Kenneth McQuaid, M.D., in the journal Current Medical Diagnosis & Treatment. HNPCC is also a hereditary disease caused by a mutation in several genes; it leads to colon cancer and is also associated with endometrial and ovarian cancers. Gardner's syndrome includes polyps and bone tumors. Ulcerative colitis and Crohn's are both diseases that involve the inflammation of the intestines.
Right-Sided Colon Cancer
People with colon cancer usually only have symptoms after the cancer has grown large enough in size. Colon cancer grows slowly. Elliot Livstone, M.D., writes in "The Merck Manual for Healthcare Professionals" that the right side of the large intestines is wide and has a thin wall. In addition, the feces in the right side is still forming; it is still in liquid form. Because colon cancer grows so slowly, it will take some time before the cancer in the right side is large enough to obstruct the passage of feces. Symptoms may include weight loss, diarrhea, loss of appetite, abdominal pain, weakness and fatigue. People with right-sided colon cancer are weak and tired because they are severely anemic. The cancer causes occult bleeding.
Left-Sided Colon Cancer
According to Dr. Livstone in "The Merck Manual for Healthcare Professionals," the large intestines on the left side have a smaller width, and the stool is no longer liquid but partially solid. Colon cancer on this side is described as having an "apple-core" look, because it grows around a section of the large intestines. The symptoms include diarrhea and constipation, stool with blood in it and abdominal pain. The pain may be colicky, meaning that it may come and go as the feces try to move past the mass of cancer.
Diagnosis
Screening should include the digital rectal exam with fecal occult blood testing, or FOB, every year, once people are 50 years old. For people who do not have a high risk for colon cancer, physicians also recommend a flexible sigmoidoscopy every five years or a colonoscopy every 10 years, once a person is 50 years old. FOBT checks for any blood in the stool. A flexible sigmoidoscopy is a flexible tube that checks part of your large intestines. A colonoscopy is a longer tube that checks your entire colon. People who have a high risk will need to be checked at an earlier age.
References
- Centers for Disease Control and Prevention: Colorectal (Colon) Cancer Incidence Rates
- Current Medical Diagnosis & Treatment 2009; Stephen McPhee, M.D., Maxine Papadakis, M.D.; 2009
- The Merck Manual for Healthcare Professionals: Colorectal Cancer
