Colon cancer currently accounts for approximately 9% of new cancer cases in men and 11% of new cancer cases in women. Colon cancer is the second leading cause of cancer in the United States. Approximately 50,000 new cases per year are identified. Each year, 60,000 deaths occur due to colorectal cancer. In addition, over 200,000 hospitalizations per year are a result of primary diagnosis of colorectal cancer.
Risk factors for the development of colon cancer include age greater than 50 years, a history of altered colitis or Crohn's disease, significant family history and a personal history of polyps. Of particular importance are those patients with chronic altered colitis. These individuals, with universal (or pancolitis), carry increased risk of colorectal carcinoma approximately one percent per year after 8 to 10 years of the disease. These individuals may have dysplasia within the colon. The diagnosis of dysplasia, made during colonoscopy, indicates that there is a high risk for an associated colon cancer somewhere in the colon. Patients with chronic altered colitis should be very carefully counseled and should strongly consider surgery when indicated by their age and fungal symptoms.
Colon cancer is a preventable disease since the precursors of the disease are actually benign.
Polyps are the precursors to colon cancer. Polyps begin as benign abnormalities of the colon. These cause no pain or symptoms. There is no change in bowel habits. In fact, the presence of colon polyps usually needs to be sought afterwards in order to identify patients with them conditions. A family history of colon polyps is extremely important. A family history of colon cancer is important as well.
The chance of developing colon cancer is significantly reduced by removing polyps. When a polyp develops, it continues to grow. If the polyp is left in place, colon cancer can begin to develop in approximately 6 to 8 years. Thus, if polyps are removed the chance of colon cancer is reduced. This fact was established by the National Polyp Study, performed on over 10,000 patients from 1980 to 1990.
Once colon cancer has been established, the patient will need to be evaluated for the extent of the disease and its location. The patient will usually need a Colonoscopy, CT scan of the abdomen and pelvis, routine blood work, a CEA (carcinoembryonic antigen) and surgery.
Surgery is very important in colon cancer since it allows a patient to have the tumor removed (resected) and the lymph nodes in the area of the tumor removed as well. By removing the lymph nodes, the extension of the tumor into the local (regional) lymph nodes can be assessed. This is an important factor in assessing the extent of disease. The process of determining the extent of disease is known as "staging". Staging of colon cancer is important since it gives your physicians information on which treatments are best and what types of outcomes occur with specific medical treatment regimens.
Staging is a sophisticated process of evaluating patients. The following is a limited description of colon cancer staging. Patients should be aware that a physician experienced with the process should perform this process. This is usually an oncologist (cancer specialist). The process takes into consideration more factors than are listed here.
Colon cancer is staged according to many factors. The main factors are size of the tumor, how aggressive the tumor is, degree of tumor penetration through the wall of the colon, the number lymph nodes in which the tumor is found and whether other organs are involved.
Based upon this, colon cancer patients may received either chemotherapy, radiation therapy or surgery alone.
Colon Cancer Screening
Colon cancer is the second largest killer in the United States. It is a preventable disease. However, to prevent this disease, patients need to participate in the process. There are several methods to screen patients for colon cancer. Your physician will assist you in determining which of these are the best for you.
Patients who are at average risk for colon cancer are characterized by the following:
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No family history of colon cancer |
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Lack of symptoms (change in bowel habits, evidence of bleeding from the rectum, thinning of the diameter of the stool and abdominal pain) |
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Tests for hidden blood in the stool are negative (fecal occult blood test) |
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Rectal exam shows no masses. |
Patients aged 50 or older who have hidden blood in their stool(fecal occult blood test positive) should undergo a colonoscopy as soon as possible by a gastroenterologist even if the patient has no symptoms or family history.
If a patient is found to have a polyp during an examination with a flexible sigmoidoscopy, then a colonoscopy is usually scheduled. The colonoscopy will then be able to examine the entire colon and remove the polyps safely from the colon. Polyps are usually not removed at the time of flexible sigmoidoscopy because of incomplete preparation of the colon. (Polyps may be safely biopsied during flexible sigmoidoscopy.) This predisposes patients to infections, etc. Thus, polyps are removed from the colon best during colonoscopy.
A gastroenterologist should evaluate patients with other symptoms so that the appropriate examinations can be scheduled.
Studies commonly used in the evaluation of patients for colon cancer include barium enema, flexible sigmoidoscopy and colonoscopy.
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