Colon and rectal cancer is the second most common cancer overall in the U.S. today.
Only lung and breast cancer occur with a higher incidence in women, while lung and prostate cancer rank first and second in men.
Of particular importance to those of us living in the Tri-State area is the fact that colorectal cancer occurs at a higher incidence here than in other parts of the country. Data accumulated over the past three years at both Deaconess Hospital and St. Mary's Medical Center have shown a consistently higher rate of colon and rectal cancer in the Tri-State area as opposed to the national average. The reason for this increase in incidence is unknown.
The American Cancer Society expects that 147,000 new cases of colon cancer will be diagnosed in the U.S. in 2003. Unfortunately approximately one-half of these patients will die of their disease. The good news about colorectal cancer is that undergoing routine screening examinations can prevent or greatly reduce the incidence of cancer.
WHAT ARE POLYPS? Most, if not all colorectal cancers actually begin as a benign growth called a polyp. These polyps are more common on the left side of the colon, although they can occur throughout the colon. It is thought that these polyps require three to five years of growth to reach a size at which there is significant risk of changing to cancer. It is during this benign phase that detection and removal can prevent the development of cancer.
WHAT ARE THE RISK FACTORS? The most common risk factors for the development of cancer of the colon and rectum are advancing age or a family history of colorectal cancer or polyps. Only 2% of cancers occur in patients under the age of 40, while 90% of patients with colon cancer are over the age of 50. Patients with inflammatory bowel disease affecting the colon are also at increased risk. Crohn's disease and ulcerative colitis are examples of two types of inflammatory bowel disease.
There are some genetic syndromes which greatly increase the risk of developing cancer. Familial polyposis is one such genetic syndrome which predisposes patients to developing large numbers of polyps at an unusually early age; therefore, predisposing these patients to development of cancer much sooner.
WHAT ARE THE EVALUATIONS LIKE? There are a number of examinations which can be done to evaluate for the presence of polyps or cancer. The type of exam recommended by a physician depends upon the patient's age, risk factors, and the presence or absence of symptoms. The most common screening methods include the following:
1) Digital rectal exam - this allows examination of the anal canal and lower rectum. The prostate gland is also evaluated during this exam.
2) Hemoccult testing - this test checks for trace amounts of blood in the stool that is not visible to the naked eye. There is a high false negative as well as a high false positive rate with this test. What this means is, that a cancer can be present even if the test is negative, while the opposite is also true - that a positive test does not always indicate the presence of a cancer. In fact, cancer is not present in the majority of cases where the test is positive.
3) Rigid proctosigmoidoscopy - this is an exam done with a short rigid scope. This is a limited exam which allows evaluation of the rectum.
4) Flexible sigmoidoscopy - this involves the use of a flexible lighted instrument which allows direct examination of the rectum and sigmoid colon. Approximately one-fourth to one-third of the colon can be examined by this method. The portion of the colon examined by this method, is that part of the colon where approximately 60-65% of polyps and cancers occur.
5) Colonoscopy - this procedure also uses a lighted flexible instrument which is long enough to examine the entire colon. This examination is done under sedation and allows for removal of polyps or biopsies of cancers and other suspicious areas. Contrary to popular belief, this exam can be done very comfortably in about 30 minutes. The use of sedation makes this a very easy examination in most patients.
6) Barium enema - this exam involves the use of a solution to fill the colon. X-rays are then taken which show the outline of the colon. This exam is limited because it only shows the outline of the colon and any abnormality must usually be evaluated by follow up endoscopic examination.
WHAT ARE THE SIGNS AND SYMPTOMS FOR COLON AND RECTAL CANCER? Rectal bleeding, blood in the stool, and changes in bowel pattern are the most common symptoms seen with this cancer. Other symptoms include abdominal pain, weight loss, urgency, or excessive mucus in the stool. It is very important to emphasize that polyps and early cancers very seldom cause symptoms. It is for this reason that routine exams are recommended for all people, especially those with risk factors. A common misconception is that a person needs an exam only when symptoms are presents. Unfortunately, by the time symptoms have developed, a patient may have advanced disease. The best approach is to do regular exams so that polyps can be detected and removed before they become cancerous.
WHEN SHOULD REGULAR EXAMS BE STARTED? Patients without symptoms are viewed as being at average or increased risk, depending upon their history. Those patients with no family history of cancer or polyps are considered at average risk. People with a family history of cancer or polyps are at increased risk to develop colorectal cancer. The American Cancer Society's current guidelines call for regular screening to begin at age 50 in those of average risk. This consists of annual rectal examination with Hemoccult testing of the stool and a flexible sigmoidoscopy exam every three to five years. If blood is detected in the stool or if polyps are discovered, a complete colonoscopy should be performed both to evaluate the entire colon and also to remove the polyps.
For patients at increased risk, total colonoscopy is recommended beginning at age 40 with repeat examinations every three to five years. Exams should be performed at an earlier age if there is a history of family members with cancer at an unusually early age.
Any patient over the age of 40 with bleeding or other symptoms should also have an examination. The type of exam is determined by the patient's physician, depending upon the exact symptoms and findings on preliminary physical examination.
Basic screening examinations can most often be done by the patient's family physician. Many family doctors are very good at performing flexible sigmoidoscopy.
Total colonoscopy and barium enema are examinations that are usually done by specialists. Most colonoscopies are done by either a colon and rectal surgeon or a gastroenterologist. These exams can also be done by general surgeons, internists, and family practioners who have had appropriate training.
Although most of us are embarrassed by these examinations, and afraid that they are associated with a great deal of pain, these exams can usually be done without significant discomfort in your doctor's office. Total colonoscopy is generally done with sedation which makes the examination very comfortable. Removal of a polyp or a biopsy is also painless due to the fact that the inside lining of the colon does not contain pain fibers. After a colonoscopy a patient can resume a normal diet immediately and there are usually no restrictions in activity once the sedation has had time to wear off.
The bottom line (no pun intended) is this; colon and rectal cancer is a common cancer and we are all at risk. This risk can be significantly reduced by undergoing regular examinations once we have reached the age of fifty, with earlier exams being done if we have a family history of cancer or have developed symptoms. The examinations can be done comfortably by well trained physicians with minimal discomfort or embarrassment to the patient.
Colorectal cancer is a preventable and curable disease especially when detected early. If you are over age 50 and have not had an exam, contact your physician soon about beginning regular screening.
James D. Waller, M.D., F.A.C.S.
Ohio Valley Colon & Rectal Surgeons, Inc.
Evansville, IN 47714