COLORECTAL CANCER
Colorectal cancer is
cancer of the colon or the rectum, and is the second largest
cause of cancer deaths in the U.S. It is estimated that 56,730
people will die in the U.S. this year, according to the American
cancer Society. 90% of cases happen to those 50 years old or
older, so increased age is a risk factor for colorectal cancer. A
family history of colorectal cancer, inflammatory bowel disease
and some hereditary syndromes are also risk factors. Alcohol
consumption, tobacco use, obesity, low-fiber and high-fat diets,
and not eating fruits and vegetables are other risk factors for
colorectal cancer. Early screening and detection is
essential.
Detecting and removing
pre-cancerous polyps can reduce the number of colorectal cancer
deaths, detect cancer earlier, and allow early treatment.
Removing these polyps or growths can prevent this type of cancer,
because these pre-cancerous polyps can appear years before the
cancer develops.
There are four tests to
screen for colorectal cancer. These are the fecal occult blood
test, a flexible sigmoidoscopy, colonoscopy, and the
double-contrast barium enema.
The fecal occult blood
test, or FOBT, finds hidden blood in three consecutive stool
samples. In the U.S., a 33% reduction of colorectal cancer deaths
and a 20% incidence reduction of colorectal cancer occurred with
people that had an annual FOBT. In Europe, a 15% to 18% reduction
in colorectal cancer deaths occurred in trials where FOBT's
were performed every other year.<
With the flexible
sigmoidoscopy exam, a flexible, lighted tube is used to visually
inspect the inside walls of the rectum and portions of the colon.
In case-control studies, a 59% to 79% reduction of colorectal
cancer cases occurred in patients that had a flexible
sigmoidoscopy over people that did not have the
procedure.
For the colonoscopy
exam, a flexible, lighted tube that is longer than the one used
for the flexible sigmoidoscopy is used to see and inspect the
interior walls of the rectum and the entire colon. Samples of
tissues can be collected and polyps can be removed with this
procedure. A colonoscopy can screen for colorectal cancer or be
used as a follow-up diagnostic tool if another screening test is
positive.
The double-contrast
barium enema exam involves x-raying the colon and the rectum in a
series, after an enema of barium dye is given and an air
injection into the lower bowel to facilitate easier
viewing.
A digital rectal exam
is not recommended as a screening method because the area
screened is limited.
For adults over 50
years old, it is recommended that an FOBT be given every year, a
flexible sigmoidoscopy be performed every 5 years, a
double-contrast barium enema be given every 5 years, and a
colonoscopy every 10 years be performed. If you have a higher
risk for colorectal cancer, you should start screening at a
younger age, and more often than the above guidelines.
The earlier you get
screened will greatly reduce your chance of getting colorectal
cancer, and can prevent your getting colorectal cancer in the
first place, or increase your chances of survival if you already
have colorectal cancer.
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