Colon
Cancer Early Detection Helps Improve Outcome
March
Is National Colorectal Cancer Awareness Month
Colorectal cancers are thought to develop slowly over a period
of several years, experts say. And, it is commonly known that
most colorectal cancers begin as a polyp, also known as an adenoma.
Over many years (usually about five to 10), these
polyps can slowly change into cancer.
Excluding skin cancers, colorectal cancer is the third
most common cancer diagnosed in both men and women in the US.
The American Cancer Society estimates
that about 106,370 new cases of colon cancer (50,400 men and 55,970
women) and 40,570 new cases of rectal cancer (23,220 men and 17,350
women) will be diagnosed in 2004.
Colorectal cancer is expected to cause about 56,730
deaths (28,320 men and 28,410 women) during 2004, accounting for about
10 percent of cancer deaths.
"The biggest thing people can do to reduce risk is to
be screened," says Dr. David A. Johnson, chief of gastroenterology at
the Eastern Virginia School of Medicine in Norfolk. "It's
critical."
Given that March is National Colorectal Cancer
Awareness Month, now could be a good time to look into screening.
Taking
the Right Steps
Early detection makes the difference in the outcome
of colorectal cancer, according to the American Cancer Society.
When the cancer is detected in a localized state, the
five-year relative survival rate is 90 percent. But only 38 percent
of colorectal cancers are discovered that quickly. If more people took
screening seriously, experts say, that number would no doubt improve.
Toward that end, stricter guidelines on colorectal cancer
screening were issued by the US Multi-Society Task Force on Colorectal
Cancer in 2003.
The new recommendations suggest that before deciding
how a person should be screened, a physician will first need
to classify the person's level of risk, based on family history of the
disease.
It is very crucial to know your risk, says Dr.
Dennis Ahnen, a gastroenterologist and staff physician at the Denver
VA Medical Center. Anyone with a family history or a personal history
of colon cancer or polyps, which can precede cancer, is high risk, he
says.
"If you have a single first-degree relative [such as
a father or brother] with colon cancer at a young age, under 50, or
more than one first-degree relative with colon cancer at any age, that
is a strong family history," Dr. Ahnen says.
Those in a high-risk category should begin screening
at age 40, or 10 years before the age at which the earliest colon cancer
in the family occurred, Dr. Ahnen says.
Intermediate risk describes someone who has one family
member with colon cancer that occurred after age 50, Dr. Ahnen says,
although some experts say over age 60. For these individuals, screening
should start at age 40.
People who have no family or personal history of cancer
or polyps and no gastrointestinal diseases such as ulcerative colitis
have an average risk, and they should start screening for cancer and
polyps beginning at age 50.
Testing
Options
Next is to decide, with your physician, the best options.
Among them are colonoscopy, sigmoidoscopy, fecal occult blood testing,
and double-contrast barium enema.
Colonoscopy involves the insertion of a long, flexible
tube with a camera mounted on the end, up through the rectum and into
the colon. The pictures taken by the camera are transmitted to a monitor.
A flexible tube is also inserted for sigmoidoscopy,
but the viewing area is limited to a smaller part of the intestine -
the sigmoid, or descending colon only.
Occult blood testing analyzes stool samples for blood,
which can be a symptom of cancer.
Double-contrast barium enema is a radiological test
in which a liquid is inserted into the rectum to better show the image
of the GI tract on an X-ray.
Although the official guidelines offer an array of options,
many experts say colonoscopy is the preferred test.
"Push as hard as you can for the best test, which is
a colonoscopy," Dr. Johnson says.
In the future, "virtual" colonoscopies, which are less
invasive than traditional colonoscopies, may become more common, Dr.
Ahnen says. They use computer-assisted tomography to survey the colon
from outside the body.
No matter which test you choose, experts say rectal bleeding, blood
in the stool, a change in bowel habits, and cramping pain in the lower
abdomen are all signs to get medical attention as soon as possible.
Always consult your physician for more information.
Online
Resources
American
Cancer Society
American
College of Gastroenterology
Centers
for Disease Control and Prevention (CDC)
Healthfinder,
US Department of Health and Human Services (HHS)
National
Cancer Institute
National
Digestive Diseases Information Clearinghouse
National
Institutes of Health (NIH)
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March 2004
Colon
Cancer Early Detection Helps Improve Outcome
Taking
the Right Steps
Testing
Options
Colorectal
Screening Guidelines
What
Is a Virtual Colonoscopy?
Online
Resources
Other
Resources:
Find
a St. John's Mercy Physician
Sports
& Therapy Services at St. John's Mercy
Men's
Health Information
St.
John's Mercy Classes and Programs
Colorectal
Screening Guidelines
Current colorectal cancer
screening guidelines from the American Cancer Society
for early detection include:
Beginning at age 50, both
men and women should follow one of the examination schedules below:
-
fecal occult
blood test (FOBT) every year
-
flexible sigmoidoscopy
(FSIG) every five years
-
annual FOBT
and FSIG every five years
-
double-contrast
barium enema every five years
-
colonoscopy every 10
years
People with any of the following colorectal cancer risk factors should
begin screening procedures at an earlier age and be screened more often:
-
strong family history
of colorectal cancer or adenomatous polyps in a first-degree relative,
in a parent or sibling before the age of 60 or in two first-degree
relatives of any age
-
family with hereditary
colorectal cancer syndromes, such as familial adenomatous polyposis
(FAP) and hereditary nonpolyposis colon cancer (HNPCC)
-
personal history of
colorectal cancer or adenomatous polyps
-
personal history of
chronic inflammatory bowel disease
What
Is a Virtual Colonoscopy?
Virtual colonoscopy compares
favorably to the current "gold standard" of conventional colonoscopy,
according to a report in the New England Journal of Medicine.
The procedure, using 3-D
imaging technology, may eventually convince experts that virtual colonoscopy
is a reliable screening tool.
"We have proved that virtual
colonoscopy is a viable screening option," says lead researcher Dr.
Perry J. Pickhardt, an associate professor of radiology at the University
of Wisconsin Medical School.
Standard colonoscopy is a
procedure that allows the physician to view the entire length of the
large intestine, and can often help identify abnormal growths such as
polyps, inflamed tissue, ulcers, and bleeding.
This test involves inserting
a colonoscope, a long, flexible, lighted tube, in through the rectum
up into the colon. The colonoscope allows the physician to see the lining
of the colon, remove tissue for further examination, and possibly treat
some problems that are discovered. Patients are usually sedated during
the procedure.
The virtual colonoscopy,
however, is completely noninvasive. In this procedure, usually a spiral
CT scan is taken of the gastrointestinal area, and then a computer puts
together an image of the person's colon for examination by a radiologist.
According to Dr. Douglas
K. Rex, president of the American College of Gastroenterology,
"Considering all available literature, conventional colonoscopy as currently
performed remains the clear gold standard for the diagnosis of colorectal
cancer and adenomas.
"Patients should be aware
that in this study of virtual colonoscopy and in some others, they are
more likely to experience significant discomfort with virtual colonoscopy
than they are with conventional colonoscopy."
Dr. Rex adds, "Thus virtual
colonoscopy is a diagnosis-only test, whereas conventional colonoscopy
remains the only strategy that allows both diagnosis and treatment in
a single session."
Always consult your physician
for more information.
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