Download Colon Cancer

Determining a Diagnosis
Colonoscopy
Charlene M. Prather, M.D., M.P.H.
Associate Professor of Internal Medicine
Saint Louis University
St. Louis, Missouri
Topics List
• What is
colonoscopy?
• What is it used for?
• How is it done?
• Are there any
alternatives?
• Interesting findings
Colonoscopy
• Sedated examination
of the colon
• Views the internal
lining of the colon
• Biopsies can be
obtained
• Polyps can be
removed
What is Colonoscopy Used For?
• Colon cancer screening
• Determining the cause of:
– Gastrointestinal tract bleeding
• Bright red blood from the rectum
• Maroon stool
• Occult (hidden) bleeding
– Unexplained diarrhea
– Iron deficiency anemia
How is Colonoscopy Performed?
• The colon must be
clean to be examined
– Liquid diet
– Laxatives
• Stop iron supplements
• You may be asked to
stop aspirin
• Blood thinners are
usually stopped
How is Colonoscopy Performed?
• An I.V. will be placed for sedatives and
pain medications
• The examination is performed on the
left side
• Oxygen will be given
• Vital signs will be monitored
throughout the procedure
• The procedure takes 30 to 60 minutes
to perform
Normal Colon and TI
March
Colon Cancer Awareness Month
• Katie Couric
underwent
colonoscopy on
national television
in March 2000
• She continues to
actively campaign
for colon cancer
screening
March
Colon Cancer Awareness Month
• Katie Couric
underwent
colonoscopy on
national television
in March 2000
• She continues to
actively campaign
for colon cancer
screening
• Other celebrities
have joined the
campaign
Colon Cancer
• Second leading cause of cancer deaths
• More the 90% of colon cancer is
preventable
• Affects men and women
• Any one can get colon cancer
– Usually strikes after age 50
• Risk is increased if a first degree
relative has had colon cancer
Colon Cancer Prevention
• Begin screening at age 50 (average risk)
– No family history of colon cancer
– No personal history of colon polyps or colon
cancer
• African Americans should begin screening at
age 45
• Higher risk may need to begin at a younger
age:
– Age 40 or 10 years younger than the relative
developed colon cancer
• The risk of colon cancer continues to
increase with age
But Doc, I feel fine!
• Early colon cancer has no symptoms
• Symptoms of colon cancer
– Rectal bleeding
• Don’t assume it’s just hemorrhoids
– Iron deficiency anemia
– Change in bowel habit
– Unexplained weight loss
The importance of early
detection
• Colon cancer confined to the colon is
curable!
– 90% alive at 5 years
• If colon cancer has spread outside the
colon
– 8% alive at 5 years
Early cancer
What About Prevention?
• Early detection
– Detecting cancer before it has spread and
when it is still curable
• Prevention
– Removing polyps before they can become
cancer
Polyps
• Small growths in the
colon
• Two main types of
polyps:
– Hyperplastic:
do not to lead to
cancer
– Adenomas:
precancerous, may
develop into cancer
over several years if
left untreated
How Common are Polyps?
• Adenomatous polyps are found in 15 –
30% of screened individuals
• Removing polyps reduces the risk of
cancer by 90%
• A single colonoscopy reduced colon
cancer death by 31%
Who is Getting Screened?
• Mammograms – 80%
• Sigmoidoscopy/colonoscopy – 20 – 30%
Tests for Colon Cancer
• Colonoscopy every 10 years
– The best screening test
• Flexible sigmoidoscopy every 5 years
– Reduces deaths from colon cancer
– Screens less than ½ the colon
• Fecal occult blood testing every year
– Reduces deaths from colon cancer
– Risk of falsely positively test
– Risk of false negatives (polyps rarely bleed)
• Barium enema every 5 years
– Radiation exposure
– Rarely done for screening any more
Who Pays for the Test?
• Most insurances cover colon cancer
screening
• CDC funded low cost screening
available in St. Louis!
– 314-879-6392
New Approaches
• Virtual colonoscopy
– Prep still required
– Rectal tube
– Not as reliable as
colonoscopy
• Stool tests
– Genetic markers of
cancer
• Capsule endoscopy
Capsule Endoscopy
Technology
PillCam™ ESO
PillCam™ SB
26 mm
26 mm
11 mm
7 frames
per second
7 frames
per second
Total = 14 frames per second
2 frames
per second
Capsule Endoscopy
• Best for evaluating the small bowel
– Bleeding
– Crohn’s disease
• Not yet good enough for evaluating the
colon
– Not clear that it will be
Interesting Findings
70 year old male with heart disease
developed sudden onset bloody diarrhea
60 year old female with sudden
onset of bloody stools
40 year old female developed severe
diarrhea after taking antibiotics
Clostridium difficile
48 year old liver transplant
patient with diarrhea
Cytomegalovirus colitis
27 year old male with abdominal
pain, weight loss and diarrhea
Crohn’s colitis ulcer
Summary
• Colonoscopy is the best colon cancer
screening test available
• Colon cancer is silent until it is too late!
• Get screened and encourage your
loved ones to get screened