COLORECTAL POLYPS AND COLORECTAL CARCINOMA
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Transcript COLORECTAL POLYPS AND COLORECTAL CARCINOMA
COLONIC POLYPS
May occur in any part of the colon
Majority of them arise in the rectum and sigmoid
colon
They tend to cause rectal bleeding (visible or
occult) and may undergo malignant change
If rectal polyps are found, the entire colon must be
investigated- total colonoscopy
The larger the lesion the more likely it is to be
malignant
COLORECTAL POLYPS
Histopathologically- three patterns of growth:
tubular adenomas
villous adenomas
tubulo-villous adenomas
PHYSICAL EXAMINATION
General examination- features suggesting malignant
disease:
Obvious weight loss
Palor of the skin
Abdominal distention
Hepatomegaly
Abdominal mass
PHYSICAL EXAMINATION
Rectal examination:
Finger can reach lesions as far as the its length 7-9 cm
Palpable fixed mass in Douglas pouch-sigmoid tumor
dropped retrorectally
The glove inspected for blood and mucus
Types of Colon Cancer
IBD
1%
Sporadic
80%
Familial
15%
Hereditary
4%
Risk Factors
Risk increases with age
Nearly 90% of colon cancer patients
are over the age of 50.
Other risk factors include:
family or personal history of colon cancer
or polyps
chronic inflammatory bowel disease
hereditary colorectal syndromes
use of cigarettes and other tobacco products
high-fat/low fiber diet
physical inactivity
Symptoms
Early colon cancer usually has no symptoms
Signs and symptoms typically occur only in advanced colon cancer.
Symptoms may include:
Change in bowel habits lasting more
than a few days
Bleeding from the rectum
Blood in the stool
Cramping or gnawing stomach pains
Weakness and fatigue
Jaundice (yellow-green color of the skin & white part of the eye)
Colon Cancer Tests
Get the test. Get the polyp. Get the cure.
Fecal occult blood testing (FOBT)
Barium enema
Flexible sigmoidoscopy
Colonoscopy
Virtual Colonoscopy
Colonoscopy
Colonoscopy
Get the polyp. Get the cure.
Advantages
Detects >90% polyps and
cancer
Provides diagnosis and
therapy
Medicare covers
average-risk
Limitations
Risks
Availability
Cost
Compliance
Are people getting tested?
Testing rates remain far too low
Fewer than half of Americans over age 50 report having had a
recent colorectal cancer screening test
Because of low testing rates, only 39% of colorectal cancers are
detected at the earliest, most treatable stage
Ethnic/Racial differences
Percentage who have never had screening
colonoscopy
Hispanics - 67%
Black - 55.8%
White, non-Hispanic – 47%
Never married 60%
Education less than high school diploma 58%
vs 52% completed high school vs 46% with
some college education
2005 data, AHRQ
Virtual Colonoscopy
Virtual Colonoscopy
Spiral CT to generate 3D images
Cleaning of bowel, distension with air
Non invasive, no complications
Not endorsed for CRC screening
Virtual Colonoscopy
Limitations Virtual Colonoscopy
Variable results
No screening studies
No longitudinal studies
Cost
Does not allow for therapy
Stool DNA
Now recommended by ACS and USMSTF for average
risk individuals
Multi-target DNA stool assay required to achieve
adequate sensitivity and detect the various gene
mutations
21 separate point mutations
P53
DIA
APC
K-ras
BAT-26
Video Capsule Colonoscopy
In the process of development
Battery life
No clinical data available
Anticipate to see clinical trials
Colon Cancer Tests
Average Risk
Average Risk Individuals
No Symptoms
Age 50
No risk factors
Current Recommendations
Average Risk
Test
FOBT
Sigmoidoscopy
FOBT + Sigmoidoscopy
Colonoscopy
Barium enema
*Preferred strategy by ACG
Interval (years)
Yearly
Every 5
Yearly, every 5
Every 10*
Every 5
Approach to Colon Cancer Testing
Asymptomatic
Men and Women
Age < 50 yr
No family Hx
Age 50 yr
YES family Hx
No Screening
HNPCC or FAP
NO family Hx
Average Screening
2 or more first-degree or
1 first-degree < 60 yrs
Genetic Counseling
Colonoscopy every
5 yrs, starting age 40
1 first-degree
60 yrs
Average-risk
screening,
starting age 40
The flat polyp
Techniques to improve detection
Narrow-band imaging
Chromoendoscopy
Endocytoscopy
Soitenko et al. JAMA
March 2008
Narrow Band Imaging
Left sided ulcerative colitis
Ulcerative colitis with extensive
pseudopolyps
FAMILIAL POLIPOSIS COLI
It is a rare autosomal dominant disorder
Multiple colorectal polyps
Rectal bleeding/ change in bowel habit
The treatment- colorectal removal with ileoanal
anastomosis, or panproctocolectomy with definitive
ileostomy
Peutz-Jeghers syndrome
It is an autosomal dominant inherited disorder
characterized by intestinal hamartomatous polyps in
association with mucocutaneous melanocytic macules.
Patients with Peutz-Jeghers syndrome (PJS) have a 15-fold
increased risk of developing intestinal cancer
compared with that of the general population.
Such cancer locations includes gastrointestinal and
extraintestinal sites.