3. Overview
Colon cancer begins when abnormal cells within the
colon start growing uncontrollably.
Symptoms may not occur initially, but as the disease
progresses, a person may notice a change in their
bowel habits or dark / bright red blood in their stools.
There are several factors that increase a person's
chance of developing colon cancer, some within a
person's control (for example, being overweight and
leading a sedentary lifestyle) and some not (for
example, having an inflammatory bowel disease).
4.
5. EPIDEMIOLOGY
• Colon cancer is the third most common cancer in the
United States, with around 100,000 new cases being
diagnosed each year
• The incidence of colon cancer varies between and within
the countries suggesting environmental factors
The ratio between male & female is almost equal
It is common in western countries but rare in Asia &
Africa
The difference is among racial groups within different
areas of the country suggesting genetic or cultural
factors are important
8. RISK FACTORS for Colon Cancer
• Age
– Colon cancer is more likely to occur as people get
older. This disease is more common in people over
the age of 50.
– However, colon cancer can occur at younger ages,
even, in rare cases, in the teens.
9. • Diet
Colon cancer seems to be associated with diet that
is high in fat(animal fat), calories, and low in fiber.
Increased fecal bile salt- Postcholecystectomy
High anaerobic bacterial count in feces
10. Polyps
• A polyp is a growth of tissue in the lining of an organ.
• There are 2 main types of colon polyps:
Hyperplastic :
Very small chance they’ll grow into cancer
Adenomatous :
Most colon cancers start as adenomatous polyps
(“adenomas”)
11.
12. • Personal Medical History.
Research shows that women with a history of cancer of
ovary, uterus, or breast may have an increased chance of
developing colon cancer.
Also, a person who had colon cancer may develop this
disease again.
• Family Medical History.
First-degree relatives (parents, siblings, children) of a
person who had colon cancer are likely to develop this
type of cancer themselves, especially if the relative had
the cancer at a young age.
If many family members have had colon cancer, the
chances increase even more.
13. Genetic factors:
• Play very important role in Colonic cancer
• The familial syndromes with increased risk of colon
carcinoma includes:
– Familial adenomatous polyposis
– HNPCC
» Lynch syndrome
» Turcots syndrome
» Peutz-jeghers syndrome
14. Hereditary Colon Cancer Syndromes:
Familial adenomatous polyposis
APC gene
• Individuals develop thousands of adenomatous polyps
in the colon
Both copies of the APC gene must be lost for
development of adenomas
• Invariably, one or more of these polyps undergoes
malignant transformation, giving rise to colon cancer
15. Non familial colon carcinomas and sporadic
adenomas
• Has homozygous loss of APC gene
16. Hereditary Colon Cancer Syndromes:
HNPCC
Hereditary non-polyposis colon cancer (HNPCC),
sometimes called Lynch syndrome,
Accounts for approximately 5% to 10% of all colon cancer
cases
The risk of colon cancer in families with HNPCC is 70% to
90%, which is several times the risk of the general
population
Gene encoding the type II TGF-β receptor is inactivated in
colon cancers that develop in patients with HNPCC
17. • Inflammatory bowel disease:
Ulcerative colitis:
Patient with extensive colitis and for long duration are
at high risk of developing colon cancer
Crohn’s disease :
Is also associated with increased risk of cancer
• Irradiation & immunosuppresion:
Irradiation is well known carcinogenic,
patient on immunosuppression drugs or disease are at
increased risk of developing colon cancer
18. PATHOLOGY
• Adenoma-carcinoma sequence
– Between 70-90 % of colon cancer arise from
adenomatous polyp.
– the adenoma- carcinoma sequence is multi-
step process involving sequential mutations or
deletions of genes
• The larger the polyp (more than 2cm in diameter)
the greater the risk of cancer
22. • Macroscopically:
colon cancers may appear to the naked eye as:
Exophytic cauliflower-type of growth
Ulcerating lesion penetrating through the
bowel wall
Annular constricting growth
or as the rare colloid mucus- secreting tumors
25. These type of cancers have two general varieties
BASED ON WHERE IN THE AFFECT YOUR WHOLE BODY
COLON THE TUMOR IS LOCATED
Change in bowl habits (1) Unexpected weight loss
a) Change in stool frequency/shape/color (2) Loss appetite
b) Constipation and diarrhea (3) Unexplained fatigue
LOCAL
SYMPTOMS
SYSTEMIC
SYMPTOMS
26. RARE SYMPTOMS
If colon cancer is not diagnosed until its advanced stages, it may
cause one or more of these symptoms:
Fever
Air bubbles in urine
Problem in breathing
Headache and neurological problems
Bone pain
27. DIAGNOSIS
PHYSICAL EXAM
DIGITAL RECTAL EXAM
COMPLETE BLOOD COUNT(CBC)
LIVER FUNCTION TEST (LFT)
COLONOSCOPY
BIOPSY
IMAGING
32. Other medical conditions with the same symptoms
one or more of the symptoms like rectal bleeding or
abdominal pain may also be reason for another medical
problem
Examples of these conditions that may mimic that of colon
cancer include:
1. Hemorrhoids
2. Appendicitis
3. Diverticulitis
4. Infectious Colitis
34. REVIEW QUESTIONS
1. What biomarker mutation do 40% of colon
cancer possess?
2. If a patient is diagnosed with colon cancer
which part of the body would be effected
first because of metastasis?
3. What genetic disorder are associated with
colon cancer?
35. R.Q
• A patient underwent colectomy and
chemotherapy after 3 months of this
cycle, she is now in remission, and when
she met her doctor for the follow up she
complained of fatigue and difficulty with
concentration at weekly bridge games
which of the following explanation could
account of her symptoms?
36. A. Symptoms may be the result of anemia
caused by chemotherapy
B. The pt. may be dehydrated
C. The pt. may be immunosuppressed
A. The pt. may be depressed
