Download 4 th most common cancer (after lung, prostate, and breast cancers)

Dr.sahel hammouri
EPIDEMIOLOGY
one of the most common cancers in the world
US:
4th most common cancer (after lung,
prostate, and breast cancers)
2nd most common cause of cancer death
(after lung cancer)
2001:
130,000 new cases of CRC
56,500 deaths caused by CRC
Typical sites of incidence and sympoms of colon cancer
Changes resulting in colon cancer
Risk factors for CRC
Age
Adenomas, Polyps
Sedentary lifestyle, Diet, Obesity
Family History of CRC
Inflammatory Bowel Disease (IBD)
Hereditary Syndromes
(familial adenomatous polyposis (FAP))
Development of CRC
result of interplay between environmental and
genetic factors
Central environmental factors:
diet and lifestyle
35% of all cancers are attributable to diet
50%-75% of CRC in the US may be preventable
through dietary modifications
Dietary factors implicated in
colorectal carcinogenesis
consumption of red meat
animal and saturated fat
increased risk
refined carbohydrates
alcohol
Dietary factors implicated in
colorectal carcinogenesis
dietary fiber
vegetables
fruits
decreased risk
antioxidant vitamins
calcium
folate (B Vitamin)
Symptoms associated with CRC
weight loss
rectal bleeding
loss of appetite
change in bowel habits
night sweats
obstruction
fever
abdominal pain & mass
iron-deficiency anemia
Staging of CRC
TNM system
Primary tumor (T)
Regional lymph nodes (N)
Distant metastasis (M)
Staging of CRC
Dukes staging system
A
B
C1
C2
D
Mucosa
Into or through M. propria
Into M. propria, + LN !
Through M. propria, + LN!
distant metastatic spread
80%
50%
40%
12%
<5%
Sites of metastasis
Via blood
Via lymphatics
Per continuitatem
Liver
Lymph nodes
Lung
Abdominal wall
Brain
Nerves
Bones
Vessels
Therapy
Surgical resection the only curative treatment
Likelihood of cure is greater when disease is
detected at early stage
Early detection and screening is of pivotal
importance
Screening
What is screening?
a public health service in which members
of a defined population are examined to
identify those individuals who would benefit
from treatment
to benefit:
to reduce the risk of a disease or its
complications
Types of Screening
fecal occult blood test (FOBT)
chemical test for blood in a stool sample.
annual screening by FOBT reduces colorectal cancer
deaths by 33%
Flexible sigmoidoscopy can detect about 65%–75% of
polyps and 40%–65% of colorectal cancers.
rectum and sigmoid colon are visually inspected
Current Screening Guidelines
regular screening for all adults aged 50 years or
older is recommended
FOBT every year
flexible sigmoidoscopy every 5 years
total colon examination by colonoscopy
every 10 years or by barium enema every
5–10 years
Molecular Biology & Pathology
CRCs arise from a series of histopathological and
molecular changes that transform normal epithelial cells
Intermediate step is the adenomatous polyp
Adenoma-Carcinoma-Sequence (Vogelstein & Kinzler)
Polyps occur universally in FAP,
but FAP accounts for only 1% of CRCs
Adenomatous Polyps in general population:
33% at age 50
70% at age 70
Summary
CRC is a leading cause of death
Early stages are detectable
Screening can prevent CRC
Katie Couric: http://www.nccra.com/about/videos.htm
thanks