colorectal cancer Flashcards
what factors increase the risk of colorectal cancer ?
history of polyps on prior colonoscopy
history of CRC in the family
history of receiving abdominal radiation for childhood malignancy
positive for history of familial polyposis syndrome
alcohol
obesity
smoking
IBD
what is the age range for CRC ?
rare before the age of 40
the risk increases significantly between 40 and 50
what are the variants of FAP ?
familial adenomatous polyposis (FAP)
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gardner’s syndrome
turcot’s syndrome
attenuated adenomatous polyposis coli
what is lynch syndrome ?
hereditary nonpolyposis colorectal cancer HNPCC
an autosomal dominant syndrome
is FAP more common or HNPCC more common ?
HNPCC
what medications are associated with a lower incidence of CRC?
aspirin and NSAIDs
what are the different presentations associated with colorectal cancer ?
asymptomatic
bleeding
vague abdominal discomfort
intestinal obstruction
how is a diagnosis of colorectal cancer madee ?
colonoscopy
lab - tumor markers, faecal occult blood test
imaging - CT colonography, barium enema
why is aspirin and nsaids associated with a lower incidence of colorectal cancer ?
they inhibit APC mutation
inhibit k-ras mutation
all which may eventually lead to adenomatous carcinoma
what are the types of colorectal polyps ?
sporadic adenoma
sessile serrated adenoma
inherited polyposis syndrome
what is the characteristic appearance of sessile serrated adenoma ?
saw toothed appeearance
what germline mutation is associated with FAP ?
APC mutation
what cancer is highly associated with FAP ?
congenital hypertrophy of the retinal pigment layer
what is the type of mutation associated with HNPCC ?
microsatellite instability
what is turcot’s syndrome ?
FAP or lynch syndrome along with a brain tumor
what is gardner’s syndrome ?
FAP along with osteoma off the skull and desmoid tumors ( soft tissue tumors )
what are the types of familial polyposis syndromes ?
FAP
HNPCC (lynch syndrome)
juvenile polyposis
peutz jeghers syndrome
what are the chances of FAP turning into CRC ?
100% of patients with FAP will develop CRC
what other malignancies are highly associated with Lynch syndrome ?
endometrial
ovarian
gastric carcinoma
what are the screening guidelines for CRC ?
screening should begin at age 40 if there is history of CRC in the family ( screen with colonoscopy)
begin screening 10 years before diagnosis of the relative and done every 10 years
what is the difference in screening protocol if there is a first degree relative with hx of CRC before 60, or advanced adenoma in 2 or more first degree relatives ?
screening done every 5 years instead of 10 beginning at age 40
what are thee stool based screening tests ?
guaiac based FOBT
faecal immunochemical test
FIT-DNA
what are the methods of direct visualization in screening for CRC ?
colonoscopy
CT colonography
Flexible sigmoidoscopy
how is the screening done ?
started with faecal occult blood test , if it is positive it is then followed by colonoscopy
which of thee stool tests require no dietary restrictions ?
faecal immunochemical test
how often and when should screening be done for average risk population ?
starts at 50 -74 and repeated 1 to 2 years
what is peutz jegher syndrome ?
type of familial polyposis syndrome
causes small bowel and colonic carcinoma
causes bowel obstruction
brown pigmentation in the mucous membranes and in the palms of the hand
