GI Neoplasia II: Bowel Tumros Flashcards
what are the different formations of polyps?
sessile
pedunculated
papilloma
What are the different types of polyps?
adenomatous (most common type)
hyperplastic
inflammatory
What are the types of adenomatous polyps?
tubular, villous or tubulo-glandular
What are hyperplastic polyps?
diminutive, dilated glands with no malignant potential. more common in the left colon
What are inflammatory polyps the result of?
long-standing IBD, not neoplastic
What is the epidemiology of colorectal cancer?
most common GI malignancy, higher incidence in developed countries (secondary to high fat, low fiber diet)
what two minerals are thought to be protective from colorectal cancer?
calcium and folate
What are factors that increase your risk for CRC? Decrease?
Increase - lack of physical activity
consumption of red meat, obesity, cigarette smoking, alcohol abuse
Decrease - multivitamins containing folic acid asa and nsaids postmenopausal hormone use calcium supplementation selenium consumption of fruits and veggies
how does CRC present when in the right colon?
occult bleeding, anemia
How does CRC present in the left colon?
obstructive symtpoms, overt bleeding
How does CRC present in the rectum?
tenesmus, pain bleeding, sense of incomplete vacuation
why does left collon have more obstructive symptoms?
smaller lumen
What is the apple core lesion?
Shown by barium enema, it shows the protruding cancer into the lumen, shaped like an apple core
What is the mainstay of colon ca tx?
surgery
When do you see a rapid drop off of prognosis in colon cancer?
when penetrating the muscularis or when it involveds lymph nodes
Explain the molecular genetic mutation pathway that leads to colon cancer
APC then KRAS/BRAF then p53, PIK3CA, LOSS OF 18Q, then P53
How long does adenoma progression to cancer take typically?
10 yrs.
What is FAP?
Familial Adenomatous Polyposis. AD, with greater than 100 adenomatous polyps starting in 2nd and 3rd decade. All will develop CRC without colectomy. May also have gastric fundic gland polyps, duodenal adenomas and cancer, periampullary adfenomas and cancer, desmoid tumors and retinal pigmented lesions
What is the genetic etiology of FAP?
one allele of the apc gene inherited mutation. Then second hit occurs.
What is HNPCC
hereditary non-polyposis crc, germline mutation, acounts for 5% of CRC in US. Proximal colon lesions are common. May also bea ssociated with endometrial, ovarian urinary and gastric cancers. More common than FAP. Also known as lynch syndrome
How can you diagnose hnpcc?
one relative with crc less than fifty yo
crc spans 2 generations
three relatives with hnpcc tumors
what are the three types of cancers associated with hnpcc?
ovarian gastric and colon
When do you see the average age of crcs?
peak around 70
when do you screen for someone with an average risk for crc?
start at age 50 if asx, stop at 75
Are tubular crcs more pedunculated or sessile?
pedunculated
are villous adenomas of crc more pedunculated or sessile?
sessile, giving them a higher risk of malignancy than tubular
what are the malignant neoplasms of adenocarcinomas
polypoid (into lumen)
annular (go deeper)
What is the characteristic description of the gross appearance of tubular adenocarcinomas?
test tubes in a rack
What is the characteristic description of villous adenocarcinomas?
fingerlike
what part of the colon are polypoid exophytic carcinoma?
greater in the right colon
where are “napkin ring” forms of annular crc seen more often
in the left colon
What are signs and symptoms of small bowel tumors?
vague, non-specific- delay in dx of 8-12 mos
abdom pain
weight loss
n/v
GI bleeding/anemia
jaundice with ampullary lesions
symptoms more likely with malignant lesions
what are the two most important risk factors for crc?
age>50 and family hx
what is the precursor lesion for most crc
adenomatous polyp
