GI Neoplasia II: CRC (Nichols/Jackson) Flashcards
Defn of polyp
Bump or nodule in the mucosa
result of KRAS mutation without APC mutation
Hyperplastic polyp
mass of mature, but disorganized tissue indigenous to site
Hamartoma
Is a papilloma a polyp?
Yes
What are the types of polyps with malignant potential?
Adenomatous
What are the types of polyps that do not have malignant potential
Hyperplastic and inflammatory
Inflammatory polyps-occur in long-standing ____
IBD
Is CRC more common in developed or underdeveloped counties
developed
What components in diet may be protective against CRC
Ca++ and folate
Increases risk for CRC
Age and FH IBD colitits Lack of exercise Consumption of red meat Obesity Smoking ETOH use
Decreases risk for CRC
Multivitamins containing folic acid Aspirin and NSAIDs HRT (post menopausal) Ca++ supplement Selenium Inc fiber in diet (veggies and fruit)
How does CRC present in the right vs left colon
Left = obstructive symptoms and overt bleeding
Right: occult bleeding and anemia
Apple core lesion
Barium enema shows this in the diagnosis of CRC
Goals of colonoscopy
Locates lesions, removes polyps, and biopsies lesions
What determines the prognosis of CRC
Extent of invasion (how deep it goes)
Is chemo used to treat CRC?
Yes, but as an adjuvant in pts with + nodes
Surgery is the mainstay
What is the molecular/mutatio pathogenesis in CRC
Loss of APC → KRAS mut → loss of p53
- *AK-53**
- This is from First aid, ppt has more confusing/detailed pictures of this
Defn Tumor suppressor gene vs oncogene
Genes that function normally in inhibition of cell growth
Vs
Activation results in uncontrolled cellular proliferation
Tumor suppressor gene or oncogene is normally inherited
Tumorsuppressor gene mutation
Mutation in Familial Adenomatous Polyposis
Autosomal dominat mutation in APC gene on chromosome 5q (2 hit hypothesis)
How does FAP present
> 100 adenomatous polyps starting in 2md to 3rd decade
Pancolonic and always involves rectum (according to First Aid)
Mutation in hereditary non-polyposis CRC
Germline mutation of DNA repair genes
What part of the colon does HNPCC affect? FAP?
HNPCC: more commonly proximal
FAP: pancolonic
How is HNPCC diagnosed?
- 1 releative with CRc < 50 yo
- CRC spans 2 generations
- 3 relatives eith HNPCC (2 must be 1st degree relatives of the first)
What are the goals of screening for CRC?
Decrease mortality from CRC and prevent CRC by removing polyps
How is fecal occult blood used to diagnose CRC
Put poop on card …. WIKI THIS
What are the limitations to fecal immunochemical test?
Does not detect upper GU bleeding
More expensive that poop card
May require 2 stool samples
What are the advantages to fecal immunochemical test?
Responds only to human Hgb
More sensitive and specific than Guiac tests
Not a colonoscopy—people don’t have to take off work and, ya know, get probed
Helical CT reconstructed into 3D images. Studies on sensitivity and specificity have been variable. Requires bowel prep
Virtual colonoscopy
What are the barriers to colon screening?
- limited acess to medical care in general
- bowel prep and time off work
- risk and expense of tests
Major complication seen with colonoscopy
Perforation
What are the types of benign adenoma polyps
Tubular and villous adenomas
Diff between tubular and villous adenomas
Tubular are more pedunculated and villous are more sessile and have a higher risk of malignancy
What are the types of malignant colon adenocarcinomas
Polypoid and annular
Poly Exophytic Carcinoma is more common in left or right side of colon?
Right
Annular “napkin ring” form is more common on left or right side of colon?
Left colon
What are the signs and syptoms of small bowel tumors
Non-specific: crampy, weight loss, nausea/vomiting, GI bleeding/anemia, Jaundice with ampullary lesions
Colon cancer is the (1st, 2nd, 3rd, 4th, 5th, 6th, or 7th) leading cause of cancer death
2nd
Most important risk factors for CRC
Age > 50 and FH
Precursor lesion to most CRC
Adenomatous polyp
The goal of screening for CRC is to
decrease mortality from colon cancer or to prevent colon cancer by removing adenomatous polyps