colorectal cancer

Question 1

adenoma-carcinoma sequence in FAP and HNPCC

Answer 1

FAP: Mutation in APC gene leads to dysplastic ACF (aberrant crypt foci) followed by K-ras mutation causing adenoma then LOH of p53 results in carcinoma
HNPCC: Same except initial mutation is in MMR leading to dysplastic ACF

Question 2

other locations of adenomas in FAP? in HNPCC?

Answer 2

fundus, duodenal/ampullary

Endometrial

Question 3

location of FAP vs HNPCC

Answer 3

left sided vs right sided

Question 4

Left vs right sided colon cancer

Answer 4

Left: more likely FAP, bright blood in stool, circumferential with stricturing (changes in frequency)
Right: more likely HNPCC, present later b/c proximal colon is larger, anemia and fatigue more likely

Question 5

CEA

Answer 5

carcinoembryonic antigen: higher is bad. marker for treatment, etc

Question 6

Endoscopic ultrasound usefulness

Answer 6

to asess depth of involvement and presence of nodes. Also allows for fine needle aspiration of nodes

Question 7

most common location of mets from rectal or colon tumors

Answer 7

liver

Question 8

when is chemo used? radiation?

Answer 8

anjuvant

rectal

Question 9

current screening recommendations

Answer 9

average risk: start at 50, FOBT yearly, flex sig every 5, combined FOBT and flex sig every 5, colonoscopy every 10
with FHx: start at 40 or 10 yrs younger than youngest affected relative, repeat every 5