Colorectal Cancer

Question 1

what are polyps

Answer 1

protrusions of epithelial surface; either flat, pedunculated (stalk) or serrated (from villous)

Question 2

what are adenomas

Answer 2

can be derived from polyps but not all are

all adenomas may form carcinoma

Question 3

what are familial adenomatous polyposis (FAP)

Answer 3

autosomal dominant condition arising from mutations in APC or p53 gene
>100 polyps, throughout colon

Question 4

what is hereditary non-polyposis colon cancer (HNPCC)

Answer 4

mutation in DNA repair mismatch repair gene responsible for maintaining stability of DNA replication - MLH-1, MLH-2, PMS-1, MDH-6
<100 polyps, right sided

Question 5

what is adenocarcinoma

Answer 5

majority of colorectal cancer

Question 6

how do adenocarcinomas form

Answer 6

from adenomas due to APC and K-ras mutations

Question 7

75% adenocarcinomas are what sided and present as what

Answer 7

left sided (rectum, sigmoid, descending)
present as blood PR, altered bowel habit and obstruction

Question 8

25% adenocarcinomas are what sided and present as what

Answer 8

right sided (caecum, ascending)
present as anaemia and weight loss

Question 9

what are symptoms

Answer 9

change in bowel habit 
weight loss
rectal bleeding
tenesmus 
iron deficiency anaemia 
cockily abdominal pain

Question 10

how is it diagnosed

Answer 10

FOBT (faecal occult BT)
colonoscopy
CT colonography
barium enema

Question 11

how is it staged

Answer 11

dukes criteria

Question 12

what is dukes a

Answer 12

confined by muscularis propria

Question 13

what is dukes b

Answer 13

through muscularis propria

Question 14

what is dukes c

Answer 14

metastatic to lymph nodes

Question 15

how is it treated

Answer 15

laparoscopic surgery suitability (right hemicolectomy, extended right hemicolectomy, transverse colectomy)

palliation (can be by stenting so bowel works until surgery)