GI Cancers

Question 0

Benign polyps

Answer 0

Tubular; as in familial polyposis
Villous adenomas; flatter with fronds secreting mucus and potassium
Tubulo-villous, the commonest and often multiple
Incidental finding, bleeding, mucus PR, tenesmus or prolapse
50% within reach of sigmoidoscope (25cm)

Question 1

Risk factors for CRC

Answer 1

Family history
Familial polyposis (autosomal dominant)
Ulcerative colitis (with pseudopolyps)
Benign adenomatous polyps
Western low fibre diet
Undiagnosed / Poorly managed coeliac disease

Question 2

Malignant change in a polyp

Answer 2

Grow into lumen
Ulcerate and bleed
Invade muscle wall
Annular stenosis “apple core” on barium enema
Involve serosa: fibrosis can cause obstruction

Question 3

Lymphatic and portal spread of CRC

Answer 3

Parabolic, mesenteric, para-aortic
Porta hepatits may compress CBD
Later portal venous spread: liver mets
25% disseminated at presentation
5FU can help palliative liver mets
Radiotherapy for recurrent pelvic disease

Question 4

Presentation of CRC

Answer 4

Iron deficiency anaemia (esp caecum ca)
Weight loss (esp caecum ca)
Large bowel obstruction
Perforation/peritonitis
Fistula (to stomach, bladder, vagina)
Change in bowel habit (descending colon)
Tenesmus and bleeding (rectum)

Question 5

Resection of CRC

Answer 5

Sometimes curative: aim for 2cm clearance
Palliative for obstruction and bleeding
Respect according to mesenteric vessels
Remove wedge with local nodes
Aim to rejoin cut ends at same operation

Question 6

TNM Classification of CRC

Answer 6

T1 - confined to mucosa and submucosa
T2 - invades muscularis propria but does not extend into the serosa
T3 - extends into serosa
T4 - invades other organs or perforates
N0 - no nodes involved
N1 - 1 to 3 nodes involved
N2 - more than 3 nodes involved
M0 - no metastatis
M1 - metastatis

Question 7

Adjuvant chemotherapy in CRC

Answer 7

Standard regime is 6 months txt with 5FU and folinic acid
25% of patients present with some degree of nodal involvement!
There is an absolute 5 year survival benefit of about 10%
Only a small benefit in early disease (approx 3% benefit at 5 years)
Oxaliplatin - common side effect of peripheral neuropathy
Capecitabine - an orally active 5FU precursor