Small Group: GI Tumors

Question 1

Is FOBT adequate as a screening tool for CRC?

Answer 1

No, it misses 90% of cancers –colonoscopy must also be done.

Question 2

What serum marker should be monitored in a person with resected adenocarcinoma of the colon?

Answer 2

CEA (carcinoembryonic antigen)

Question 3

Carcinoid syndrome presents with what two markers?

Answer 3

Chromogranin and synaptophysin

Question 4

Carcinoid tumors originate from cells that normally exist in what layer of the GI wall?

Answer 4

The submucosa (enterochromaffin cells)

Question 5

Carcinoid tumors of the ___________ rarely metastasize; in the ____________ they’re usually benign; but in the ____________ they are often aggressive.

Answer 5

foregut; hindgut; midgut

Question 6

True or false: most patients with neuroendocrine tumors have carcinoid syndrome.

Answer 6

False. Only about 1 in 10.

Question 7

Why do carcinoid tumors have to metastasize to the liver for patients to develop carcinoid syndrome?

Answer 7

Because the liver breaks down serotonin, so if tumors are in the gut, serotonin flows to the liver and is degraded. If the tumor is in the liver, however, the serotonin can escape the liver before being degraded and thus cause carcinoid syndrome.