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Flashcards in Tumors of the bowel Deck (68)
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1

What is the lifetime risk of colorectal cancer?

5-6%

However, the incidence is declining

2

How much time does it take for a benign adenoma to become a colon cancer?

5-12 yrs

3

How common is CRC?

3rd most common form of cancer in men and women. 3rd leading cause of cancer death in US

4

What are the intrinsic risk factors of colorectal cancer?

Race
Ethnic background
Occupational hazards

5

What are the controllable risk factors in colorectal cancer?

1. Caloric intake/obesity
2. Red meat consumption
3. Alcohol consumption
4. Smoking

6

Where are most colorectal cancers found?

Distal to the splenic flexure of the colon

7

What genetic factors increase your risk of CRC?

1. History of colorectal neoplasia
2. IBD
3. HNPCC mutation
4. FAP

8

Most cases of CRC occur after the age of:

50

9

If you meet someone who has CRC under the age of 50...what are you worried about?

FAP/HNPCC/PJS/IBD/MUTYH

10

How is FAP inherited? What gene is mutated?

Autosomal dominant disorder
-Mutated APC gene

11

What is peutz-jeghers syndrome?

Autosomal dominant disorder
-Multiple hamartomatous polyps of the entire GI tract
-melanosis of lips and buccal mucosa

12

Are PJ polyps malignant?

No, but these patients have a higher incidence of carcinoma elsewhere in the colon (breast, pancreas, ovary, uterus, lung)

13

How and when should you treat FAP?

Cancer develops early (late 30's). Treat early on with a total colectomy, before the age of 25

14

What are the carcinogens identified in colorectal cancer?

1. Fecal bile acids
2. Heterocyclic amines
3. Fecapentenes (anaerobic breakdown of fatty acids)
4. 3-ketosteroids (oxidation product of cholesterol)

15

What are some protective measures for colorectal cancer?

NSAIDS
vitamin D
calcium
folic acid
Fiber consumption

16

Does the two-hit hypothesis apply to CRC?

Yes. Molecular pathways to sporadic and inherited cancers are the same

17

How is familial colorectal cancer inherited?

We don't understand this. Family hx plays a role but this isn't a typical inherited syndrome

18

Do you have to have a family history of FAP to get FAP?

No. 25% have a spontaneous germline mutation

19

How do you diagnose FAp?

>100 polyps in the colon and rectum

20

What is the most common cause of death in FAP?

Desmoid tumors

21

How is MYH polyposis inherited?

autosomal recessive

22

Which gene is mutated in MYH polyposis?

mutY homolog gene, which does base excision repair for oxidative DNA damage

23

What does MYH polyposis look like when you do endoscopy?

usually 15-100 adenomas. Early (age 45) CRC

24

Where do MYH polyposis cancers occur?

In the ascending colon. Important to consider if early polyps and many polyps but no APC gene abnormality

25

What is the most common inherited colon cancer syndrome?

Hereditary Non-Polyposis Colon Cancer (HNPCC)

26

How is HNPCC inherited?

autosomal dominant

27

Where is the mutation in HNPCC?

Mismatch repair genes (MMR)

28

How do you diagnose HNPCC?

Clinically indistinguishable from sporadic CRC (only one poly developing into CRC) Can only diagnose through personal and family history

29

What are the two types of HNPCC (lynch syndrome)

Lynch syndrome 1: CRC only
Lynch syndrome 2: CRC + endometrial and other cancers)

30

What is the main difference btw HNPCC and Sporadic CRC?

HNPCC has an accelerated development of cancer (3.5 years btw polyp-carcinoma)
The polyps themselves are flatter and smaller.