EXAM #3: COLORECTAL CANCER Flashcards Preview

Gastrointestinal System > EXAM #3: COLORECTAL CANCER > Flashcards

Flashcards in EXAM #3: COLORECTAL CANCER Deck (52)
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1

What are the landmarks for the colon?

1) Tenia coli
2) Transition from colon to rectum where the Tenia coli "splay"

2

What are the major arteries that branch from the SMA to the colon?

SMA supplies proximal 2/3 of the colon--branches include:
1) Ileocolic
2) Right colic
3) Middle colic

3

What are the major arteries that branch from the IMA to the colon?

IMA supplies the distal 1/3 of the colin--branches include:
1) Left colic
2) Sigmoidal branches
3) Superior rectal

4

What arteries supply the rectum? Where do these arteries branch from?

1) Superior rectal from the IMA
2) Middle and inferior rectal from the internal iliac arteries

5

Review the layers of the GI mucosa.

1) Mucosa
- Epithelium
- Lamina propria
- Musclaris mucosa
2) Submucosa
3) Muscularis Propria
4) Serosa

6

How prevalent is colon cancer?

3rd most common cancer

7

List the risk factors for colon cancer.

1) Family history
2) IBD
3) Smoking
4) Alcohol
5) Obesity
6) Inactivity
7) Diet rich in red meat and animal fat

8

What factors are protective against colon cancer?

1) Hormone Replacement Therapy
2) NSAIDs
3) Diet rich in fiber, fruits, and veggies

9

Outline the Adenoma-Carcinoma Sequence.

1) APC= early adenoma
2) K-RAS= intermediate adenoma
3) DCC= late adenoma
4) p53= carcinoma

*Note that this normally takes roughly 10 years.

10

How can adenomatous polyps be removed via colonoscopy?

Snare excision

11

What are the four most common etiologies of colon cancer?

1) Sporadic
2) Non-syndromic familial colorectal cancer
3) FAP
4) HNPCC or Lynch Syndrome

12

What mutation is associated with FAP?

Autosomal dominant APC mutation

(Chromosome 5)

13

What is the clinical manifestation of FAP?

1,000 of adenomatous polyps
- Early onset
- WILL get colon cancer

14

What is the treatment for FAP?

Total colectomy

15

What genetic defect is seen in HNPCC?

Defects in DNA mismatch repair genes

16

What are the clinical manifestations of HNPCC?

- 100s of polyps
- Accelerated progression to colon cancer

*Not a 100% progression to cancer like APC.

17

What cancers are associated with HNPCC in addition to colon cancer?

Endometrial
Ovarian

18

What is the treatment for HNPCC?

Colectomy

19

What sign is associated with advanced polyps?

Fecal occult blood test

20

What are the three major screening modalities for colorectal cancer?

1) Colonoscopy*
2) Flexilble sigoidoscopy
3) FOBT (Fecal Occult Blood Test)

*Gold standard

21

What imaging modalities are used to screen for colorectal cancer?

1) Double contrast barium enema
2) CT Colongraphy

22

What is the difference between colonscopy and flexible sigmoidoscopy?

Flexible sigmoidoscopy isn't as long (will only reach the splenic flexure)

*Note that you develop more polyps in the distal colon/rectum, which is why this is used as a good alternative to colonoscopy

23

What is the drawback to the fecal occult blood tests?

Detects more ADVANCED polyps or cancer

24

What are the drawbacks to double contrast barium enemas?

1) Still requires bowel prep
2) Give rectal air and contrast
3) Only detects advanced polyps

Plus, if its positive, you still have to get a colonoscopy.

25

What are the drawbacks to CT Colonography?

Same as barium enema.

26

What are the screening recommendations for colorectal cancer?

1) Colonoscopy every 10 years
2) Flexible sigmoidoscopy every 5 years AND FOBT every 3 years
3) FOBT every year

27

When do you start screening?

If AVERAGE risk, start at 50 y/o

*Average= no family history or personal history of polyps/cancer

28

What gives a patient a positive family history of colon cancer?

1) First degree relative with hx at less than 60
2) 2x first degree at ANY age
3) Second degree relative less than 50

29

When do you start screening for patients with a family history of colon cancer?

40 y/o AND repeat every 5 years

30

What are the screening recommendations for colon cancer in patients with IBD?

1) Start colonoscopy 8-10 years after onset of sx.
2) Collect 4x random biopsies every 10cm (total of 30+)

*Repeat every 1-2 years