EXAM #3: COLORECTAL CANCER Flashcards Preview

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

31

When do you start screening for colon cancer in HNPCC?

Age 20-25 y/o

*Repeat every 1-2 years

32

What are the screening recommendations for FAP?

Age 10-12 y/o

*Repeat every 1-2 years

33

What is the most common cause of colon obstruction in adults?

Colorectal cancer

34

What symptoms are associated with colorectal cancer?

- Vague abdominal pain
- Change in bowel habits e.g. pencil-thin stool
- GI Bleeding

35

For a person that presents with symptoms suggestive of colon cancer, what imaging should be ordered?

1) KUB
2) CT abdomen and pelvis with IV and enteral contrast
3) Colonoscopy or Proctoscopy
- TATTOO the lesion!

36

What is the serum tumor marker for colon cancer? How is this used?

CEA= carcinoembryonic antigen

*Clinically this is used for surveillance s/p resection

37

What is the TNM classification system?

T= invasion depth of Tumor

N= extent of regional lymph Node involvement

M= Metastasis

38

Outline the different T-stages of tumors.

Tis= intraepithelial
T1= Submucosa
T2= Muscularis propria
T3= Pericolorectal tissue
T4a= Penetrates peritoneum
T4b= invading adjacent organs

39

Outline the N-stages.

N0= no nodes
N1= 1-3 regional nodes
N2= 4+ nodes

40

How many nodes need to be examined for adequate staging?

At least 15 nodes

41

Outline the M-stages.

M0= no mets
M1= distant mets

42

What resection margins do you need to have in the treatment of colon cancer?

5cm

(1-2cm in the rectum)

43

What determines your resection margin in the treatment of colon cancer?

The resected artery

*All bowel associated with artery needs to be removed

44

What is a Low Anterior Resection (LAR)?

Rectosigmoid resection below the peritoneal reflection

*This procedure preserves the anal sphincter and opening

45

What is an Abdominal Perineal Resection (APR)?

Rectosigmoid resection including:
- Anal sphincters
- Anal opening

46

When does colon cancer require the addition of chemotherapy to surgical resection?

1) Any nodal disease
2) Some T3 and any T4+ disease

47

What colon cancer mets are treated with resection?

Liver and lung metastases

48

What colon cancers are treated primary with chemotherapy and secondarily with palliative resection?

1) Bleeding
2) Obstruction
3) Perforation

49

What is the treatment for Tis and T1 rectal cancer?

Transanal excision

50

What is the treatment for T2 rectal cancer?

Surgical resection

51

What is the treatment for T3, T4, or N+ rectal cancer?

1) Neoadjuvant (i.e. begin with) chemoradiation
2) Surgical resection

52

After surgical resection, what are the recommendations for surveillance?

1) H and P every 3-6 months for 5 years
2) CEA same
3) CT annually for 5 years