Colon Cancer

Question 1

What is the flexure of the right colon?

Answer 1

Hepatic flexure

Question 2

What is the flexure on the left side of the colon?

Answer 2

Splenic flexure

Question 3

What are the folds that help hold stool in the rectum?

Answer 3

Transverse rectal folds

Question 4

What are the branches of the SMA?

Answer 4

ileocolic
Right colic
Middle colic

Question 5

What are the branches of the IMA?

Answer 5

Left colic
Sigmoidal
Rectal

Question 6

What is the blood supply to the superior part of the rectum? What is this a branch of?

Answer 6

Superior hemorrhoidal

Branch of the IMA

Question 7

What is the blood supply to the inferior part o the rectum? What are these branches of?

Answer 7

Middle rectal
Inferior rectal

Both branches of the internal iliac

Question 8

What are the four histological layers of the colon?

Answer 8

Mucosa
Submucosa
Muscularis propria
Serosa

Question 9

What are the three big CAs? (as far as incidence, in order)

Answer 9

Prostate/breast
Lung
Colon

Question 10

What are the risk factors for the development of colon CA?

Answer 10

IBDs

Obesity

Question 11

What diet is a risk factor for colon cancer?

Answer 11

Red meats and animal fats

Question 12

What are the three protective factors for colon cancer?

Answer 12

Hormone replacement therapy
NSAID use
Fiberous diet

Question 13

What are the four DNA proteins that are implicated in colon CA?

Answer 13

APC
KRAS
DCC
p53

Question 14

What is the order of genetic mutations of the adenoma-carcinoma sequence?

Answer 14

APC
KRAS
DCC
p53

Question 15

How long does it take for the adenoma-carcinoma sequence to develop?

Answer 15

10 years

Question 16

What changes with APC gene mutation?

Answer 16

Dysplastic aberrant crypt foci

Question 17

What changes with KRAS mutation?

Answer 17

Intermediate adenoma

Question 18

What happens with DCC mutation?

Answer 18

Late adenoma

Question 19

What happens with -53 mutation?

Answer 19

Carcinoma development

Question 20

Most etiologies of colon cancer are from what?

Answer 20

sporadic (80%)

Question 21

What is the genetic mutation in familial adenomatous polyposis? How does this present? What is the treatment for this?

Answer 21

APC gene mutation on chromosome 5q

Tons o’ polyps early on
Total colectomy

Question 22

What is Hereditary Non-Polyposis Colon Cancer (HNPCC/lynch syndrome)? Presentation? Treatment?

Answer 22

Mismatch defect in repairing chromosomes

Hundreds of polyps
Total colectomy

Question 23

What are the ssx of early poylps? Late?

Answer 23

asymptomatic early

Maybe positive fecal occult blood test for late

Question 24

What are the three major screening modalities for colon CA screening?

Answer 24

Colonoscopy
Flexible sigmoidoscopy
FOBT

Question 25

What are the two radiological modalities of screening for colon cancer?

Answer 25

Double contract Ba enema CT colonography

Question 26

What is the gold standard for colon CA screening?

Answer 26

Colonoscopy

Question 27

What is flexible sigmoidoscopy? Advantages/disadvantages?

Answer 27

similar to colonoscopy, but only reaches the splenic flexure Do not have to prep as much and less sedation Cannot excise polyps***

Question 28

What does stool guaiac blood test assess for?

Answer 28

Peroxidase activity

Question 29

What does the fecal immunochemical test assess for?

Answer 29

Antibody test

Question 30

What is a double contrast Ba enema?

Answer 30

Rectal air and contrast instilled and visualize the colon wall Requires cathartic bowel prep

Question 31

What is a CT colonography?

Answer 31

Rectal air and contrast instilled, as well as cathartic bowel prep

Question 32

How often do you repeat colonoscopies? Flexible sigmoidoscopies? FOBTs?

Answer 32

Colonoscopy = 10 yrs Flexible sigmoid = 5 yrs + FOBT 3 years FOBT = every 1-3 years

Question 33

What are the three characteristics of "average risk" for colon CA?

Answer 33

Asymptomatic No family h/o CA No personal h/o polyps/CA

Question 34

What are the three characteristics of the higher risk pt that should start colonoscopies at age 40, and repeat every 5 years?

Answer 34

- First degree relative less than 60 yo - 2x first degree relatives any age - Second degree relative age less than 50

Question 35

What should colonoscopies begin with IBDs? What is different about these (frequency, what is done)?

Answer 35

8-10 years, 1-2 years | must collect 4x random biopsies

Question 36

When should colonoscopies begin with lynch syndrome? Frequency?

Answer 36

20-25, repeat 1-2 years

Question 37

When should colonoscopies being in pts with FAP/APC mutation? Frequency? When should a total colectomy be performed?

Answer 37

10-12 yo Repeat 1-2 years Colectomy as soon as polyps are seen

Question 38

What are the ssx of colon CA (if any)? (5)

Answer 38

- Vague abdominal pain - Change in bowel habits - Bleeding - Obstruction - Perforation

Question 39

Where do colon CAs usually metastasize to?

Answer 39

inguinal lymph nodes

Question 40

What is the dye that is used to tattooing the site of a polypectomy?

Answer 40

Methylene blue

Question 41

During a proctoscopy, from where do you measure from to the polyp?

Answer 41

Sphincter

Question 42

What is the serum marker for colon CA? What is this used for?

Answer 42

CEA Used as a surveillance marker

Question 43

What is the purpose of doing a CT/PET scan after biopsy of a malignant polyp?

Answer 43

Check for mets

Question 44

T1 tumor = ?

Answer 44

Muscularis mucosa into submucosa

Question 45

T2 tumor = ?

Answer 45

INvades muscularis propria

Question 46

T3 tumor = ?

Answer 46

INvades pericolorectal tissues

Question 47

T4a tumor = ?

Answer 47

Penetrates peritoneum

Question 48

T4b tumor = ?

Answer 48

Invades adjacent organs

Question 49

Tis tumor = ?

Answer 49

Intraepithelial

Question 50

N0 = ?

Answer 50

No regional node mets

Question 51

N1 = ?

Answer 51

1-3 mets in nodes

Question 52

N2 = ?

Answer 52

4+ nodes

Question 53

How many nodes need to be examined for adequate node staging?

Answer 53

15 nodes

Question 54

Where are nodes collected from for staging colon CA?

Answer 54

Visceral mesentery

Question 55

What are the M stages?

Answer 55

``` M0 = no mets M1 = distant mets ```

Question 56

What are the margins needed for colon resections? How is this determined?

Answer 56

5 cm Based on blood supply--All bowel supplied by the resected vessel must be removed

Question 57

What is involved in a colectomy?

Answer 57

Resected colon with associated mesentery

Question 58

What is involved in a low anterior resection (LAR)?

Answer 58

Rectosigmoid resection extending below the peritoneal reflection

Question 59

What is involved in an abdominal perineal resection?

Answer 59

Rectosigmoid resection including anal sphincters, anal opening, and associated mesorectum

Question 60

What is the treatment for T1, T2, or T3 colon cancers?

Answer 60

Surgical resection is enough

Question 61

What is the treatment for T3, T4 colon cancers?

Answer 61

Surgical resection with chemo

Question 62

N1 or N2 colon cancers treatment = ?

Answer 62

Surgical resection + chemo

Question 63

What is done with mets from colon CA to the live or other nearby organs? Why is this different than other CAs?

Answer 63

Resect them--provide better outcome. Others "cat's out of the bag"

Question 64

What are the three palliative resection cases for colon CA?

Answer 64

Bleeding Perforation Obstruction

Question 65

What is the treatment for Tis or T1 rectal CA?

Answer 65

Transanal excision

Question 66

What is the treatment for T2 rectal CA?

Answer 66

Surgical resection

Question 67

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

Answer 67

Neoadjuvant chemoradiation + surgical resection

Question 68

What are the three surveillance measures for rectal CA? Frequency?

Answer 68

H&P ever 3-6 yrs CEA " " Ct x5 years