Anorectal Neoplasms

Question 1

4 tissue layers of colonic wall

Answer 1

1) mucosa (columnar epithelium)
2) submucosa
3) muscular propria
4) serosa

Question 2

What is muscularis mucosa?

Answer 2

small interwoven inner muscle layer just below mucosa but above basement membrane

Question 3

What portions of colon are retroperitoneal?

Answer 3

ascending, descending, sigmoid

Question 4

What are the transverse bands that form the haustra called?

Answer 4

Plicae semilunares

Question 5

What are Taenia coli?

Answer 5

3 bands that run longitudinally along colon. At rectosigmoid junction, the taeniae become broad and completely encircle the bowel.

Question 6

Blood supply for ascending and 2/3 of transverse colon

Answer 6

SMA (ileocolic, right and middle colic arteries)

Question 7

Blood supply for 1/3 transverse, descending, sigmoid colon and upper portion of rectum

Answer 7

IMA (left colic, sigmoid branches, superior rectal artery)

Question 8

This artery provides collateral flow by connecting SMA to IMA

Answer 8

Marginal artery

Question 9

This is a short direct connection between SMA and IMA

Answer 9

Arc of Riolan

Question 10

Superior rectal artery is a branch of what artery?

Answer 10

IMA

Question 11

Middle rectal artery is a branch of what artery?

Answer 11

Internal iliac (the lateral stalks during LAR or APR contain the middle rectal arteries)

Question 12

Inferior rectal artery is a branch of what artery?

Answer 12

internal pudendal (which is a branch of internal iliac)

Question 13

Where do superior and middle rectal veins drain?

Answer 13

IMV and eventually the portal vein

Question 14

Where do inferior rectal veins drain?

Answer 14

internal iliac veins and eventually the caval system

Question 15

Lymphatic drainage of:
Superior/Middle rectum
Lower rectum

Answer 15

Superior/Middle rectum- drain to IMA nodal lymphatics

Lower rectum- drains primarily to IMA nodes, also to internal iliac nodes

Question 16

Watershed areas of colon and rectum

Answer 16

Splenic flexure (Griffith's point)- SMA and IMA junction
Rectum (Sudak's point)- superior rectal and middle rectal junction

Question 17

External Sphincter:
Muscle
Innervation

Answer 17

Puborectalis muscle (continuation of elevator ani muscle)
under CNS voluntary control
Inferior rectal branch of internal pudendal nerve

Question 18

Internal Sphincter:
Muscle
Innervation

Answer 18

Muscularis propria
involuntary control
is normally contracted
Pelvic splanchnic nerves (parasympathetic)

Question 19

Inner nerve plexus

Answer 19

Meissner’s plexus

Question 20

Outer nerve plexus

Answer 20

Auerbach plexus (between inner circular and outer longitudinal muscle)

Question 21

Measurements from anal verge:

Anal Canal

Answer 21

0-5 cm

Question 22

Measurement from anal verge:

rectum

Answer 22

5-15 cm

Question 23

Measurement from anal verge:

rectosigmoid junction

Answer 23

15-18 cm

Question 24

What structure marks the transition between anal canal and rectum?

Answer 24

Levator ani

Question 25

Main nutrient of colonocytes

Answer 25

short-chain fatty acids

Question 26

Denonvilliers fascia

Answer 26

Anterior rectovesicular and rectoprostatic fascia in men rectovaginal fascia in women

Question 27

Waldeyer's fascia

Answer 27

Posterior | rectosacral fascia

Question 28

T1 staging CRC

Answer 28

invasion into submucosa

Question 29

T2 staging for CRC

Answer 29

invasion into muscularis propria

Question 30

T3 staging for CRC

Answer 30

invasion into subserosa or through muscular propria if no serosa present

Question 31

T4 staging for CRC

Answer 31

through serosa into free peritoneal cavity or into adjacent organs/structures if no serosa is present

Question 32

The most common polyp; no cancer risk

Answer 32

hyperplastic polyp

Question 33

most common (75%) intestinal neoplastic polyp

Answer 33

tubular adenoma

Question 34

These characteristics of polyps increase cancer risk:

Answer 34

> 2 cm sessile villous

Question 35

If unable to excise all of polyp endoscopically, next step is

Answer 35

segmental resection (often occurs with sessile polyp)

Question 36

When to start screening for CRC?

Answer 36

50 for normal risk | 40, or 10 years before youngest case for intermediate risk (family history)

Question 37

Treatment if polypectomy shows T1 lesion

Answer 37

polypectomy is adequate if margins are clear (2mm), is well differentiated, and has no vascular/lymphatic invasion; otherwise, need formal colon resection

Question 38

Treatment for extensive low rectal villous adenomas with atypia

Answer 38

``` transanal excision (can try mucosectomy) No APR unless cancer is present ```

Question 39

Pathology shows T1 lesion after transanal excision of villous rectal polyp

Answer 39

transanal excision if adequate if margins are clear (2mm), it is well differentiated, and it has no vascular/lymphatic invasion

Question 40

Pathology shows T2 lesion after transanal excision of villous rectal polyp

Answer 40

APR or LAR

Question 41

Dietary risk factors for CRC

Answer 41

red meat and fat

Question 42

Most common sight of primary in CRC

Answer 42

sigmoid colon

Question 43

CRC disease spread

Answer 43

nodal metastasis first

Question 44

Most important prognostic factor in CRC

Answer 44

nodal status

Question 45

Top 2 sights of metastasis of CRC

Answer 45

1) Liver 2) lungs

Question 46

Prognosis of patients with CRC with liver metastases

Answer 46

if resectable and leaves adequate liver function, patients have 35% 5 year survival rate

Question 47

Prognosis of patients with CRC with lung metastasis

Answer 47

25% 5 yr survival rate in selected patients after resection

Question 48

Rectal carcinoma can metastasize directly to spin via

Answer 48

Batson's plexus (venous)

Question 49

Goals of CRC resection

Answer 49

En bloc resection adequate margins (2 cm? 5 cm?) mesocolon regional adenectomy

Question 50

What fascia do you need to take for excision of rectal tumors?

Answer 50

Waldeyer's (posterior) and Denonvillier's (anterior) fascia

Question 51

Size of margin needed for LAR

Answer 51

Need at least a 2 cm margin (meaning 2 cm from elevator ani muscles) for LAR otherwise will need APR

Question 52

Morbidity of APR

Answer 52

Impotence and bladder dysfunction if pudendal nerve injured

Question 53

If patient with rectal cancer with complete response to chemo-XRT, what do you do

Answer 53

Surgical resection based on initial pathology, watch and wait strategy shown to have worse survival, higher rate of distant progression

Question 54

Stage 0

Answer 54

Tis, N0, M0

Question 55

Stage I

Answer 55

T1-2, N0, M0

Question 56

Stage IIa

Answer 56

T3, N0, M0

Question 57

Stage IIb

Answer 57

T4, N0, M0

Question 58

Stage 3a/b/c

Answer 58

N1+

Question 59

Stage 4

Answer 59

Any T, Any N, M1

Question 60

Low rectal T2 or higher gets what treatment

Answer 60

LAR or APR

Question 61

Low rectal T1 gets what treatment

Answer 61

transanal excision if <4 cm, has negative margins (need 2 mm), well differentiated, no LVI

Question 62

Stage 2 and Stage 3 rectal cancer get what initial tx

Answer 62

neoadjuvant chemo + XRT (followed by re-staging)

Question 63

Stage 4 rectal Ca Tx

Answer 63

neoadjuvant chemo + XRT, +/- APR (may want to avoid morbidity of APR in patients with metastatic disease, can divert via colostomy)

Question 64

Chemo for CRC

Answer 64

5FU, leucovorin, oxaliplatin (FOLFOX)???

Question 65

XRT damage

Answer 65

rectum most common site of injury (vasculitis, thrombosis, ulcers, strictures, bleeding)

Question 66

Limitations of TAE

Answer 66

Lesion must be: within 8 cm of anal verge no more than 3 cm in size occupy no more than 40% rectal circumference