Surgical Oncology Board Review - Colorectal

Front 1

Define T staging of colorectal cancer.

Back 1

Tis Carcinoma in situ

T1 Tumor invades submucosa

T2 Tumor invades muscularis propria

T3 Tumor invade into pericolorectal tissues

T4a Tumor penetrates to the surface of the visceral peritoneum

T4b Tumor invades or adhere to other organs

Front 2

Define N staging of colorectal cancer.

Back 2

N0 none

N1a 1 node

N1b 2-3 nodes

N1c Tumor deposit in subserosa, mesentery, or nonperitonealized pericolonic tissues without nodal metastasis

N2a 4-6 nodes

N2b 7 or more nodes

Front 3

Define M staging of colorectal cancer.

Back 3

M1a Single organ metastasis

M1b Multiple organ metastases

Front 4

Define Stage II colon cancer and its subgroups.

Back 4

IIA = T3 N0 M0

IIB = T4a N0 M0

IIC = T4b N0 M0

Front 5

Define Stage III colon cancer and its subgroups.

Back 5

IIIA

T1 or T2, N1, M0

T1, N2a, M0

IIIB

T3 or T4a, N1, M0

T2 or T3, N2a, M0

T1 or T2, N2b, M0

IIIC

T4a, N2a, M0

T3 or T4a, N2b, M0

T4b, N1 or N2, M0

Front 6

Which patients with colon cancer should have tumors sent for MSI testing?

Back 6

US Task Force on CRC recommends universal genetic testing.

NCCN recommends selective approach, involves testing all patients < 70 with colorectal cancer, those that meet Bethesda criteria, and all patients with Stage II cancer.

Front 7

What is the management of an invasive cancer within a pedunculated or sessile polyp?

Back 7

No additional surgery if completely resected AND favorable histologic features:

- Grade 1/2

- No angiolymphatic invasion

- Negative resection margin

Colectomy if

- Specimen is fragmented

- Margins cannot be assessed or positive

- Specimen shows unfavorable histopathology (Grade 3, + lymphovascular invasion)

Front 8

What adjuvant therapy should be recommended for a patient with a poorly differentiated Stage II (i.e. T3 N0 M0), MSI-H resected colon cancer?

Back 8

None. Patients with stage II MSI-H tumors have a very good prognosis and do not benefit from adjuvant 5-FU. Note that poorly differentiated histology is not considered a high risk factor for MSI-H patients with Stage II disease.

Front 9

What is the treatment for patient with persistent anal SCC following treatment with Nigro protocol? (Also, what is the Nigro protocol)

Back 9

Salvage APR if disease persists up to 20 weeks following treatment

Nigro = RT + 5-FU/mitomycin C

Front 10

What are the two ways in which patients develop loss of MLH1, or microsatellite instability?

Back 10

1) BRAF mutation leading to hypermethylation of MLH1 promoter and silencing of the MLH1 gene (sporadic)

2) Germline mutation in MLH1 (Lynch/HNPCC)

Thus, patients with MSI-H tumors should undergo BRAF testing to rule out sporadic mutation prior to undergoing germline MLH1 testing.

Remember, MSI-H tumors don't benefit from 5-FU-based adjuvant chemotherapy.

Front 11

Mutations in which gene predict poor response to EGFR inhibitors such as cetuximab and panitumumab?

Back 11

KRAS.

Front 12

Discuss sacral chondroma.

Back 12

- Arise from cellular remnants of the notochord

- Indolent and slow growing

- Treatment is wide local resection including sacrum and then adjuvant radiation.

- Often recur following resection

- Insensitive to chemotherapy agents

Front 13

What test should be used if a patient with history of resected colon cancer now presents with elevated CEA but no disease on CT?

Back 13

PET CT

Front 14

What did the MOSAIC trial show?

Back 14

No difference in overall survival was found between stage II colon cancer patients treated with FOLFOX vs observation

Landmark trial establishing adjuvant chemo as standard of care for Stage III patients!

Front 15

What did the German Rectal Cancer Trial show?

Back 15

As compared with postoperative chemoradiation therapy, preoperative chemoradiation therapy was associated with a lower 5-year local recurrence rate (13% vs. 6%) and less toxicity

Front 16

What is the management of stage II rectal cancer (vs stage II colon cancer)?

Back 16

Stage II rectal cancer --> Neoadjuvant chemoradiation, resection, adjuvant chemotherapy

Stage II colon cancer --> Resection, observation vs adjuvant chemotherapy only if high risk features

Front 17

What are the indications for transanal excision of rectal cancer?

Back 17

T1 N0 by EUS or MRI

Low grade

Well to moderately differentiated

<3cm

<30% circumference

<8cm of anal verge

No lymphovascular invasion

Front 18

Is there data that shows that T2 N0 rectal cancers are best treated with colorectal resection?

Back 18

NCDB data showed that local excision was associated with decreased 5-year overall survival compared with standard resection (68% vs. 77%) and an increase in risk for local recurrence (22% vs. 15%).

Front 19

What should be the management of rectal cancer involving lateral lymph nodes (iliac, obturator, external iliac)?

Back 19

Neoadjuvant chemoradiation, LAR/APR, selective node dissection

Front 20

What is the prognosis for metastatic colorectal cancer?

Back 20

Unresectable: > 24 months with sequential chemotherapy/targeted agents

Resectable: 5-year survival may exceed 60%

Front 21

Name 5 trials that looked at laparoscopic vs open resection for rectal cancer.

Back 21

CLASICC (UK)

COREAN (Korea)

COLOR II (Europe)

ACOSOG Z6051 (US)

ALaCaRT (Australia)

Last could not demonstrate that the laparoscopic approach was equivalent or superior compared to open when considering the quality of the pathologic specimen (TME, circumferential margin, distal margin).

Front 22

What features on immunohistochemical analysis of a colorectal cancer specimen should prompt referral to genetic counseling and consideration for germline testing for Lynch syndrome?

Back 22

- Patients found to be MSI-H after indeterminate immunohistochemistry

- Patients found to have loss of MLH1 or PMS2 AND BRAF wild type (ie no hypermethylation)

- Patients found to have loss of other MMR proteins

Front 23

The finding of tumor-infiltrating lymphocytes on pathologic review of a colon cancer should prompt workup for what condition?

Back 23

TILs are associated with DNA mismatch repair–deficient colorectal cancers, so you should test for Lynch syndrome

Front 24

Discuss medical management of desmoid tumors.

Back 24

Early lesions < 10 cm, slow growing, mildly symptomatic --> tamoxifen, NSAIDs

Advanced lesions 10-20 cm, symptomatic --> tamoxifen, NSAIDs --> if poor response, treat with chemotherapy (doxorubicin, dacarbazine)

Front 25

Describe Gardner syndrome and Turcot syndrome

Back 25

Gardner - FAP, osteomas, desmoids, dental abnormalities

Turcot - FAP, CNS tumors

Front 26

How would you divert a patient with a locally advanced obstructing rectal tumor?

Back 26

Loop transverse colostomy

Don't risk creating a closed loop by performing end colostomy or loop ileostomy (will create closed loop if ileocecal valve is competent)

Front 27

What is the treatment for anal SCC of perianal skin?

Back 27

Wide local excision

Front 28

What factors make Stage II colon cancer high risk and should prompt consideration for adjuvant chemo?

When beneficial, by what percent does adjuvant chemo increase survival in Stage II patients?

Back 28

- < 12 lymph nodes retrieved

- Poorly differentiated (and not MSI-H)

- Lymphovascular invasion present

- Obstructing cancers

- Perforated cancers

- Close or positive margins or indeterminate margins

**Benefit is not greater than 5%

Front 29

When should you stop performing annual surveillance CEA and CT scans?

Back 29

5 years

Front 30

What is the most important pathologic staging parameter in rectal cancer?

Back 30

The circumferential resection margin (CRM)

Front 31

Define RECIST criteria.

Back 31

CR (complete response) = disappearance of all target lesions

PR (partial response) = 30% decrease in the sum of the longest diameter of target lesions

PD (progressive disease) = 20% increase in the sum of the longest diameter of target lesions

SD (stable disease) = small changes that do not meet above criteria

(30 down, 20 up)