Colon Cancer

Question 1

Differential diagnosis of LUQ pain

Answer 1

Colon ca, diverticulitis, ischemic colitis (bloody diarrhea), splenomegaly (hematologic malignancies), neoplasm (pancreatic tail, adrenal/kidney cancer, RP sarcoma)

Question 2

What percentage of colon cancer is transverse colon?

Answer 2

10%

Question 3

Complications of colon mass

Answer 3

Perforation, fistulaization, obstruction

Question 4

Most important thing to consider with an obstructing colon mass

Answer 4

Competent vs. Incompetent ileocecal valve
Incompetent: pressure that builds up proximal decompresses into the small bowel (decompression, rehydration)
Competent: surgical emergency; tension on proximal colon wall; LaPlace –>fourth potency of radius of cavity (largest radius / cecum will suffer the greatest tension)

Question 5

What happens with increased tension on the cecum?

Answer 5

Collapse of intra-mural capillaries and ischemia –> perforation

Question 6

Pre-operative staging of colon mass

Answer 6

CT A+P with IV/PO; CXR/CT chest; CEA; full colonoscopy

Question 7

In patients with bulky splenic flexure mass in whom it is not possible to do a colonoscopy, what other options are there to r/o synchronous lesion?

Answer 7

Barium enema
On-table colonoscopy through appendiceal orifice
5% incidence of synchronous lesion
If not possible – go to OR and do a 6 month C-scope

Question 8

Best option for an obstructive colon mass with competent ileocecal valve

Answer 8

Stent

Question 9

During a primary resection of splenic flexure mass, what must you also resect

Answer 9

Bowel segment with R0 resection; lymphvascular pedicle (12 LN’s)
- Left colic vessels, L branches of middle colic, IMV

Question 10

1, 2, 3 stage procedure for colon cancer

Answer 10

1. Resection/mosis
2. Resection/ostomy; ostomy takedown
3. Ostomy followed by resection

Question 11

Advantages of MIS for colon cancer

Answer 11

Smaller incisions, less pain, less narcotics, faster ROBF, shorter hospital stay, lower wound complications, lower CV complications, faster recovery, decrease overall cost

Question 12

Who gets adjuvant CTX in colon cancer?

What CTX regimen? Any biologics?

Answer 12

Stage 3 (positive LN); stage 4 (distant mets)

• High risk: LV/PNI, lack of MSI, Oncotype/high-risk
• FOLFOX (Oxaliplatin, 5-Fu) CTX +/- Avastin

Question 13

What percentage of colon cancer recur within 3 years of surgery?

Answer 13

85% (majority between 3-5)

Question 14

Screening post colon cancer surgery

Answer 14

Annual CT C/A/P for 3 years, colonoscopy at 3 yeares, H+P every 3-6 months for 3 years & q 6 months during years 4-5; CEA every 3 month for 3 years

Question 15

Leak rate of sigmoid colectomy

Answer 15

5%

Question 16

Study to confirm early colectomy leak

Answer 16

Water-soluble contrast enema

Question 17

Should patients be marked by stoma nurse prior to take back for a leak?

Answer 17

Yes

Question 18

Left vs. Right leaks

Answer 18

RIGHT: resect/redo if stable; end loop stoma if unstable
LEFT: Repair/redo with proximal diversion if stable; resect/stoma if unstable

Question 19

Rectal bleeding DDX

Answer 19

Diverticular disease, hemorrhoids, anal fissure, IBD, cancer

Question 20

Objective of colonoscopy for a known/suspected colon mass

Answer 20

Visualize; tissue for pathology; exclude synchronous lesion

Question 21

Staging for known colon mass

Answer 21

CT C/A/P

Question 22

Local staging for rectal mass

Answer 22

MRI – site/involved structures, clinical T, nodal status, CRM (circumferential radial margin)

Question 23

Tumor marker for colon cancer

Answer 23

CEA

Question 24

Rectal cancer: above/below peritoneal reflection

Answer 24

Below

Question 25

Approximate distance of rectal lesion from anal verge

Answer 25

< 15 cm

Question 26

cT1-4 of rectal cancer

Answer 26

1: mucosa/submucosa 2: muscularis propria 3: peri-rectal fat/mesorectum 4: prostate/seminal vesicles/vagina

Question 27

Pain and rectal cancer may indicate

Answer 27

Sphincter involvement

Question 28

What modality is being used more frequently than MRI for local staging?

Answer 28

Endorectal ultrasound; MRI is superior for staging bulky/locally advanced lesions

Question 29

Locally advanced rectal cancer (Stage 2/3; c T3-4 or N+)

Answer 29

May require NA downstaging

Question 30

Neoadjuvant chemo/radiotherapy for rectal cancer is:

Answer 30

Oral capecitabine or infusional FU in combination of 5040 cGy 25-28 fractions M-F 5.5 weeks --> repeat staging

Question 31

When is surgery performed following NA therapy for rectal cancer?

Answer 31

8-12 weeks

Question 32

Yes or No post-op CTX for locally advanced rectal cancer?

Answer 32

Yes -- Capecitabine or 5-FU with oxaliplatin

Question 33

What is post-op LAR syndrome

Answer 33

Sexual + bladder dysfunction + stool frequency/urgency/clustering (can take 12-24 months to plateau)

Question 34

When do LAR leaks present?

Answer 34

4-7 days post-op

Question 35

Highest incidence of LAR leaks (anatomic location)

Answer 35

< 7 cm from verge

Question 36

T/F post-op adjuvant CTX is standard of care for stage 3 colon cancer

Answer 36

True

Question 37

Long-term follow-up for rectal cancer

Answer 37

CEA/exam every 3-6 months for 2 years and then every 6 months for 3 years; q annual CT chest x 3 years