Colon cancer Q1-10

Questions in Colon Cancer Surgery for MCH Aspirants

Q1. Risk of Colon Cancer in Adenomatous polyp is related to all except

 a) Size of the poylp
b) Number of polyps
c) Histological appearance
d) Dysplasia


Polyp in Colon

Most colon cancer arise from adenomatous polyps over an interval of 8-10 years.
The risk of cancer is related to the type of polyp  ( if it is  tubular, villous or  tubulovillous), size ie more than 2 cm and the severity of dysplasia.
Cumulative risk of colon cancer developing at the site of poylp is 2.5% at 5 years, 8% at 10 years
 Schakelford 6th edition   page 2153

Q2. Colon polyps are generally managed endoscopically. Which of the following is not an indication for colon resection surgery?
a) Lymphovascular invasion
b) Poor differentiation
c) Flat or ulcerated lesion
d) Lesion in upper 1/3rd of submucosa

2. d
Malignant poylp is one in which the colon cancer has spread beyond muscularis mucosa into lamina propria or muscularis mucosae. Colonscopic polypectomy maybe done in favourable polyps
The indications for colectomy are
a) Poor differentiation
b) Lympho vascular invasion
c) Flat or Ulcerated Lesion
d) Invasion in lower 1/3rd of submucosa and not upper 1/3rd
e) Cancer with in 2 mm of resected polyp
 Schakelford 6th edition   page 2156

 Q3. Which of the following organs are not involved in Familial Adenomatous Polyposis
 a) Adrenals
b) Thyroid
c) Astrocytomas in brain
d) Hepatoblastomas

3. c                                              

Familial Adenomatous polyposis

 Familial Adenomatous Polyposis (FAP) is associated with cancer of colon and rectum
Rare tumors associated with it are
Sabiston 17th page 1452

Q4. What is not true for HNPCC
 a) It is the most common hereditary colorectal cancer syndrome in USA
b) It is associated with MMR gene mutation
c) It is associated with APC mutation
d) It is associated with carcinoma colon and extraintestinal cancers

4. c
HNPCC is associated with mutations of MMR (Mismatch Repair) genes and not APC gene which is mutated in FAP
Sabistion 17th 1453

Q5. Which of the following is not fermented by colonic bacteria
 a) Lignin
b) Pectin
c) Cellulose

5. a
Lignin is a non carbohydrate component of plants which is not fermented by colonic bacteria. It attracts water producing bulk.
Lignin is used to treat constipation
Cellulose is partly fermented

Pectin is completely fermented and used to treat diarrhea.

 Q6.  True about Ulcerative Colitis with colon cancer
a) It has a better prognosis                   
b) Is related to disease activity
c) Is related to duration of ulcerative colitis
d) Malignancy is more in anorectal ulcerative colitis

6 .c
Colon Cancer afflicts patients with ulcerative colitis 7 to 30 times more frequently than it does the general population.
The risk of colon cancer in ulcerative colitis is related to two factors:
(1) duration of the colitis, and
(2) extent of colonic involvement.
The risk of colon cancer for patients who have had the disease less than 10 years is low, but this risk steadily increases. The cancer risk for patients who have had disease activity for 10 to 20 years is 23 times that of the general population, while a disease duration of more than 20 years is associated with a cancer risk 32 times greater than that of the general population. The extent of colonic involvement in colitis also influences the risk of cancer.
The incidence of cancer when ulcerative colitis is limited to the rectum or to the left side of the colon is much lower than when ulcerative colitis involves the entire colon.
The colon cancer associated with ulcerative colitis is generally an adenocarcinoma evenly scattered throughout the colon. The adenocarcinoma is often flatter than cancers in the general population and has fewer overhanging margins. It is generally considered extremely aggresive
The American Cancer Society guidelines recommend surveillance colonoscopy every 1 to 2 years, beginning 8 years after the onset of pancolitis and 12 to 15 years after the onset of left-sided colitis.
This strategy is based on the premise that a dysplastic lesion can be detected endoscopically before invasive carcinoma has developed

Ref Sabiston page 1342

Q7.  In ulcerative coilitis with toxic megacolon lowest rate of  recurrence is seen in which colon resection surgery
a) Complete proctocolectomy and Brook's ileostomy
b) Ileo rectal anastomoses
c) kock's pouch
d) Ileo anal pull through procedure

7. a                                                 

Brooked spout
Brooke Ileostomy
Total proctocolectomy with brooke's ileostomy removes almost all of the diseased segment.
IRA and IPAA leave behind rectal mucosa which may or may not be diseased

Q8)  All are precancerous for colon cancer except
 a. Crohn's disease
b. Bile acids
c. Fats
d. Carotene

8) d
Carotene, Vit C and Calcium reduce the risk of colon cancer


Q9.  Regarding colorectal anastomoses which of the  following is true
a) Stapler Anastomoses is definitely better than hand sewn anastomoses
  b) In Hand sewn anastomoses doubled layer closure is better than single layer
  c) Monofilament suture has lower leak rates than other sutures

d) None of the above is correct

9 .d
There was a Cochrane review  published in  2012 which  included 1233 patients. It concluded that hand sewn technique in colorectal anastomoses  had similar leak and complication rates as stapled anastomoses.
Ref    Stapled versus hand-sewn methods for colorectal anastomosis surgery.  Cochrane Database Syst Rev . (2): 2012;CD003144
A randomised trial by Burch showed that single layer anastomoses is quicker and has similar leak rates as doubled layer anastomoses
Single-layer continuous versus two-layer interrupted intestinal anastomosis: a prospective randomized trial.  Ann Surg 231. (6): 832-837.2000
Most surgeons prefer a monofilament suture as it has less inflamatory potential but variois studies have shown that leak rates are not dependent on choice of suture material

 Q10. In a recently diagnosed case of sigmoid diverticulitis with intermittent pain abdomen and alternating diarrhea with  constipation the management would include
a) Oral antibiotic with broad spectrum coverage against gram negative bacteria
b) Oral Prednisolone
c) Ondansetron

d) Fiber supplement and increased fluid intake

The patient has diverticular disease and not diverticulitis. Uncomplicated diverticular disease has no signs of obstruction, perforation and is managed with high fibre diet and increase in fluid intake.
Antibiotics are indicated in persistent left lower quadrant pain which is not relieved on passing stools