Mod 5-5 LB Cancer

Question 1

Large bowel cancer is primarily a disease of the _____ population. Peak incidence is between ___ and ___ years old.

Answer 1

older; 50 - 70

Question 2

What percentage of large bowel cancers appear in the rectum or sigmoid area where they can be palpated or seen with a sigmoidoscope?

Answer 2

50%

Question 3

What are the two diseases that precispose to cancer of the large bowel?

Answer 3

• Long standing ulcerative colitis (UC)
• Familial polyposis

Question 4

Large bowel cancer is the _____ leading cause of death from cancer in the US.

Answer 4

second

Question 5

What is familial polyposis?

Answer 5

A hereditary disease in which a myriad of polyps develop in the large bowel and elsewhere in the intestinal tract.

Question 6

What are some other factors that are linked to the development of cancer in the colon?

Answer 6

• heavy consumption of beef and animal fat
• family history (other than familial polyposis)
• diet low in fiber
• large bowel is a common site for metastasis

Question 7

List areas of the bowel and frequency of tumors appearing at each site.

Answer 7

• Sigmoid 30%
• Rectum 25%
• Ascending colon 20%
• Descending colon 5-10%
• Transverse colon 15%

*Note rectosigmoid area accounts for 55%

Question 8

What are the clinical signs of large bowel cancer?

Answer 8

Changes in bowel pattern or habits that include…

• pain
• blood
• change in caliber of stool
• large bowel obstruction

Question 9

Why is it important to understand that about 1% of all patients with large bowel cancer have more than 1 cancerous site in the bowel at the time of discovery?

Answer 9

So we understand that every projection is important in the BE series to ensure every portion is visualized as many times as possible to increase the chance of detecting those multiple cancers in the few patients who have them.

Question 10

What is early diagnosis of large bowel cancer?

Answer 10

An exercise in polyp detection because polyps are considered precancerous and the earlier they are found and removed the better the patient’s chances of not developing cancer from that site.

Question 11

What are the two polyp classifications and what do they mean?

Answer 11

• Sessile (without a stalk)
• Pedunculated (with a stalk)

Question 12

What are the characteristics of sessile (without stalks) polyps?

Answer 12

• Tend to be malignant
• Present an irregular outline on the bowel wall
• Shows a pulling or retracting of the bowel wall that surrounds it
• Those greater than 2 cm in dia are highly suspicious for malignancy

Question 13

What are the characteristics of a pedunculated (with stalk) polyp?

Answer 13

• Has a stalk
• Round or lobulated (lobe) appearance
• Less serious of the two types

Question 14

What are annular carcinomas?

Answer 14

Ring-shaped or encircling structures that begin as flat tumor plaques on a portion of the bowel wall.

Question 15

_______ carcinomas are easily overlooked, especially when…?

Answer 15

Annular; poor radiographic techniques are employed

Question 16

What happens as an annular carcinoma tumor grows?

Answer 16

It expands around and through the bowel wall rather htan moving into the lumen of the bowel.

Question 17

“What are the characteristics of the annular tumor as it grows?

Answer 17

“apple-core” or “napkin-ring” lesion is produced constricting and narrowing the lumen of the bowel

Question 18

What is the pattern of growth of an annular tumor?

Answer 18

• Irregular, creating ulcerations (sometimes large) and overhanging margins.
• Fecal material that passes becomes thin and narrow
• blood may be present in the stool as the cancer erodes blood vessels
• Progressive narrowing of the lumen will eventually lead to obstruction of the bowel

Question 19

This condition also has overhanging edges that may simulate cancer but is benign.

Answer 19

Crohn’s disease

*Clnical symptoms and history will vary in cancer and Crohn’s and a diagnosis will be made after suitable testing.

Question 20

What is the effect of LB cancer on radiographic technique?

Answer 20

There is none, however do remember those with Crohn’s and ulcerative colitis have a higher incidence of developing a bowel malignancy than does the general population. Proper imaging is very important.