53. Colorectal cancer

Question 1

epidimiology ( age, persentage of family histolry )

Answer 1

• more patients are over 50

25% have family historu

Question 2

risk factors

Answer 2

1. adenomatous polys
2. serrated polys
3. familiar cancer syndromes
4. inflammantory bowel disease
5. tobacco use
6. diet of processed meat with low fiber

Question 3

location ( in order)

Answer 3

rectosigmoid> ascending > descending

Question 4

presentantion ( according to location

Answer 4

right side bleeds, left side obstruct
Ascending –> exophitic mass, iron deficiency anemia, weight loss
Descending –> infiltrating mass ( napkin ring) , partial obstruction , colicky pain, hematochezia

Question 5

microbe associated with colorectal cancer

Answer 5

rarely, bactermia with S. bovis

Question 6

whent os uspect colorectal CA

Answer 6

iron deficiency anemia in males over 50 and postmenopausal females

Question 7

clorectal cancer - screening

Answer 7

screen patients over 50 with

1. colonoscopy
2. flexible sigmoidoscopy
3. fecal blood test
4. fecal DNA test

Question 8

the stool DNA test is a noninvasive laboratory test that identidies

Answer 8

DNA changes in the cells of a stool sample –> specifically looks for DNA alterations associated with colon polyps and colon cancer

Question 9

barium enema x-ray

Answer 9

: apple core” lesion

Question 10

markers / characteristcis

Answer 10

CEA tumor marker –> food for monitoring recurrence, should not used for screening

Question 11

• A patient is diagnosed with right-sided colon cancer. What type of symptoms would you observe in this patient to reach your diagnosis?

Answer 11

An exophytic mass, iron deficiency anemia, weight loss

Question 12

• Name at least three risk factors for colorectal cancer.

Answer 12

Adenomatous and serrated polyps, familial cancer syndromes, IBD, tobacco use, diet of processed meat with low fiber

Question 13

• How do you screen for colorectal cancer?

Answer 13

Colonoscopy, flexible sigmoidoscopy, or stool occult blood testing

Question 14

• A patient with past history of colorectal cancer is constantly monitored for recurrence. What nonspecific serum tumor marker is used?

Answer 14

Carcinoembryonic antigen (CEA)

Question 15

• A man has fevers, hypotension, and a new murmur. Blood cultures grow a streptococcal species. Why might you want to perform a colonoscopy?

Answer 15

Although rare, colorectal cancer can be associated with Streptococcus bovis bacteremia (this patient may need a colonoscopy once stabilized)

Question 16

• A male patient with iron deficiency anemia is concerned about colon cancer risk. Should he be concerned? Who else should be concerned?

Answer 16

Yes, as iron deficiency anemia can be a presenting sign of colorectal cancer, from occult GI bleeding; postmenopausal females

Question 17

• Put in order (from most to least common) where colorectal cancer presents: descending colon, ascending colon, rectosigmoid junction.

Answer 17

Rectosigmoid junction, ascending colon, descending colon

Question 18

• A man is worried about colon cancer. He wants a screening CEA level drawn, because he is “scared of colonoscopies.” What do you tell him?

Answer 18

CEA levels cannot be used for screening—they can be used only to monitor for recurrence in previously diagnosed patients