Colorectal CA

Question 1

Colorectal CA is the _____ leading cause of cancer mortality for ____ and third leading cause for ________ in ______

Answer 1

second

males

females

Canada

Question 2

Etiology/Risks (7)

Answer 2

1. idiopathic
2. aging
3. familial predisposition
4. IBD
5. Adenomatous polyposis
6. Poor diet
7. Protective role of aspirin?

Question 3

Etiology: What is Idiopathic?

Answer 3

The cause is largely unknown and carcinogens are idiopathic .

Question 4

Etiology: 90% of persons who dev Colorectal CA are older than ____ years of age. Why?

Answer 4

Most colorectal CA occur after 50 y/o.

d/t accum. exposure to carcinogens

Question 5

Etiology: those who have two or more _____ or _____-degree _____ with colorectal CA make up ____% of all persons who have it (familial predisposition)

Answer 5

1. first
2. second
3. relatives
4. 20%

Question 6

Etiology: What two conditions have higher incidence of colorectal CA?

Answer 6

1. Crohn’s disease

2. Ulcerative Colitis

Question 7

Etiology: What is adenomatous polyposis? Adeno-?

Answer 7

A disorder with abundance of polyps projecting into the lumen of the large bowel.

Greater risk of dev Colorectal CA.

Adeno= meaning granular epithelial cells

Question 8

Etiology: What diet contribute to Colorectal CA?

Answer 8

Diet is not well balanced –>there is high fat content and refined sugar intake in diet.

Question 9

How does high fat content lead to Colorectal CA?

Answer 9

Fat is emulsified and broken down by bile.

Fat in diet increase synthesis of bile acids in liver which may be converted to potential carcinogens by bacterial flora in colon.

Normal flora in gut converts bile acid to carcinogens ( a chemical product of the processing)

Question 10

How does refined CHO (sugar) contribute to Colorectal CA?

Answer 10

Refined CHO nourishes bacteria and promote bacteria proliferation

Question 11

Etiology: How does aspirin protect colorectal CA? Role of Prostaglandins. What does COX2 do?

Answer 11

Prostaglandins mediate pain during inflm and promote cell proliferation and trigger formation of tumors.

COX 2 (cyclooxygenase) enzyme converts arachidonic acid to prostaglandins.

Aspirin inhibits cyclooxygenase (COX2) which catalyzes the conversion of arachidonic acid in cell membrane to prostaglandins.

Regular ASA use appears to reduce the risk of colorectal CA that overexpresses COX2

Question 12

Patho: How many stages is in Colorectal CA? Are they progressive and how is it staged?

Answer 12

1. 4
2. yes
3. global staging levels of tumors

Question 13

Stage I of Colorectal CA (What tissue layer is impacted? survival rate? %?)

Answer 13

Stage I is limited to the mucosa and submucosa layer of colon.

If detected in stage I, there is a 5 year survival rate of 90-100%.

Question 14

Stage II (tissue layer impacted? lymph nodes involvement?survival rate? %?

Answer 14

There is infiltration in the muscularis externa (mucosa and submucosa layers still affected)

No lymph node involvement yet.

5 year survival rate of 70-85%

Question 15

Stage III: tissue layer impacted? lymph nodes involvement?survival rate? %?

Answer 15

All layers previously + serosa.

Lymph nodes positive –> malignant cells spread to lymph nodes

5 year survival rate is 40-60%

Question 16

Stage IV: tissue layer impacted? lymph nodes involvement? survival rate? ________ is present

Answer 16

Metastatic tumor penetrates the serosa and adjacent organs

Much poorer prognosis.

Seeding

Question 17

Manifestations (4): Late or early onset?

Answer 17

usually late onset

1. hemorrhage (early): frank blood in stool is a relatively early sign
2. alternate bowel habits, diarrhea, and constipation: nonspecific
3. pain: is severe and late sign

Question 18

Diagnosis (4)

Answer 18

1. DRE: digital rectal exam
2. fecal occult blood (screen)
3. barium enema
4. sigmoidoscopy, and colonoscopy

Question 19

What is DRE? Is it routine (age?)?

Answer 19

rectum and colon is palpated with finer to determine lumps and change in consistency

Routine physical exam after age 50

Question 20

What is fecal occult blood screening? What does it test for? Routine?

Answer 20

stool sample is collected and put onto a test strip to be sent to a lab to tests for occult blood

routine physical exam after age 50

Question 21

What is barium enema? When is it done?

Answer 21

Barium is introduced in rectum and x-ray is taken to visualize the malignancy

When screens are positives

Question 22

What is sigmoidoscopy? when is it done?

Answer 22

to examine the rectum and sigmoid colon with a hollow lighted tube that is inserted thru the rectum

When screens are positives

Question 23

What is colonoscopy? when is it done?

Answer 23

to examine the entire bowel ending at the cecum

When screens are positives

Question 24

What can be done during the scope?

Answer 24

removal of polyps and tissue can be obtained for biopsy

Question 25

treatment ( 3)

Answer 25

1. sx
2. preoperative radiation to shrink tumor
3. postoperative chemotherapy used w/ radiation

Question 26

In palliative treatment what is used?

Answer 26

radiation and chemo `

Question 27

What tx in some cases demonstrate increase 5 year survival rate?

Answer 27

preoperative radiation

Question 28

What is the only curative approach and is shown to be quite successful?

Answer 28

Sx