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GI > Tumors of the bowel > Flashcards

Tumors of the bowel Flashcards

1
Q

What is the lifetime risk of colorectal cancer?

A

5-6%

However, the incidence is declining

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2
Q

How much time does it take for a benign adenoma to become a colon cancer?

A

5-12 yrs

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3
Q

How common is CRC?

A

3rd most common form of cancer in men and women. 3rd leading cause of cancer death in US

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4
Q

What are the intrinsic risk factors of colorectal cancer?

A

Race
Ethnic background
Occupational hazards

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5
Q

What are the controllable risk factors in colorectal cancer?

A
  1. Caloric intake/obesity
  2. Red meat consumption
  3. Alcohol consumption
  4. Smoking
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6
Q

Where are most colorectal cancers found?

A

Distal to the splenic flexure of the colon

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7
Q

What genetic factors increase your risk of CRC?

A
  1. History of colorectal neoplasia
  2. IBD
  3. HNPCC mutation
  4. FAP
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8
Q

Most cases of CRC occur after the age of:

A

50

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9
Q

If you meet someone who has CRC under the age of 50…what are you worried about?

A

FAP/HNPCC/PJS/IBD/MUTYH

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10
Q

How is FAP inherited? What gene is mutated?

A

Autosomal dominant disorder

-Mutated APC gene

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11
Q

What is peutz-jeghers syndrome?

A

Autosomal dominant disorder

  • Multiple hamartomatous polyps of the entire GI tract
  • melanosis of lips and buccal mucosa
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12
Q

Are PJ polyps malignant?

A

No, but these patients have a higher incidence of carcinoma elsewhere in the colon (breast, pancreas, ovary, uterus, lung)

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13
Q

How and when should you treat FAP?

A

Cancer develops early (late 30’s). Treat early on with a total colectomy, before the age of 25

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14
Q

What are the carcinogens identified in colorectal cancer?

A
  1. Fecal bile acids
  2. Heterocyclic amines
  3. Fecapentenes (anaerobic breakdown of fatty acids)
  4. 3-ketosteroids (oxidation product of cholesterol)
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15
Q

What are some protective measures for colorectal cancer?

A 
NSAIDS
vitamin D
calcium
folic acid
Fiber consumption
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16
Q

Does the two-hit hypothesis apply to CRC?

A

Yes. Molecular pathways to sporadic and inherited cancers are the same

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17
Q

How is familial colorectal cancer inherited?

A

We don’t understand this. Family hx plays a role but this isn’t a typical inherited syndrome

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18
Q

Do you have to have a family history of FAP to get FAP?

A

No. 25% have a spontaneous germline mutation

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19
Q

How do you diagnose FAp?

A

> 100 polyps in the colon and rectum

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20
Q

What is the most common cause of death in FAP?

A

Desmoid tumors

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21
Q

How is MYH polyposis inherited?

A

autosomal recessive

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22
Q

Which gene is mutated in MYH polyposis?

A

mutY homolog gene, which does base excision repair for oxidative DNA damage

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23
Q

What does MYH polyposis look like when you do endoscopy?

A

usually 15-100 adenomas. Early (age 45) CRC

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24
Q

Where do MYH polyposis cancers occur?

A

In the ascending colon. Important to consider if early polyps and many polyps but no APC gene abnormality

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25
Q

What is the most common inherited colon cancer syndrome?

A

Hereditary Non-Polyposis Colon Cancer (HNPCC)

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26
Q

How is HNPCC inherited?

A

autosomal dominant

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27
Q

Where is the mutation in HNPCC?

A

Mismatch repair genes (MMR)

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28
Q

How do you diagnose HNPCC?

A

Clinically indistinguishable from sporadic CRC (only one poly developing into CRC) Can only diagnose through personal and family history

29
Q

What are the two types of HNPCC (lynch syndrome)

A

Lynch syndrome 1: CRC only

Lynch syndrome 2: CRC + endometrial and other cancers)

30
Q

What is the main difference btw HNPCC and Sporadic CRC?

A

HNPCC has an accelerated development of cancer (3.5 years btw polyp-carcinoma)
The polyps themselves are flatter and smaller.

31
Q

Where are HNPCC cancers localized?

A

In proximal colon usually

–High rate of synchronous/metachronous cancers

32
Q

What would lead to test for HNPCC genetically?

A

CRC < 50
Synchronous/metachronous CRC
Microsatellite instability
CRC diagnosed in 1+ relatives, with one of them diagnosed under age of 50
CRC diagnosed in 2 or more 1st/2nd degree relatives

33
Q

What is the amsterdam criteria for HNPCC?

A

3-2-1 rule:
3+ relatives with HNPCC cancer/associated cancer
2+ generations
1+ diagnosed before age 50

34
Q

What are microsatellite repeats? Why do they increase the risk of mutation?

A

repetitive sequences. Replication machinery slips and makes more errors on these sequences

35
Q

How is MSI related to HNPCC?

A

90% of HNPCC cancers have microsatellite instability. This is b/c MMR defects cannot repair microsatellite repeats

36
Q

How can you diagnose a mutation in MMR?

A

Immunohistochemistry for MMR proteins

37
Q

What are some examples of non-neoplastic polyps?

A
  1. Hyperplastic
  2. Hamartomatous (juvenile or peutz-jeghers)
  3. Inflammatory pseudopolyps
38
Q

What polyp characteristics imply an increased risk of malignant behavior?

A

size > 2cm

Villous adenoma>tubulovillous>tubular

39
Q

What is the most common type of adenoma?

A

tubular adenoma

40
Q

What is the morphology of a tubular adenoma?

A

Pedunculated with packed glands. The stalk is made out of submucosa material

41
Q

How common is a villous adenoma?

A

Uncommon (1%)

42
Q

Where do villous adenomas show up?

A

Rectum and rectosigmoid

43
Q

What kind of polyps do you see in villous adenomas?

A

sessile masses with frond-like villi. Mucus is rich of K+

44
Q

Tubulovillous adenoma: What are you at risk for?

A

in situ or invasive carcinoma. Risk correlates with amount of villous material.

45
Q

How do you treat invasive CRC?

A

Controversial resectqability. But try to remove!

46
Q

Hyperplastic polyp

A

A small sessile polyp that is NOT neoplastic.

47
Q

Juvenile/retention polyp

A

Hamartomatous malformation in the rectum. Seen in children. Not malignant

48
Q

What do juvenile polyps look like?

A

Cystically dilated glands and inflamed lamina propria

49
Q

What are Peutz-Jeghers polyposis pts at risk for?

A

Cancer of the pancreas, breast, lung, ovary, and uterus.

-LKB1 mutation

50
Q

Left sided colorectal adenocarcinomas

A

Left sided tumors grow as annular, circumferential masses. Obstruction is common

51
Q

Right sided colorectal adenocarcinomas

A

Right sided tumors grow as polypoid exophytic masses. Occult bleeding/melena seen INSTEAD of obstruction

52
Q

How do you stage in CRC?

A

In situ (intraepithelial and intramucosal) has low risk of metastasis

  • pT1: invasion into submucosa
  • pT2: muscularis propria
  • pT3: muscularis propria
  • pT4: penetration of serosa/adjacent viscera
53
Q

What staging indicates a poor prognosis?

A

Nodal involvement, penetration into the serosa, and distant mets

54
Q

Why are there more complications with cancers of the rectum?

A

Anatomic constraints of the pelvis. Local recurrence following surgery ends up happening more often. Lower risk of recurrence by using postop chemo/XRT

55
Q

What do you do if you see a hepatic metastasis?

A

En bloc resection and follow up chemo

56
Q

When should you begin CRC screening in someone with a family history?

A

age 40 or 10 years younger than when family member got it.
LYNCH: screen every 1-2 years
FAP: yearly from age 12-13 years
IBD: Screen every 2 years after 10 years of dz

57
Q

How does small bowel carcinoma present?

A

Vague symptoms usually from bowel obstruction(pain, nausea, wt loss, bleeding)
Diagnostic delay at advanced stages
Poor outcomes

58
Q

How do you diagnose small bowel neoplasms?

A

If pain, use CT or MRI enterography

If bleeding, use Colonoscopy or UGI endoscopy

59
Q

How do you treat small bowel neoplasms?

A

Segmental resection OR whipple if the duodenum is involved

60
Q

Carcinoid tumors represent a proliferation of what kind of cells?

A

Neuroendocrine

61
Q

When is the prognosis of carcinoid tumors good?

A

Benign if in appendix or rectum
Benign if not penetrating the muscularis
Benign if tumor < 2 cm

62
Q

What is the most common symptom of carcinoid tumors?

A

pain/obstruction. 90% of symptomatic pts will have metastatic dz

63
Q

What is carcinoid syndrome?

A

Release of serotonin into the systemic circulation with skin flushing/cyanosis
diarrhea/cramps
bronchospasm
subendocardial fibrosis

64
Q

Where do adenocarcinomas of the small intestine occur?

A

Duodenum and proximal jejunum. Often advanced at time of diagnosis.

65
Q

What are the risk factors for adenocarcinoma?

A

Crohn’s and FAP/HNPCC

66
Q

What are gastrointestinal stromal tumors?

A

Mesenchymal tumor resembling modified smooth muscle and neural tissue

67
Q

What kinds of cells make up GIST?

A

Interstitial cells of cajal, the pacemaker cells of the gut. They can range from benign to malignant

68
Q

What are Cajal cells positive for?

A

CD117.

GI (27 decks)

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