L7: Colon polyps and cancer Flashcards

1
Q

2 Non-neoplastic polyps (benign hyperplastic)

A

Hyperplastic

Pseudopolyps

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2
Q

Who gets pseudopolyps?

A

IBD (they’re inflammatory)

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3
Q

2 classifications of Neoplastic polyps

A

Adenomas

Sessile serrated polyps

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4
Q

Facts about adenomas

A

2/3 of all colon polyps
Common in adults older than 50
Usually asymptomatic, large→ +/- bleed
Risk of colorectal cancer increases by number of adenomas, size, histology→ influences surveillance interval recommendations
70% of colorectal cancers arise from adenomas, takes 10 years→ Early detection & removal is key

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5
Q

Most common adenoma which causes 95% of colorectal cancers

A

Tubular adenoma

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6
Q

Types of adenomas

A

Tubular adenoma (most common)
Tubulovillous adenoma
Villous adenoma

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7
Q

An adenoma is considered “advanced” if…

A

1 cm
villous or tubulovillous
high grade dysplasia

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8
Q

Colorectal cancer is more common in the ______ colon

A

Left sided colon, but right sided rates are rising

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9
Q

Risk factors for colorectal cancer

A
Adenomas or colon cancer
Familial adenomatous polyposis
Hereditary nonpolyposis colon CA
>50 years, but rising in younger adults
8-10 years of IBD
African american
Tobacco, ETOH
High fat/low fiber
Red meat, Obesity, DM
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10
Q

Colorectal cancer presenation

A
*Often asymptomatic*
Cachetic
Pallor
Lymphadenopathy
Abdominal distention, ascites, mass, organomegaly
DRE→ hemoccult (+), rectal mass
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11
Q

Colorectal cancer red flags

A
Change in bowel habits
Hematochezia or occult blood in stool
*Iron Deficiency Anemia*
Anorexia/Weight loss
Abdominal Pain
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12
Q

Colorectal cancer diagnostics

A

CBC→ chronic blood loss→ iron deficiency anemia

Elevated Alk phos→ liver mets

Carcinoembryonic antigen (CEA) → prognostic indicator, monitor for recurrence
*Not used for screening*

Colonoscopy→ biopsy to confirm

Chest/abdominal/pelvic CT→ tumor extension/complication, regional lymphatic and distal metastasis

Barium enema→ “apple core lesion”

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13
Q

Colorectal cancer mangement

A

Partial colectomy with wide margins and adjacent lymph node removal

Chemo→ metastasis

Radiation→ rectal adenocarcinoma

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14
Q

Colorectal cancer surveillance

A

Serial CEA levels

Annual surveillance CT chest/abd/pelvis

Periodic colonoscopy

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15
Q

What’s CEA used for again?

A

prognosis
monitor for recurrence
NOT for screening

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16
Q

Gold standard for colon cancer screening

A

Colonoscopy

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17
Q

Colonoscopy sees
Flex sig sees
CT Colonography sees

A

Colonoscopy: entire colon
Flex sig: 60 cm=distal 1/3 of colon, less protection against right-sided cancer
CT Colonography: “virtual”, 2D/3D imaged of bowel mucosa, sees polyps >1 cm but can miss small or flat ones

18
Q

Considerations for colonoscopy

A

Requires bowel prep, sedation/chaperone, time off work
Risk of perforation/bleeding
Not infallible:
1. Operator dependence
2. Poor prep→ precludes adequate visualization→ misses small/flat polyps

19
Q

Considerations for flex sig

A

Limited prep, no sedation
Lower cost
Lower risk of perforation

20
Q

Considerations for CT colonography

A
Requires bowel prep
No sedation
Lower risk of perforation 
Air insufflation with rectal tube 
Radiation exposure
Incidental extracolonic findings
21
Q

If a flex sig is positive

A

colonoscopy to rule out proximal lesions (right sided)

22
Q

If a CT colonoscopy is positive

A

Colonoscopy

23
Q

The thing to remember about screening tests that check for blood

A

most polyps don’t bleed

24
Q

gFOBT definition

A

Fecal occult blood test (FOBT) , “stool Guaiac”
Identifies hgb by peroxidase reaction→ (+) blue paper
Hemoccult Sensa (gFOBT)→ take home, better sensitivity

25
Q

FIT definition

A

FIT=Fecal Immunochemical Test
Noninvasive test for presence of human hemoglobin
Preferred colorectal detection test

26
Q

FIT-DNA definition

A

FIT+ testing for altered DNA biomarkers in cells shed by CA
Noninvasive, expensive
Excellent negative predictive value

27
Q

Which stool test requires a special diet?

A

gFOBT
avoid red meat, iron supps
Vit C, NSAIDS

28
Q

Stool tests and false positives

A

gFOBT>FIT-DNA>FIT

29
Q

Stool tests specimen

A

gFOBT: 2 specimens on 3 consecutive stools

FIT: Single specimen of spontaneously passed stool

FIT-DNA: Entire bowel movement

30
Q

Start colon cancer screening at _____ for most individuals

A
50 years (average risk)
45 years (african americans)
31
Q

For high risk individuals, start colon cancer screening _______

A

Single first degree relative with colorectal cancer or advanced adenoma <60 years OR 2 1st degree relatives diagnosed at any age
Screen at 40 OR 10 years younger than age at which relative was diagnosed

Single first degree relative with colorectal cancer or advanced adenoma >60 years OR 2+ first degree relatives
Screening at age 40→ normal→ screen as average risk individual

32
Q

Discontinue colon cancer screening…

A

Up to date with screening
Negative prior screening
Age 75 or life expectancy <10 years

33
Q

For colon cancer screening among individuals aged 76-85

A

more beneficial in healthy adults who have never been screened
(depending on age/comorbidities)

34
Q

For colon cancer screening among individuals aged 76-85

A

more beneficial in healthy adults who have never been screened
(depending on age/comorbidities)

35
Q

Familial Adenomatous Polyposis genetics

A

Autosomal dominant APC gene mutation

36
Q

Hereditary Nonpolyposis Colon Cancer genetics

A

Autosomal dominant

Germline mutation in a DNA mismatch repair gene

37
Q

Lynch Syndrome

A

Hereditary Nonpolyposis Colon Cancer

38
Q

Familial Adenomatous Polyposis presentation

A

> 100 adenomatous polyps begin to emerge at 16 years→ all develop cancer by ~39 if untreated

Increased risk of extracolonic manifestations:
Gastric/duodenal/ampullary carcinoma
Follicular or papillary thyroid cancer
Hepatoblastoma in children, CNS tumors

39
Q

Familial Adenomatous Polyposis management

A
Genetic testing/counseling
Prophylactic colectomy
Screening:
SIgmoidoscopy/colonoscopy annually starting at age 10-12 until age 40
Routine EGD
Screening for extracolonic malignancies
40
Q

Hereditary Nonpolyposis Colon Cancer presentation

A

Increased risk of (right-sided) cancer by 45-60 years
Lifetime risk increased 22-75%
Multiple family members affected
Increased risk of multiple cancers:
Endometrial, ovarian, gastric, small bowel, hepatobiliary system, renal/ureter/bladder, brain

41
Q

Hereditary Nonpolyposis Colon Cancer management

A

Genetic testing/counseling

Screening:
Annual colonoscopy at 20-25 years OR 2-5 years prior to earliest diagnosed relative
Screening for extracolonic malignancies:
Pelvic + endometrial biopsy
Transvaginal ultrasound
EGD at 30-35 years q2-3 years

42
Q

3-2-1 rule

A

Amsterdam Criteria:
Diagnosis of Hereditary Nonpolyposis Colon Cancer
3 relatives across 2 successive generations, 1 diagnosed <50 years