L7: Colon polyps and cancer

Question 1

2 Non-neoplastic polyps (benign hyperplastic)

Answer 1

Hyperplastic

Pseudopolyps

Question 2

Who gets pseudopolyps?

Answer 2

IBD (they’re inflammatory)

Question 3

2 classifications of Neoplastic polyps

Answer 3

Adenomas

Sessile serrated polyps

Question 4

Facts about adenomas

Answer 4

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

Question 5

Most common adenoma which causes 95% of colorectal cancers

Answer 5

Tubular adenoma

Question 6

Types of adenomas

Answer 6

Tubular adenoma (most common)
Tubulovillous adenoma
Villous adenoma

Question 7

An adenoma is considered “advanced” if…

Answer 7

1 cm
villous or tubulovillous
high grade dysplasia

Question 8

Colorectal cancer is more common in the ______ colon

Answer 8

Left sided colon, but right sided rates are rising

Question 9

Risk factors for colorectal cancer

Answer 9

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

Question 10

Colorectal cancer presenation

Answer 10

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

Question 11

Colorectal cancer red flags

Answer 11

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

Question 12

Colorectal cancer diagnostics

Answer 12

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”

Question 13

Colorectal cancer mangement

Answer 13

Partial colectomy with wide margins and adjacent lymph node removal

Chemo→ metastasis

Radiation→ rectal adenocarcinoma

Question 14

Colorectal cancer surveillance

Answer 14

Serial CEA levels

Annual surveillance CT chest/abd/pelvis

Periodic colonoscopy

Question 15

What’s CEA used for again?

Answer 15

prognosis
monitor for recurrence
NOT for screening

Question 16

Gold standard for colon cancer screening

Answer 16

Colonoscopy

Question 17

Colonoscopy sees
Flex sig sees
CT Colonography sees

Answer 17

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

Question 18

Considerations for colonoscopy

Answer 18

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

Question 19

Considerations for flex sig

Answer 19

Limited prep, no sedation
Lower cost
Lower risk of perforation

Question 20

Considerations for CT colonography

Answer 20

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

Question 21

If a flex sig is positive

Answer 21

colonoscopy to rule out proximal lesions (right sided)

Question 22

If a CT colonoscopy is positive

Answer 22

Colonoscopy

Question 23

The thing to remember about screening tests that check for blood

Answer 23

most polyps don’t bleed

Question 24

gFOBT definition

Answer 24

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

Question 25

FIT definition

Answer 25

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

Question 26

FIT-DNA definition

Answer 26

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

Question 27

Which stool test requires a special diet?

Answer 27

gFOBT avoid red meat, iron supps Vit C, NSAIDS

Question 28

Stool tests and false positives

Answer 28

gFOBT>FIT-DNA>FIT

Question 29

Stool tests specimen

Answer 29

gFOBT: 2 specimens on 3 consecutive stools FIT: Single specimen of spontaneously passed stool FIT-DNA: Entire bowel movement

Question 30

Start colon cancer screening at _____ for most individuals

Answer 30

``` 50 years (average risk) 45 years (african americans) ```

Question 31

For high risk individuals, start colon cancer screening _______

Answer 31

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

Question 32

Discontinue colon cancer screening...

Answer 32

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

Question 33

For colon cancer screening among individuals aged 76-85

Answer 33

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

Question 34

For colon cancer screening among individuals aged 76-85

Answer 34

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

Question 35

Familial Adenomatous Polyposis genetics

Answer 35

Autosomal dominant APC gene mutation

Question 36

Hereditary Nonpolyposis Colon Cancer genetics

Answer 36

Autosomal dominant | Germline mutation in a DNA mismatch repair gene

Question 37

Lynch Syndrome

Answer 37

Hereditary Nonpolyposis Colon Cancer

Question 38

Familial Adenomatous Polyposis presentation

Answer 38

>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

Question 39

Familial Adenomatous Polyposis management

Answer 39

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

Question 40

Hereditary Nonpolyposis Colon Cancer presentation

Answer 40

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

Question 41

Hereditary Nonpolyposis Colon Cancer management

Answer 41

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

Question 42

3-2-1 rule

Answer 42

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