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MS2 GI > 10/9- Colorectal Cancer Syndromes and Screening > Flashcards

10/9- Colorectal Cancer Syndromes and Screening Flashcards

1
Q

Colorectal cancer is the __ most common cancer among men and women in the US

  • __ leading COD of cancer
  • Can largely be prevented with _____
A

Colorectal cancer is the 3rd most common cancer among men and women in the US

  • 2nd leading COD of cancer
  • Can largely be prevented with CRC screening
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2
Q

What is the lifetime risk of colorectal cancer?

A

5%

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3
Q

Death rates of colorectal cancer (male vs. female)?

A

Death rates per 100,000

Male: 32%

Female: 28%

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4
Q

What is the 5 yr survival rate if found at local stage?

A

Local stage: 90% 5 yr survival

  • Only 40% diagnosed at early stage (low screening rates)
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5
Q

What are the stages of colon cancer?

A

Polyp

  • Most colon cancers develop from these nancancerous growths

In situ

  • Cancer has formed but is not yet growing inside the colon or rectum walls

Local

  • Cancer is now growing int he colon or rectum walls; nearby tissue unaffected

Regional:

  • Growth beyond the colon or rectum walls and into tissue or LNs

Distant:

  • Cancer has spread to other parts of the body such as liver or lungs
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6
Q

The adenomatous polyp is precursor of __% of colorectal cancers

  • Sequence?
A

The adenomatous polyp is precursor of 90% of colorectal cancers

  • Adenoma to carcinoma sequence: 7-10 yrs
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7
Q

What are clinical features related to polyps and cancer risk?

A

Polyp size correlates to probability of containing cancer:

  • Polyps < 1.5 cm: < 2%
  • Polyps > 2.5 cm: 10%

Histology: villous > tubulovillous > tubular

Number of polyps

Appearance: sessile vs. pedunculated

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8
Q

___% of population will develop adenomatous polyps over lifetime

__% of polyps become malignant

__% of CRC diagnosed after __ yo

A

30-50% of population will develop adenomatous polyps over lifetime

1-3% of polyps become malignant

>90% of CRC diagnosed after 55yo

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9
Q

Is more colorectal cancer sporadic or familial?

A

Sporadic

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10
Q

What are risk factors for colorectal cancer?

A

Age: 90% of cases occur in people > 50yo

Gender: slight male predominance (but occur in both)

Race/ethnicity:

  • African Americans have highest incidence and mortality rate of all groups in U.S. (it has been recommended to start screening at age 45)
  • Increased rates also documented in Alaska natives, some American Indian tribes and Ashkenazi Jews

Increased risk also with:

  • Personal history of inflammatory bowel disease, adenomatous and serrated polyps or colon cancer
  • Family history of adenomatous polyps, colon cancer or other conditions (including hereditable gastrointestinal polyposis syndromes)
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11
Q

What are screening recommendations based on different degrees of family history/risk?

A
  • Screening colonoscopy is recommended at age 40 or 10 years before the youngest relative’s diagnosis, to be repeated every 5 years:*
  • If a single 1st degree relative was diagnosed before 60 years with CRC or advanced adenoma
  • If ≥2 relatives had CRC or advanced adenomas at any age
  • Advised to be screened as average-risk persons beginning at age 50*
  • For individuals with some increased risk (1st degree relative with CRC or advanced adenoma diagnosed >60 years)
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12
Q

What are dietary factor risks for CRC?

A
  • High fat diets correlate w/ high rates of CRC
  • Protective effects of fiber are still unproven
  • Excessive calorie intake may enhance risk
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13
Q

What are behavior factor risks for CRC?

A
  • Physical activity may reduce risk
  • Excessive alcohol use and smoking have been associated with increased risk
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14
Q

What is infectious risk for CRC?

A

Streptococcus Bovis Bacteremia

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15
Q

What are clinical features of CRC?

A
  • Right sided- may be asymptomatic, or have symptoms of anemia
  • Tumors more distal may have symptoms related to obstruction of the passage of stool
  • Distal tumors may also present with bright red blood
  • Unexplained Iron deficiency anemia warrants endoscopic evaluation
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16
Q

What is flexible sigmoidoscopy?

  • Can identify what
  • Sedation needed?
A
  • Identifies lesions in the distal 60 cm of the bowel
  • Requires minimal patient preparation
  • Does not require sedation
  • Performed by trained clinicians
  • Abnormal findings require a full colonoscopy
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17
Q

What is colonoscopy?

  • Requires what
  • Miss rate
A
  • Requires bowel preparation
  • Conscious sedation
  • Lesions can be removed during the procedure
  • Risk of perforation (3/1000) and bleeding
  • 5-10% miss rate
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18
Q

What is a Double Contrast Barium Enema

  • Visualizes what
  • Safety
  • Miss rate
A
  • Visualizes the entire large bowel
  • Relatively safe
  • Detects 50% of >1cm polyps
  • Positive test requires colonoscopy
19
Q

What is CT colonography?

  • Requires what
  • Risks
A
  • Requires aggressive bowel preparation
  • Does not require sedation
  • Positive findings require colonoscopy
  • Extracolonic findings
  • Cumulative dose of radiation may increase cancer risk
  • Most insurance companies do not currently cover CTC as a screening modality

Picture-

Left: colonoscopy

Right: CT?

20
Q

What is patient preference for CRC screening tests?

A
  • Colonoscopy was the preferred test
  • Patients were least satisfied with DCBE
21
Q

What is FOBT?

A

Fecal Occult Blood Test

  • Low sensitivity for polyps
  • Low specificity for significant disease therefore leading to workup on false positive testing
  • Non-invasive
  • Inexpensive
  • Positive tests require a colonoscopy
22
Q

Compare the sensitivity of take home vs. in office FOBT

A
23
Q

What is FIT?

  • How does it compare to FOBT?
A

Fecal immunochemical test (FIT)

  • More expensive than guaiac-based tests
  • Higher sensitivity for detecting advanced colorectal neoplasia than guaiac-based tests
  • Does not require a restricted diet; only detects human globin
  • Does not detect UGI bleeding
  • Positive tests should be followed up with colonoscopy
  • (No use in acute setting/acute GI bleeding)*
24
Q

What does stool DNA (DNA) look for?

  • Sensitivity?
A

Stool DNA tests look for abnormal DNA from cells that are passed into stool

  • Sensitivity for cancer with one time testing 46-91%
  • DNA testing detected more cancers than FIT, but had more false positives (leading to unnecessary testing)
25
Q

When should you stop screening patients?

A

When a patient’s life expectancy is less than 10 years

26
Q

Don’ts of Colon Cancer Screening

A
  • Don’t perform stool testing after someone has had a colonoscopy
  • Don’t check FIT testing on young patients or in the setting of acute GI bleed
27
Q

What are surveillance guidelines for the following conditions?

A
28
Q

What is CEA?

  • Uses
A

Tumor marker: carcinoembryonic antigen

  • Used for monitoring/recurrence but NOT for screening
29
Q

Take home points:

  • ______ should be the primary goal of colon cancer screening
  • Screening of average-risk individuals can reduce CRC mortality by detecting cancer at an early, curable stage and by detecting and removing clinically significant adenomas
  • All screening tests aside from colonoscopy require a colonoscopy if positive
A
  • Colon cancer prevention should be the primary goal of colon cancer screening
  • Screening of average-risk individuals can reduce CRC mortality by detecting cancer at an early, curable stage and by detecting and removing clinically significant adenomas
  • All screening tests aside from colonoscopy require a colonoscopy if positive
30
Q

What are some autosomal dominant inheritable GI syndromes?

A
  • Familial Adenomatous Polyposis
  • Lynch Syndrome
  • Peutz-Jeghers Syndrome
  • Juvenile Polyposis
31
Q

Characteristics of Familial Adenomatous Polyposis (FAP):

  • __% of CRC
  • Genetic inheritance
  • Gene
  • Disease characteristics
A
  • 1% of CRC
  • Colorectal cancer in these pts is inevitable
  • Autosomal Dominant
  • Mutation of APC (Adenomatous Polyposis Coli) gene, located on chromosome 5
  • Hundreds to thousands of adenomas in colon
32
Q

What is the typical clinical course of CRC with FAP pts?

A
  • 15 yo onset of polyps
  • 33 yo symptoms appear
  • 39 yo colorectal cancer
  • 42 yo death
33
Q

What is Gardner’s syndrome?

A

Variant of FAP

Extra-intestinal manifestations including:

  • Soft tissue and bony tumors
  • Congenital hypertrophy of the retinal pigment epithelium
  • Mesenteric desmoid tumors
  • Ampullary cancers
34
Q

What are screening recommendations for FAP?

A
  • Annual flexible sigmoidoscopy starting at age 12 OR
  • DNA testing for mutation of APC gene
35
Q

Treatment of FAP?

A

Colectomy- preferably with the removal of the rectum because of risk of rectal ca

36
Q

What is Lynch Syndrome?

  • Genetic inheritance
  • Gene
  • Location
  • Age of onset
  • Lifetime risk of CRC
A
  • Previously known as HNPCC
  • Autosomal Dominant
  • Mismatch repair gene mutation with subsequent microsatellite instability
  • Proximal location of colorectal cancer
  • Early age of onset of colorectal cancer
  • 70-80% lifetime risk of CRC
37
Q

What is the Amsterdam Criteria?

A

For Lynch Syndrome: (3-2-1 rule)

  • 3 or more relatives with CRC, 1 is a 1st degree of the other 2
  • CRC involving 2 generations
  • ≥ 1 CRC case diagnosed before the age of 50
38
Q

What are the revised Bethesda guidelines regarding CRC tumors and testing for MSI?

A

Tumors from individuals should be tested for MSI in the following situations:

  1. Colorectal cancer diagnosed in a patient who is less than 50 years of age.
  2. Presence of synchronous, metachronous colorectal, or other HNPCC-associated tumors, regardless of age
  3. Colorectal cancer with the MSI-H histology diagnosed in a patient who is less than 60 years of age.
  4. Colorectal cancer diagnosed in one or more first-degree relatives with an HNPCC-related tumor, with one of the cancers being diagnosed under age 50 years.
  5. Colorectal cancer diagnosed in two or more first- or second-degree relatives with HNPCC-related tumors, regardless of age.
39
Q

What is Lynch Syndrome prognosis?

A
  • Better prognosis than sporadic CRC
  • Multiple primary malignancies including:
  • Endometrial
  • Ovarian
40
Q

Screening for Lynch Syndrome?

A
  • Screen 1st degree relatives with genetic testing or
  • Colonoscopy every 1-2 years starting between 20-30 and annually after age 40
  • Endometrial cancer screening
41
Q

What is Turcot syndrome?

A

Colorectal cancer or colorectal adenomas in addition to tumors of the central nervous system. (FAP or Lynch syndrome + CNS tumor)

42
Q

What is Peutz-Jeghers Syndrome?

  • Genetic inheritance
  • Disease manifestations
  • Transformation
  • Histology
  • Associated lesions
A
  • Autosomal Dominant
  • Polyps occur in small intestine, but can also be in colon and stomach
  • Increased risk for GI cancer
  • Neoplastic transformation of PJ polyp is infrequent
  • Histology: Hamartoma Associated lesions
  • Mucocutaneous pigmentation
  • Tumors of the ovary, breast, pancreas, and endometrium
43
Q

What is Juvenile Polyposis?

  • Genetic inheritance
  • Histology
  • Disease manifestations
  • Risk
A
  • Autosomal Dominant
  • Histology: hamartoma
  • Polyps can be present in the large, small intestine and stomach
  • Increased risk for development of colon cancer

MS2 GI (26 decks)

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