colon polyps and cancer Flashcards by Melicia Sanchez

what is a polyp?

growth on inner surface of colon

some undergo malignant transformation and some don’t

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endoscopic features of colon polyps?

pedunculated –> attached by stem/stalk

sessile –> flat

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what are the different types of polyps?

Hyperplastic (non-neoplastic)
“Pseudopolyps” (non-neoplastic) seen w/IBD
Adenomas (neoplastic - “pre-cancerous”)
Sessile serrated polyps (pre-cancerous)

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what are the different types of adenomas (polyps)?

Tubular = MC
Tubulovillous
Villous

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Adenomas are MC at what age?

> 50

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why is early detection of colon polyps key?

70% of colorectal cancers arise from adenomas

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characteristics of “advanced” adenomas?

≥ 10 mm in size
Villous component (Villous or tubulovillous)
High grade dysplasia

** Risk of CRC increases by #, size, and histology

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what is colorectal cancer?

Malignant growth on the inner wall of the colon and/or rectum

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MC site of origin of CRC?

LEFT side

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Risk factors for CRC:

Personal or Family hx:

Adenomas or Colon CA
FAP (Familial Adenomatous Polyposis)
HNPCC (Hereditary nonpolyposis colon cancer)

Age >50, IBD >8-10 years, AA,

Modifiable –> smoking, excess alcohol intake, diet, T2DM, obesity

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presentation for CRC

Patients are often asxs

cachectic, pallor, lymphadenopathy, abd distention, ascites, mass, oragnomegaly, DRE w/heme + stool, rectal mass

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Red flags for CRC

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

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labs for CRC?

CBC –> Fe def anemia
LFT–> alk phos elevated w/liver mets
Carcinoembryonic –> prognostic indicator

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diagnostic studies for CRC?

colonoscopy

chest/abd/pelvic CT

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Describe the TNM system

Tumor – > depth of tumor invasion
Node –> regional lymph node involvement
Metastasis –> presence or absence of metastasis

Staging 0-4

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management of CRC

Partial colectomy
chemotherapy (if metastasis)
radiation therapy

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surveillance for CRC?

Serial CEA levels every 3-6 months for 3-5 years

CT chest/abd/pelvis annually

Colonoscopy within one year of resection (if normal repeat in 3yrs –> every 5 yrs)

what is screening?

Process of detecting early-stage CRCs and precancerous lesions in asxs pts w/ no prior hx

what is surveillance?

F/u testing (interval use of colonoscopy) in patients with history of polyps, CA, or IBD

what are some preventative tests that can detect colon polyps and CRC?

Colonoscopy
Flex Sigmoidoscopy
CT Colonography

what are some stool tests that can detect but don’t prevent CA?

gFOBT (Hemoccult SENSA)
FIT (Fecal Immunochemical Test)
FIT-DNA (Cologuard®)

what is the gold standard for CRC screening tests?

colonoscpy (diagnostic AND therapeutic): ability to visualize entire colon, remove polyps, take bx’s

describe a colonoscopy

Requires bowel preparation
Requires sedation/chaperone
Invasive/risk of major complications
not infallible (operator dependent & can be missed if bad prep)

when should pt have repeat colonoscopy following a polypectomy?

of polyps, size, histologic features

Endoscopist provides recommendations for repeat scope

Describe the flex sigmoidoscopy?

Reaches to ~ 60 cm (distal 1/3 of colon) - can miss proximal (R-sided CA) limited prep (enema), no sedation, lower cost, lower perf risk

what is a CT colonography?

“Virtual” colonoscopy Sensitivity of detecting polyps > 1 cm is 90% (can miss flat or smaller polyps) unable to remove polyps or do bx if positive --> colonoscopy radiation exposure

what is the hemoccult SENSA test?

take-home guaiac test recommended (better sensitivity)

what is GFOBT screening test?

Guaiac based test – identifies hgb by a peroxidase rxn (if + paper turns blue) Requires two specimens on 3 consecutive stools False + stimulates many colonoscopies special diet recommended (red meat)

what is the FIT screening test for CRC?

Noninvasive Tests for presence of human hgb Less false +'s than FOBT Single specimen of spontaneously passed stool No dietary restrictions Preferred CRC detection test (ACG)

what is the FIT-DNA (Cologuard) screening test?

Combines FIT with testing for altered DNA biomarkers in cells shed by CRC, noninvasive requires entire BM & > False positives than FIT

CRC screening for average risk according to MSTF?

start at 50y/o unless AA than 45y/o colonoscopy and FIT

CRC screening for increased risk according to MSTF?

FHx: single 1st deg relative or advanced adenoma dx < 60 y/o OR two 1st deg relative dx any age Single 1st degree relative w/ CRC or advanced adenoma dx ≥ 60 y/o or ≥ two 2nd degree relatives -->> Begin screening at age 40 and if normal screen as average risk

when do you discontinue CRC screening according to MSTF?

UTD w/screening neg prior screen age 75 life expectancy < 10yrs no screening consider up to age 85y/o

when do you discontinue CRC screening according to USPSTF?

Begin screening avg risk, asymptomatic adults at age 50 and continue until age 75 Decision to screen for CRC in 76-85 y/o should be individualized

How often should prevention tests be performed?

colonoscopy = every 10yrs CT colonography = every 5yrs Flexible sigmoidoscopy = every 5-10yrs (10yrs w/annual FIT)

how often should screening tests that detect colon cancer be performed?

gFOBT = annually FIT = annually FIT-Fecal DNA = every 1-3yrs

what is familial adenomatous polyposis (FAP)?

autosomal dominant, APC gene mutation >100 adenomatous polyps ~ 16 y/o will develop CRC by age 39 if untrx'd increased risk of extracolonic malignancies

what are extracolonic malgnancies?

Gastric/Duodenal/Ampullary carcinoma Follicular/Papillary thyroid cancer Hepatoblastoma (children) CNS tumors

who should receive FAP screening and what does it involve?

screen pts who are gene carriers or fam hx w/out genetic confirmation Sigmoidoscopy/Colonoscopy annually starting at age 10-12 until 40 if neg Routine EGD recommended

what is HNPCC?

aka "lynch" syndrome, autosomal dominant Increased risk for CRC (usu R-sided); aged 45-60 y/o Multiple family members affected Increased risk of multiple CA: Endometrial (MC)

Screening for HNPCC?

Screen w/colonoscopy every 1-2 yrs beginning at age 20-25 or 2-5 years prior to earliest age of onset of affected family member extracolonic malignancies (pelvic exam, transvag u/s, EGD)

what criteria is used for HNPCC diagnosis?

Amsterdam Criteria "3-2-1 rule" 3 affected members, 2 generations, 1 under age 50