Colon cancer Flashcards
What is a colon polyp
Growth on the inner surface of the colon
Can undergo malignant transformation, but not always
What are endoscopic features of colon polyps
Pedunculated (attached by stem/stalk)
Sessile (flat)
How can you histologically classify polyps
Hyperplastic (non-neoplastic)
Pseudopolyps (non-neoplastic)- ass. w/ IBD
Adenomas (neoplastic, pre-cancer)
Sessile serrated (pre-cancer)
What are the types of adenomatous polyps
Tubular adenoma (MC)- may bleed if large, but not common for any polyp to bleed
Tubulovillous adenoma
Villous adenoma
Key to surviving an adenoma in the colon is
Early detection and removal
It takes appx 10 years for a polyp to morph into adenocarcinoma
What is an “advanced” carcinoma
> 10mm in size
Villous component (villous, tubulovillous)
High grade dysplasia
(risk of colorectal cancer is higher 2/2 size, #, and histology)
Highlight:::
Go over the "take away" slides in this ppt to review 13 29 54 65 66
What is colorectal cancer
malignant growth on the inner wall of the colon/rectum
>95% are adenocarcinomas
Where is CRC MC found
Left colon (sigmoid) however right sided colon cancer rates are rising
What are some RF for CRC
FHx of adenomas, colon cancer, FAP, HNPCC
>50
Hx of IBD x 8-10 years
African American
Smoking, excess alcohol, high fat low fiber diet, a lot of red meat, T2DM, obesity
How does CRC present
ASx!! So watch for red flags: Change in bowel habits Hematochezia/Occult blood in stool Iron deficiency anemia Anorexia, weight loss Abdominal pain
On PE for CRC what may you find
Cachectic skin pallor LAD Abdominal distention, ascites, mass, organomegaly DRE: hemoccult +, rectal mass
What diagnostics should you complete for CRC
CBC: iron deficiency anemia
LFT: Elevated Alk Phos
Carcinoembryonic antigen (CEA) a prognostic indicator and monitoring marker
Colonoscopy
Chest, Abd/pelvic CT: tumor extension, complication, regional lymphatic and distant mets
Classic CRC finding on imaging is
Apple core lesion
How do you stage colon cancer
Based on TNM system; Tumor, Nodes, Mets
Stage 0-4
How do you manage colon cancer
Partial colectomy w/ wide margins and adjacent lymph node removal
Chemotherapy (if mets present)
Radiation (for rectal carcinoma)
What does CRC surveillance include
Serial CEA q3-6 months for 3-5 years
CT chest, A&P yearly
Colonoscopy w/in 1 yr of resection. If normal, repeat in 3 years. If normal, q5 years
How are screening and surveillance different
Screen: detecting early stage CRC and precancerous lesions in ASx people with NO prior Hx
Surveillance: follow up testing in pt w/ Hx of polyps, CA, or IBD
What tests can be used for screening
Preventive: colonoscopy, flex sig, CT colonography Stool test (detect but do not prevent): gFOBT, FIT, FIT-DNA
What is gold standard diagnostic AND therapeutic test
Colonoscopy
Can visualize the entire colon, remove polyps, take biopsies
Detect precancerous lesions and CRC
What does a colonoscopy require
Bowel prep (if not done correctly, can block masses)
Sedation
Chaperone
Time off from work
-Invasive and has risk of complications. Also depends on operator efficacy
What is a polypectomy
Ligation and resection of a pedunculated polyp
Do you need surveillance after a polypectomy
Yes, frequency depends on # of polyps, size, and histologic features
What is a Flex Sigmoidoscopy
limited colonoscopy that reaches distal 1/3 of colon (less protection against right sided cancer)
If you do find polyps, need to do a colonoscopy to assess proximal colon
Only need an enema prep
No sedation required
Lower cost
Lower risk of perforation
What is a CT colonography
Virtual colonoscopy created with CT scans
Can easily miss flat or smaller polyps
Can’t remove a polyp if you find one- will need colonoscopy
Still need bowel prep, but no sedation
Get a lot of radiation exposure
Air insufflation w/ rectal tube is not comfortable
What is a gFOBT test
Fecal occult blood test, ID hgb by a peroxidase reaction (+ if paper turns blue)
Hemoccult SENSA is a take home guaiac test, more sensitive
Need 2 specimens on 3 consecutive stools
False + leads to colonoscopies
Do special diet prior to testing; no red meat, iron, vitamin C, or NSAIDs
What is a FIT test
non-invasive test for presence of hgb
less false + than FOBT
Single specimen of spontaneously passed stool
No diet restrictions
What stool test is preferred for CRC detection
FIT test!
What is FIT-DNA test
Combines FIT with testing for altered DNA markers in cells shed by CRC non-invasive Higher rate of false + No diet restrictions Requires entire bowel involvement
When should you start CRC screening for ASx with no RF
at age 50 (45 for black)
Colonoscopy and FIT tests should be considered first
(american cancer society says start in 45 for everyone)
When should you start CRC screening in high risk pt
Colonoscopy q5 years starting at 40 y/o, or 10 years prior to age of family member diagnosed
-If it is one 1st degree relative dx 60+ or 2 second degree, screen at 40 and if normal, they are average risk
When should you stop colon cancer screening per MSTF
Up to date with screening Negative prior screening 75+ Life expectancy <10 years No prior screening at 85 y/o
When do you stop colon cancer screening per USPSTF
Start screening at 50, stop at 75
Individualize need to screen 76-85 y/o (healthy never been screened more likely to benefit)
How often can you use screening tests
colonoscopy: 10 years CT colonography: 5 years Flex Sig: every 5-10 years gFOBT: yearly FIT: yearly FIT-DNA: q1-3 years
What do you have to convey well to patients when reviewing screening
That abnormal results require a colonoscopy for further visualization
What is familial adenomatous polyposis
Auto Dom disease 2/2 ACP gene mutation
Causes polyps to emerge around 16 y/o, with almost 100% developing CRC by 39 y/o if not treated
Increased risk of extra-colonic malignancies
How do you treat FAP
Prophylactic colectomy
What extracolonic malignancies are associated with FAP
Gastric, duodenal, ampullary carcinoma
follicular or papillary thyroid cancer
hepatoblastoma in kids
CNS tumor
If a family member has FAP, when should you screen the kid
Sigmoidoscopy or colonoscopy annually starting at 10-12 years old
Routine EGD recommended
Thyroid US and other to r/o extracolonic malignancies
What is HNPCC
Auto dom syndrome (lynch syndrome) 2/2 germline mutation in 1 of several DNA mismatch repair genes
Increased risk of CRC by 45-60 y/o
Multiple family members are affected!
Increased risk of multiple cancers
What cancer is associated with HNPCC
Endometrial (MC)
ovary, gastric, small bowel renal, ureter, brain
How do yuo diagnose HNPCC
Amsterdam criteria for lynch syndrome has “3-1-2” rule
3: need 3 consecutive relatives
2: need 2 successive generations affected
1: one fam member diagnoses before 50
What is the HNPCC screening crazy
Colonoscopy q1-2 years starting at 20-25, or 2-5 years prior to earliest stage of diagnosis of family
HNPCC screening also manages what extra-curricular activities
Pelvic exam w/ endometrial bx and transvaginal US
EGD (starting at 30-35, q2-3 years)
