Feb27 M1-Colorectal Cancer Screening

Question 1

dx test vs screen

Answer 1

screen = just to check

dx test = suspect disease

Question 2

signs and symptoms in colorectal cancer

Answer 2

• bowel habit changes
• bleeding (BRBPR)
• abd pain, bloating
• incomplete evacuation
• weight loss (cancer cachexia)
• fatigue (anemia, liver metastases)

Question 3

(IMPORTANT) big 3 cancers in adults

Answer 3

lung, breast, colorectal

Question 4

(IMPORTANT) how cancer incidence differs in age groups

Answer 4

adults 30+: the big 3

youth: different cancers have the higher incidences (CNS AND LEUKEMIA in youth)

Question 5

how incidence and prevalence of CRC (colorectal cancer) changing

Answer 5

worlwide: increasing incidence
Canada: decreasing incidence
Increasing prevalence

Question 6

normal seq of CRC dev

Answer 6

normal - proliferative epithelium - adenoma - carcinoma

Question 7

how CRC develops

Answer 7

series of genetic alterations over 7-10 yrs: FIRST HEAT IS APC (adenomatous polyposis coli gene)

Question 8

order of genetic hits in CRC

Answer 8

APC (get proliferative epithelium), 18q deletion, TP53 = CA

Question 9

2 hereditary CRC

Answer 9

FAP (familial. no APC). 
Lynch syndrome (germline mutation in mismatch repair genes)

Question 10

2 pathways to CRC

Answer 10

• chromosomal instability (sporadic)

- microsatellite unstability (mismatch repair genes)

Question 11

MMR genes problems (micro sat unstability): CRC is where + often related to what

Answer 11

• right side CRC

- linked with hereditary non polyposis colon cancer (HNPCC)

Question 12

non modif risk factors in CRC

Answer 12

age, ethnic background (ashkenazi jews and african americans), genetics (heredity)

Question 13

modif risk factors in CRC

Answer 13

• diet
• phys activity
• meds
• other conditions (diabetes, obesity)

Question 14

what age CRC risk rises a lot and consequence

Answer 14

50 yrs old. so gvt screening starts at 50

Question 15

diet factors in CRC

Answer 15

• red meat (iron, N-nitroso compounds, polycyclic aromatic hydrocarbons, heterocyclic amines, heme)
• fruits may help (antioxidants: indoles, carotene)
• dietary fiber: less ADENOMA (should help for less CA in theory)

Question 16

micronutrients in CRC

Answer 16

Ca, vit D and dairy helps

Question 17

diet types in CRC

Answer 17

• alcohol bad
• medit diet good
• prudent diet good (poultry, fish, fruits)

Question 18

meds in CRC

Answer 18

aspirin and NSAIDS reduce CRC risk

Question 19

obesity, exercise in CRC

Answer 19

• obesity = higher risk
• exercise = less risk
• estrogens (women) decrease risk

Question 20

fecal occult blood test (FOBT) at home (3x over 7 days): benefit

Answer 20

15-33% reduction in CRC mortality

Question 21

overt vs obscure vs occult bleeding

Answer 21

overt = see blood
obscure = see blod but don't know where it's from
occult = only seen on test (not with eyes)

Question 22

importnt thing in FOBT

Answer 22

helps even more to reduce mortality if done every year instead of every 2 years (age 50 to 74)

Question 23

(IMPORTANT) DX TEST done if FOBT is positive

Answer 23

FULL OPTICAL COLONOSCOPY

Question 24

how FOBT helps

Answer 24

indirectly leads us to go and find the polyp and remove it

Question 25

better version of FOBT

Answer 25

fetal IHC test (FIT test): more SENSITIVE. no diet restriction. DISTAL GI blood

Question 26

(IMPORTANT) DX test if FIT test is positive

Answer 26

FULL OPTICAL COLONOSCOPY

Question 27

NNT of FIT test

Answer 27

200. is a good number

Question 28

to remember in FIT test and FOBT

Answer 28

bleeding may have other cause than CRC (polyp)

Question 29

radiological tests for CRC screening + in who

Answer 29

1. barium enema (double contrast): look for apple core lesion 2. virtual colonography: CT scan reconstruct inside of colon FOR NORMAL ASYMPTOMATIC person

Question 30

(IMPORTANT) DX test if radiological screening for CRC is positive

Answer 30

FULL OPTICAL COLONOSCOPY

Question 31

barium enema problems

Answer 31

not best test for sensitivity + not proven to help for CRC mortality

Question 32

virtual colonoscopy problem

Answer 32

need bowel prep + insufflate air with no sedation, very uncomfortable for pt

Question 33

optical tests for CRC + important principle

Answer 33

-flexible sigmoidoscopy -colonoscopy REDUCE MORTALITY 50%

Question 34

(EXAM) 6 screening recommendations)

Answer 34

1. high sens FOBT or FIT ANNUALLY 2. flexible sigmoidoscopy every 5 years + FOBT or FIT annually 3. double contrast barium enema every 5 years 4. CT colonography every 5 years (air thing) 5. colonoscopy every 10 yrs 6. fecal DNA testing

Question 35

(EXAM) preferred strategy for screening

Answer 35

colonoscopy every 10 years

Question 36

(EXAM) screening for CRC in Quebec

Answer 36

annual FIT

Question 37

(EXAM) BLOOD in stool or Lynch patients: screening recommendations

Answer 37

annual colonoscopy

Question 38

(EXAM) why annual FIT test if choose flexible sigmoidoscopy every 5 years

Answer 38

to not miss right sided cancers and polyps. (sigmoidoscopy covers left side, sigmoid and rectum)

Question 39

(EXAM) where most CRC cancers occur

Answer 39

left side, sigmoid colon and rectum

Question 40

(EXAM) normal mucosa to cancer time

Answer 40

7-10 years