Colon Cancer

Question 1

Colorectal cancer – risk factors
Unmodifiable

Answer 1

• Age
• Risk increases with age.
• 90% of new diagnoses in those > 55
years.
• Personal history
• Family history
• Inherited disorders such as familial
adenomatous polyposis (FAP) or
Lynch Syndrome.
• Inflammatory bowel disease
(ulcerative colitis or crohn’s disease)
substantially increases risk

Question 2

Colorectal cancer – risk factors
modifiable

Answer 2

• Diabetes Mellitus (RR of 1.38)
• Obesity and high waist circumference
(RR 1.334 and 1.455 respectively)
• Lifestyle
• Alcohol consumption (> 2 drinks per day) limit alcohol
• Smoking (increased risk and
mortality)
• Diet (high in red meats and processed meats, low in fresh fruits and vegetables) - dont eat a lot of fibre
• Low physical activity levels

Question 3

Colon Cancer Prevention

Answer 3

 Health diet
 limit intake of red meat and processed meat
 Eat foods high in dietary fibre
 Limit alcohol
 Moderate to high activity level
 evidence stronger for colon than rectal cancer
 Smoking cessation
 Early detection through screening – MOST IMPORTANT

Question 4

CRC Screening for Average Risk Canadians

Answer 4

• Data from RCTs shows screening reduces incidence of late stage CRC and CRC mortality
– Only risks of screening are those associated with follow up investigations
• Average-risk, asymptomatic, age 50-74
– Fecal Immunochemical Test (FIT) every 1-2 years
– If positive, promptly follow-up with colonoscopy
– If colonoscopy is normal, restart FIT screening at 10 years (unless quality of colonoscopy is questionable, then its 5 years)
• If symptomatic, screening should NOT be done with FIT (Increased diarrhea)

Question 5

screening for age >75

Answer 5

• Average risk, age ≥75
• individualized decision.
• As a general practice, if asymptomatic with life expectancy < 10 years,
don’t screen.
• >75 at higher risk of having a positive FIT test and then bleed from
colonoscopy, especially with co-morbidities.

If someone will probably pass away with something else, might not screen them

Question 6

CRC Screening for Increased Risk Albertans

how to screen for family history

Answer 6

• Family History:
• If one first degree relative diagnosed with CRC at 60 years or older, then
initiate screening with FIT test q1-2 years at 40 years.
• If one first degree relative with CRC (or high risk adenomas) diagnosed at UNDER 60 or two or more affected relatives then refer for consideration of
colonoscopy at age 40, or 10 years prior to the index case, whichever is earliest

Question 7

CRC Screening for Increased Risk Albertans

how to screen for personalhistory

Answer 7

• Personal history of CRC, colonic adenomas or Inflammatory Bowel Disease,
ongoing monitoring/follow up with colonoscopy

Question 8

CRC Screening for High Risk Albertans

who are high risk?

Answer 8

• Example Lynch syndrome (germline mutation) or FAP
• Patient to be closely monitored by local CRC screening program (FIT test
is insufficient screening).

Question 9

how does Fecal Immunochemical Test (FIT) work?

Answer 9

• Home stool test
• Different ways to collect stool:
– a hat-shaped plastic container placed over the toilet bowl or loosely placed plastic wrap over the toilet bowl
• FIT uses antibodies for human blood to find trace
amounts of blood
– Patients do not need to change their diet
– *FIT test can reduce CRC mortality by 25-45%
• Guaiac fecal occult blood testing (gFOBT)
– an alternate screening test using chemical reaction
– similar specificity but lower sensitivity than FIT

Question 10

Screening – Things to think about

Answer 10

• A recent cross-sectional study on screening rates
determined that 55.2% of Canadians between 50-74
were being screened appropriately
• Endoscopy with removal of precancerous lesions
(polyps) reduces risk
• Colorectal cancer is over 90% curable if detected early
• Our screening rates are not good enough

Question 11

Colorectal cancer – signs and
symptoms

Answer 11

• Change in bowel habits
• Tenesmus: Recurrent inclination to evacuate the bowels (always have to go)
• Change in stool shape
• Melena
• Dark sticky feces (containing partly digested blood)
• Weight loss (unexplained)
• Fatigue
• Pallor (pale) - may be becoming anemic
• Ileus
• Obstruction of ileum or other part of the bowel

Always feek kike they have to go

Any cancer - losing weight, tired
Eat up energy ewith mass of cells

Question 12

Colon Cancer - Workup
• Before resecting the mass/lesion (before
surgery)

Answer 12

– Colonoscopy to explore (rule out) existence of other
malignancies/masses
– CT chest, abdomen, pelvis to explore (rule out) existence of
metastases and to provide base line for surveillance
– Pre-operative CEA (and postoperative CEA if high pre-op)
• Can be a prognostic biomarker of poorer survival

Question 13

what is most important prognostic factor of colorectal cancer

Answer 13

5 year overall survival (OS) by stage
• Stage is the most important prognostic factor:
– Stage I – 93%
– Stage II – 78%
– Stage III – 64%
– Stage IV – 8%

Question 14

Goals of Therapy
• Overall, roughly speaking:
– For Stage I, II, III goals are:

Answer 14

• CURE of disease
• Minimizing toxicities of treatment
• Maintaining /Improving quality of life

Question 15

Goals of Therapy
stage IV

Answer 15

• Possibly curable if metastases are in lungs or liver only and are very limited and resectionable (i.e. if metastectomy is possible and successful).
• Most cases no longer curable.
– If well enough to tolerate, offer palliative chemo to extend survival
• Other goals are minimizing toxicity and maintaining quality of life

Question 16

• PK is scheduled for surgery. His pre-op CEA is normal
and CT of chest, abdomen and pelvis did not reveal
any potential metastases.
• Surgery team removed the lesion and sent to
pathology. Pathologist confirms a right sided
malignant tumour. The tumour has infiltrated the
lamina muscularis propria (but not beyond) and
there are cancer cells detectable in ONE regional
lymph node. Surgeons believe they have “negative
surgical margins”

what does negative surgical margins mean?

Answer 16

Means they think they cut it all, borders have no cancer
Don’t think there is any other cancer

Positive surgical margin - we didn’t get it all, there’s still cancer we can see

Question 17

Colon cancer treatment:
non-metastatic disease

Answer 17

Surgical resection is always the mainstay of
treatment if possible
– Depending on the extent/site of surgery, patients
MIGHT have a stoma after surgery
• Diverting ileostomy (stoma) just during healing
– divert stool from surgical anastomosis
• Permanent colostomy (if tumour is low like in rectum)

• Adjuvant therapy may or may not be indicated depending on stage

Question 18

Stage 0 tumours (carcinoma in situ) or stage I
tumours adjuvant treatment?

Answer 18

adjuvant therapy not indicated
– Observation
– Colonoscopy at 1 year, then 3 years, then 5 years

Question 19

Stage II tumours adjuvant treatment?

Answer 19

adjuvant therapy usually not used
– Unless high risk features present, 5-year DFS is similar with or without chemo

• If tumour has high risk features, may be treated
similar to stage III
• High risk features include:
– Poorly differentiated (high grade) tumours
– Perforation or obstruction
– Lymphovascular invasion
– Close or positive surgical margins

Question 20

Stage III tumours – adjuvant treatment?

Answer 20

adjuvant antineoplastic therapy is
indicated
• When compared with surgery alone, the addition of
fluorouracil based chemotherapy, reduced relative risk of
death by 30-36%
– 5 year DFS 49% (no adjuvant chemo) vs 64% (with adjuvant chemo)

Question 21

3 options of adjuvant tx

Answer 21

– PREFERRED:
• “CAPOX” for 4-8 cycles (1 cycle = 21 days)
• “FOLFOX6” for 6 - 12 cycles (1 cycle = 14 days)
– OTHER:
• Capecitabine for 8 cycles (1 cycle = 21 days)

• FOLFOX6 every two weeks x 6-12 cycles (3-6 months)
• CAPOX every three weeks x 4-8 cycles (3-6 months)

– Capecitabine X 8 cycles
– 1 cycle = 3weeks
– ORAL TABLETS TWICE DAILY ON DAYS 1-14 of 21 day cycle (3rd week is a break)

Dont need to remember which are in folfox6
Know that oxaliplatin and capecitabine are good for adjuvant chemo

Question 22

PK has been diagnosed with stage IIIA colon cancer
that has been successfully resected (surgically
removed). He is now going to receive ADJUVANT
CHEMOTHERAPY to destroy any undetectable cancer
cells that remain. What are the goals of therapy for
PK?

Shrink the remaining tumour (extend life)
Prevent recurrence of colon cancer (cure)
Palliation (improve comfort and quality of life)
Maintain quality of life

Answer 22

prevent recurrence - Make sure it’s not coming back
Negative margins
Possible there is a little piece that imaging missed ((lungs, lver)

If positive margins, shrink remaining tumor

Question 23

Common Toxicities Seen with
Curative Treatment of CRC

which with oxaiptin, which with capectitabine

Answer 23

• Nausea/vomiting (usually mild to moderate)
• Myelosuppression (usually mild to moderate)
• Hand-foot syndrome (with capecitabine)
• Mucositis (with capecitabine)
• Diarrhea (with capecitabine)
• Peripheral neuropathy (with oxaliplatin)