Colorectal Cancer

Question 1

How prevalent is colorectal cancer?

Answer 1

it is the 2nd leading cause of cancer deaths in Canada

Question 2

What causes colorectal cancer?

Answer 2

idiopathic (genetic mutation)

Question 3

What are risk factors for colorectal cancer?

Answer 3

• adenomatous polyps (benign epithelial cell tumours in the GI tract), or adenomatous polyps in your family
• increased age (90% occurs in those over 50 years old)
• family history of cancer
• having Crohn’s or ulcerative colitis (IBD)
• poor diet: diet high in fat (because increases bile which may be converted to carcinogens by gut bacteria), sugar (feed bacteria), low in fibre (increases stool bulk and dilutes/removes carcinogens) and low in vitamins A, C, E (removes free radicals)

Question 4

What are protective factors for colorectal cancer

Answer 4

• diet high in fibre and vitamins A, C, E
• aspirin use (may be because it suppresses COX-2, which promotes inflammation and cell proliferation, COX-2 is over-expressed in many with colorectal cancer)

Question 5

What are the 4 TNM stages of colorectal cancer?

Answer 5

stage 1) invasion of mucosal and submucosal layers
stage 2) infiltrates into muscularis externa of colon
stage 3) invasion of serosal layer, regional node involvement
stage 4) tumour penetrates serosa or adjacent organs (metastatic)

prognosis decreases as stages progress

Question 6

What are the manifestations of colorectal cancer?

Answer 6

• bleeding
• change in bowel habits
• urgency or incomplete emptying
• pain

Question 7

How is colorectal cancer screened?

Answer 7

• digital rectal exam is part of routine physical
• people who are asymptomatic and over 50 should have a FOBT every 1-2 years
• if FOBT positive, have a colonoscopy or sigmoidoscopy and biopsy
• barium study

Question 8

How is colorectal cancer treated?

Answer 8

• surgical removal
• radiation may be used pre-op
• chemo may be used post-op
• radiation and chemo may be used palliatively