ICL Colorectal Cancer - Week 4

Question 1

Pathophysiology of colorectal cancer

Answer 1

• Chromosomal instability (seen in familial adenomatous polyposis) – caused by mutations in oncogenes (K-ras) and tumour suppressor genes (TP53, APC and DC)
• Microsatellite instability (seen in hereditary non-polyposis colorectal cancer/Lynch syndrome) – involves methylation/mutation in mismatch repair genes MLH1 or MSH2
• Hypermethylation phenotype – involves hypermethylation of CpG islands
• COX-2 overexpression

Question 2

Predisposing factors of colorectal cancer include

Answer 2

• Age – reduced telomere length, gradual cell/DNA damage
• Irritable Bowel Disease (e.g., Crohn’s & ulcerative colitis)
• FHx
• Lynch syndrome
• Familial adenomatous polyposis

Question 3

Risk factors of colorectal cancer include

Answer 3

• Obesity
• Poor diet
• Lack of exercise
• High insulin levels
• High leptin levels
• High red meat & processed meat consmption
• Smoking
• Male

Question 4

What is leptin?

Answer 4

‘Hunger hormone.’ Produced by adipose tissue.

Question 5

What part of the colon is most at risk during colonoscopy/colorectal surgery of perforation?

Answer 5

Caecum.

Question 6

Follow up management for screening of recurring colorectal cancer

Answer 6

• CEA blood tests
• CT scans
• Colonoscopies

Question 7

Follow-up over time post colorectal diagnosis & treatment

Answer 7

• Year 1 post-diagnosis: every 3-6 mths
• Year 2/3: every 6 mths
• Year 4/5: every 12 mths

Question 8

CEA blood test expand.

Answer 8

Carcinoembryonic antigen.

Question 9

Surgical & oncological treatment options for colorectal cancer.

Answer 9

Surgical options include:
* Polypectomy & local excision
* Colectomy
* Stent
* Colostomy.
Oncological management options include:
* Neoadjuvant therapy – chemotherapy, radiation or hormonal therapy (administered pre and/or post surgery)
* Palliative care.