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Common Colorectal Cancer exam questions for medical finals, OSCEs and MRCP PACES


Question 1.

What are complications of colon cancer?

  • Local
    • Obstruction
    • Perforation
    • Bleeding (and/or iron deficiency anaemia)
    • Colovesical fistula
  • Distant
    • Metastasis

Question 2.

Other than surgery, what treatment would you consider for local colorectal cancer?

  • Adjuvant oxaliplatin-based chemotherapy should be given in stage III (node positive) disease, for six months.
    • e.g. oxaliplatin plus 5-FU, or oxaliplatin plus capecitabine
  • Rectal cancer should be treated with neoadjuvant chemoradiotherapy if locally invasive or node positive
  • All other rectal cancer of stage II or higher should be treated with chemoradiotherapy post-operatively

Question 3.

What are the initial investigations used to diagnose colon cancer?

  • Bloods
    • FBC, U&E, LFT, Calcium
    • Clotting, group and save
  • Colonoscopy
    • Identifies cancers and co-incident second cancers (synchronous lesions), and obtain tissue for histology: brushings, biopsy or resection
    • CT colonography may be used in those unlikely to tolerate colonoscopy
  • If cancer is confirmed, further imaging for staging should be undertaken
    • CT abdomen-pelvis to assess local invasion of the primary, lymphadenopathy, and hepatic metastases
    • CT chest is usually undertaken, though only 10% of nodules seen are colorectal metastases

Question 4.

What are the major risk factors for colorectal cancer?

  • Demographic risk factors
    • Age
    • Male sex
    • Ethnicity (black people have a higher risk but this may be due to confounding variables)
  • Family history
  • Previous history
    • Previous colorectal cancer or previous polyps >1cm exhibiting high grade dysplasia or with villous/tubulovillous histology
  • Comorbidities
    • Inflammatory bowel disease (risk increases with extent and duration of colitis)
    • Abdominal radiation
    • Immunosuppression
    • Diabetes
  • Modifiable risk factors
    • Smoking
    • Obesity
    • Processed meat
    • Alcohol

Question 5.

What genetic disorders are associated with colorectal cancer?

  • Hereditary non-polyposis colorectal cancer (HNPCC)
    • Autosomal dominant, due to mutations in various mismatch repair genes and responsible for 3% of colorectal cancers
    • Also increases the risk of endometrial cancer, other GI tract cancers and ovarian cancer
  • Familial adenomatous polyposis (FAP)
    • Autosomal dominant defect in APC gene
    • Causes numerous colonic polyps in childhood and colorectal cancer by the age of 45 in 90% of patients
  • MUTYH-associated polyposis
    • Autosomal recessive condition which may cause polyposis and confers increased colorectal cancer risk

Click here to learn about the diagnosis and management of colorectal cancer

Free colon cancer revision for medical student exams, finals, OSCEs and MRCP PACES

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