General Oncology

Question 1

ECOG score

Answer 1

Question 2

Agents for fracture risk reduction in malignancy

Answer 2

• Denosumab better than placebo, zoledronic acid and pamidronate at reducing risk of fractures in those with cancer
• Denosumab:
  
  • Can be used in renal impairment
  • Higher risk of hypocalcaemia
  • Increases risk of skin infection
  • Similar risk to zoledronic acid at causing osteonecrosis of jaw
• All monthly injections

Question 3

Mechanism of action aprepitant

Answer 3

• Neurokinin-1 (NK-1) receptor antagonist
• Used for delayed chemotherapy nausea usually in combination with ondansetron and dexamethasone
• CYP3A4 inhibitor
  
  • Dexamethasone substrate of CYP3A4 → needs dose reduction when used with aprepitant to prevent toxicity

Question 4

Mechanism of action ondansetron

Answer 4

• Serotonin (5-HT3) antagonist
• Palonosetron - serotonin antagonist with highest affinity for the 5-HT3 receptor

Question 5

Summary of the cell cycle

Answer 5

• G0 → resting, cell exists in a quiescent state
• Interphase: preparation for cell division. 3 stages:
  
  • G1 → starts with end of previous M phase until beginning of DNA synthesis → high metabolic rate, protein synthesis
  • S phase → DNA replication, when completed all chromosomes have been replicated
  • G2 phase → production of microtubules
• M phase → division of cell into two daughter cells

Question 6

Notes on Karnofsky performance scale

Answer 6

• Correlates with survival in cancer
• KPS <50% consistently suggests ife expectancy < 8 weeks for patients enrolled in palliative care programmes

Question 7

Normalisation of which tumour marker predicts best overall survival?

Answer 7

• AFP in testicular cancer

Normalisation in serum B-HCG within 2 weeks and AFP within 25-30 days suggests elimination of tumour → monitoring B-HCG and AFP most sensitive means of detecting early relapse

Question 8

Malignancies that metatastasise to bone

Answer 8

• Lung
• Breast
• Prostate

Lesions may be lytic or blastic

• Prostate predominantly blastic
• Lytic lesions → xray
• Blastic lesions → radionuclide bone scans

Question 9

Tumour lysis syndrome

Answer 9

• Laboratory criteria → Hyperuricaemia, hyperphosphataemia, hyperkalaemia, hypocalcaemia
• Clinical criteria → increased serum creatinine, cardiac arrhythmia, seizure activity, sudden death
• Associated with highly proliferative, bulky, chemosensitive malignancies
  
  • Lymphomas (Burkitts)
  • Leukaemias (ALL)
• Risk factors:
  
  • Good treatment response
  • Pre-existing renal impairment or dehydration
  • High LDH
  • High WCC
• Historically hyperuricaemia main mechanism of AKI in TLS → with urate lowering drugs main mechanism is now hyperphosphataemia and deposition of calcium phosphate (nephrocalcinosis)

Question 10

Prevention of tumour lysis syndrome

Answer 10

• Low risk → regular monitoring of biochemistry and assessment of fluid balance and vitals
• Intermediate risk → IVF 2 days prior to chemo.
  
  • If urine output not satifactory despite volume repletion → loop diuretics (but caution as can cause precipitation of uric acid and calcium phosphate in tubules)
  • Allopurinol → prevents degradation purine → urate (contraindicated in combination with capecitabine)
  • Rasburicase if allopurinol fails
• High risk → same as above and rasburicase from the start

Rasburicase transforms uric acid → allantoin (more soluble in urine than uric acid)