A woman is prescribed docetaxel as part of her chemotherapy for breast cancer.
What is the mechanism of action of docetaxel?
Correct Answer C: Taxanes (e.g. Docetaxel) prevent microtubule disassembly.
Like other taxanes the principal mechanism of action is the prevention of microtubule disassembly.
Cytotoxic agents: The table below summarizes the mechanism of action and major adverse effects of commonly used cytotoxic agents:
A 58-year-old man is reviewed in clinic. Six months ago he had a Whipple procedure for pancreatic cancer and is currently undergoing chemotherapy.
Which one of the following blood tests is most useful in monitoring his disease?
Correct Answer E:
Tumour markers:
Tumour markers may be divided into:
It should be noted that tumour markers usually have a low specificity.
A patient is due to start chemotherapy for metastatic colorectal cancer.
What is the main advantage of using capecitabine instead of fluorouracil?
Correct Answer C: Capecitabine is an orally administered prodrug which is enzymatically converted to 5-fluorouracil in the tumour.
Cytotoxic agents:
The table below summarizes the mechanism of action and major adverse effects of commonly used cytotoxic agents:
Which one of the following is least associated with hepatocellular carcinoma?
Correct Answer D:
Hepatocellular carcinoma: Hepatocellular carcinoma (HCC) is the third most common cause of cancer worldwide. Chronic hepatitis B is the most common cause of HCC worldwide with chronic hepatitis C being the most common cause in Europe.
The main risk factor for developing HCC is liver cirrhosis, for example secondary* to hepatitis B & C, alcohol, haemochromatosis and primary biliary cirrhosis. Other risk factors include:
Features:
Screening with ultrasound (+/- alpha-fetoprotein) should be considered for high risk groups such as:
Management options:
*Wilson's disease is an exception.
A 30-year-old man inquires about screening for haemochromatosis as his brother was diagnosed with the condition 2 years ago. The patient is currently well with no features suggestive of haemochromatosis.
What is the most appropriate investigation?
Correct Answer B:
Screening for haemochromatosis:
Serum transferrin saturation is currently the preferred investigation for population screening. However, the patient has a sibling with haemochromatosis and therefore HFE gene analysis is the most suitable investigation. In clinical practice this would be combined with iron studies as well.
Haemochromatosis: investigation: Haemochromatosis is an autosomal recessive disorder of iron absorption and metabolism resulting in iron accumulation. It is caused by inheritance of mutations in the HFE gene on both copies of chromosome 6*.
The British Committee for Standards in Haematology (BCSH) published guidelines for the investigation and management of haemochromatosis in 2000. There is continued debate about the best investigation to screen for haemochromatosis. The 2000 BCSH guidelines suggest:
These guidelines may change as HFE gene analysis become less expensive.
Diagnostic tests:
Typical iron study profile in patient with haemochromatosis:
Monitoring adequacy of venesection:
Joint x-rays characteristically show chondrocalcinosis.
*There are rare cases of families with classic features of genetic haemochromatosis but no mutation in the HFE gene.
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