Blue Book: Myelosppression Flashcards
What are the two causes of myelosuppression in cancer?
Consequence of the disease or more commonly, as a consequence of the treatment.
How does chemotherapy cause myelosuppression?
Which cells are affected the greatest?
When is the ‘nadir’ (lowest point) and how long does it take to recover?
Toxic to bone marrow cells= deficiency in peripheral blood cells.
Leukocytes and platelets
10-12 days (can be up to 5 weeks)
2 weeks to recover.
Is myelosuppression always to the same degree?
No. Depends on dose and type of agent. Different agents affect different components of the bone marrow.
eg Carboplatin= thrombocytopenia.
What type of myelosuppression is seen in bone marrow infiltration.
Which types of cancer cause this more commonly?
Pancytopenia.
Haematological malignancies
Some solid: breast, lung, prostate
NB: anti tumour therapy can reduce the pancytopenia.
What form of myelosuppression can para-neoplastic syndromes cause?
(What is a para-neoplastic syndrome?
Pancytopenia or single line haematopoietic lineages.
a syndrome that is a consequence of cancer in the body but not due to local presence of cancer cells. Often mediated by humoral factors.
How to investigate myelosuppression?
Blood film
Haematinics: Vit B12, ferritin, EPO, red cell folate.
Bone marrow aspirate
Trephine (remove circle of bone)
When and how to treat anaemia?
<10g/dl = blood transfusion
recombinant erythropoietin to prevent symptomatic anaemia can be beneficial.
What are the clinical signs of thrombocytopenia?
Common in conventional chemo?
Petechial haemorrhage
Spontaneous nose bleeds
Corneal haemorrhage
Haematuria
Rare in conventional doses of chemo/
When is platelet transfusion required?
Urgently if < 10 x 10.9/L
If between 10-20 x 10.9/L (particularly if complications such as infection)
If there is failure of platelets to rise immediately after transfusion, what is the problem? How can it be overcome?
Development of specific antibodies to the platelets.
Need for single donor (rather than pooled) or HLA matched platelets.
(For neutropenia see oncological emergencies)
How do you prevent myelosuppression?
Prophylactic antibiotics: only used in COPD
Dose modification
Colony stimulating factors:
