Acute Leukaemia

Question 1

What is acute leukaemia?

Answer 1

Cancer of the blood cells, it is the result of accumulation of early myeloid or lymphoid precursors in the bone marrow, blood and other tissues

Question 2

Why does acute leukaemia normally occur?

Answer 2

As a result of a somatic mutation within a population of early progenitor cells, may arise de novo (first presenting event) or be the terminal event of a pre-existing blood disorder (eg. CML)

Question 3

What are the 4 basic types of leukaemia, how is each classified?

Answer 3

Depending on whether it occurs from a progenitor of the myeloid line or lymphoid line:
1) Myeloid leukaemia
2) Lymphoblastic leukaemia
Whether it is acute or chronic

Question 4

What are therefore the 2 main sub groups of acute leukaemia?

Answer 4

1) AML = acute myeloid leukaemia

2) ALL = acute lymphoblastic leukaemia

Question 5

How can ALL and AML be further subdivided?

Answer 5

On morphological grounds into various subcategories

Question 6

What is the name given to the immature cells which appear in the blood in acute leukaemia?

Answer 6

Blast cells - immature neoplastic cells which cannot perform their function

Question 7

Do the appearance of blast cells vary between ALL and AML how can the appearance be used?

Answer 7

Yes - the morphology is important in determining the subtype but other tests must be performed to confirm the sub type before any therapy is started

Question 8

What are the 4 main clinical features of leukaemia?

Answer 8

Presents with the features of bone marrow failure:
1) Anaemia
2) Infections
3) Easy bruising and haemorrhage
Organ infiltration by leukaemia cells may also occur eg. spleen, liver, meninges, testes and skin

Question 9

Why are unusual severe infections common in leukmaemia?

Answer 9

Because as a result of the leukaemia the immune system is incompetent

Question 10

Give 3 unusual infections which could occur in leukaemia?

Answer 10

1) Staph aureus infection of orbit
2) Severe oral candida infection
3) E Coli and Strep faecalis causing perianal infection

Question 11

Morphology is the cornerstone of diagnosis of sub-type of acute leukaemia, however what second modality is used to confirm diagnosis and look at prognosis?

Answer 11

Looking at immunological markers

Question 12

How are immunological markers identified and thus a diagnosis made in leukaemia?

Answer 12

Immunofluorescence and fluorescence activated cell sorting (FACS) which now allows rapid leukaemia diagnosis
Use a monoclonal Abs which are designed to attach to cell surface Ag which differ depending on the type of blast cell. These Ab are fluorescently labelled and those which are bound can be identified, to determine the cell surface Ag and thus the form of leukaemia

Question 13

What are the 2 classification systems for AML and what is each based on?

Answer 13

FAB classification - based on morphology )
Has been supersceeded by
WHO classification - more risk adapted and based on prognosis

Question 14

What does the M6 FAB classification refer to?

Answer 14

Leukaemia of erythroblasts which is rare

Question 15

What are the 5 modalities used in diagnosis of leukaemia?

Answer 15

1) Morphology
2) Cytochemistry - still sometimes done
3) Immunological markers
4) Cytogenetics, FISH - required in diagnosis of certain subtypes
5) Molecular Techniques - PCR

Question 16

What do cytogenetic abnormalities refer to?

Answer 16

Changes to the structure/ number of whole chromosomes not individual genes

Question 17

How can cytogenetics aid diagnosis of leukaemia?

Answer 17

1) May help to confirm diagnosis and indicate subtype

2) Can enable you to identify certain cytogenetic abnormalities which correlate with prognosis

Question 18

Give 2 cytogenetic abnormalities that confer good prognosis in AML?

Answer 18

1) t(8,21)

2) t(15,17)

Question 19

Give 1 cytogenetic abnormality in AML and one in ALL which confer bad prognosis?

Answer 19

1) Monosomy 7 in AML

2) t(9,22) in ALL

Question 20

Which cytogenetic abnormality is famously found in CML and is also found in AML?

Answer 20

t(9,22) - the Philadelphia chromosome

ABL-BCR fusion gene = increased tyrosine kinase activity

Question 21

What is meant by molecular abnormalities?

Answer 21

Changes at the individual gene level

Question 22

For what 2 reasons are molecular abnormalities important in acute leukaemia?

Answer 22

1) Chr translocations cause molecular changes which may be important in aetiology eg. AML-ETO gene fusion product in t(8,21) - ie can monitor levels of this product in the blood and marrow to check responses to treatment and also catch relapses early
2) Molecular changes may be important in developing treatment strategies eg. use all trans retinoic acid (ATRA) to treat APML (a type of leukaemia) because it targets the PML-RARalpha fusion gene in t(15,17) translocation present in APML

Question 23

Give 3 mutations found in AML which lead to abnormal cell proliferation?

Answer 23

1) FLT3 mutations - associated with bad prognosis
2) Ras mutations
3) c-KIT mutations

Question 24

Give 3 molecular abnormalities found in AML which are associated with a block in differentiation?

Answer 24

1) CBF AML (t(8,21) and inv(16))
2) PML-RAR alpha (t(15,17))
3) MLL translocations (11q23)

Question 25

Give a molecular abnormality found in AML associated with tumour suppression?

Answer 25

NPM1

Question 26

Which of FLT3 and NPM1 is associated with a good and poor prognosis?

Answer 26

Good = mutations in NPM1
Bad = mutations in FLT3

Question 27

What is the significance of molecular markers in current management of AML?

Answer 27

1) Risk assessment is complex as more than one abnormality may be present
2) Current interest is development of molecular signature using micro-array analysis (assess each individuals leukaemia genetic profile with an assay of common molecular abnormalities)
3) Minimal residual disease monitoring (MRD) using PCR may allow detection of early relapse and allow earlier treatment of some subtypes eg. APML
4) Some may be the target for therapy eg. FLT3 inhibitors

Question 28

Give 6 factors which confer poor prognosis in ALL?

Answer 28

1) Increasing age
2) High WCC
3) Male sex
4) Certain cytogenetic abnormalities
5) Poor response to treatment
6) T-ALL and null ALL

Question 29

What is the treatment for AML? 2

Answer 29

1) Induction treatment to obtain remission, then consolidation with further courses of combination chemo
2) In younger patients consider and bone marrow transplant (sibling or MUD - matched unrelated donor)

Question 30

What is the treatment for ALL? 4

Answer 30

1) All patients receive induction chemotherapy followed by consolidation therapy
2) All patients receive prophylaxis of meningeal leukaemia with intra-thecal methotrexate (and cranial radiation)
3) Following this maintenance chemotherapy is given or:
4) Bone marrow transplantation in bad risk patients

Question 31

Why are patients given prophylaxis for meningeal leukaemia?

Answer 31

Brain is a sanctuary sight for leukaemia cells and often chemo doesnt reach there (the same is true for testes) so need to prevent meningeal leukaemia

Question 32

How are high risk patients with ALL identified for bone marrow transplantation?

Answer 32

Patients with factors conferring poor prognosis such as poor response to treatment and certain cytogenetic abnormalities

Question 33

How is bone marrow transplant carried out? 2

Answer 33

1) Traditionally a large bore needle to the posterior ilium
2) Now peripheral blood stem cell transplantation can be carried out - now give patients GCSF (granulocyte colony stimulating factor) which stimulates production of stem cells so they spill out into peripheral blood and can be harvested

Question 34

Why is sepsis such a significant complication of leukaemia therapy?

Answer 34

Neutropenic sepsis occurs
All pts receiving intensive chemo will become neutropenic for 10-21 days - frequently the neutrophil count will fall to levels below 0.2 or be unrecordable

Question 35

How is neutropenic fever defined?

Answer 35

Pyrexia in the presence of a neutrophil count of less than 0.1 x 10^9/L

Question 36

What is the cornerstone of management of neutropenic sepsis?

Answer 36

Immediate administration of broad spectrum IV Abx (often Tazocin and Gentamicin) given empirically before the results of cultures are available

Question 37

In addition to the administration of immediate Abx at the first sign of fever, what 5 other methods are used in prevention of neutropenic sepsis?

Answer 37

1) Protective isolation
2) Prophylactic Abx eg. levofloxacin
3) Use of GCSF (granulocyte colony stimulating factors)
4) Strict hand hygiene
5) Patient education - pt will be going home with neutropenia and thus still at high risk of sepsis

Question 38

What is one of the main risks of intensive chemotherapy for leukaemia?

Answer 38

Neutropenic sepsis