Haematology summary 17

Haematology summary 17

Chapter 17 in haematology (Acute lymphoblastic leukaemia)summary

-Acute lymphoblastic leukaemia (ALL) is casued by an accumulation of lymphoblasts in the bone marrow. It isthe most common malignant disease of clidhood-75% of cases occur before the age of 6 years. Eighlty-five per cent of cases are of B-cell lineage with the rest being of T-cell lineage.

-The first genetic mutation ocuurs in amy cases in utero, with a secondary genetic event occuring later inclidhood,possibly as a reaction to an infection.

-The clinical presentation is with the features of bone marrow failure (anaemia,infection and bleeding) together with symptoms of tissue infiltration by tumour cells, leading to bone pain or swollen lymph nodes.

-Diagnosis is by examination of blood and bone marrow.important tests include microscopic examination of the tumour cells, immunophenotyping and genetic analysis.

-ALL is subclassified according to the underlying genetic defect and a wide varity of genetic lesions are seen . The number of chromosomes in the tuomour cell has prognostic impotance: hyperdiploid cell have >50 chromosomes and generally have a good prognosis whereas hypodiploid cases (>44 chromosomes)carry a poor prognosis.

-Treatment protocols for ALL are extremely complex and usually have four compoents- remission induction ,intensification ,CNS- directed therapy and maintenance.

-Treatment is risk adjusted to reduce the treatment given to patients with good prognosis.This is based on age ,gender, white cell count and cytogenetics at presenatation.

-Small numbers of tumour cells may sometimes be detected by FACS or molecular analysis even when the blod and bone marrow apear to be clear of leukaemia. This minimal residual disease has prognostic significance and is used in planing therapy.

-If relapse occurs during chemotherapy the outlook is poor but if it happens after years off all treatment the outlook is better. Further chemotheraoy and allogeneic SCT should be cosidered.

-Overall,85% of chlidren can now expect to be cured. The cure rate in adults drops significantly to less than 5% over the age of 70 years.

 

From book: Essentail Haematology A.V.HOFFBRAND,P.A.H.MOSS.6EDITION