Treating acute lymphoblastic leukaemia (ALL)

Chemotherapy is the main treatment for childhood ALL. Usually a combination of chemotherapy drugs is given according to a treatment plan.

The treatment, which is mostly given on an outpatient basis, is given in several ‘blocks’:

Block I: Remission induction

The aim of the first few weeks of treatment is to return both the blood and the bone marrow to normal function – this is called achieving a remission.

This intensive phase of treatment involves the use of several drugs in combination to clear all detectable leukaemia cells from the blood and the bone marrow.

Children will spend part of this stage of treatment as inpatients because of the risks of infection and haemorrhage.

Block II: Central nervous system (CNS) directed therapy

Some leukaemia cells may cross the barrier into the cerebro-spinal fluid (CSF) which surrounds the brain and spinal cord. Unfortunately the anti-leukaemia drugs do not penetrate this barrier very well and so it is necessary to inject drugs directly into the spinal fluid to prevent leukaemia cells from surviving in this site. This is called an intrathecal injection.

Radiotherapy may also be used to target leukaemia cells in the CNS – but only if the patient has evidence of CNS disease at the time of diagnosis.

Block III: Delayed intensification therapy

The disappearance of leukaemia cells from the blood and the bone marrow does not mean that all the leukaemia cells in the body have been killed. Therefore it is necessary to give further blocks of treatment in order to maintain the remission.

Standard treatment involves two courses of powerful drugs given at roughly four and eight months from diagnosis. The drugs will affect the child’s bone marrow and its ability to produce blood cells, leading to a fall in their blood count and associated problems such as infection and bleeding. Children may need to be admitted to hospital during this period of their treatment.

Block IV: Maintenance therapy

This phase of extended low-dose oral chemotherapy is unique to the treatment of ALL. Without this phase of treatment, which lasts 14 months for girls and 26 months for boys, there is an increased risk of relapse.

Treatment during this stage involves taking daily tablets and having monthly injections of chemotherapy drugs.

The maintenance stage takes the total treatment duration to two years for girls and three years for boys. It is carried out as an outpatient, with treatment provided on a ‘shared care’ basis with a partnership between the specialist treatment centre and the child’s local hospital.

Although the specialist centre retains overall responsibility, much of the care is provided by the local hospital. This has major benefits for the child and family – it avoids the need for long journeys and reduces the disruption to family life and the child’s education. The child should be able to resume normal activities during this time.