[Children with acute lymphoblastic leukemia: prognostic significance of polymerase-chain-reaction analysis of minimal residual disease].

OBJECTIVE

Determination of the usefulness of polymerase chain reaction (PCR) for the detection of minimal residual disease (MRD) in bone marrow in children suffering from progenitor-B cell acute lymphoblastic leukaemia during and after treatment.

DESIGN

Descriptive.

SETTING

Emma's Children's Hospital, Academic Medical Centre, University of Amsterdam and Central Laboratory of the Dutch Red Cross, Amsterdam.

METHOD

Of 50 children suffering from progenitor-B cell ALL, stored bone marrow samples and bone marrow slides were investigated: 328 bone marrow samples were analysed by PCR for IgH/TCR delta; 34 patients were analysed at the end of induction therapy. Follow-up period was 20 to 133 months.

RESULTS

Twenty-two patients stayed in continuous complete remission (CCR), 28 patients experienced a recurrence (REC). Reduction of tumour mass was higher in the CCR group. At the end of induction therapy 2/18 CCR patients and 10/16 REC patients were PCR positive (p = 0.005). PCR positivity was not related with known prognostic factors. After recurrence 6/8 patients, who became PCR negative, stayed in remission. All patients who stayed positive after treatment for their recurrence died from leukaemia (p = 0.006). All children who were only temporary PCR negative suffered a recurrence.

CONCLUSION

Analysis of MRD by means of PCR on bone marrow samples during and after treatment for progenitor-B cell ALL is of prognostic importance.