Br. J. Cancer Br. J. Cancer
S54-S57 (1992), XVIII, S54-557 Suppl. XVIII, 66, Suppl. (1992), 66,
'." ©
Macmillan Press Ltd., 1992 Macmillan
Press
Ltd.,
Leukaemia in the young child J.M. Chessells Leukaemia Research Fund Centre for Childhood Leukaemia at the Department of Haematology and Oncology, Hospitalfor Sick Children and Institute of Child Health, London, UK. Summary Leukaemia is rare in infancy with an equal predominance of lymphoblastic and myeloblastic cases. Acute lymphoblastic leukaemia in infants under one year is characterised by a high leucocyte count, organomegaly, early B-cell phenotype, sometimes with evidence of monocytoid differentiation and cytogenetic abnormalities. This is reflected in its poor prognosis. The toddler (aged 1-2) tends to develop typical childhood ALL which is responsive to treatment, but remains vulnerable to late effects of therapy, particularly radiation. The distribution of subtypes of AML differs in the younger and older child and results of treatment have improved in all age groups. A uniform strategy appears desirable for all cases of childhood AML. It seems probable that different genetic and environmental factors may be involved in the genesis of infant ALL, childhood ALL and AML in children. The management of leukaemia in children under two poses a considerable challenge.
Leukaemia in the young child may have special biological features and be relatively resistant to chemotherapy, while the patients themselves are vulnerable to both early and late effects of treatment. The study of leukaemia in this age group should lead to a better understanding of prenatal and perinatal events influencing leukaemogenesis and thereby perhaps a better understanding of normal haemopoesis in the fetus and young child. Any classification of leukaemia dictated by some arbitrary cut off by age is of course artificial, but this paper will focus on the under-twos, and the differences between this group and older children with acute leukaemia. In order to simplify the discussion children under one year will be referred to as infants and those between one and two as toddlers. Patients and methods This paper presents an overview of the problems of leukaemia in the young child by using the experience of the author and colleagues in investigation and management of children at the Hospitals for Sick Children (HSC) with additional information from children who have been entered into the national MRC UKALL X trial for acute lymphoblastic leukaemia. All leukaemias were classified according to the FAB criteria (Bennett et al., 1981; 1985a,b) by at least two independent observers while immunophenotyping, DNA analysis and cytogenetic analysis were performed as previously described (Katz et al., 1990).
but subsequently with short-term intensive chemotherapy as described (Phillips et al., 1991).
Clinical and laboratory features Acute Lymphoblastic Leukaemia (ALL) The clinical features of ALL in infancy differ markedly from those in children, and even in toddlers, although there is clearly no absolute cut-off at any age. We have previously reported that infants tend to have more organomegaly and initial CNS involvement than older children (Leiper et al., 1986) and that their pretreatment leucocyte count is also higher. Table I shows the distribution of initial count in children aged 0-15 years entered in MRC UKALL X and it can be seen that over half the infants have counts greater than 100 x 10-1 9' 1-' (P=
S54-S57 (1992), XVIII, S54-557 Suppl. XVIII, 66, Suppl. (1992), 66,
'." ©
Macmillan Press Ltd., 1992 Macmillan
Press
Ltd.,
Leukaemia in the young child J.M. Chessells Leukaemia Research Fund Centre for Childhood Leukaemia at the Department of Haematology and Oncology, Hospitalfor Sick Children and Institute of Child Health, London, UK. Summary Leukaemia is rare in infancy with an equal predominance of lymphoblastic and myeloblastic cases. Acute lymphoblastic leukaemia in infants under one year is characterised by a high leucocyte count, organomegaly, early B-cell phenotype, sometimes with evidence of monocytoid differentiation and cytogenetic abnormalities. This is reflected in its poor prognosis. The toddler (aged 1-2) tends to develop typical childhood ALL which is responsive to treatment, but remains vulnerable to late effects of therapy, particularly radiation. The distribution of subtypes of AML differs in the younger and older child and results of treatment have improved in all age groups. A uniform strategy appears desirable for all cases of childhood AML. It seems probable that different genetic and environmental factors may be involved in the genesis of infant ALL, childhood ALL and AML in children. The management of leukaemia in children under two poses a considerable challenge.
Leukaemia in the young child may have special biological features and be relatively resistant to chemotherapy, while the patients themselves are vulnerable to both early and late effects of treatment. The study of leukaemia in this age group should lead to a better understanding of prenatal and perinatal events influencing leukaemogenesis and thereby perhaps a better understanding of normal haemopoesis in the fetus and young child. Any classification of leukaemia dictated by some arbitrary cut off by age is of course artificial, but this paper will focus on the under-twos, and the differences between this group and older children with acute leukaemia. In order to simplify the discussion children under one year will be referred to as infants and those between one and two as toddlers. Patients and methods This paper presents an overview of the problems of leukaemia in the young child by using the experience of the author and colleagues in investigation and management of children at the Hospitals for Sick Children (HSC) with additional information from children who have been entered into the national MRC UKALL X trial for acute lymphoblastic leukaemia. All leukaemias were classified according to the FAB criteria (Bennett et al., 1981; 1985a,b) by at least two independent observers while immunophenotyping, DNA analysis and cytogenetic analysis were performed as previously described (Katz et al., 1990).
but subsequently with short-term intensive chemotherapy as described (Phillips et al., 1991).
Clinical and laboratory features Acute Lymphoblastic Leukaemia (ALL) The clinical features of ALL in infancy differ markedly from those in children, and even in toddlers, although there is clearly no absolute cut-off at any age. We have previously reported that infants tend to have more organomegaly and initial CNS involvement than older children (Leiper et al., 1986) and that their pretreatment leucocyte count is also higher. Table I shows the distribution of initial count in children aged 0-15 years entered in MRC UKALL X and it can be seen that over half the infants have counts greater than 100 x 10-1 9' 1-' (P=
