Neoplasia in childhood--25 years of progress.

BACKGROUND

Several factors have contributed to the improved prognosis for the survival and quality of life of children with cancer. Childhood tumours tend to have their origin in intrinsic genetic abnormalities, and are usually disseminated by the time of diagnosis. As a result, conventional treatments, such as ablative surgery and/or radiotherapy (the effects of which are detrimental to the growth and development of normal tissues), are rarely successful. The advent of effective combination chemotherapy, given as an adjuvant to eradicate micrometastases, has led also to the dramatic regression of inoperable primary tumours. Subsequent surgery often enables complete resection without the need for radiotherapy. Primary surgery is now used to obtain sufficient tissue to make a precise diagnosis, and recently developed molecular techniques make this possible with great precision from needle biopsies in many instances. The development of an effective treatment regimen is the single most important prognostic factor. This also permits analysis of the differences between successfully treated groups and those not cured by standard treatment. These prognostic factors usually have a biological basis that is identifiable at diagnosis, allowing stratification of treatments and further development. Some of the worst prognosis cases on past standard therapy, such as B-cell acute lymphoblastic leukaemia, have an excellent prognosis when specific treatment regimens are designed to fit their particular characteristics. The finding of specific genetic mutations underlying many childhood tumours may now provide an 'Achilles heel' to enable the development of highly specific therapies that are relatively non-toxic to the normal tissues undergoing rapid growth and development during childhood. The rarity of childhood cancer and the need for multidisciplinary management make it impossible for the ordinary district hospital to deliver optimal treatment, though 'maintenance' treatment and follow-up can be delivered locally as part of 'shared care' with a regional centre. These centres are members of the U.K. Children's Cancer Study Group which was formed in 1977 and now treats 75%. of all cases of childhood malignancy, with sufficient numbers to run randomized clinical trials for most tumour types, often in collaboration with other national paediatric oncology groups in Europe and the U.S.A.

CONCLUSION

Children with cancer are likely to be major beneficiaries from the recent advances in the understanding of neoplasia, many of which stem from work on paediatric malignancies. It is therefore important and mutually advantageous to foster and maintain close links with mainstream 'adult' oncology and with the cancer research institutions.