Neuroblastoma. Current clinical and therapeutic aspects. Contributions of modern biology

: Neuroblastoma is a malignant tumour of the sympathetic tissue observed in children, generally before 6 years and before 1 year in one-third of the cases. In most cases the primary tumour lies in the retroperitoneal region, and in particular in the adrenal gland. Metastases affect the bones and bone-marrow after the age of 1 year and the liver in infants. Children whose metastases are present at the time of diagnosis are the most numerous. The therapeutic problems posed by non-metastatic forms are almost exclusively due to the difficulties encountered in complete excision of the tumour. For this reason, tumour reduction by preoperative chemotherapy plays a large role in the therapeutic approach. The prognosis of metastatic forms is totally different in infants and in older children: in infants, hepatic metastases without bone lesions have a favourable prognosis as a rule and sometimes regress without treatment. In older children, the usual osteomedullary damage still has a very sombre prognosis despite the recent therapeutic advances due to high-dose chemotherapy with bone-marrow transplantation. Cytogenetic studies and molecular biology have improved our understanding of these differences in the outcome of the disease. Amplification of Nmy cellular oncogene, ploidy and chromosome 1 short-arm deletion are essential prognostic factors in this particular tumour.