INTENSIVE CHEMOTHERAPY WITH STEM-CELL SUPPORT-EXPERIENCE IN PEDIATRICSOLID TUMORS

A recent Consensus Conference in Lyon reviewed the role of high-dose t herapy with stem cell rescue in a variety of malignancies including ch ildhood tumours. The conclusion was that with the exception of metasta tic neuroblastoma there is still no proven role for this treatment str ategy. It is more than 10 years since this approach was used in neurob lastoma and it has subsequently been applied to most of the common chi ldhood solid rumours. Although a single randomised study has suggested that the progression-free survival is significantly prolonged with hi gh-dose melphalan, the superiority of this over continued intensive co nventional therapy is unclear. It seems likely that a selected subgrou p of children with stage IV disease may benefit from megatherapy and t he results of current randomised trials are awaited. In rhabdomyosarco ma, the duration of treatment may be shortened by dose escalation, but the impact on the outcome in very high-risk patients remains unproven . In Ewing's sarcoma, there has been difficulty defining high-risk pat ients, but recent studies suggest that megatherapy may have a role in patients with bone or bone marrow disease who have little chance of lo ng-term survival with conventional chemotherapy approaches. In brain t umours, the results have been disappointing for gliomas, but there is currently enthusiasm about a possible role in the chemosensitive primi tive neuroectodermal tumours. In this group of diseases which are inhe rently chemosensitive, the poor results from chemotherapy in the past have resulted from a failure to achieve appropriate drug levels at the tumour site and this may be potentially overcome by dose escalation. In Wilms' tumour, although the overall cure rate is very high, there a ppears to be a useful role for megatherapy in certain high-risk relaps ed patients who have little chance of cure with conventional salvage t herapy. There is an urgent need for international collaboration to des ign randomised studies which will as rapidly as possible address the i ssue of the role of these expensive and high morbidity procedures in c hildhood cancer.