Intensification with repeated i.v. MTX in the setting of low-dose LCV rescue was associated with a higher risk for acute NT and LE, especially in patients who received concomitant TIT. The long-term consequences for affected patients remain unknown.

We studied the relation between the DNA content of neuroblastoma cells and the response to therapy in 35 infants under one year of age with a diagnosis of neuroblastoma. Using flow cytometric techniques, we found that in 27 cases the primary malignant stem line consisted of neuroblasts with hyperdiploid DNA content, ranging from 1.07 to 2.42 times the finding in normal diploid cells. All remaining cases had diploid stem lines. Diploidy was more common in infants with clinical Stage D neuroblastoma (metastases beyond regional lymph nodes) than in those with other, less advanced stages: 6 of 10 as compared with 2 of 25 (P = 0.003). Of 17 evaluable patients with unresectable hyperdiploid tumors, 15 had complete responses and two had partial responses to cyclophosphamide and doxorubicin; six others with diploid tumors did not respond (P = 0.00001). We also found that each of the four infants with Evans' Stage IV-S neuroblastoma, an unusual form of disseminated neuroblastoma with a relatively good prognosis, had hyperdiploid tumor cells of clonal origin. We conclude that in neuroblastoma of infants, hyperdiploidy of tumor cells is associated with a better response to chemotherapy than is diploidy.

In previously treated patients, topotecan produced CRs and PRs in patients with neuroblastoma, Ewing's tumor, and retinoblastoma. In hepatoblastoma, rhabdomyosarcoma, and a few rare tumors, long-lasting MRs and SDs with excellent symptom control were seen. The toxicity of topotecan, predominantly myelosuppression, was tolerable.

The cranial magnetic resonance (MR) images of 25 children with acute lymphocytic leukemia (ALL) who were undergoing chemotherapy were retrospectively studied to determine the frequency of white matter changes and to analyze the significance of these observed changes in predicting subsequent neuropsychologic deficiencies. MR images showed transient white matter abnormalities in 17 of the 25 patients during consolidation therapy. Twelve of 20 children showed neuropsychologic deficits. There was no correlation between white matter changes and neuropsychologic deficits. In the subgroup of children under age 5 years at the time of diagnosis, 10 of 11 showed neuropsychologic deficits, and eight of 11 had white matter changes. Children under age 5 who undergo chemotherapy for ALL are at high risk to develop neuropsychologic deficiencies. Age at diagnosis is a reliable predictor of subsequent neuropsychologic deficits.

Isotretinoin can induce durable clinical and laboratory responses in patients with juvenile CML.