Two-stage phase II study of imatinib mesylate in subjects with refractory or relapsing neuroblastoma.

BACKGROUND: Cure rate for subjects with refractory or relapsing metastatic neuroblastoma is <5%. In the search for a novel therapy, continuous daily oral administration of imatinib mesylate was evaluated. PATIENTS AND METHODS: Twenty-four subjects were enrolled in a two-stage study. Imatinib was administered for the first 4 weeks (cycle) at 170 mg/sqm b.i.d. If no major toxicity occurred, the dose was escalated to 300 mg/sqm b.i.d. for a maximum of 12 cycles. Clinical response and toxicity were evaluated according to international criteria. Pharmacokinetics (PK) profiles and tyrosine hydroxylase (TH) mRNA expression were also determined in a subset of subjects. RESULTS: Five (21%) complete responses, with one subject still alive at 68 months, and 2 (8%) partial responses lasting up to 29 months were obtained. No grade 4 toxicity was observed. At steady-state, PK exposure (69.7 µg h/ml) was similar to that of adults receiving 1000 mg/die. Responses appear to correlate with the absence or presence of metastasis in the bone marrow (BM) alone, with low TH expression levels at study entry and low imatinib exposure. CONCLUSIONS: Imatinib mesylate was well-tolerated and effective in the subset of subjects with low BM infiltration as only site of metastasis. Study identifier EudraCT: 2005-005778-63.

Role of low-cost thyroid follow-up in children treated with radiotherapy for primary tumors at high risk of developing a second thyroid tumor.

AIM: Differentiated thyroid cancer (DTC) is uncommon in childhood and data on its prevalence as a second malignant neoplasm (SNM) after radiotherapy (RT) for malignancies are limited. We evaluated: 1) the incidence DTC in pediatric-oncologic patients treated with RT; 2) the relationship between DTC, RT and the features of the first malignancy; 3) the usefulness of thyroid follow-up in irradiated oncological patients. METHODS: We have followed up 252 patients treated with RT out of 966 oncologic pediatric patients. Thyroid follow-up included TSH level evaluation and neck ultrasonography. In the presence of thyroid nodule/s ≥1 cm and/or with ultrasonography suspicious for malignancy, fine needle aspiration biopsy (FNAB) was performed. When papillary/follicular lesions were detected by cytology, thyroidectomy was performed. If DTC was confirmed, patients underwent radioactive iodine (RAI) treatment. RESULTS: At least one thyroid nodule was detected in 106 irradiated patients (42%): 45 patients underwent FNAB and 27 underwent thyroidectomy. Seventeen DTC (6.7%) were found on histology. A higher incidence of DTC was seen in patients with neuroblastoma (38%) or Wilms' tumor (18%). One third of DTC showed capsule invasion, and one fourth node involvement. Eleven patients, treated with a single RAI treatment, showed undetectable thyroglobulin levels after rh-TSH-stimulation. Five patients underwent at least two RAI treatments: four patients showed complete remission and one patient partial remission. CONCLUSION: A high rate of DTC, often with invasive features, was observed in children treated with RT for primary tumors. This finding underlines the usefulness of thorough low-cost thyroid follow-up in this high-risk population.