Preclinical studies of pegylated- and non-pegylated liposomal forms of doxorubicin as radiosensitizer on orthotopic high-grade glioma xenografts.

PURPOSE: Free doxorubicin (DXR) is not currently used to treat brain tumors because (i) the blood-brain barrier limits the drug deposition into the brain (ii) lethal toxic effects occur when combined with radiation therapy. Since encapsulation of DXR within liposomal carriers could overcome these drawbacks, the present study aimed at evaluating the radiosensitizing properties of non-pegylated (NPL-DXR) and pegylated (PL-DXR) liposomal doxorubicin on orthotopic high-grade glioma xenografts (U87). METHODS: DXR accumulation in brain tissues was assessed by a high-performance liquid chromatography method and antitumor efficacy was evaluated by mice survival determination. RESULTS: We showed that encapsulation of DXR ensured a preferential deposition of DXR in tumoral tissue in comparison with normal brain tissue: the best AUC tumor tissue/AUC normal tissue ratio depended greatly on the schedule. Overall, thanks to the optimization of the delivery schedule, we demonstrated a radiosensitizing effect for both liposomal DXR without toxicity of this combination on the U87 human malignant glioma orthotopic xenografts. CONCLUSION: This study shows that the use of nanocarriers, allowing targeting of intracerebral tumor, renders relevant the combination of anthracyclin with radiation therapy to treat brain tumors, opening a new field of therapeutic applications. However, our results point out that, for each new delivery system, the administration schedules need to be rigorously optimized.

Development of an osteosarcoma following dental extraction after allogeneic stem cell transplantation.

OBJECTIVES: Radio-induced sarcoma is known to occur several years following bone irradiation especially when this treatment is combined to high dose chemotherapy regimens prior to allogeneic haematopoietic stem cell transplantation (HSCT) in very young children. However, little is known about the stimulus of aggressive bony surgery in the development of these tumours. MATERIAL AND METHODS: We report the case of a young girl in whom dental extraction was rapidly followed by the occurrence of a localized tumour 11 years after allogeneic haematopoietic stem cell transplantation using total body irradiation (TBI) for a haemophagocytic lymphophistiocytosis (HLH). RESULTS: This tumour involved tooth socket and all the right side of the mandible and was diagnosed as an osteogenic osteosarcoma of the zygomatic bone. CONCLUSION: This tumour had the characteristics of a radio-induced sarcoma. Thanks to the very short time between the dental extraction and the occurrence of the osteosarcoma at the same location, we discuss the role of the dental extraction as a trigger of osteosarcoma development.

[Ewing sarcoma located in the mandible: A case report]. / Tumeur d'Ewing de localisation mandibulaire. À propos d'un cas.

Ewing sarcoma is the second most common primary malignant bone cancer in children and adolescents. Clinical presentation is usually dominated by local pain and a palpable mass. These symptoms justify imaging investigations: the first one, when an osseous lesion is suspected, is usually a conventional radiograph in two planes. Ewing sarcoma appears as a poorly defined osteolytic lesion that may frequently be associated with cortical erosion or laminar periosteal response ("onion skin"). However, this aspect is not pathognomonic and the definitive diagnosis is made by biopsy. Absence of pain or an unusual localization can lead to misdiagnosis. We report the case of a 7-year-old boy with Ewing sarcoma located in the mandible with a clinical picture including progressive mandibular swelling but no pain.

Mandibulo-acral dysplasia.

We report on a 7 year-old-girl with mandibulo-acral dysplasia. When she was 3 years of age it mimicked scleroderma because of skin atrophy and later on a Hutchinson-Gilford progeria syndrome (HGP). Acro-mandibular dysplasia was diagnosed because of facial hypoplasia and mandibular hypoplasia. The bilateral proximal mid-humeral notch seen in this case is unusual.

Phase I trial and pharmacological study of a 3-hour paclitaxel infusion in children with refractory solid tumours: a SFOP study.

The maximum tolerated dose of paclitaxel administered by 24-hour continuous infusion in children is known. Short infusion might offer equivalent antitumour efficacy and reduced haematological toxicity, without increasing the allergic risk. Our aims were to determine the maximum tolerated dose and the pharmacokinetics of paclitaxel in children when administered in 3-h infusion every 3 weeks. Patients older than 6 months, younger than 20 years with refractory malignant solid tumours were eligible when they satisfied standard haematological, renal, hepatic and cardiologic inclusion criteria with life expectancy exceeding 8 weeks. Paclitaxel was administered as a 3-hour infusion after premedication (dexamethasone, dexchlorpheniramine). Pharmacokinetic analysis and solvent assays (ethanol, cremophor) were performed during the first course. 20 courses were studied in 17 patients; 4 dosage levels were investigated (240 to 420 mg/m(2)). No dose-limiting haematological toxicity was observed. Severe acute neurological and allergic toxicity was encountered. One treatment-related death occurred just after the infusion at the highest dosage. Delayed peripheral neurotoxicity and moderate allergic reactions were also encountered. Pharmacokinetic analysis showed dose-dependent clearance of paclitaxel and elevated blood ethanol and Cremophor EL levels. Although no limiting haematological toxicity was reached, we do not recommend this paclitaxel schedule in children because of its acute neurological toxicity.