Intensity modulated radiotherapy (IMRT) in the treatment of children and Adolescents - a single institution's experience and a review of the literature

<p>Abstract</p> <p>Background</p> <p>While IMRT is widely used in treating complex oncological cases in adults, it is not commonly used in pediatric radiation oncology for a variety of reasons. This report evaluates our 9 year experience using stereotactic-guided, inverse planned intensity-modulated radiotherapy (IMRT) in children and adolescents in the context of the current literature.</p> <p>Methods</p> <p>Between 1999 and 2008 thirty-one children and adolescents with a mean age of 14.2 years (1.5 - 20.5) were treated with IMRT in our department. This heterogeneous group of patients consisted of 20 different tumor entities, with Ewing's sarcoma being the largest (5 patients), followed by juvenile nasopharyngeal fibroma, esthesioneuroblastoma and rhabdomyosarcoma (3 patients each). In addition a review of the available literature reporting on technology, quality, toxicity, outcome and concerns of IMRT was performed.</p> <p>Results</p> <p>With IMRT individualized dose distributions and excellent sparing of organs at risk were obtained in the most challenging cases. This was achieved at the cost of an increased volume of normal tissue receiving low radiation doses. Local control was achieved in 21 patients. 5 patients died due to progressive distant metastases. No severe acute or chronic toxicity was observed.</p> <p>Conclusion</p> <p>IMRT in the treatment of children and adolescents is feasible and was applied safely within the last 9 years at our institution. Several reports in literature show the excellent possibilities of IMRT in selective sparing of organs at risk and achieving local control. In selected cases the quality of IMRT plans increases the therapeutic ratio and outweighs the risk of potentially increased rates of secondary malignancies by the augmented low dose exposure.</p

Creating localized DNA double-strand breaks with microirradiation.

We describe a protocol for creating localized DNA double-strand breaks (DSBs) with minimal requirements that can be applied in cell biology and molecular biology. This protocol is based on the combination of 5-bromo-2\u27-deoxyuridine (BrdU) labeling and ultraviolet C (UVC) irradiation through porous membranes. Cells are labeled with 10 μM BrdU for 48-72 h, washed with Ca(2+)- and Mg(2+)-free PBS(-), covered by polycarbonate membranes with micropores and exposed to UVC light. With this protocol, localized DSBs are created within subnuclear areas, irrespective of the cell cycle phase. Recruitment of proteins involved in DNA repair, DNA damage response, chromatin remodeling and histone modifications can be visualized without any specialized equipment. The quality is the same as that obtained by laser microirradiation or by any other focal irradiation. DSBs become visible within 30 min of UVC irradiation.without figure

Quantification of patient-reported outcome measures of radiation-induced skin reactions for use in clinical trial design

Purpose Skin toxicity is a common effect from radiotherapy, although difficult to predict on an individual basis, and there is little evidence-based management. This study aimed to quantify inter-patient variation in patient-reported outcome measures for radiation-induced skin reactions (RISR) to enable the determination of the number of patients required for adequate power in a comparative trial of RISR management strategies. Methods The study included 154 patients scheduled to receive breast cancer radiotherapy. Patients filled in a weekly questionnaire during and up to 4 weeks following the end of radiotherapy scoring five aspects of their experience of RISR: skin redness, and bother from redness like itching, burning sensation and tenderness/pain. Results Assessment of patients’ reported experience of their RISR was shown to be feasible, with 91 % of patients returning at least two questionnaires. The mean score increase between weeks 1 and 4 was 25 points (p value <0.0001, 95 % CI 21–29), and the estimated standard deviation at 4 weeks was 18 (95 % CI 16–21). Conclusions Patients’ assessment of their reaction was not predicted on the basis of treatment and patient-related characteristics. Based on the observed variance in scores at 4 weeks, we could calculate the sample size required for a comparative study of two RISR management policies would be 200 patients to have statistical power to detect a clinically significant difference in patient-rated scores of their skin reactions. A trial employing this tool would help provide an evidence base to guide policy in advising patients how to manage their RISR