Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology
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We fit phenomenological tumor control probability (TCP) models to biopsy outcome after three-dimensional conformal radiation therapy (3D-CRT) of prostate cancer patients to quantify the local dose-response of prostate cancer. ⋯ Dose-response of prostate cancer, quantified by TCD(50) and gamma(50), varies by prognostic subgroup. Our observations are consistent with the hypothesis that the shallow nature of clinically observed dose-response curves for local control result from a patient population that is a heterogeneous mixture of sub-populations with steeper dose-response curves and varying values of TCD(50). Such results may eventually help to identify patients, based on their individual pre-treatment prognostic factors, that would benefit most from dose-escalation, and to guide dose prescription.
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Multicenter Study Clinical Trial
Up-front centralized data review and individualized treatment proposals in a multicenter pediatric Hodgkin's disease trial with 71 participating hospitals: the experience of the German-Austrian pediatric multicenter trial DAL-HD-90.
A systematic procedure for up-front centralized data review and the set-up of individualized treatment proposals was integrated prospectively into the German-Austrian multicenter trial DAL-HD-90 for pediatric Hodgkin's disease (HD) in order to introduce local radiotherapy according to the individual patient's spread of disease within a combined-modality treatment. This paper investigates the feasibility of such a procedure and its impact on the final definition of the extent and stage of disease as well as on the choice of treatment. ⋯ The up-front centralized review of patient data and consecutive set-up and delivery of individualized treatment proposals for almost every patient are feasible within a large multicenter trial. Sufficient time and manpower at the study center are needed for the review process and the set-up of individualized treatment proposals. Such a procedure has a significant impact on the homogeneity of stage definition, allocation to TG, and individualized treatment proposals.
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Multicenter Study Comparative Study
Conformal radiotherapy for lung cancer: different delineation of the gross tumor volume (GTV) by radiologists and radiation oncologists.
Delineation of the gross tumor volume (GTV) and organs at risk constitutes one of the most important phases of conformal radiotherapy (CRT) procedures. In the absence of a clear redefinition of the GTV, for a given pathology, complemented by detailed contouring procedures, the GTV are likely to be estimated rather arbitrarily with the risk of tumor underdosage or detriment to the surrounding healthy tissues. The objective of this study was to compare the delineation of the GTV of intrathoracic tumors by radiologists and radiation oncologists with experience in the field in various centers. ⋯ Major discordances were observed between the radiation oncologists' and the radiologists' delineations, indicating that this step needs to be improved. A better training of radiation oncologists in thoracic imaging and collaboration between radiation oncologists and radiologists should decrease this variability. New imaging techniques (image fusion, positron emission tomography, magnetic resonance imaging spectroscopy, etc.) may also provide a useful contribution to this difficult delineation.
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We have tested the camptothecin analogs, RFS-2000 or CPT-11, in combination with both etoposide and ionizing radiation in vitro to examine the radiation enhancing potential of topoisomerase I plus topoisomerase II (Topo I+Topo II) inhibition in human cancer cells. ⋯ These data show that the combination of Topo I inhibitors, RFS-2000 or CPT-11 plus Topo II inhibitor etoposide, is a more effective radiation enhancer than either agent alone in human lung cancer cells. The mechanism of radiation enhancement may involve inhibition of SLDR with RFS-2000 plus etoposide, but other mechanisms may be involved in the combined treatment including CPT-11.
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Many patients with non-small cell lung cancer (NSCLC) receive external beam radiation therapy as part of their treatment. Three-dimensional conformal radiation therapy (3DCRT) commonly uses computed tomography (CT) to accurately delineate the target lesion and normal tissues. Clinical studies, however, indicate that positron emission tomography (PET) has higher sensitivity than CT in detecting and staging of mediastinal metastases. Imaging with fluoro-2-deoxyglucose (FDG) PET in conjunction with CT, therefore, can improve the accuracy of lesion definition. In this pilot study, we investigated the potential benefits of incorporating PET data into the conventional treatment planning of NSCLC. Case-by-case, we prospectively analyzed planning target volume (PTV) and lung toxicity changes for a cohort of patients. ⋯ The incorporation of PET data improves definition of the primary lesion by including positive lymph nodes into the PTV. Thus, the PET data reduces the likelihood of geographic misses and hopefully improves the chance of achieving local control.