International journal of radiation oncology, biology, physics
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Int. J. Radiat. Oncol. Biol. Phys. · Jan 2005
Impact of supplemental external beam radiotherapy and/or androgen deprivation therapy on biochemical outcome after permanent prostate brachytherapy.
To evaluate the impact of supplemental external beam radiotherapy (EBRT) and/or androgen deprivation therapy (ADT) on 8-year biochemical outcome after permanent prostate brachytherapy. ⋯ Prostate brachytherapy results in a high probability of 8-year biochemical progression-free survival for low-, intermediate-, and high-risk patients. Although the role of supplemental EBRT could not be adequately evaluated in high-risk patients, it did not improve biochemical outcome in low- and intermediate-risk patients. However, ADT resulted in a statistically significant improvement in progression-free survival for high-risk patients.
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Int. J. Radiat. Oncol. Biol. Phys. · Jan 2005
Impact of tumor repopulation on radiotherapy planning.
Biologic/functional imaging (e.g., fluorodeoxyglucose/3'-deoxy-3'-fluorothymidine-positron emission tomography) is promising to provide information on tumor cell repopulation. Such information is important in the design of biologically conformal radiotherapy for cancer. The questions remaining unclear are whether it is necessary to escalate the dose to the regions with rapid cell repopulation in the tumor target and, if so, by how much. The purpose of this work was to address these questions using radiobiologic modeling. ⋯ Dose escalation is necessary to offset the accelerated tumor cell repopulation during prolonged treatment courses. This study provides a preliminary estimate of the dose escalation for prostate cancer based on the in situ measurements of potential doubling time and radiobiologic models. The proposed dose prescriptions are technically feasible for clinical trials.
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Int. J. Radiat. Oncol. Biol. Phys. · Jan 2005
Randomized Controlled Trial Clinical TrialConcurrent chemo-radiotherapy with mitomycin C compared with porfiromycin in squamous cell cancer of the head and neck: final results of a randomized clinical trial.
Previous randomized trials have shown a benefit with concurrent use of the hypoxic cell cytotoxin mitomycin C (MC) and radiation (RT) in the management of squamous cell cancer of the head and neck (SCCHN). We conducted a randomized trial comparing MC with porfiromycin (POR) in combination with RT in the management of SCCHN. ⋯ Despite promising preclinical data, and an acceptable toxicity profile, POR was inferior to MC as an adjunct to RT in the management of SCCHN. This randomized trial emphasizes the need for randomized studies to evaluate new agents in the management of SCCHN.
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Int. J. Radiat. Oncol. Biol. Phys. · Jan 2005
Atlas-based automatic segmentation of MR images: validation study on the brainstem in radiotherapy context.
Brain tumor radiotherapy requires the volume measurements and the localization of several individual brain structures. Any tool that can assist the physician to perform the delineation would then be of great help. Among segmentation methods, those that are atlas-based are appealing because they are able to segment several structures simultaneously, while preserving the anatomy topology. This study aims to evaluate such a method in a clinical context. ⋯ Results demonstrate that the method is repeatable, provides a good trade-off between accuracy and robustness, and leads to reproducible segmentation and labeling. These results can be improved by enriching the atlas with the rough information of tumor or by using different laws of deformation for the different structures. Qualitative results also suggest that this method can be used for automatic segmentation of other organs such as neck, thorax, abdomen, pelvis, and limbs.