International journal of radiation oncology, biology, physics
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Int. J. Radiat. Oncol. Biol. Phys. · Jul 2000
Modeling normal tissue complication probability from repetitive computed tomography scans during fractionated high-dose-rate brachytherapy and external beam radiotherapy of the uterine cervix.
To calculate the normal tissue complication probability (NTCP) of late radiation effects on the rectum and bladder from repetitive CT scans during fractionated high-dose-rate brachytherapy (HDRB) and external beam radiotherapy (EBRT) of the uterine cervix and compare the NTCP with the clinical frequency of late effects. ⋯ The NTCP for the rectum was almost consistent with the clinical frequency of late effects, whereas the NTCP for bladder was too high. To obtain reliable (SD of 12-13%) NTCP values, 3-4 CT scans are needed during 5-7 fractions of HDRB treatments.
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Int. J. Radiat. Oncol. Biol. Phys. · Jul 2000
Dose-dependent induction of transforming growth factor beta (TGF-beta) in the lung tissue of fibrosis-prone mice after thoracic irradiation.
The lung is the major dose-limiting organ for radiotherapy of cancer in the thoracic region. The pathogenesis of radiation-induced lung injury at the molecular level is still unclear. Immediate cellular damage after irradiation is supposed to result in cytokine-mediated multicellular interactions with induction and progression of fibrotic tissue reactions. The purpose of this investigation was to evaluate the acute and long-term effects of radiation on the gene expression of transforming growth factor beta (TGF-beta) in a model of lung injury using fibrosis-sensitive C57BL/6 mice. ⋯ This study demonstrates an acute and long-lasting increase in the expression of TGF-beta in lung tissue following thoracic irradiation with 12 Gy. The predominant localization of TGF-beta in areas of inflammatory cell infiltrates and fibrosis suggests involvement of this cytokine in the pathogenesis of radiation-induced pulmonal fibrosis. Further studies should be performed to explore the role of other cytokines in the development of radiation injury. An improved understanding of the underlying mechanisms of pulmonary fibrosis may eventually lead to modulatory intervention at the molecular level to modify the fibrotic process.
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Int. J. Radiat. Oncol. Biol. Phys. · Jul 2000
Randomized Controlled Trial Clinical TrialValidation of the RTOG recursive partitioning analysis (RPA) classification for brain metastases.
The Radiation Therapy Oncology Group (RTOG) previously developed three prognostic classes for brain metastases using recursive partitioning analysis (RPA) of a large database. These classes were based on Karnofsky performance status (KPS), primary tumor status, presence of extracranial system metastases, and age. An analysis of RTOG 91-04, a randomized study comparing two dose-fractionation schemes with a comparison to the established RTOG database, was considered important to validate the RPA classes. ⋯ This analysis indicates that the RPA classes are valid and reliable for historical comparisons. Both the RTOG and other clinical trial organizers should currently utilize this RPA classification as a stratification factor for clinical trials.
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Int. J. Radiat. Oncol. Biol. Phys. · Jul 2000
Application of recursive partitioning analysis and evaluation of the use of whole brain radiation among patients treated with stereotactic radiosurgery for newly diagnosed brain metastases.
To evaluate the usefulness of whole brain radiotherapy (WBRT) and of the Radiation Therapy Oncology Group recursive partitioning analysis (RPA) for brain metastases among patients receiving stereotactic radiosurgery (SRS). ⋯ Despite the inherent biases to select more favorable patients for SRS, the RPA class retains its prognostic value. Omission of WBRT from the initial management was not detrimental in terms of overall survival; however, progressive disease occurred in over 50% of patients treated in this manner. Further studies are required to determine which, if any, patients should be considered for SRS with WBRT held in reserve.
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Int. J. Radiat. Oncol. Biol. Phys. · Jul 2000
Clinical TrialA phase II study of paclitaxel, carboplatin, and hyperfractionated radiation therapy for locally advanced inoperable non-small-cell lung cancer (a Vanderbilt Cancer Center Affiliate Network Study).
We conducted a prospective phase II study to determine the response rate, toxicity, and survival rate of concurrent weekly paclitaxel, carboplatin, and hyperfractionated radiation therapy (paclitaxel/carboplatin/HFX RT) followed by 2 cycles of paclitaxel and carboplatin for locally advanced unresectable non-small cell lung cancer (NSCLC). The weekly paclitaxel and carboplatin regimen was designed to optimize the radiosensitizing properties of paclitaxel during the concurrent phase of treatment. ⋯ Weekly paclitaxel, carboplatin, plus concurrent hyperfractionated RT is a well-tolerated outpatient regimen. The response rate from this regimen is encouraging and appears to be at least equivalent to the more toxic chemoradiation trials. These findings warrant further clinical evaluation of weekly paclitaxel/carboplatin/HFX RT in a phase III study.