International journal of radiation oncology, biology, physics
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Int. J. Radiat. Oncol. Biol. Phys. · Mar 2008
Incidence of late rectal and urinary toxicities after three-dimensional conformal radiotherapy and intensity-modulated radiotherapy for localized prostate cancer.
To report the incidence and predictors of treatment-related toxicity at 10 years after three-dimensional conformal radiotherapy (3D-CRT) and intensity-modulated radiotherapy (IMRT) for localized prostate cancer. ⋯ Serious late toxicity was unusual despite the delivery of high radiation dose levels in these patients. Higher doses were associated with increased GI and GU Grade 2 toxicities, but the risk of proctitis was significantly reduced with IMRT. Acute symptoms were a precursor of late toxicities in these patients.
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Int. J. Radiat. Oncol. Biol. Phys. · Mar 2008
Has the pattern of practice in the prescription of radiotherapy for the palliation of thoracic symptoms changed between 1999 and 2006 at the rapid response radiotherapy program?
Eleven randomized controlled trials (RCT) comparing various radiotherapy (RT) schedules for locally advanced lung cancer published since 1991 found no difference in palliation of intrathoracic symptoms. The most commonly prescribed schedule by Canadian Radiation Oncologists (RO) (20 Gy in five fractions [20 Gy/5]), when first evaluated versus 10 Gy/1 in a 2002 RCT, showed a significant survival benefit. A subsequent RCT assessing 20 Gy/5 found worse survival versus 16 Gy/2. This study examines whether the RT prescription for lung cancer palliation in the Rapid Response Radiotherapy Program (RRRP) has changed over time. ⋯ RT schedule for palliation of intrathoracic symptoms did not mirror the results of sequential, conflicting RCTs, suggesting that factors other than the literature influenced practice patterns in palliative thoracic RT.
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Int. J. Radiat. Oncol. Biol. Phys. · Mar 2008
Proton magnetic resonance spectroscopic imaging in newly diagnosed glioblastoma: predictive value for the site of postradiotherapy relapse in a prospective longitudinal study.
To investigate the association between magnetic resonance spectroscopic imaging (MRSI)-defined, metabolically abnormal tumor regions and subsequent sites of relapse in data from patients treated with radiotherapy (RT) in a prospective clinical trial. ⋯ Metabolically active regions represented a small percentage of pretreatment MRI abnormalities and were predictive for the site of post-RT relapse. The incorporation of MRSI data in the definition of RT target volumes for selective boosting may be a promising avenue leading to increased local control of glioblastomas.
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Int. J. Radiat. Oncol. Biol. Phys. · Mar 2008
Universal survival curve and single fraction equivalent dose: useful tools in understanding potency of ablative radiotherapy.
Overprediction of the potency and toxicity of high-dose ablative radiotherapy such as stereotactic body radiotherapy (SBRT) by the linear quadratic (LQ) model led to many clinicians' hesitating to adopt this efficacious and well-tolerated therapeutic option. The aim of this study was to offer an alternative method of analyzing the effect of SBRT by constructing a universal survival curve (USC) that provides superior approximation of the experimentally measured survival curves in the ablative, high-dose range without losing the strengths of the LQ model around the shoulder. ⋯ The USC can be used to compare the dose fractionation schemes of both CFRT and SBRT. The USC provides an empirically and a clinically well-justified rationale for SBRT while preserving the strengths of the LQ model for CFRT.
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Int. J. Radiat. Oncol. Biol. Phys. · Mar 2008
Multicenter Study Clinical TrialMulti-institution prospective trial of reduced-dose craniospinal irradiation (23.4 Gy) followed by conformal posterior fossa (36 Gy) and primary site irradiation (55.8 Gy) and dose-intensive chemotherapy for average-risk medulloblastoma.
Limiting the neurocognitive sequelae of radiotherapy (RT) has been an objective in the treatment of medulloblastoma. Conformal RT to less than the entire posterior fossa (PF) after craniospinal irradiation might reduce neurocognitive sequelae and requires evaluation. ⋯ This prospective trial has demonstrated that irradiation of less than the entire PF after 23.4 Gy craniospinal irradiation for average-risk medulloblastoma results in disease control comparable to that after treatment of the entire PF.