International journal of radiation oncology, biology, physics
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Int. J. Radiat. Oncol. Biol. Phys. · Feb 2005
Multicenter Study Comparative StudyFailure definition-dependent differences in outcome following radiation for localized prostate cancer: can one size fit all?
To compare long-term outcome using alternative failure definitions after external beam radiation for localized prostate cancer. ⋯ There are notable differences in both short- and long-term outcomes after definitive radiation for prostate cancer depending on the failure definition applied. Failure definitions must be tested objectively for sensitivity and specificity in predicting clinical outcome, and it is only in this manner that reasonable choices can be made. Although traditional surgical-type failure definitions do not seem applicable to patients treated with external beam radiation, further analysis of definitions across multiple therapeutic modalities is necessary to determine whether a universal failure definition might be feasible, at least for research and comparative purposes.
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Int. J. Radiat. Oncol. Biol. Phys. · Feb 2005
Clinical TrialA dose-escalation trial with the adaptive radiotherapy process as a delivery system in localized prostate cancer: analysis of chronic toxicity.
To evaluate the validity of the chosen adaptive radiotherapy (ART) dose-volume constraints while testing the hypothesis that toxicity would not be greater at higher tumor dose levels. ⋯ By applying the ART process--namely, developing a patient-specific PTV--to prostate cancer patients, significant dose escalation can be achieved without increases in genitourinary or gastrointestinal toxicity. Our data validate the rectal and bladder dose-volume constraints chosen for our three-dimensional conformal and IMRT prostrate radiotherapy planning.
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Int. J. Radiat. Oncol. Biol. Phys. · Feb 2005
Clinical TrialPhase I study of conformal radiotherapy with concurrent gemcitabine in locally advanced bladder cancer.
A prospective phase I trial was conducted to determine the maximal tolerated dose of gemcitabine given once weekly during hypofractionated conformal radiotherapy to patients with locally advanced transitional cell carcinoma of the bladder. Eight male patients, median age 69 years, with Stage T2 (n = 4) or T3 (n = 4) N0M0, were enrolled in cohorts of 3. Treatment comprised conformal radiotherapy (52.5 Gy in 20 fractions) within 4 weeks, with concurrent gemcitabine once weekly for four cycles. The weekly gemcitabine dose was escalated from 100 mg/m(2) in increments of 50 mg/m(2) per cohort. Dose-limiting toxicity was defined as any acute Radiation Therapy Oncology Group (RTOG) toxicity Grade 3 or greater arising in >1 of 3 patients in each cohort. Tumor response was assessed cystoscopically and radiologically at 3 months. ⋯ The maximal tolerated dose for gemcitabine given once weekly with concurrent hypofractionated conformal bladder radiotherapy was 150 mg/m(2), with a maximal recommended dose of 100 mg/m(2). This dose regimen has now entered Phase II clinical trials.
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Int. J. Radiat. Oncol. Biol. Phys. · Feb 2005
Postoperative radiation therapy for grade II and III intracranial ependymoma.
To retrospectively determine the long-term outcome of intracranial ependymoma patients treated with surgery and postoperative radiation therapy. ⋯ Our long-term follow-up indicates that half of ependymoma patients will have disease recurrences, indicating the need for more effective treatments.
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Int. J. Radiat. Oncol. Biol. Phys. · Feb 2005
Low-dose megavoltage cone-beam CT for radiation therapy.
The objective of this work was to demonstrate the feasibility of acquiring low-exposure megavoltage cone-beam CT (MV CBCT) three-dimensional (3D) image data of sufficient quality to register the CBCT images to kilovoltage planning CT images for patient alignment and dose verification purposes. ⋯ We believe that the quality of these images, along with the rapid acquisition and reconstruction times, demonstrates that MV CBCT performed by use of a standard linear accelerator equipped with a flat-panel imager can be applied clinically for patient alignment.