Reduction in acute morbidity using hypofractionated intensity-modulated radiation therapy assisted with a fluoroscopic real-time @entity5 -tracking system for XXXX : preliminary results of a phase I/II study.

@entity1 @entity137 @entity263 @entity5 @entity344 @entity1486
PURPOSE: The positioning of the prostate is improved with the use of the fluoroscopic real-time @entity5 -tracking radiation therapy system for @entity263 . The acute radiation reaction and preliminary @entity5 response of @entity263 to hypofractionated intensity-modulated radiation therapy assisted with real-time @entity5 -tracking radiation therapy were investigated in this study. METHODS: @entity1 were classified into prognostic risk groups on the basis of the presence of the pretreatment @entity1486 , clinical stage, and histologic differentiation. Neoadjuvant hormonal therapy was administered to @entity1 in the high-risk group for 6 months before radiation therapy commenced. The intensity-modulated radiation therapy employed a segmental multileaf collimator, which generated a field made up of two or more shaped subfields using forward planning. Real-time @entity5 -tracking radiation therapy was used for the precise positioning of the prostate to minimize geometric uncertainties, while the dose was escalated in increments of 5 Gy from 65 Gy using a daily dose of 2.5 Gy (65 Gy/2.5 Gy), following the dose-escalation rules. Acute and late gastrointestinal and genitourinary morbidities due to radiation therapy were scored according to the @entity137 criteria of Radiation Therapy Oncology Group/European Organization for Research and Treatment of @entity5 . RESULTS: Thirty-one @entity1 were enrolled in this study between 1998 and 2001. Eighteen @entity1 were classified as being members of the high-risk group. Total dose was escalated, with 65 Gy/2.5 Gy being administered to 12 @entity1 and 70 Gy/2.5 Gy to 19 @entity1 . The median follow-up period was 37 months (range, 30-43 months), and 19 months (range, 10-27 months), for the 65-Gy and 70-Gy arms, respectively. @entity1 experienced no acute @entity137 and grade 1 late @entity344 (8.3%) in the 65-Gy/2.5-Gy arm. @entity1 in the 70-Gy/2.5-Gy arm experienced grade 1 acute @entity344 (5.3%) and grade 1 and 2 acute genitourinarytoxicities (15.8%). No @entity1 experienced dose-limiting @entity137 (defined as a grade 3 or higher acute @entity137 ) or a grade 2 or higher late complication in this study period. One and two @entity1486 relapses were observed in the 65-Gy and 70-Gy arms, respectively. CONCLUSION: Up to 70 Gy/2.5 Gy, equivalent to 80 Gy with a daily dose of 2.0 Gy, assuming alpha/beta ratio of 1.5, intensity-modulated radiation therapy assisted with real-time @entity5 -tracking radiation therapy was administered safely with a reasonable biochemical control rate. A further dose-escalation study using this system is justifiable.
