François Lucia1, Stéphane Key2, Gurvan Dissaux2, Gaëlle Goasduff2, Anne-Sophie Lucia2, Luc Ollivier2, Olivier Pradier3, Ulrike Schick3. 1. Radiation Oncology Department, University Hospital, Brest, France; LaTIM, INSERM, UMR 1101, University of Brest, ISBAM, UBO, UBL, Brest, France. Electronic address: francois.lucia@chu-brest.fr. 2. Radiation Oncology Department, University Hospital, Brest, France. 3. Radiation Oncology Department, University Hospital, Brest, France; LaTIM, INSERM, UMR 1101, University of Brest, ISBAM, UBO, UBL, Brest, France.
Abstract
INTRODUCTION: The aim of this study was to analyze the impact of inhomogeneous versus homogeneous dose distribution on local control (LC) and radionecrosis (RN) in patients treated with fractionated stereotactic radiotherapy (SRT) for newly-diagnosed brain metastases (BM). PATIENTS AND METHODS: From 2014 to 2017, 134 patients (median age 61 years) underwent SRT for BM (n = 114 with ≤2, n = 20 with 3-6 BM) at our institution. Treatment was delivered using volumetric modulated arc therapy on a linear accelerator. Ninety-one consecutive patients (BM = 136) were irradiated at a dose of 21-23.1 Gy in 3 fractions delivered homogeneously (99% of the dose had to cover 99% of the planning target volume (PTV)) (group 1) whereas the following 43 patients (BM = 72) received an inhomogeneous dose of 10 or 11 Gy prescribed to the isocenter with the 70% isodose line covering the PTV (group 2). Variables analyzed included dose distribution, age, gender, histology, diagnosis-specific Graded Prognostic Assessment score, number of brain metastases, presence of extracranial metastases, and tumor volumes. RESULTS: After a median follow-up of 12.4 months (range, 1.4-33.1), the 1-year LC and RN rate were 78% and 7.5% in group 1 and 93% and 0% in group 2, respectively (p = 0.005). In multivariate analysis, improved LC was significantly correlated with SRT dose distribution (p = 0.009) and tumor volume (p = 0.03). The number of metastases (p = 0.03) and SRT dose distribution (p = 0.04) were both associated with increased risk of RN. CONCLUSION: SRT delivered with inhomogeneous dose distribution resulted in better LC and a lower risk of RN compared to homogeneous distribution.
INTRODUCTION: The aim of this study was to analyze the impact of inhomogeneous versus homogeneous dose distribution on local control (LC) and radionecrosis (RN) in patients treated with fractionated stereotactic radiotherapy (SRT) for newly-diagnosed brain metastases (BM). PATIENTS AND METHODS: From 2014 to 2017, 134 patients (median age 61 years) underwent SRT for BM (n = 114 with ≤2, n = 20 with 3-6 BM) at our institution. Treatment was delivered using volumetric modulated arc therapy on a linear accelerator. Ninety-one consecutive patients (BM = 136) were irradiated at a dose of 21-23.1 Gy in 3 fractions delivered homogeneously (99% of the dose had to cover 99% of the planning target volume (PTV)) (group 1) whereas the following 43 patients (BM = 72) received an inhomogeneous dose of 10 or 11 Gy prescribed to the isocenter with the 70% isodose line covering the PTV (group 2). Variables analyzed included dose distribution, age, gender, histology, diagnosis-specific Graded Prognostic Assessment score, number of brain metastases, presence of extracranial metastases, and tumor volumes. RESULTS: After a median follow-up of 12.4 months (range, 1.4-33.1), the 1-year LC and RN rate were 78% and 7.5% in group 1 and 93% and 0% in group 2, respectively (p = 0.005). In multivariate analysis, improved LC was significantly correlated with SRT dose distribution (p = 0.009) and tumor volume (p = 0.03). The number of metastases (p = 0.03) and SRT dose distribution (p = 0.04) were both associated with increased risk of RN. CONCLUSION: SRT delivered with inhomogeneous dose distribution resulted in better LC and a lower risk of RN compared to homogeneous distribution.
Authors: Joshua D Palmer; Nikhil T Sebastian; Jacquline Chu; Dominic DiCostanzo; Erica H Bell; John Grecula; Andrea Arnett; Dukagjin M Blakaj; John McGregor; James B Elder; Lanchun Lu; Wesley Zoller; Mark Addington; Russell Lonser; Arnab Chakravarti; Paul D Brown; Raju Raval Journal: Adv Radiat Oncol Date: 2019-09-16
Authors: Alexandra Hellerbach; Markus Eichner; Daniel Rueß; Klaus Luyken; Mauritius Hoevels; Michael Judge; Christian Baues; Maximilian Ruge; Martin Kocher; Harald Treuer Journal: Strahlenther Onkol Date: 2021-12-09 Impact factor: 4.033