Advancements in imaging and dose delivery enable boosting of the dominant intraprostatic lesions (DIL), while maintaining organs-at-risk (OAR) tolerances. This study aimed to assess the feasibility of DIL boosting for volumetric modulated arc therapy (VMAT), intensity modulated proton therapy (IMPT) and high dose rate brachytherapy (HDR-BT).
DILs were defined on multiparametric magnetic resonance imaging and fused with planning CT for twelve patients. VMAT, IMPT and HDR-BT plans were created for each patient with an EQD2α/β DIL aimed at 111. 6Gy, PTVinitialDpres was 80. 9Gy (EBRT) with CTV D90%=81. 9Gy (HDR-BT). Hard dose constraints were applied for OARs.
Higher boost doses were achieved with IMPT compared to VMAT, keeping major OAR doses at similar levels. Patient averaged EQD2α/β D50% to DIL were 110. 7, 114. 2 and 150. 1Gy(IsoE) for VMAT, IMPT and HDR-BT, respectively. Respective rectal wall Dmean were 30. 5±5. 0, 16. 7±3. 6, 9. 5±2. 5Gy(IsoE) and bladder wall Dmean were 21. 0±5. 5, 15. 6±4. 3 and 6. 3±2. 2Gy(IsoE).
DIL boosting was found to be feasible with all investigated techniques. Although OAR doses were higher than for standard treatment approach, the risk levels were reasonably low. HDR-BT was superior to VMAT and IMPT, both in terms of OAR sparing and DIL boosting.
Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology. 2015 Sep 06 [Epub ahead of print]
Piotr Andrzejewski, Peter Kuess, Barbara Knäusl, Katja Pinker, Petra Georg, Johannes Knoth, Daniel Berger, Christian Kirisits, Gregor Goldner, Thomas Helbich, Richard Pötter, Dietmar Georg
Dept. of Radiation Oncology, Comprehensive Cancer Center, Medical University Vienna, Austria; Christian Doppler Laboratory for Medical Radiation Research for Radiation Oncology, Medical University of Vienna, Vienna, Austria. Dept. of Radiation Oncology, Comprehensive Cancer Center, Medical University Vienna, Austria; Christian Doppler Laboratory for Medical Radiation Research for Radiation Oncology, Medical University of Vienna, Vienna, Austria. , Dept. of Radiation Oncology, Comprehensive Cancer Center, Medical University Vienna, Austria; Christian Doppler Laboratory for Medical Radiation Research for Radiation Oncology, Medical University of Vienna, Vienna, Austria. , Dept. of Biomedical Imaging and Image-guided Therapy, Austria; Christian Doppler Laboratory for Medical Radiation Research for Radiation Oncology, Medical University of Vienna, Vienna, Austria. , Christian Doppler Laboratory for Medical Radiation Research for Radiation Oncology, Medical University of Vienna, Vienna, Austria; EBG MedAustron GmbH, Wiener Neustadt, Austria. , Dept. of Radiation Oncology, Comprehensive Cancer Center, Medical University Vienna, Austria. , Dept. of Radiation Oncology, Comprehensive Cancer Center, Medical University Vienna, Austria. , Dept. of Radiation Oncology, Comprehensive Cancer Center, Medical University Vienna, Austria; Christian Doppler Laboratory for Medical Radiation Research for Radiation Oncology, Medical University of Vienna, Vienna, Austria. , Dept. of Radiation Oncology, Comprehensive Cancer Center, Medical University Vienna, Austria; Christian Doppler Laboratory for Medical Radiation Research for Radiation Oncology, Medical University of Vienna, Vienna, Austria. , Dept. of Biomedical Imaging and Image-guided Therapy, Austria; Christian Doppler Laboratory for Medical Radiation Research for Radiation Oncology, Medical University of Vienna, Vienna, Austria. , Dept. of Radiation Oncology, Comprehensive Cancer Center, Medical University Vienna, Austria; Christian Doppler Laboratory for Medical Radiation Research for Radiation Oncology, Medical University of Vienna, Vienna, Austria. , Dept. of Radiation Oncology, Comprehensive Cancer Center, Medical University Vienna, Austria; Christian Doppler Laboratory for Medical Radiation Research for Radiation Oncology, Medical University of Vienna, Vienna, Austria.