Feasibility of dominant intraprostatic lesion boosting using advanced photon-, proton- or brachytherapy.
OBJECTIVE
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).


METHODS
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 EQD2(α/β) DIL aimed at 111.6 Gy, PTV(initial) D(pres) was 80.9 Gy (EBRT) with CTV D90%=81.9 Gy (HDR-BT). Hard dose constraints were applied for OARs.


RESULTS
Higher boost doses were achieved with IMPT compared to VMAT, keeping major OAR doses at similar levels. Patient averaged EQD2(α/β) D50% to DIL were 110.7, 114.2 and 150.1 Gy(IsoE) for VMAT, IMPT and HDR-BT, respectively. Respective rectal wall D(mean) were 30.5±5.0, 16.7±3.6, 9.5±2.5 Gy(IsoE) and bladder wall D(mean) were 21.0±5.5, 15.6±4.3 and 6.3±2.2 Gy(IsoE).


CONCLUSIONS
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.
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. Electronic address: piotr.andrzejewski@meduniwien.ac.at.
Piotr
P
Andrzejewski
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.
Peter
P
Kuess
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.
Barbara
B
Knäusl
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.
Katja
K
Pinker
Christian Doppler Laboratory for Medical Radiation Research for Radiation Oncology, Medical University of Vienna, Vienna, Austria; EBG MedAustron GmbH, Wiener Neustadt, Austria.
Petra
P
Georg
Dept. of Radiation Oncology, Comprehensive Cancer Center, Medical University Vienna, Austria.
Johannes
J
Knoth
Dept. of Radiation Oncology, Comprehensive Cancer Center, Medical University Vienna, Austria.
Daniel
D
Berger
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.
Christian
C
Kirisits
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.
Gregor
G
Goldner
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.
Thomas
T
Helbich
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.
Richard
R
Pötter
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.
Dietmar
D
Georg
D000328:Adult; D000368:Aged; D001918:Brachytherapy / Q000379:methods*; D005240:Feasibility Studies; D006801:Humans; D008297:Male; D058958:Organs at Risk; D017785:Photons / Q000627:therapeutic use*; D011471:Prostatic Neoplasms / Q000532:radiotherapy*; D061766:Proton Therapy / Q000379:methods*; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods*; D012007:Rectum / Q000528:radiation effects; D001743:Urinary Bladder / Q000528:radiation effects
DIL; HDR-BT; IMPT; Prostate cancer; SIB; VMAT