Amar U. Kishan
Joseph Kaminski3,4
Filippo Alongi- 1Department of Radiation Oncology, University of California, Los Angeles, Los Angeles, CA, United States
- 2Department of Urology, University of California, Los Angeles, Los Angeles, CA, United States
- 3Department of Radiation Oncology, University of Tennessee Health Science Center, Memphis, TN, United States
- 4Department of Radiology, Memphis Veterans Administration Medical Center, Memphis, TN, United States
- 5Advanced Radiation Oncology department, IRCCS Ospedale Sacro Cuore Don Calabria, Negrar dì Valpolicella (Verona), Verona, Italy
- 6Department of Radiation Oncology, University of Brescia, Verona, Italy
Editorial on the Research Topic:
Stereotactic body radiotherapy for prostate cancer
Over the past few years, there has been an enormous growth in the strength of data suggesting the safety and efficacy of stereotactic body radiotherapy (SBRT) for prostate cancer. These include long-term data on ultrahypofractionated radiotherapy delivered with older techniques from the HYPO-RT-PC trial (1), early but robust data on modern SBRT from the PACE-B trial (2), and long-term follow-up data from a multi-institutional SBRT consortium (3). Further multi-institutional data (4) and several small randomized phase II trials (5, 6) have built a case for SBRT in high-risk prostate cancer and for use for metastasis-directed therapy in oligometastatic prostate cancer. Exciting clinical data also highlight the potential role for SBRT in the post-prostatectomy setting (7–10) and as a re-irradiation modality in radiorecurrent disease (11–13). Moreover, technological advances in real time image guided SBRT with MRI or PET have great potential. For example, the MIRAGE trial, the first randomized trial comparing MRI-guided with standard CT- guided SBRT seems to confirm a promising role for this innovative technique in prostate SBRT. (14) Yet, despite these advances, questions still remain. Can urinary and rectal toxicity be further mitigated? What patient factors—clinical, demographic, or otherwise—impact treatment efficacy? How can we better understand response to SBRT, both in the definitive setting and in the oligometastatic setting? And how does SBRT compare to other forms of re-irradiation?
This collection features 14 articles exploring the role of SBRT in prostate cancer across the entire spectrum of its natural history. Five manuscripts focus on practical considerations and interventions that might optimize the therapeutic ratio when delivering SBRT. Pham et al. explore the geometric distortions and variations in the urethra that might have dosimetric consequences for patients undergoing SBRT. Panizza et al. describe intrafraction motion during intact prostate SBRT as captured by electromagnetic tracking. Repka et al. review the rationale for using hydrogel spacers with prostate SBRT (Repka et al), while Kundu et al. provide a dosimetric and toxicity analysis of patients who received SBRT and either had or did not have a spacer placed. Finally, Greco et al. describe seven year outcomes following dose-escalated SBRT wherein an endorectal balloon was used for mobilization/stabilization and a Foley catheter with implanted electromagnetic beacons was used to track and spare the urethra.
The next set of six articles explore efficacy and toxicity profiles among patients receiving SBRT for localized prostate cancer. Fuller et al. provide long-awaited 10-year outcomes from a multi-center phase II trial of high dose rate brachytherapy-like SBRT for intermediate risk prostate cancer. Three reports from the Georgetown SBRT group explore the incidence and natural history of post-SBRT hematospermia (Shah et al.), the implications of treatment interruptions (Pepin et al.), and the financial burden of SBRT (Sholklapper et al.). Correa and Loblaw provide a detailed review of the clinical evidence for SBRT in the context of high-risk disease. Finally, Liu et al. describe the ARGOS/CLIMBER protocol, in which men have pre-treatment and scheduled post-treatment multiparametric MRI and prostate specific membrane antigen positron emission tomography to establish imaging biomarkers of treatment response.
The collection is rounded out by three articles focusing on patients with recurrent disease. Cuccia et al. report on the outcomes of MRI-guided SBRT for re-irradiation of the prostate in men with radiorecurrent disease. Ryg et al. similarly explore long-term outcomes following salvage high dose-rate brachytherapy vs. salvage CT-guided SBRT. Finally, Mercier et al. report survival outcomes and failure patterns among men getting metastasis-directed SBRT for hormone sensitive or castrate resistant metastatic prostate cancer.
SBRT has demonstrated great success thus far for the definitive treatment of localized prostate cancer, but multiple important areas of investigation exist. These include: optimizing treatment by minimizing toxicity, evaluating long-term results in low and intermediate risk disease, better understanding its role in high risk disease, developing better markers of radioresponsiveness, exploring SBRT in the post-prostatectomy setting and for re-irradiation of radiorecurrent disease, and optimizing SBRT for metastasis-directed therapy. We hope that this broad collection of articles summarizes these exciting areas of active research while underscoring the efficacy and safety of SBRT for prostate cancer.
Author contributions
All authors listed have made a substantial, direct, and intellectual contribution to the work and approved it for publication.
Conflict of interest
The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
Publisher’s note
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References
1. Widmark A, Gunnlaugsson A, Beckman L, Thellenberg-Karlsson C, Hoyer M, Lagerlund M, et al. Ultra-hypofractionated versus conventionally fractionated radiotherapy for prostate cancer: 5-year outcomes of the HYPO-RT-PC randomised, non-inferiority, phase 3 trial. Lancet (2019) 394(10196):385–95. doi: 10.1016/s0140-6736(19)31131-6
2. Brand DH, Tree AC, Ostler P, van der Voet H, Loblaw A, Chu W, et al. Intensity-modulated fractionated radiotherapy versus stereotactic body radiotherapy for prostate cancer (PACE-b): acute toxicity findings from an international, randomised, open-label, phase 3, non-inferiority trial. Lancet Oncol (2019) 20(11):1531–43. doi: 10.1016/s1470-2045(19)30569-8
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9. Ma TM, Ballas LK, Wilhalme H, Sachdeva A, Chong N, Sharma S, et al. Quality-of-Life outcomes and toxicity profile among patients with localized prostate cancer after radical prostatectomy treated with stereotactic body radiation: The SCIMITAR multi-center phase 2 trial. Int J Radiat Oncol Biol Phys (2022). doi: 10.1016/j.ijrobp.2022.08.041
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12. Jereczek-Fossa BA, Rojas DP, Zerini D, Fodor C, Viola A, Fanetti G, et al. Reirradiation for isolated local recurrence of prostate cancer: Mono-institutional series of 64 patients treated with salvage stereotactic body radiotherapy (SBRT). Br J Radiol (2019) 92(1094):20180494. doi: 10.1259/bjr.20180494
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14. Kishan AU, Lamb J, Casado M, Wang X, Ma TM, Low D, et al. Magnetic resonance imaging-guided versus computed tomography-guided stereotactic body radiotherapy for prostate cancer (MIRAGE): Interim analysis of a phase III randomized trial. J Clin Oncol (2022) 40(6_suppl):255–5. doi: 10.1200/JCO.2022.40.6_suppl.255
Keywords: prostate SBRT, prostate, active surveillance, spacer, MRI
Citation: Kishan AU, Kaminski J and Alongi F (2022) Editorial: Stereotactic body radiotherapy for prostate cancer. Front. Oncol. 12:1034987. doi: 10.3389/fonc.2022.1034987
Received: 02 September 2022; Accepted: 12 September 2022;
Published: 17 October 2022.
Edited and Reviewed by:
Timothy James Kinsella, Brown University, United StatesCopyright © 2022 Kishan, Kaminski and Alongi. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
*Correspondence: Amar U. Kishan, aukishan@mednet.ucla.edu