Target coverage and organs at risk dose in hypofractionated salvage radiotherapy after prostatectomy.

Autor:	Staal FHE; University of Groningen, University Medical Centre Groningen, Department of Radiation Oncology, Hanzeplein 1, Postbus 30.001, 9700 RB Groningen, The Netherlands., Janssen J; University of Groningen, University Medical Centre Groningen, Department of Radiation Oncology, Hanzeplein 1, Postbus 30.001, 9700 RB Groningen, The Netherlands., Krishnapillai S; University of Groningen, University Medical Centre Groningen, Department of Radiation Oncology, Hanzeplein 1, Postbus 30.001, 9700 RB Groningen, The Netherlands., Langendijk JA; University of Groningen, University Medical Centre Groningen, Department of Radiation Oncology, Hanzeplein 1, Postbus 30.001, 9700 RB Groningen, The Netherlands., Both S; University of Groningen, University Medical Centre Groningen, Department of Radiation Oncology, Hanzeplein 1, Postbus 30.001, 9700 RB Groningen, The Netherlands., Brouwer CL; University of Groningen, University Medical Centre Groningen, Department of Radiation Oncology, Hanzeplein 1, Postbus 30.001, 9700 RB Groningen, The Netherlands., Aluwini S; University of Groningen, University Medical Centre Groningen, Department of Radiation Oncology, Hanzeplein 1, Postbus 30.001, 9700 RB Groningen, The Netherlands.
Jazyk:	angličtina
Zdroj:	Physics and imaging in radiation oncology [Phys Imaging Radiat Oncol] 2024 Jun 19; Vol. 31, pp. 100600. Date of Electronic Publication: 2024 Jun 19 (Print Publication: 2024).
DOI:	10.1016/j.phro.2024.100600
Abstrakt:	Background and Purpose: Introducing moderately hypofractionated salvage radiotherapy (SRT) following prostatectomy obligates investigation of its effects on clinical target volume (CTV) coverage and organ-at-risk (OAR) doses. This study assessed interfractional volume and dose changes in OARs and CTV in moderately hypofractionated SRT and evaluated the 8-mm planning target volume (PTV) margin. Materials and Methods: Twenty patients from the PERYTON-trial were included; 10 received conventional SRT (35 × 2 Gy) and 10 hypofractionated SRT (20 × 3 Gy). OARs were delineated on 539 pre-treatment Cone Beam CT (CBCT) scans to compare interfractional OAR volume changes. CTVs for the hypofractionated group were delineated on 199 CBCTs. Dose distributions with 4 and 6 mm PTV margins were generated using voxel-wise minimum robustness evaluation of the original 8-mm PTV plan, and dose changes were assessed. Results: Median volume changes for bladder and rectum were -26 % and -10 %, respectively. OAR volume changes were not significantly different between the two treatment schedules. The 8-mm PTV margin ensured optimal coverage for prostate bed and vesicle bed CTV (V95 = 100 % in >97 % fractions). However, bladder V60 <25 % was not achieved in 5 % of fractions, and rectum V60 <5 % was unmet in 33 % of fractions. A 6-mm PTV margin resulted in CTV V95 = 100 % in 92 % of fractions for prostate bed, and in 86 % for vesicle bed CTV. Conclusions: Moderately hypofractionated SRT yielded comparable OAR volume changes to conventionally fractionated SRT. Interfractional changes remained acceptable with a PTV margin of 6 mm for prostate bed and 8 mm for vesicle bed. Competing Interests: The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: The PERYTON-trial is sponsored by Dutch Cancer Society (KWF Kanker Bestrijding grant number 12649). S. Aluwini reports a role as Chair of the LPRU (Landelijk Platform Radiotherapie Urologische Tumoren). J.A. Langendijk reports a relationship with Dutch Cancer Society that includes: funding grants. J.A. Langendijk reports a relationship with Global Scientific Advisory Board of IBA. That includes: board membership. J.A. Langendijk reports a relationship with RayCare International Advisory Board of RaySearch that includes: board membership. J.A. Langendijk reports a relationship with IBA that includes: speaking and lecture fees. J.A. Langendijk reports a relationship with the Netherlands Society for Radiation Oncology that includes: board membership. (© 2024 The Authors. Published by Elsevier B.V. on behalf of European Society of Radiotherapy & Oncology.)
Databáze:	MEDLINE
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