Background: Magnetic resonance(MR)-guided ultra-hypofractionated radiotherapy with whole-pelvic irradiation(UHF-WPRT)is a novel approach to radiotherapy for patients with high-risk(HR)and very high-risk(VHR)prostate c...Background: Magnetic resonance(MR)-guided ultra-hypofractionated radiotherapy with whole-pelvic irradiation(UHF-WPRT)is a novel approach to radiotherapy for patients with high-risk(HR)and very high-risk(VHR)prostate cancer(PCa).However,the inherent complexity of adaptive UHF-WPRT might inevitably result in longer on-couch time.We aimed to estimate the delivered dose,study the feasibility and safety of adaptive UHF-WPRT on a 1.5-Tesla MR-Linac.Methods: Ten patients with clinical stage T3a-4N0-1M0-1c PCa,who consecutively received UHF-WPRT,were enrolled prospectively.The contours of the target and organ-at-risks on the position verification-MR(PV-MR),beam-on 3D-MR(Bn-MR),and post-MR(after radiotherapy delivery)were derived from the pre-MR data by deformable image registration.The physician then manually adjusted them,and dose recalculation was performed accordingly.GraphPad Prism 9(GraphPad Prism Software Inc.)was utilized for conducting statistical analyses.Results: In total,we collected 188 MR scans(50 pre-MR,50 PV-MR,44 Bn-MR,and 44 post-MR scans).With median 59 min,the mean prostate clinical target volume(CTV)-V_(100%)was 98.59%±2.74%,and the mean pelvic CTVp-V_(100%)relative percentages of all scans was 99.60%±1.18%.The median V29 Gy change in the rectal wall was−2%(−18%to 20%).With a median follow-up of 9 months,no patient had acute Common Terminology Criteria for Adverse Events(CTCAE)grade 2 or more severe genitourinary(GU)or gastrointestinal(GI)toxicities(0%).Conclusion: UHF-RT to the prostate and the whole pelvis with concomitant boost to positive nodes using an Adapt-To-Shape(ATS)workflow was technically feasible for patients with HR and VHR PCa,presenting only mild GU and GI toxicities.The estimated target dose during the beam-on phase was clinically acceptable based on the 3D-MR-based dosimetry analysis.Clinical trial registration Chinese Clinical Trial Registry ChiCTR2000033382.展开更多
基金This work was supported by the Non-profit Central Research Institute Fund of the Chinese Academy of Medical Sciences,Longevity and Health Project,2021-JKCS-003.
文摘Background: Magnetic resonance(MR)-guided ultra-hypofractionated radiotherapy with whole-pelvic irradiation(UHF-WPRT)is a novel approach to radiotherapy for patients with high-risk(HR)and very high-risk(VHR)prostate cancer(PCa).However,the inherent complexity of adaptive UHF-WPRT might inevitably result in longer on-couch time.We aimed to estimate the delivered dose,study the feasibility and safety of adaptive UHF-WPRT on a 1.5-Tesla MR-Linac.Methods: Ten patients with clinical stage T3a-4N0-1M0-1c PCa,who consecutively received UHF-WPRT,were enrolled prospectively.The contours of the target and organ-at-risks on the position verification-MR(PV-MR),beam-on 3D-MR(Bn-MR),and post-MR(after radiotherapy delivery)were derived from the pre-MR data by deformable image registration.The physician then manually adjusted them,and dose recalculation was performed accordingly.GraphPad Prism 9(GraphPad Prism Software Inc.)was utilized for conducting statistical analyses.Results: In total,we collected 188 MR scans(50 pre-MR,50 PV-MR,44 Bn-MR,and 44 post-MR scans).With median 59 min,the mean prostate clinical target volume(CTV)-V_(100%)was 98.59%±2.74%,and the mean pelvic CTVp-V_(100%)relative percentages of all scans was 99.60%±1.18%.The median V29 Gy change in the rectal wall was−2%(−18%to 20%).With a median follow-up of 9 months,no patient had acute Common Terminology Criteria for Adverse Events(CTCAE)grade 2 or more severe genitourinary(GU)or gastrointestinal(GI)toxicities(0%).Conclusion: UHF-RT to the prostate and the whole pelvis with concomitant boost to positive nodes using an Adapt-To-Shape(ATS)workflow was technically feasible for patients with HR and VHR PCa,presenting only mild GU and GI toxicities.The estimated target dose during the beam-on phase was clinically acceptable based on the 3D-MR-based dosimetry analysis.Clinical trial registration Chinese Clinical Trial Registry ChiCTR2000033382.
