EURURO Vol. 72 No. 4

617 656

Prostate Cancer
Vessel-sparing Radiotherapy for Localized Prostate Cancer to
Preserve Erectile Function: A Single-arm Phase 2 Trial
Daniel E. Spratt y, Jae Y. Lee , Robert T. Dess Vrinda Narayana Cheryl Evans
Adam Liss Raymond Winfield Matthew[1_TD$DIFF] J. Schipper Theodore S. Lawrence
Patrick W. McLaughlin
a Department of Radiation Oncology, University of Michigan, Ann Arbor, MI, USA; b Department of Urology, Providence Cancer Center, Southfield, MI, USA;
c Department of Biostatistics, University of Michigan, Ann Arbor, MI, USA; dDepartment of Radiation Oncology, Providence Cancer Center, Southfield, MI, USA
ava ilable at
journal homepage:
Article info
Article history:
Accepted February 4, 2017
Associate Editor:
James Catto
Keywords:
Erectile dysfunction
Prostate cancer
Radiotherapy
Vessel-sparing radiation
Abstract
Background: Erectile dysfunction remains the most common side effect from radical treat-
ment of localized prostate cancer. We hypothesized that the use of vessel-sparing radiother-
apy, analogous to the functional anatomy approach of nerve-sparing radical prostatectomy
(RP), would improve erectile function preservation while maintaining tumor control for men
with localized prostate cancer.
Objective: To determine erectile function rates after vessel-sparing radiotherapy.
Design, setting, and participants: Men with localized prostate cancer were enrolled in a phase
2 single-arm trial (NCT02958787) at a single academic center.
Intervention: Patients received vessel-sparing radiotherapy utilizing a planning MRI and
MRI-angiogram to delineate and avoid the erectile vasculature.
Outcome measurements and statistical analysis: Both physician- and patient-reported in-
ventories were used to capture erectile function at baseline and at 2 and 5 yr after treatment.
Validated model-based comparisons were performed to compare vessel-sparing results to
nerve-sparing RP and conventional radiotherapy.
Results and limitations: From2001 to 2009, 135men underwent vessel-sparing radiotherapy.
After a planned interim analysis, the trial was stopped after meeting the primary endpoint.
The median follow-up was 8.7 yr, with a 94% response rate to all inventories at each time
point. At 5 yr, 88% of patients were sexually active with or without the use of sexual aids. The
2-yr erectile function rates were significantly improved with vessel-sparing radiotherapy
(78%, 95% confidence interval [CI] 71–85%) compared to modeled rates for convention
radiotherapy (42%, 95% CI 38-45%; p < 0.001) or nerve-sparing prostatectomy (24%, 95% CI
22–27%; p < 0.001). At 2 yr after treatment, 87% of baseline-potent men retained erections
suitable for intercourse. The 5- and 10-yr rates of biochemical relapse–free survival were
99.3% and 89.9%, and at 5 yr the biochemical failures were limited to the National Compre-
hensive Cancer Network high-risk group. The single-arm design is a limitation.
Conclusions: Vessel-sparing radiotherapy appears to more effectively preserve erectile func-
tion when compared to historical series and model-predicted outcomes following nerve-
sparing RP or conventional radiotherapy, with maintenance of tumor control. This approach
warrants independent validation.
Patient summary: In this interim analysis we looked at using a novel approach to spare
critical erectile structures to preserve erectile function after prostate cancer radiotherapy. We
found that almost 90% of patients at 5 yr after treatment remained sexually active, signifi-
cantly higher than previous studies with surgery or radiotherapy.
# 2017 European Association of Urology. Published by Elsevier B.V. All rights reserved.
y These authors contributed equally to this work.
* Corresponding author. Department of Radiation Oncology, University of Michigan Medical Center,
1500 E. Medical Center Drive, Ann Arbor, MI 48109, USA. Tel. +1 248 8493321; Fax: +1 248 8498448.
E-mail address: (P.W. McLaughlin).
0302-2838/# 2017 European Association of Urology. Published by Elsevier B.V. All rights reserved.