ESTRO 36 Abstract Book

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S295 ESTRO 36
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PV-0552 Urethra-sparing SBRT for prostate cancer:
acute toxicity results from a randomized phase II trial
T. Zilli 1, S. Jorcano2, S. Bral3, C. Rubio 4, A. Bruynzeel5, A.
Oliveira6, U. Abacioglu7, H. Minn 8, Z. Symon9, R.
Miralbell1,2
1 Hôpitaux Universitaires de Genève, Radiation Oncology,
Geneva, Switzerland
2 Teknon Oncologic Institute, Radiation Oncology,
Barcelona, Spain
3 Onze-Lieve-Vrouwziekenhuis, Radiation Oncology, Aalst,
Belgium
4 Hospital Universitario Sanchinarro, Radiation Oncology,
Madrid, Spain
5 VU University Medical Center, Radiation-Oncology,
Amsterdam, The Netherlands
6 Portuguese Institut of Oncology, Radiation Oncology,
Porto, Portugal
7 Neolife Medical Center, Radiation Oncology, Istanbul,
Turkey
8 University Hospital Turku, Radiation Oncology, Turku,
Finland
9 Sheba Medical Center, Radiation Oncology, Ramat Gan,
Israel
Purpose or Objective
To present the acute toxicity results from a prospective
multicenter phase II randomized trial of short or
protracted urethra-sparing stereotactic body radiotherapy
(SBRT) for localized prostate cancer (PCa).
Material and Methods
From 08/2012 to 12/2015, 170 patients (pts) from nine
European centers with cT1c-3a N0 M0 PCa and a low risk
of nodal involvement (≤20%, according to Roach et al.)
were recruited and randomized according to two different
overall treatment time (OTT) schedules: either 9 days
(arm A, 84 pts), or 28 days, once-a-week, the same week-
day (arm B, 86 pts). The prescribed dose was 36.25 Gy in
5 fractions of 7.25 Gy to the prostate ± seminal vesicles in
both arms. The prostatic urethra, with a surrounding
margin of 3 mm, received a lesser dose of 5 x 6.5 Gy = 32.5
Gy. All patients were treated either with a VMAT or IMRT
technique under stereotactic conditions using Novalis
linacs and ExacTrac image-guided technology.
Genitourinary (GU) and gastrointestinal (GI) toxicity
(CTCAE v4.0 grading scale), IPSS, and QoL scores (EORTC
QLQ-PR25) were assessed at baseline, at the 5th fraction
(5fx), and 12th weeks (12W) since SBRT start.
Results
82 (median age 70 years) and 83 (median age 69 years)
pts, respectively, from arms A and B, were retained for
this analysis. Low-, intermediate-, and high-risk
presentation was respectively 22%, 63%, and 15% (arm A)
and 22%, 64%, and 14% (arm B). A 6-months androgen
deprivation was used in 44% and 45% of the pts in arm A
and B, respectively. The toxicity stopping rule of the study
during the first 3-months was never activated. In both
arms, Grade 1 GI toxicity increased from baseline to 5fx
(from 19.5% to 38% and from 23% to 32% for arms A and B,
respectively) returning back to baseline by W12 (18% for
Arm A and 25% for Arm B). Only 2 cases of grade 2 GI
toxicity (2.5%) were observed at 5fx in arm A. Grade 2 GU
toxicity rates at baseline, 5fx, and W12 were 2%, 17%, and
11% vs. 5%, 19% and 6% in arms A and B, respectively
(mainly moderate irritative and voiding symptoms). Only
one grade 3 GU toxicity was observed at W12 in arm B
(desobstructive TURP in a patient with a preexisting
history of acute urinary retention). Median IPSS scores at
the same endpoints were 6, 10, and 6 vs. 6, 10, and 7 for
arms A and B, respectively, with similar IPSS-based QoL
rates at baseline and W12 (80% of pts satisfied). No
changes in EORTC QLQ-PR25 scores for GU, GI, and sexual
domains were observed in both arms between baseline and
W12.
Conclusion
Preliminary results of this trial demonstrate for both study
arms the feasibility, tolerance, and acceptable toxicity
profile of this treatment approach. Longer follow-up is
needed to assess the impact of OTT and urethra-sparing
on outcome, late toxicity, and QoL.
PV-0553 Prognostic significance of Testosteron Level
in prostate carcinoma patients treated with TAB and
RT
G. Ozyigit1, F. Akyol1
1Hacettepe University- Faculty of Medicine, Department
of Radiation Oncology, Ankara, Turkey
Purpose or Objective
The aim of this study is to evaluate the prognostic
significance of testosterone levels measured during total
androgen blockade (TAB) in intermediate risk (IR) and high
risk (HR) non-metastatic prostate adenocarcinoma
patients treated with three dimensional conformal
radiotherapy (3D-CRT) or intensity modulated radiation
therapy (IMRT).
Material and Methods
The clinical data of 329 eligible T1-3N0M0 (AJCC 2010)
prostate adenocarcinoma patients treated at our
department between 1996-2011 with either 3D-CRT or
IMRT were evaluated. The median age was 67 years.
D'Amico 1998 risk classification was used, and 80 patients
were in IR, as 249 patients were in HR group, respectively.
The total 3D-CRT and IMRT dose was 70 Gy, 76 Gy
respectively in 2 Gy daily fraction doses. All patients
received TAB (combined LHRH agonist and bicalutamide),
and 61% of patients were given less than 12 months of TAB.
Total testosteron levels were measured in every 3 months
during hormonal therapy. The castration level for
testosteron was accepted as ≤20 ng/dL according to the
European Association of Urology (EAU) criteria; and
patients were categorized as castrated group (C) and non-
castrated group (nC), accordingly. Log-rank test was used
for univariate analyses (UVA), and Cox-regression model
was used for multivariate analyses (MVA).
Results
Median follow-up was 9.2 years. There were no
statistically significant differences between C and nC
groups in terms of age, RT technique, TAB duration, risk
group, Gleason score, PSA levels, T stage and RT dose.
Five and 10 year overall survival (OS) rates were 97%, 91%
for C group, and 90%, 75% for nC group (p<0.001). Five
and 10 year biochemical relapse free survival rates (BRFS)
were 87%, 83 % for C , and 71%, 51% for nC group
(p<0.001). MVA revealed that testosteron level above 20
ng/dL (p=0.001) and Gleason score of 8-10 (p0.01) were
found to be independent significant poor prognostic
factors in predicting OS and BRFS.
Conclusion
The prognostic significance of testosteron levels was
previously demonstrated in metastatic prostate cancer
patients receiving hormonal therapy, but not for non-
metastatic patients receiving TAB and radiotherapy . In a
median follow-up of 9.2 years, we found that non-castrate
levels of testosteron (>20 ng/dL) measured during TAB had
significant detrimental effects both on overall and
biochemical relapse free survival in intermediate-high risk
non-metastatic prostate cancer patients. Thus, we
recommend to continuously monitor testosteron levels
during TAB in order to measure the efficacy of castration.
PV-0554 Patient-reported outcomes from the phase III
prostate HYPRO trial: urinary toxicity
R.C. Wortel1, L. Incrocci1, F.J. Pos2, R.J. Smeenk3, A.D.G.
Krol4, S. Aluwini 1, M.G. Witte2, B.J.M. Heijmen 1, W.D.
Heemsbergen2
1Erasmus MC Cancer Institute, Radiation Oncology,
Rotterdam, The Netherlands
2Netherlands Cancer Institute, Radiation Oncology,