ESTRO 36 Abstract Book

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S709 ESTRO 36 2017
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radiotherapy versus conventional radiotherapy in the
treatment of intermediate- to high-risk localized PCa.
Material and Methods
Relevant studies were identified through searching
PubMed, Embase and Web of Science databases till
August, 2016. Hazard ratio (HR) or risk ratio (RR) with its
corresponding 95% confidence interval (CI) was used as
pooled statistics for all analyses.
Results
Six clinical cohorts were included with a total of 1621
intermediate- to high-risk localized PCa patients. The
meta-analysis results showed that overall survival
(HR=1.00, 95% CI: 0.85-1.17, p=0.980) and biochemical
failure (RR=0.87, 95% CI: 0.68-1.12, p=0.274) were similar
in two groups. The incidence of acute adverse
gastrointestinal event (grade ≥ 2) was higher in the
hypofractionated radiotherapy (RR=1.87, 95% CI: 1.21-
2.91, p=0.005). Acute genitourinary adverse event (grade
≥ 2) was similar among the groups (RR=1.02, 95% CI: 0.92-
1.14, p=0.671). Gastrointestinal (RR=1.17, 95% CI: 0.90-
1.51, p=0.238) or genitourinary (RR=1.11, 95% CI: 0.94-
1.30, p=0.228) late adverse event (grade ≥ 2) data were
not significant differences between two radiotherapy
schedules. No publication bias was detected in this meta-
analysis (all p＞0.05).
Conclusion
Hypofractionated radiotherapy in intermediate- to high-
risk localized prostate cancer was not superior to
conventional radiotherapy and showed higher acute
gastrointestinal adverse event in this meta-analysis.
However, these findings should be utilized cautiously
when directed in clinical treatment due to some
limitations.
EP-1336 Effect of bladder,trigone,urethra doses on
acute genitourinary toxicity in prostate cancer
treatment
L.Z. Arican (Turkey), N. Akturk, K. Meltem, B. Aydin, H.
Ellidokuz, I. Bilkay Gorken
1 Dokuz Eylul Univ. Health Sciences Institute, Department
of Radiation Oncology, IZMIR, Turkey
2 Dokuz Eylul Univ. Health Sciences Institute, Department
of Preventive Oncology, IZMIR, Turkey
Purpose or Objective
To evaluate the relationship between acute GUS toxicities
and the dose/volume values of the bladder, trigone,
urethra in prostate cancer(PCa) patients who were treated
by volumetric modulated arc therapy(VMAT).
Material and Methods
Twenty seven moderate/high-risk PCa patients who were
treated between January 2014 and November 2015 were
retrospectively evaluated. According to the D’Amico
classification 59% of the patients were at high risk. All
patients recieved hormonotherapy (2-4 months neo/6-24
months adjuvant).Simulation was performed with a full
bladder and empty rectum. Total doses of peripheral
lymphatic, seminal vesicle and prostate were 56, 65 and
78 Gy in 37 fractions,respectively. Image guided
radiotherapy was performed. The urethra, bladder and
trigone were re-contoured respectively on planning CT
fused with magnetic resonance images obtained before
treatment. The minimum,maximum,mean and Vdose(V20-
80) values of the bladder, trigone and urethra were
obtained. Acute GUS toxicites were graded according to
RTOG. Age,history of previous abdominal surgery,TUR-
P,diabetes,smoking, target and bladder, trigone and
urethra volumes were evaluated as factors that affect
grade ≥2 GUS toxicity. The Chi-square, ROC,Mann-Whitney
U and Wilcoxon regression tests were used in the
statistical analyses.
Results
The median age is 68 (59-76) years. Grade 2 acute GUS
toxicities were observed in 59% of the patients, and there
was no grade 3-4 toxicity. The average dose values were
5335 (4337-5995) cGy for the bladder, 7068 (6479-7873)
cGy for the trigone and 7901 (7624-7995) cGy for the
urethra, respectively. No significant relation was
demonstrated between acute GUS toxicities and patient’s
previous history (p>0.05).There was a tendency towards a
statistically significant relationship between the trigone
V55 (p= 0.07) and the V60, and a statistically significant
association was found between the minimum trigone dose
(p= 0.02) and V65 (p= 0.02).Due to the low number of
patients and events, a cut-off value could not be
identified in the ROC analysis.
Conclusion
The demonstration of a significant relationship between
acute GUS toxicities and increasing trigone doses shows
that this structure should be taken into consideration
when planning treatment. Besides this, more patients
need to be included in the study to identify a cut-off value
that clearly reflects the association between grade ≥ 2
GUS toxicity and the trigone volume.
EP-1337 High hypofractionation using beacon
transponders in intermediate-risk prostate cancer:
first results
L. Di Brina1, G. D'agostino1, C. Franzese1, D.
Franceschini1, T. Comito1, F. De Rose1, P. Navarria 1, A.
Tozzi 1, C. Iftode 1, A. Ascolese 1, E. Clerici1, L. Pasini2, A.
Benetti2, M. Scorsetti1
1Istituto Clinico Humanitas, Radiotherapy and
Radiosurgery, Rozzano Milan, Italy
2Istituto Clinico Humanitas, Urology, Rozzano Milan,
Italy
Purpose or Objective
In the last decades, an improved diagnostic accuracy has
led to an increased incidence of early stage prostate
cancer(PC). For these patients a traditional course of
radiotherapy(RT) remains a critical issue. Furthermore
acceleration of RT could improve therapeutic ratio,
especially in intermediate risk patients. Therefore we
designed a study of hypo-fractionated stereotactic body
radiation therapy(SBRT) delivered by Volumetric
Modulated Arc Therapy(VMAT) with Flattening Filter
Free(FFF) beams and gated using beacon transponders. We
report our preliminary results on feasibility and early side
effects.
Material and Methods
This is a prospective phase II study. Inclusion criteria
were: age≤85 years, PS≤2, PSA≤20 ng/ml and Gleason
Score (GS) 7 (NCCN intermediate class of risk), no distant
metastases, no previous surgery other than transurethral
resection of the prostate (TURP), no malignant tumors in
the previous 5 years, IPSS≤ 7. Patients underwent pelvic
MRI. Three beacons transponders were
positioned transrectally within the prostate parenchyma
by an urologist with an ultrasounds-guided procedure that
was performed 7-10 days before simulation CT-scan. MR
images were registered with those of simulation CT.
The RT schedule was 38 Gy in 4 fractions delivered every
other day with VMAT and 10MV FFF photons. Toxicity
assessment was performed according to Common
Terminology Criteria for Adverse Events (CTCAE) v4.0
scale.
Results
Between September, 2012 and May, 2016, 23 patients
were recruited in the protocol and treated. Median
follow-up (FUP) was 16 months (range: 7-27). Median age
was 74 years (59-79), Median initial PSA (iPSA) was 7.0
ng/ml (range 3.12-12.7 ng/ml). All patients completed the
treatment as scheduled, in a median 8 days (8-11). Median
nadir-PSA after treatment was 0.78 ng/ml (range 0.2-4).
Acute Toxicities were as follow: three patients (13%)
presented G1 proctitis. Genito-urinary toxicity was
observed in 57% of patients (n=13): in particular, 6
patients had G1 cystitis (26%) with 4 of these presenting
even G1 increased urinary frequency (17%) ; G2 cystitis