732 / 1096
S716
ESTRO 36
_______________________________________________________________________________________________
Conclusion
In our experience CK-SRT seem to be safe and reliable in
the LPC. No severe toxicities were reported and the
patients were very compliant. Careful patient selection is
critical to achieve maximum effectiveness by CK SRT.
More patients and longer follow up are necessary in order
to evaluate the real advantage of SRT respect to standard
fractionation in terms of overall survival, biochemical free
survival and late toxicity.
EP-1335 Hypofractionated versus conventional
radiotherapy in intermediate- to high-risk prostate
cancer
W. Guo
1
, X.S. Gao
1
, X.B. Gu
1
, M.W. Ma
1
1
Peking University First Hospital, Department of
Radiation Oncology, Beijing, China
Purpose or Objective
Prostate cancer is one of the most common cancers in the
world, and the population of patients with intermediate-
to high-risk localized prostate cancer (PCa) occupies a
large proportion. The results of treatment after
hypofractionated radiotherapy only have been reported
from several small randomized trials. Therefore, we
pooled the relevant data and conducted a meta-analysis
to compare clinical outcomes of hypofractionated
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