ESTRO 36 Abstract Book

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S960 ESTRO 36 2017
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adding additional clinical studies, not necessary of
brachytherapy as monotherapy. Those limitations are: the
fit is over conditioned by the only fraction datum, the data
are heterogeneous, and its external validity may be
limited, we do not properly know the associated
uncertainties nor the dose distributions.
References
[1] Prada PJ et al. Radiother Oncol 2016;119:411-6.
EP-1769 Hypofractionated EBRT and single fraction
HDR brachytherapy for patients with prostate cancer.
D.E. Kazberuk1, T.M. Filipowski2, A. Szmigiel-Trzcińska3,
M. Niksa3 , D. Hempel4, J. Topczewska-Bruns2, W. Nowik5,
B. Pancewicz-Janczuk6
1 Bialystok Comprehensive Cancer Center, Brachytherapy,
Bialystok, Poland
2 Bialystok Comprehensive Cancer Centre, Radiotherapy,
Bialystok, Poland
3 Bialystok Comprehensive Cancer Centre, Brachytherapy,
Bialystok, Poland
4 Bialystok Comprehensive Cancer Center, Radiotherapy,
Bialystok, Poland
5 Bialystok Comprehensive Cancer Centre, Physics,
Białystok, Poland
6 Bialystok Comprehensive Cancer Centre, Physics,
Bialystok, Poland
Purpose or Objective
To evaluate the short term efficacy, early toxicity and
dosimetric aspects of combined HDR-BT with EBRT in the
radical treatment of prostate cancer patients (PCPs).
Material and Methods
40 PCPs underwent combined treatment including
hypofractionated EBRT (37.5 Gy in 15 fractions over 3
weeks) and conformal HDR-BT between September 2013
and May 2015. The mean age was 69 years with average
PSA 6,7 ng/ml and median Gleason score 6,8. T stage was
distributed from T1 to T2c. Half of the patients received
androgen deprivation. Treatment was delivered
using IMRT with an 6- or 15-MV linear accelerator. HDR
brachytherapy catheter insertion was performed under
spinal anaesthesia. The median number of catheters was
17 (14-18). HDR brachytherapy was delivered using an
Iridum-192 source (Nucletron) and treatment planning
system: SWIFT 2.11.8 and Oncentra Prostate 3.0.9./4.0.
Dose volume constraints included: prostate V 100 ≥95 %,
V150 and V200 below 40%; maximal urethral dose ≤ 120%
and average rectal dose ≤ 85% of the prescription dose.
Patients were monitored weekly during radiotherapy and
in 3 months intervals after treatment. Follow-up visit
included clinical examination and PSA value assessment.
The acute toxicities were graded according to the
EORTC/RTOG scales.
Results
The median V100 was 93% and median D90 was 103%. All
patients finished the scheduled therapy without
interruption. The most common urinary symptoms were:
urgency, frequency, dysuria and nocturia. The rectal
symptoms (urgency, frequency) were rare. No grade 3 and
4 acute toxicities were recorded. No patient developed
clinical or biochemical progression. The constant decrease
of PSA level was observed during follow up.
Conclusion
Single fraction 15 Gy HDR-BT with hypofractionated
EBRT enables dose escalation with excellent dosimetric
parameters for the radical treatment of PCPs. The
treatment was well tolerated by all patients with
satisfactory disease control in the short and medium term.
EP-1770 Unpredictable PSA failure in intermediate-risk
prostate cancer after seed implant brachytherapy
K. Kikuchi1, R. Nakamura1, H. Kakuhara1, S. Yamaguchi 1,
H. Oikawa 1, W. Obara2, H. Ariga1
1 Iwate Medical University, Radiation Oncology, Morioka,
Japan
2Iwate Medical University, Urology, Morioka, Japan
Purpose or Objective
The role of seed implant brachytherapy (BT) in
radiotherapy for organ-confined prostate cancer (OPC) is
not yet fully established. The aim of this study was to
disclose potential factor inducing biochemical relapse
(BRFS) after BT for OPC patients (pts) when its strategy
modified by D’Amico risk classification.
Material and Methods
From December 2004 to June 2014, 691 pts with low (280),
intermediate (274), and high (137)-risk were treated with
BT by real-time transrectal ultrasound-guided
implantation under prescribed dose of 160Gy as
monotherapy or 110Gy in combined with external beam
radiotherapy (EBRT) delivering to prostate and seminar
vesicle of 40Gy or 45Gy of each risk group. Anti-androgen
therapy (ADT) of a mean 10.2 months was administered in
336 (49%) pts. All patients were followed at clinics with
PSA determinations. The date of biochemical relapse was
determined by the Phoenix (nadir + 2 ng/mL) definition.
Interval between the date of last radiotherapy day (the RT
day) and relapse day were calculated and constructed
Kaplan-Meier plots. Differences in plots were evaluated by
log-rank test among pts (KM-test) divided by risk
classification, history of ADT, or combination of EBRT. In
addition, The other proven factors were explored if it
dichotomizes pts by different BRFS such as DVH
parameters of BT or BT+EBRT, positive core rates of biopsy
specimen (PCR), number of D’Amico risk class belong to
intermediate or high.
Results
A total of 46 pts, 11/ 22/ 13 of each risk group, showed
PSA relapse a mean 67.6 (6-135) months after the RT day.
It accompanied distant bone metastasis (10), PSA increase
>25 ng/ml (3) or regional lymph node metastasis (1).
Twenty-four pts died during the study period due to the
disease progression (2), cancer other than prostate or
other disease (10). The BPFS achieved at 10 years was
91.1% for all patients. KM-test between low and
intermediate risk pts showed significant difference (94.7
vs 88.7 %), but not between intermediate and high (88.7
vs 87.5 %). In intermediate pts, there were differences in
the mean DVH parameters including pD90 (179 vs 156 Gy,
P=0.000), pV100 (94 vs 90 %, p=0.001), or PCR (0.30 vs 0.39,
p=0.024).
Conclusion
Intermediate risk group pts showed a BPFS similar to that
of high risk. Those pts who relapsed had a higher risk of
BPFS and were treated with RT degraded in dose and
coverage. We need a modification in D’Amico
intermediate classification and strategy.
EP-1771 Low dose rate brachytherapy for prostate
cancer: A Brazilian Institution experience.
E.T.T. Leite1, J.L.F.D. Silva1, E. Capelletti 1, G.N. Marta 1
1Hospital Sirio Libanes, Radiation Oncology, Sao Paulo,
Brazil
Purpose or Objective
Prostate cancer is the most common type of cancer in
men, excluding nonmelanoma skin cancers. The main
modalities of treatment are radical prostatectomy (RP),
brachytherapy (BT), and external beam radiation therapy
(EBRT) with or without androgen deprivation. BT is a
treatment option with equal efficacy to EBRT or RP alone
in patients with low- or intermediate-risk prostate cancer.
The objective of this study was to estimate biochemical
failure-free survival (BFFS), metastasis-free survival
(MFS), disease-specific free survival (DSFS), overall
survival (OS) and treatment-related toxicities in patients
with prostate cancer who underwent LDR-BT alone in a
single Brazilian Institution.
Material and Methods