ESTRO 36 Abstract Book

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S974 ESTRO 36
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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
2 Iwate 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), pV 100 (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. Capelletti1, G.N. Marta1
1 Hospital 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
Patients treated with Iodine-125 BT with post-implant
dosimetry after at least 5 years of follow-up were
retrospectively assessed. Patients who received
combination therapy (EBRT and BT) and salvage BT were
excluded.
Results
From 616 patients treated between March 2001 and
November 2010, 406 of them were included in the study.
65.5% were low-risk; 30%, intermediate-risk; 4.5%, high-
risk. After a median follow-up of 87.5 months, 61 (15.0%)
patients developed biochemical recurrence. BFFS at 5
and 10 years was 90.6% and 82.2% respectively. There
were no significant differences in the BFFS among the
risk groups (p = 0.294). Nadir ≥ 1 ng/ml was associated
with higher risk of biochemical failure (HR = 5.81; CI 95%:
3.39 to 9.94; p ≤ 0.001). MFS at 5 and 10 years was 98.3%
and 94% respectively. Three patients (0.3%) died from
prostate cancer during follow-up. OS at 5 and 10 years
was 96.2% and 85.1% respectively. Acute and late grade ≥
2 and grade ≥ 3 gastrointestinal toxicity were observed in
5.6% and 0.5% and 4.6% and 0.5%, respectively. Acute
and late grade ≥ 2 and grade ≥ 3 genitourinary toxicity
were 57.3%, 3.6% and 28%, 3.1%, respectively.
Conclusion
Iodine-125 LDR-BT is a safety and efficient treatment for
well-selected prostate cancer patients.
EP-1772 HDR Brachytherapy in the treatment of
Prostate Cancer – the Vienna Experience
O. Komina1, C. Seitz-Kästner 1, J. Hofbauer1, M. Kuntner1,
J. Wimmer1, T. Knocke-Abulesz1, E. Nechvile1
1KH Hietzing mit Neurologischem Zentrum Rosenhügel,
Sonderabteilung für Strahlentherapie, Wien, Austria
Purpose or Objective
Radiation Therapy (RT) plays a crucial role in the
treatment of prostate cancer. The advantage of high dose
rate brachytherapy (HDR-BT) as monotherapy or boost to
deliver high radiation dose to the tumor and to spare
organs at risk (OAR) was recently shown in clinical studies.
Material and Methods
We summarized the overall patient data collected in our
institution since 2010 when we implemented the real time
planning system based on 3D ultrasound imaging. Between
2010 and 2015 a total of 256 patients were treated and
584 implants being performed. 47% of the patients with
local disease received HDR-BT alone (4 x 9 Gy on a weekly
basis [n= 22], after 2012 3 x 10,5 Gy every other week [n=
99]). 53% of the patients received combination therapy for
treatment of intermediate or high-risk prostate cancer.
These patients received one or two fractions of HDR-BT
with the doses of 9 or 10,5 Gy respectively combined with
local external beam RT of the prostate only or additional
pelvic lymph node irradiation. 17 patients were treated in
terms of salvage therapy after radical prostatectomy
(RPE), external beam or brachytherapy.
Results
Median age was 69,2 years (range 44,8 - 87,5). The
majority of patients (37%) had Gleason 6 histology, 29%
Gleason 7a, and 9% 7b. High risk patients receiving
exclusively combination therapy had Gleason 8 in 13%,
Gleason 9 in 11% and Gleason 10 in 1% of the cases. The
median V100 for the prostate was 93,7%. No acute grade
≥3 toxicity was observed in the whole cohort of the
patients. Late rectal toxicity was observed predominantly