726 / 1096
S710
ESTRO 36
_______________________________________________________________________________________________
PET/CT compared to contrast enhanced CT and its impact
on RT management was analysed.
Results
129 pts (20 at initial diagnosis, 49 with PSA relapse and 60
with PSA persistence after radical prostatectomy)
received
68
Ga-PSMA PET/CT prior to RT. The majority of
pts (71.3%) had
68
Ga-PSMA PET/CT positive findings (55.1%
of pts with PSA recurrence, 75% of pts with PSA
persistence and 100% of newly diagnosed pts). The uni-
and multivariate analysis found no significant association
between PET-positive results and above mentioned factors
with exception of PSA before PET/CT: Pts with PSA ≤ 0.2
ng/ml had a detection rate of 33.3%, with PSA 0.21 ≤ 0.5
ng/ml a rate of 41.2% and with PSA 0.51 ≤ 1.0 ng/ml a rate
of 69.2% (figure 1). Median PSA before PET/CT in pts with
pathological findings (n=92) was 1.90ng/ml and without
(n=37) 0.30ng/ml, in newly diagnosed pts 12.4ng/ml, in
pts with PSA relapse 0.49ng/ml and in pts with PSA
persistence 0.99ng/ml.
68
Ga-PSMA PET/CT had a high
detection rate of PCa recurrence outside the prostatic
fossa in pts being considered for salvage RT (figure 2):
22.4% of these pts had PET-positive pelvic lymph nodes
and 4.1% distant metastases. In pts considered for salvage
RT with a PSA < 0.5 ng/ml
68
Ga-PSMA PET/CT still detected
in 16.0% local recurrences within the prostatic fossa and
in 20.0% PET-positive pelvic lymph nodes.
68
Ga-PSMA
PET/CT had a significantly higher diagnostic value
compared to the contrast enhanced CT scan. This resulted
in a modification of RT in 56.6% of pts equally observed in
high risk (59.2%) as in low/intermediate risk pts (53.8%)
(p=
0.825).
Conclusion
The detection of PCa is strongly associated with PSA level
at time of
68
Ga-PSMA PET/CT.
68
Ga-PSMA PET/CT
differentiates local, regional and distant metastatic
disease with considerable implications for disease
management.
68
Ga-PSMA PET/CT narrows the diagnostic
gap in post-prostatectomy pts with rising PSA ≤ 0.2 ng/ml
considered for salvage RT.
EP-1324 Single-fraction HDR brachytherapy boost in
combination to EBRT for prostate cancer
A. HuertaS
1
, P. Blanchard
1
, L. Calmels
1
, M. Edouard
1
, A.
Bossi
1
1
Gustave Roussy, Department of Radiation Oncology,
Villejuif, France
Purpose or Objective
To describe efficacy and safety of a single-fraction high-
dose-rate brachytherapy (HDRBT) boost for patients
diagnosed with NCCN intermediate and high risk prostate
cancer using real-time transrectal ultrasound (TRUS)
based planning in combination to external beam radiation
therapy (EBRT)
Material and Methods
The records of 146 patients treated with a single-fraction
HDRBT boost of 14 Gy using real-time TRUS based planning
were reviewed. External beam radiation therapy (46
Gy/23 fractions or 50 Gy/25 fractions) was performed
before (76%) or after (24%) HDRBT boost. Genito-urinary
(GU) and gastro-intestinal (GI) toxicity were assessed
according to CTCAE v4.0 every 6 months after the end of
combined treatment, as well as PSA evaluation.
Results
The median follow-up was 30 months. Antiandrogen
deprivation was administered in 53.6% of the patients.
Thirteen patients (8.9%) experienced failure. The
biological progression-free survival (bPFS) rate at 24
months was 94%. Ten patients experienced urinary
retention within five days after treatment. There were
two cases of grade 3 toxicity (rectal bleeding and dysuria).
GI and GU toxicity was reported in 14.4% and 54% of the
patients respectively.
Conclusion
Single-fraction HDRBT boost of 14 Gy using real-time TRUS
in combination to pelvic EBRT is a feasible and promising
treatment option for intermediate and high risk prostate
cancer patients.
EP-1325 Risk adapted dose-intensified postoperative
Tomotherapy RT in prostate cancer using a SIB.
M. Beck
1
, T. Barelkowski
1
, A.H. Thieme
1
, S. Wecker
1
, D.
Kaul
1
, W. Wlodarczyk
1
, V. Budach
1
, P. Wust
1
, P. Ghadjar
1
1
Department of Radiation Oncology, Charite
Universitätsmedizin, Berlin, Germany
Purpose or Objective
To evaluate a novel risk adapted dose-intensified
postoperative radiation therapy (RT) scheme for patients
with prostate cancer.
Material and Methods
A consecutive series of prostate cancer patients who
received postoperative RT after radical prostatectomy
(RP) using helical Tomotherapy between 04/2012 and