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ESTRO 36 2017
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was observed between pain response and ALP response in
this cohort.
EP-1360 Stereotactic body radiotherapy for
oligometastatic prostate cancer recurrence after local
treatment.
P.A. laurent
1
, E. Martin
1
, F. Cousin
2
, M. Quivrin
1
, F.
Bidault
3
, F. Mazoyer
3
, A. Bertaut
2
, G. Crehange
1
1
Centre Georges-François Leclerc, Radiation Oncology,
Dijon, France
2
Centre Georges-François Leclerc, Statistics, Dijon,
France
3
Centre Georges-François Leclerc, Medical Physics, Dijon,
France
Purpose or Objective
To analyse patients treated by stereotactic body
radiotherapy (SBRT) for a node or bone oligometastatic
recurrence of a prostate cancer (Pca) previously locally
treated, and identify possible pronostic factors of early
biochemical failure (BF) after SBRT.
Material and Methods
In this retrospective study, we analyzed castrate and non-
castrate patients treated by SBRT between November
2011 and April 2016 for 1 to 3 metastases, bone or node,
diagnosed on a positron emission tomography - computed
tomography (PET-CT) or on a bone-scintigraphy with
technetium-99, following biochemical recurrence of a
prostate cancer after a local curative treatment.
Recurrence-free survival (RFS) was the primary end-point
defined as the time interval between the first day of SBRT
and biochemical failure, defined as 2 consecutive
elevations of PSA with last dosage superior to PSA dosage
before treatment, or clinical failure, defined as new
metastases found on an imaging check-up (PET-CT or
scintigraphy). PSA dosage before SBRT, type of metastase
(bone or node), number of lesions treated in SBRT,
patient's ages, nadir of PSA after SBRT, and concomittant
androgen deprivation therapy (ADT) were analyzed in
univariate and multivariate logistic regression to identify
pronostic factors of poor response to SBRT.
Results
With a median follow-up from time of SBRT of 12 months,
we treated 40 patients and 56 metastatic lesions, with a
local-control rate of 85%. 19 patients were treated for 1
to 3 bone lesions and 21 patients for 1 to 3 node lesions.
8 patients with bone oligo-metastasis and 13 patients with
node oligometastasis had a recurrence. The primary
involved metastatic sites were lymph nodes ( 52 %) and
bone ( 52 %), with 3 patients having both node and bone
recurrence . A 2
nd
and 3
rd
course of radiotherapy was
delivered in 8 and 1 patients respectively. Median RFS
was 345 days (134 ; 426) in the node metastatic group and
494 days (85 ; 877) in the bone metastatic group. On
bivariate analysis, a PSA nadir up to 0,51 ng/mL after SBRT
was identified as a pronostic factor of low RFS. This result
was not confirmed in multivariate analysis. There might
be a significative difference in RFS between node group
and bone group.
Conclusion
There might appear that patients treated by SBRT for
node oligometastatic prostate cancer recurrence after a
local curative treatment could have a lower recurrence-
free survival than patient treated for bone oligometastatic
disease in the same conditions. This observation justifies
further analysis.
Ep-1361 Prostate sbrt in 5 fractions , report of 185
patients and late toxicity analysis.
P. Castro Peña
1
, O. Muriano
1
, A. Henao
1
, P. Murina
1
, C.
Niño de Guzman
1
, D. Venencia
1
, S. Zunino
1
1
Instituto Privado de Radioterapia, Radiation Oncology,
Cordoba, Argentina
Purpose or Objective
To analyze late urinary and rectal toxicity in patients with
prostate cancer who underwent SBRT 5 fractions
Material and Methods
Among November'13 and June'15, 185 patients with
positive biopsy of prostate cancer were treated; PSA-
baseline mean = 14.99 ng / ml [0.42-123.3] and prostate
volume average = 52.6 g [20.6-134].All were irradiated
with SBRT technique in 5 fractions (every other day),
according to institutional protocol. IGRT (intra and
interfraction) were ExacTrac based, 2 weeks before, 5
intraprostatic titanium fiducial markers were implanted.
Virtual simulation based on CT-scan was done every 1mm
at prostate level. Drawing volumes and dosimetry planning
were done at Iplan-Net system. Prescribed dose at 95%
PTV-prostate = 40 Gy or 36.25, depending the risk
group.Patients were irradiated with Novalis Tx (BrainLab-
Varian) technology, high-resolution multileaf collimator
(HDMLC) with leaf of 2.5mm. Planned and irradiated with
IMRT-dynamics technique, using 9 portals of 6 MV
beams.Genitourinary toxicity (GU) was evaluated using
the scale IPSS (International Prostate Symptom Score) and
gastrointestinal (GI) according to RTOG criteria.
Results
The mean age was 69.1 years [48.1-86.6]. The distribution
by risk group was 12.3%, 59.5% and 28.2% low, medium and
high respectively.Mean follow-up = 15.1 months [3.8-
31.7]The mean IPSS was before SBRT = 6.2 [0-35]. Post-
SBRT = 5.6 [0-34]; 5.1 [0-31]; 5.6 [0-30]; 4.8 [0-22] and 5.6
[0-28] for 2; 6; 12; 18 and 24 months respectively.The rate
and extent of post-SBRT rectal toxicity was at 2 months
G0 = 80.5%; G1 = 14.1% = 5.4% and G2. At 6 months: G0 =
85%; G1 = 4.1%, 4.9% and G2 = G3 = 1.6. At 12 months: G0
= 92.1%; G1 = 3.3%; G2 = 2.6%, G3= 0.7 and G4 = 1.6% At
18 months: G0 = 96.4%; G1 = 2.4%; G2 = 1.2. At 24 months:
G0 = 97.3%; G1 = 2.7%; G2 = 0
Conclusion
According to the presented results we can strongly suggest
that Prostate SBRT- Novalis based platform is suitable for
a patient acceptable toxicity rate
EP-1362 Correlations between dose to small intestine
and bladder volume in patients receiving pelvic IMRT
M. Alfayez
1
, A. Sadozye
1
1
Beatson West of Scotland Cancer Centre, clinical
oncology, Glasgow, United Kingdom
Purpose or Objective
Background
The use of IMRT to treat various tumour sites has gained
wider acceptance in recent years due to its ability to
decrease the radiation dose to organs at risk. Various
manoeuvres have been implemented to reduce the doses
to organs at risk (OAR), such as the small bowel.
Aims/Objectives
We evaluated the effect of bladder filling on dose
distributions for the small bowel as measured by V20, V30,
V40 and V50.
Material and Methods
We studied sixty patients undergoing pelvic IMRT (pelvic
nodes plus Prostate & Seminal Vesicles) to treat prostate
cancer. The minimum dose to the PTV was 95% of the
prescribed dose (7200 cGy in 32 fractions). All patients
were scanned with a full bladder. PTV and OARs, including
the small bowel were contoured by 6 different clinical
oncologists to reflect day-to-day practice. Bladder
volumes, dose-volume histograms (DVH), V20, V30, V40
and V50 for the small bowel were obtained for each
patient.
Results
We ran the Pearson correlation coefficient to measure the
strength of the linear relationship between the bladder
volume and the dose to the small bowel. Results showed a
negative correlation between the bladder volume and the
dose to the small bowel (p< 0.0001).
Conclusion