ESTRO 36 Abstract Book

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S89 ESTRO 36
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Salvage HDR-BT was given in 3 fractions with weekly
intervals. The target volume covered the peripheral zone
of the prostate and the PET-positive area and was treated
with 10 Gy per fraction. The isodose coverage of the
treatment in clinical practice followed this priority: the
peripheral zone> rectum> urethra> the whole gland. The
biologic equivalent dose of the salvage brachytherapy in 2
Gy per fraction was 98 Gy by assuming an α/β ratio of 1.5
and 78 Gy by a α/β ratio of 3.
Overall survival (OS) and biochemical failure were
calculated after the salvage brachytherapy using the
Kaplan- Meier method. Acute and late genitourinary and
gastrointestinal toxicities were documented according to
common terminology criteria for adverse events (CTCAE v
4.0).
Results
22 patients had a minimum follow-up of 60 months after
salvage treatment. 3 patients died after salvage
treatment; causes of death were malignant melanoma,
multiple organ failure and pneumonia. The 5-year OS was
95.5% with a disease-specific survival of 100% after 5
years. The 5-year biochemical control was 45%. Late grade
2 gastrointestinal toxicities were observed in 2 patients
(9%). No grade 3 or higher gastrointestinal late toxicities
were observed. Urinary incontinence was found in 2
patients (9%) and grade 2 obstruction of urinary tract
occurred in 1 patient (4%).
Conclusion
Interstitial HDR brachyther apy was feasible and effective
in the treatment of locally recurrent prostate cancer after
definitive radiotherapy. The long-term toxicity was low
and acceptable.
OC-0173 Low incidence of severe toxicity by focal sa
lvage HDR brachytherapy in prostate cancer
recurrences
M. Maenhout 1, M. Van Vulpen1, M.A. Moerland1, M.
Peters1, M.A.A. Van den Bosch2, J.R.N. Van der Voort van
Zyp1
1 UMC Utrecht, Department of Radiation Oncology,
Utrecht, The Netherlands
2 UMC Utrecht, Department of Radiology, Utrecht, The
Netherlands
Purpose or Objective
Whole gland salvage treatment for locally recurrent
prostate cancer after primary radiotherapy has a high rate
of severe toxicity. The standard of care in case of a local
recurrence is androgen deprivation therapy (ADT), which
has significant side-effects and influence on quality of life.
Focal salvage treatment might lead to acceptable toxicity
and concurrently postpone or even avoid the use of ADT.
Here, acute toxicity and preliminary biochemical
outcomes are described after MRI-guided focal salvage
high dose rate (HDR) brachytherapy in patients with
radiorecurrent prostate cancer.
Material and Methods
17 patients with a pathology proven local recurrence have
been treated with an outpatient single fraction of 19Gy
focal HDR brachytherapy in a suite equipped with a 1.5
Tesla MRI scanner for treatment guidance. Primary
radiotherapy consisted of external beam radiotherapy or
brachytherapy. Gross tumor volume (GTV) delineation was
performed using Ga-68-PSMA or F18-Choline PET together
with multiparametric 3.0Tesla MRI in all patients. A
margin inside the prostate of 5 mm was added to define
clinical target volume (CTV) and no margin for planning
target volume (PTV) was added. Catheters were inserted
under ultrasound guidance and definitive treatment
planning was based on the actual MRI based catheter
positions and delineations. All patients had a PSA at time
of recurrence of <10ng/mL and a PSA- doubling time of ≥1
year. Toxicity was measured using the CTCAE version 4.
Results
In all treatments constraints to rectum, bladder and
urethra were met. Average dose to the treatment volume
was D95: 18.9Gy (SD 2.4Gy). On average 9.4 catheters
(range 6-13) were used. Treatment volume was on average
7.4cc (SD2.9cc). With a median follow-up of 6 months
(range 1-24 months) a biochemical recurrence according
to Phoenix criteria (rise of > 2 ng/mL) had occurred in 1
of 17 patients. There was one patient with late grade 3
urinary incontinence toxicity.
Conclusion
Focal salvage treatment for local recurrence after primary
external beam radiotherapy or brachytherapy is an
effective treatment modality with regards to acute
toxicity. Whether this treatment option might lead to cure
or successfully postpone ADT with acceptable long term
toxicity needs further investigation.
OC-0174 Salvage LDR-brachytherapy for recurrent
prostate cancer: results from a single institution
S. Magrini1, F. Barbera1
1Spedali Civili di Brescia, Department of Radiation
Oncology "Istituto del Radio", Brescia, Italy
Purpose or Objective
To evaluate the results of whole gland salvage
brachytherapy (SBT) after primary external beam
radiotherapy in terms of toxicity/QoL and efficacy.
Material and Methods
We retrospectively analyzed the clinical data of 19
patients consecutively treated with SBT at our Institution
from June 2012 through November 2015. Local
recurrences were identified with 11C-Choline PET/CT and
MRI after biochemical recurrence according to Phoenix
criteria. The prescription dose was 130Gy-LDR-BT to the
whole prostate gland. Acute and late toxicities were
graded with the CTCAE-4.0 scoring system. Data from IPSS
(International Prostatic Symptoms Score) and IIEF
(International Index of Erectile Function) questionnaires
at baseline and at 6, 12 and 24 months after SBT were also
reported (higher IPSS and lower IIEF indicate
deterioration). Univariate analysis was done to identify
predictors of biochemical control and toxicities.
Results
Median follow up after SBT was 24 months. Observed
severe late toxicities were as follows: 2/19 G3 cystitis
(10,2%) and 1/19 G4 proctitis (5,3%). Median IPSS scores
pre-SBT and after 6,12,24 months were respectively
4,11,12 and 5. Median IIEF score pre-SBT and after 6,12,24
months were respectively 5,2,4 and 4. At the time of
analysis 2/19 patients showed biochemical relapse (3-
years-FFBF 85,2%). At univariate analysis only interval to
relapse after primary EBRT < 70 months (p=0,05) and PSA
reduction between pre-and post SBT level > 80% (p=0,008)
were significantly related to further biochemical failure.
No statistically significant correlations were found
between IPSS and IIEF score before SBRT and post
treatment toxicity.
Conclusion
SBT for recurrent prostate cancer after primary EBRT
seems to be a feasible treatment for selected patients.
The severity of the observed toxicities shows a peak after
6 months/1 year after local re-treatment and then
decreases. Early FFBF rates are good. These preliminary
results suggest further accrual of patients and the
collection of longer term data.
OC-0175 Salvage HDR-BT in prostate local recurrence
after radiation therapy: Retrospective analysis
C. De la Pinta1, T. Muñoz1, C. Vallejo1, S. Sancho1, F.
López1, M. Martin1, A. Hervás1
1Hospital Ramon y Cajal, Radiation Oncology, Madrid,
Spain