ESTRO 36 Abstract Book

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S724 ESTRO 36
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EP-1350 Stereotactic re-irradiation for prostate cancer
recurrence after upfront surgery and radiotherapy
V. Di Cataldo1, G. Simontacchi2, B. Detti2, M. Loi2, P.
Bonomo 2, L. Masi1 , R. Doro1, I. Bonucci1, S. Cipressi1, D.
Greto2, M. Mangoni2 , I. Desideri2, I. Meattini2, S.
Scoccianti 2, E. Olmetto2, C. Muntoni2, G.A. Carta2, L. Livi2
1 IFCA, Department of Radiotherapy, Firenze, Italy
2 University of Florence, Radiation Therapy Department,
Florence, Italy
Purpose or Objective
Recurrence of prostatic cancer after radical
prostatectomy and external-beam radiation therapy
(EBRT) is a common occurrence in daily clinical practice.
We present our experience of re-irradiation with robotic
stereotactic body radiation therapy (rSBRT) for isolated
recurrence in the prostatic bed from prostate cancer
previously treated with surgery and radiation therapy.
Material and Methods
Between June 2012 and February 2016, rSBRT was
administered for isolated local relapse to 22 patients
previously treated with prostatectomy and adjuvant (9,
40.1%) or salvage (13, 59.9%) EBRT. After primary
treatment, all patients experienced a biochemical
recurrence with an isolated relapse in the prostatic bed
diagnosed with 18F-choline positron emission tomography–
computed tomography (PET) with or without pelvic
magnetic resonance (MRI). The gross tumor volume (GTV)
was defined on the basis of clinical and radiological
findings by image fusion of PET and/or MRI. The total dose
was 30 Gy in 5 fractions prescribed to the 80% isodose line.
PSA was assessed at 2, 6 and every 3 months, following
rSBRT. Toxicity was assessed by the Common Terminology
Criteria for Adverse Events toxicity scale (CTCAE v.4.03).
Results
Twenty-two patients were treated and followed for a
median time of 19.5 months (range: 59,4-74.0 months).
Prior EBRT had a median total dose of 68 Gy (range 59,4-
74.0 Gy ) in 1,8-2 Gy for fraction. Median time from EBRT
to relapse was 73,3 months (range: 16,9-203.1). Seven
patients were receiving androgen deprivation therapy
(ADT) following prior biochemical failure; median pre-re-
irradiation PSA value was 1.9 ng/ml (0,4-30). Eighteen
patients had biochemical response at 2 and 6 months, with
a median PSA decrease of 44,9% and 64,9% respectively;
four patients experienced early PSA progression at 2 and
6 months, the median PSA rise was 85,1% and 228,6%
respectively. At the time of our analysis, 10 patients
showed no evidence of disease, in 2 patients an hormonal
treatment was continued with stable PSA levels, while 10
patients had biochemical relapse and four of these had
metastatic disease. Biological Progression-free Survival
(bPFS) was 81.8% and 68.2% at 6 and 12 months,
respectively. Treatment was well tolerated, genitourinary
acute and late G1-G2 toxicity occurred in 6 and 5 patients
respectively, while two patients experienced late rectal
G1-G2 toxicity. At univariate and multivariate analysis of
pre-treatment variables, impaired biochemical relapse-
free survival (BRFS) was correlated with the use of ADT at
the moment of the treatment (p=0.013). Subset analysis
in responding patients did not found predictor of BRFS.
Conclusion
RSBRT for isolated recurrence in the prostatic bed from
prostate cancer previously treated with prostatectomy
and EBRT showed favourable results in biochemical control
with low and acceptable toxicity, however further
prospective studies are needed to confirm these results.
EP-1351 Stereotactic radiotherapy in recurrent
prostate cancer previously treated by radical irradiation
M. Loi 1, B. Detti2, G. Simontacchi2, V. Di Cataldo3, P.
Bonomo 2, L. Masi3, R. Doro3, I. Bonucci3, S. Cipressi3, I.
Desideri 2, D. Greto 2, M. Perna2, V. Carfora2, G.
Francolini2, I. Meattini2, M. Mangoni2, S. Scoccianti2, L.
Livi2
1Azienda Ospedaliera Universitaria Careggi,
Radiotherapy Unit, Firenze, Italy
2Universita degli Studi di Firenze, Radiotherapy
Department, Florence, Italy
3IFCA, Radiotherapy Department, Florence, Italy
Purpose or Objective
Biochemical recurrence can occur following definitive
external beam radiation therapy (EBRT) for localized
prostate cancer. Focal robotic stereotactic body
radiotherapy (rSBRT) to the recurrent intraprostatic tumor
is emerging as a valuable option in this setting. In this
retrospective study we evaluated efficacy and toxicity of
robotic SBRT for exclusive local failure after primary
EBRT.
Material and Methods
Data from 28 patients treated at our Institution from
September 2012 to December 2015 with rSBRT for
prostate cancer recurrence after definitive EBRT were
retrospectively reviewed. Local intraprostatic recurrence
was assessed by 18F-choline positron emission tomography–
computed tomography (PET); a dose of 30 Gy was
delivered in 5 fractions. PSA was assessed at 2 months, 6
months, and every 3 months following rSBRT. Toxicity was
assessed by the Common Terminology Criteria for Adverse
Events toxicity scale (CTCAE v.4.03).
Results
Patients were stratified in low (5, 17.9%), intermediate (9,
32.1%) and high risk group (14, 50.0 %) at diagnosis. Median
patient age at rSBRT was 78.5 (62-86) years. All patients
received prior EBRT for a median total dose of 76 Gy (62-
80 Gy) in 2 (1.8-3.1) Gy/fraction. Median time from
primary treatment to relapse was 74.1 (19.3-149.2)
months. Five patients were receiving androgen
deprivation (AD) following prior biochemical failure;
median pre-treatment PSA value was 2.7 (2.1-14.4) ng/ml.
Twenty-five patients showed biochemical response to
treatment at 2 and 6 months, median PSA decline -54.0%
(2.2-95.0) and -76.0% (35.9-95.0%) respectively; three
patients experienced early PSA progression at 2 and
6 months, median PSA elevation+112.3% (20.0-204.5%)
and +267.0% (41.9-309.1%), respectively. At the time of
our analysis, after a median follow-up of 20.9 (6.3-49.2)
months, 10 patients showed no evidence of disease, 2
patients pursued AD with stable PSA levels, while 10
patients experienced biochemical relapse; among them,
metastatic recurrence occurred in 4 cases. Biochemical
Progression-Free Survival (bPFS) was 96.4% and 75.0% at
12 and 18 months, respectively. Rectal and bladder acute
toxicity grade 1-2 was found in 4 and 1 cases, respectively
; grade 1-2 late rectal and bladder toxicity occurred in 1
and 7 cases, respectively. One patient experienced both
grade 3 acute and chronic bladder toxicity, consisting of
acute urinary retention and hematuria respectively. At
univariate and multivariate analysis of pre-treatment
variables, impaired bPFS was correlated only with high risk
category at diagnosis (HR:13.06, p=0.021). No predictive
factor for improved bPFS was found at subset analysis in
responding patients, though a trend was observed for PSA
decline at 6 months >76.0% (p=0.06).
Conclusion
Focal rSBRT can achieve long-lasting remission and delay
initiation of medical treatment,in particular in
low/intermediate risk patients at diagnosis, with
acceptable incidence of acute and late toxicity.
EP-1352 Single-fraction stereotactic body
radiotherapy for nodal oligorecurrent prostate cancer
M. Loi1, G. Simontacchi2, B. Detti2, V. Di Cataldo3, P.
Bonomo2, L. Masi3, R. Doro3, I. Bonucci3, S. Cipressi3, I.
Desideri2, D. Greto2, C. Becherini2, C. Delli Paoli2, R.