ESTRO 36 Abstract Book

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S713 ESTRO 36
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established treatment dose specifications and DHV
constraints: in particular, for PTV, plans were optimised
aiming to obtain V95%>95% D98%>94%, V2%<108%;
concerning the rectum, the requirements were:
mean<18Gy, V20<35%, V32 <10%, V37<5%,D1%<40Gy while
for the bladder, the goal was to keep mean dose <14 Gy
and V21 <40%, V33 < 30%, V38 <13%,D1%<40Gy. Routine
institutional image-based patient position verification
protocols foresaw daily on-line matching by CBCT. The
acute and late toxicities were recorded using the
RTOG/EORTC scale. Additional data were collected by
means of I-PSS e IIEF-5 questionnaires. Biochemical failure
was determined using the Phoenix definition.
Results
The median follow-up duration was 27 months (range: 24
to 36 months). The median age was 74 years (range: 57–80
years). Most dosimetric parameters for the OARs
are well within the protocol constraints, with the n
otable exception of maximal doses to rectum and bladder
(exceeding in about 20% of cases), but we did not find any
statistical correlation with late toxicities. Acute GU
toxicity of grade 2 (increase in urinary frequency) was
observed in 7% patients. The incidence rates of late GI and
GU toxicity of any grade were 14.2% and 35.7%,
respectively. The late GU toxicity of grade ≥ 2 was 4.7%.
No GE late toxicity ≥ 2 was noted. Previous abdominal
surgery appeared to be statistically significant (p= 0.004;
Fisher’s test) for the increase of probability of late GE
toxicity. The 3-year local recurrence-free survival rate
was 98%, only one patient had clinical abdominal lymph
node failure. Among the dosimetric data, only V21 (mean
value: 22.1%; range: 8.5-55.2%) revealed to be statistically
significant for the late GU (p= 0.035; Wilcoxon Mann
Whitney Test).
Conclusion
Our experience with VMAT-based SBRT in low-and
intermediate–risk prostate cancer demonstrates favorable
efficacy in tumor control and toxicity profile with no
decrease in QOL as determined by I-PSS, IIEF. The general
good quality of the clinical outcome and the results
concerning GI and GU toxicities seem to confirm the
robustness of the dosimetric paradigm adopted. Longer
follow-up is needed to investigate complete safety and
efficacy of the stereotactic treatments.
EP-1330 Predictive factors for urinary toxicity in
patients treated with radical ebrt for prostate cancer
C. Pisani1, A. Galla1, D. Beldì1, G. Apicella 1, G. Loi2, M.
Krengli1
1 University Hospital Maggiore della Carità,
Radiotherapy, Novara, Italy
2 University Hospital Maggiore della Carità, Medical
Physics, Novara, Italy
Purpose or Objective
Acute and late toxicity scores in patients treated with
radical external beam radiotherapy (EBRT) for prostate
cancer were correlated with dosimetry and clinical data in
order to identify some predictors for urinary (GU) toxicity.
Material and Methods
This study enrolled 280 patients (pts) treated with EBRT
as primary treatment for prostate cancer in our University
Hospital. All patients had at least 24 months follow-up,
with a median of 47 months (range: 40-98).
According with NCCN risk classification, 18% of pts were at
low risk, while the others were at intermediate or high
risk. Prescribed dose was 74-78 Gy. Adjuvant androgen
deprivation consisting of a luteinizing hormone-releasing
hormone analog, was administered in 192 patients
(68.6%).
All patients completed a pre-EBRT questionnaire,
registering baseline GU symptoms and patients’ medical
history (diabetes,hypertension, previous surgery, and
smoking) and were assessed by International Prostatic
Symptom Score (IPSS). Toxicity was registered following a
grading system based on the Radiation Therapy Oncology
Group (RTOG). Acute toxicity was defined as toxicity
occurring during or within 3 months after the end of EBRT.
Late toxicity was defined as toxicity occurring for the first
time >3 months after the end of EBRT or as acute toxicity
lasting longer than 3 months. Acute and late GU toxicities
were correlated with dosimetry and clinical parameters
(age , presence of co-morbidities including previous TURP,
tumor stage, initial PSA and Gleason Score).
Results
Median age was 74 years (range: 64-83); performance
status according with Karnofsky scale was 90 (80-100).
Fifty percent of pts had cardiovascular disease and 13% of
them had undergone TURP before EBRT. Thirty-two
percent of pts were treated with IMRT and 20% with IGRT.
Median bladder volume at simulation was 263 cc. Thirty-
one percent of pts experienced acute G1 GU toxicity, 24%
G2 and 3% G3. No G4 GU acute toxicity was reported.
Fourteen percent of pts experienced G1 late toxicity and
3% G2. We did not report any G3 or G4 GU toxicity.
IPSS baseline value significantly correlated with acute GU
toxicity in univariate (p=0.009) and multivariate
(p=0.0002) analysis.
The presence of nicturia (p=0.002), bladder urgency
(p=0.024) and incontinence (p=0.024) also significantly
correlated with GU toxicity. Bladder volume <200 cc at
CT-simulation was also associated with toxicity (p=0.014),
while maximum dose to bladder was correlated with late
toxicity (p=0.014). The use of 3D-EBRT was significantly
associated both with increased acute (p=0.032) and late
(p=0.03) toxicity.
Conclusion
In our study pretreatment IPSS, nicturia, urgency and
urinary incontinence at diagnosis, bladder volume < 200 cc
during CT-simulation, the use of 3D-EBRT and maximum
dose to the bladder was predictive for specific moderate–
severe acute urinary symptoms.
EP-1331 Efficacy and safety of re-irradiation of locally
recurrent prostate cancer with FFF-VMAT
G.R. D'Agostino 1, C. Franzese1, L. Di Brina 1, S. Tomatis 1,
C. Iftode1, D. Franceschini1, E. Clerici1, G. Reggiori1, A.
Tozzi 1, P. Navarria1, M. Scorsetti1
1Istituto Clinico Humanitas, Radiotherapy and
Radiosurgery, Rozzano Milan, Italy
Purpose or Objective
Despite considerable advances in technologies, especially
with the introduction of IMRT, IGRT, and VMAT, re-
treatment of locally recurrent prostate cancer with
external beams radiation therapy remains controversial
because of fear of major complications or unbearable side
effects. In this study we report our experience on re-
irradiation in a sample of 17 patients previously irradiated
for prostate cancer.
Material and Methods
Patients affected by prostate cancer and previously
submitted to radiotherapy were included in this study,
provided that they had an increased PSA, diagnostic for
biochemical relapse, and a PET-Choline revealing the
presence of a local recurrence of disease. Re-irradiation
consisted of a stereotactic treatment delivered by FFF
IGRT-VMAT technology in 5 daily fractions. Clinical
response was evaluated with PSA and physical
examination. Toxicity assessment according to CTCAE (v.
4.01) criteria. During follow-up, PET-Choline was
performed in the cases of PSA rising.
Results
Between November, 2012 and May, 2016, 17
patients (median age 78 years, range 59-82) were
submitted to re-irradiation on prostate (n=10, 58.8%),