ESTRO 36 Abstract Book

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S717 ESTRO 36
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when planning treatment. Besides this, more patients
need to be included in the study to identify a cut-off value
that clearly reflects the association between grade ≥ 2
GUS toxicity and the trigone volume.
EP-1337 High hypofractionation using beacon
transponders in intermediate-risk prostate cancer:
first results
L. Di Brina1, G. D'agostino1, C. Franzese1, D.
Franceschini1, T. Comito1, F. De Rose1, P. Navarria1, A.
Tozzi1 , C. Iftode1, A. Ascolese1, E. Clerici1, L. Pasini2, A.
Benetti2, M. Scorsetti1
1 Istituto Clinico Humanitas, Radiotherapy and
Radiosurgery, Rozzano Milan, Italy
2 Istituto Clinico Humanitas, Urology, Rozzano Milan,
Italy
Purpose or Objective
In the last decades, an improved diagnostic accuracy has
led to an increased incidence of early stage prostate
cancer(PC). For these patients a traditional course of
radiotherapy(RT) remains a critical issue. Furthermore
acceleration of RT could improve therapeutic ratio,
especially in intermediate risk patients. Therefore we
designed a study of hypo-fractionated stereotactic body
radiation therapy(SBRT) delivered by Volumetric
Modulated Arc Therapy(VMAT) with Flattening Filter
Free(FFF) beams and gated using beacon transponders. We
report our preliminary results on feasibility and early side
effects.
Material and Methods
This is a prospective phase II study. Inclusion criteria
were: age≤85 years, PS≤2, PSA≤20 ng/ml and Gleason
Score (GS) 7 (NCCN intermediate class of risk), no distant
metastases, no previous surgery other than transurethral
resection of the prostate (TURP), no malignant tumors in
the previous 5 years, IPSS≤ 7. Patients underwent pelvic
MRI. Three beacons transponders were
positioned transrectally within the prostate parenchyma
by an urologist with an ultrasounds-guided procedure that
was performed 7-10 days before simulation CT-scan. MR
images were registered with those of simulation CT.
The RT schedule was 38 Gy in 4 fractions delivered every
other day with VMAT and 10MV FFF photons. Toxicity
assessment was performed according to Common
Terminology Criteria for Adverse Events (CTCAE) v4.0
scale.
Results
Between September, 2012 and May, 2016, 23 patients
were recruited in the protocol and treated. Median
follow-up (FUP) was 16 months (range: 7-27). Median age
was 74 years (59-79), Median initial PSA (iPSA) was 7.0
ng/ml (range 3.12-12.7 ng/ml). All patients completed the
treatment as scheduled, in a median 8 days (8-11). Median
nadir-PSA after treatment was 0.78 ng/ml (range 0.2-4).
Acute Toxicities were as follow: three patients (13%)
presented G1 proctitis. Genito-urinary toxicity was
observed in 57% of patients (n=13): in particular, 6
patients had G1 cystitis (26%) with 4 of these presenting
even G1 increased urinary frequency (17%) ; G2 cystitis
was observed in 7 patients (30%) with a G2 urinary
frequency observed in two of these patients (9%); in only
one patient a G2 urinary retention was observed and it was
treated with transient catheterization and oral and rectal
medications. No acute gastrointestinal ≥ G2 or genito-
urinary ≥ G3 toxicity was found. No other toxicities were
observed. At a median FUP of 16 months (range 7-27, from
the time of diagnosis), only one patient presented an
outfield relapse of disease, that was treated with
androgen deprivation therapy (ADT). No other biochemical
recurrence or progression of disease was observed.
Conclusion
Preliminary findings show that our schedule
of hypofractionated radiotherapy, delivered with FFF-
VMAT and gated using beacon transponders, is a valid
option for intermediate risk PC. Early results in terms of
feasibility, toxicity profile and disease control are
encouraging to warrant the pursuance of the study.
EP-1338 High precision radiotherapy for early
prostate cancer with concomitant boost to the
dominant lesion.
G. Riva1, G. Timon1, D. Ciardo 1, A. Bazani2, D. Maestri2,
D. De Lorenzo3, F. Pansini2, R. Cambria 2, F. Cattani2, G.
Marvaso1, D. Zerini1, D.P. Rojas1, S. Volpe 1, F. Golino1, V.
Scroffi1, C. Fodor 1, G. Petralia4, O. De Cobelli 5, R.
Orecchia6, B.A. Jereczek-Fossa 7
1Istituto Europeo di Oncologia - IEO, Radiotherapy,
MIlan, Italy
2Istituto Europeo di Oncologia - IEO, Medical Physics,
MIlan, Italy
3Istituto Europeo di Oncologia - IEO, Scientific Direction,
MIlan, Italy
4Istituto Europeo di Oncologia - IEO, Radiology, MIlan,
Italy
5Istituto Europeo di Oncologia - IEO, Urology, MIlan, Italy
6Istituto Europeo di Oncologia - IEO, Medical Imaging and
Radiation Sciences, MIlan, Italy
7Istituto Europeo di Oncologia - IEO- Università degli
Studi di Milano, Radiotherapy, MIlan, Italy
Purpose or Objective
To report preliminary results, in terms of acute toxicity,
of an innovative hypofractionated treatment with
concomitant boost to the dominant lesion for patients
with early stage prostate cancer (PCa).
Material and Methods
This prospective phase II trial, supported by AIRC
(Associazione Italiana per la Ricerca sul Cancro), started
in June 2015. Patients with low- and intermediate-risk PCa
who met the inclusion criteria underwent
hypofractionated radiotherapy (RT) to the prostate with a
total dose of 36.25 Gy in 5 fractions (biologically
equivalent to a 90.6 Gy, considering a α/β ratio of 1.5 Gy)
and a simultaneous integrated boost (SIB) to the dominant
intraprostatic lesion (DIL) of 37.5 Gy in 5 fractions
(biologically equivalent to a 96.4 Gy, considering a α/β
ratio of 1.5 Gy). The DIL was identified by a
multiparamentric magnetic resonance imaging (mpMRI)
co-registered with planning CT. The treatment was
delivered using a Varian TrilogyTM with RapidArc®
technology. Toxicity was assessed according to CTCAE v4.0
and RTOG/EORTC criteria. The preliminary evaluation of
the first 13 patients was required to assess the feasibility
of the treatment before completing the enrollment of 65
patients.
Results
The first 13 patients completed the treatment between
June 2015 and February 2016. Patients’ characteristics are
reported in Table 1. An example of dosimetric distribution
is shown in Figure 1. With a median clinical follow-up of
5.9 months, ranging from 1 to 6 months, no grade 3 or 4
acute toxicity was reported. At the end of RT, only one
patient experienced G2 gastrointestinal (GI) toxicity, and
4 patients had G1 genitourinary (GU) events. After one
month, G1 GI toxicity was reported in 2 patients and G1
GU in 4 patients; no toxicity higher than G2 has been
recorded. At 6 months from the end of treatment, 8
patients have been evaluated and no events higher than
G2 have been experienced: 1 patient had G1 GI toxicity
and 3 patients had G1 GU toxicity.