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ESTRO 36 2017
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schedule: 24/58 (41%) patients with BR received 2.25 Gy
in 32 fractions (Total dose:72 Gy); 34/58 (59%) patients
with LR received 2.1 Gy in 33 fractions (Total dose: 69.3
Gy) to the prostate/seminal vesicle bed and 2.25 Gy in 33
fractions to the LR site (total dose:74.25 Gy) using a
simultaneous integrated boost (SIB) technique; 6/58 (10%)
patients received 1.6 Gy to the pelvic lymph nodes (total
dose 52.8 Gy), using a SIB technique. Hormone therapy (
HT-LHRH analogue and/or anti-androgen) was
administered to 17 patients (29%) with high risk features.
Toxicity was graded according to the Common
Terminology Criteria for Adverse Events version v4.0.
Biochemical failure was defined by ASTRO criteria. The
Kaplan-Meier method determined time-to-acute toxicity
events and the Mann-Whitney test compared clinical and
dosimetric variables in groups with and without acute
toxicity.
Results
The median follow-up was 12 months (range:3-41).The
median duration of HT was 85 months (range 2-168). Only
G1-G2 acute genitourinary (GU) and intestinal (GI)
toxicities occurred. Acute grade 1 GU toxicity occurred in
28 patients (48%), with 25 (43%) developing cystitis and
3 (5%) hematuria. Acute grade 2 GU toxicity (cystitis)
developed in 6/58 (10%) patients, with 1 also affected by
urinary retension (2%). Acute grade 1 GI toxicity (proctitis)
occurred in 25/58 patients (43%), which was associated
with rectal bleeding in 2 (3%). Acute grade 2 GI toxicity
(proctitis) developed in 4/58 (7%) patients, which was
associated with rectal bleeding in 1 (2%). Post Hypo-ART
the median PSA was 0.1 ng/ml (range:0-7.01) and the
nadir was 0.03 ng/ml (range: 0-5.67). Biochemical
recurrence and /or loco-regional relapse occurred in
10/58 (17%) patients at a median of 19 months after
treatment (range: 10-40). Statistical analysis: after Hypo-
ART there was 50% probability of developing acute GU
toxicity on day 52 and GI toxicity on day 43. Dmax to the
prostate/seminal vesicle bed was greater in patients who
developed acute GI toxicity.
Conclusion
Low grade acute GU and GI toxicity and early biochemical
response demonstrated that moderate Hypo-SRT was safe
and effective. A longer follow-up is required to confirm
these outcomes.
EP-1354 Delayed Salvage Radiotherapy for Macroscopic
Local Recurrence after Radical Prostatectomy
M. Shelan
1
, S. Odermatt
1
, B. Bojaxhiu
1
, O. Elicin
1
, D.M.
Aebersold
1
, A. Dal Pra
1
1
Bern University Hospital, Radiation Oncology, Bern,
Switzerland
Purpose or Objective
Salvage radiotherapy (SRT) is the only potentially curative
therapy available for patients experiencing biochemical
recurrence after radical prostatectomy (RP), and likely
more effective when offered early at low PSA levels. This
work aims to retrospectively assess clinical outcome and
toxicity of patients treated with delayed SRT to
radiologically and/or histologically proven macroscopic
local recurrence.
Material and Methods
We report on a cohort of 56 patients with radiologically
detected isolated macroscopic local recurrence on MRI
and/or CT scan and treated with SRT between 2001 and
2015. Histological confirmation was available in 35 (63%)
patients. A dose of 64-66 Gy (2 Gy/fr) was delivered to the
prostatic bed followed by a dose escalation to 72-74 Gy (2
Gy/fr) to the site of macroscopic disease using image-
guided IMRT (IG-IMRT). Patients were treated with
concomitant short-course (6 months) of androgen
deprivation therapy. Biochemical relapse-free survival
(PSA nadir + 0.2 ng/ml; bRFS) and clinical relapse-free-
survival (cRFS) were calculated using Kaplan-Meier
method. Baseline, acute and late urinary and
gastrointestinal (GI) toxicity rates were reported using
CTCAE v4.
Results
Median age at SRT was 71 years (57-81). Out of 56
patients, 9 (16%) had pT3b disease and 19 (34%) had
positive surgical margins. Sixteen patients (29%) had
Gleason score ≥ 8 at RP. The median time from RP to SRT
was 58 months (5-172). Median pre-RT PSA was 2.8 ng/ml
(0.2-29). At a median follow-up of 39 months (8-153) post-
SRT, 20 patients (36%) had biochemical failure and 8 (14%)
developed distant metastasis. Median time to BF after SRT
was 30 months (13-116). The 3- and 5-year bRFS were
70.5% and 53,5%, respectively. The 3- and 5-year cRFS was
89.2% and 80%, respectively. High-risk patients (pT3b
and/or Gleason score ≥ 8) had 3- and 5-year bRFS of 54%
and 27%, while 3- and 5-year cRFS was 66.7% and 44.4%,
respectively. Univariate and multivariate analyses showed
that Gleason score ≥ 8 and perineural invasion were
associated with lower bRFS (p=0.005 and 0.046,
respectively). High-risk patients presented lower bRFS and
cRFS when compared to lower risk patients (p= 0.03 and
0.001, respectively). At baseline, 4 patients (7%) had
grade 3 urinary toxicity. Twelve patients (21%) developed
grade ≥ 2 acute urinary toxicities. Three patients (5%) had
grade 2 acute GI toxicities. No grade ≥ 3 acute GI toxicity
occurred. Nine patients (16%) had grade ≥ 2 late urinary
toxicities. No grade ≥ 2 late GI toxicity was reported.
Conclusion
Delayed SRT using dose escalated IG-IMRT to isolated
macroscopic local recurrence is associated with poor
oncological outcomes particularly in high risk patients
(i.e. pT3b and/or Gleason score ≥ 8). Toxicity profile
seems to be acceptable at a medium term follow up.
Patients with high risk features should be strongly
considered for earlier and intensified treatment
approaches.
EP-1355 Comparing toxicity in IMRT and particle
therapy of prostate cancer in a ROCOCO in silico trial
Y. Van Wijk
1
, E. Roelofs
2
, B. Vanneste
2
, S. Walsh
2
, P.
Lambin
2
1
Maastricht university, School for Oncology and
Developmental Biology, Maastricht, The Netherlands
2
MAASTRO clinic, Radio Oncology, Maastricht, The
Netherlands
Purpose or Objective
Studies have shown that dose escalation has positive
effect on tumour control probability when treating high
risk prostate cancer. However, due to the higher dose in
the rectum, the normal tissue complication probability
(NTCP) for gastral intestinal (GI) toxicity is increased. The
goal of this study is to investigate whether radiotherapy of
high-risk prostate cancer with light-ion particles results in
reduced NTCP when compared to IMRT. A comparison
between doses and NTCP was made for three modalities:
IMRT, proton therapy (IMPT) and carbon-ion therapy (IMIT)