ESTRO 36 Abstract Book

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S383 ESTRO 36 2017
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Conclusion
Extreme hypofractionated radiotherapy, delivering 4
fractions of 9.5 Gy with either HDR-brachytherapy or
SBRT, is well-tolerated and safe with comparable late
toxicity as other treatment modalities for low and
intermediate risk prostate cancer. Compared to HDR,
SBRT resulted in a slightly increased grade 2 GU toxicity
rate and can therefore be used as an alternative for
patients not eligible for brachytherapy.
PO-0736 Long term outcomes of IG-IMRT dose-
escalation to pelvis and prostate for advanced prostate
cancer
H. Lieng1 , T. Rosewall1 , H. Jiang2, A. Berlin 1, R. Bristow1,
C. Catton1, P. Chung1, J. Helou1, P. Warde1, A. Bayley1
1 Princess Margaret Cancer Centre, Department of
Radiation Oncology- Radiation Medicine Program,
Toronto, Canada
2 Princess Margaret Cancer Centre, Department of
Biostatistics, Toronto, Canada
Purpose or Objective
To evaluate late toxicity and long-term biochemical
control for men with high-risk or node-positive (N1)
prostate cancer treated with image-guided IMRT (IG-IMRT)
and dose escalation to both the pelvic lymph nodes and
prostate/seminal vesicles.
Material and Methods
Between 2002 and 2009, men with high-risk or N1 prostate
cancer received dose-escalated IG-IMRT to the pelvis and
prostate on a phase II clinical trial. The planned
prescription dose was 55.1 Gy in 29 fractions to the
prostate/seminal vesicles (P/SV) and pelvic lymph nodes
(PLN), with a sequential boost dose of 24.7 Gy in 13
fractions to P/SV. Dose reductions were mandated to meet
organ at risk constraints. Late RTOG gastrointestinal (GI)
and genitourinary (GU) toxicity scores were recorded at
each visit and biochemical failure was defined using the
Phoenix criteria. Probability of toxicity and biochemical
control were estimated using cumulative incidence
function. Overall survival was calculated using the Kaplan-
Meier method. Difference between groups was evaluated
by Gray’s test or log-rank test.
Results
124 men received IG-IMRT to the prostate and pelvic
lymph nodes. Median follow-up was 99.7 months (range 5
– 162 months). Men had T3-T4 (45%), N1 (13%), Gleason 8-
10 (52%) disease with median PSA 24 ng/mL. The median
age was 68 years and 85% received at least 2 years of
androgen deprivation therapy. 112 (82%) received the
total prescription dose to P/SV, with 67 (54%) receiving
the planned dose to PLN of 55.1 Gy, and 106 (85%)
receiving at least 50 Gy to PLN.
The 5- and 7-year cumulative incidence of late GI grade ≥
2 was 16.3% and 17.3%, with cumulative incidence of late
GU grade ≥ 2 toxicity of 8.3% and 13.1% respectively. Late
GI grade ≥ 3 toxicity at 5 and 7 years was 4.9% and 5.8%
respectively, and late GU grade ≥ 3 toxicity was 2.6% and
4.5% respectively. The incidence of GI and GU Grade 3
toxicity was 6% for each. At last follow-up visit there were
no GI Grade ≥ 3 toxicities and 2 GU Grade 3 toxicities.
There was no significant difference in late GI nor late GU
toxicity between patients receiving pelvic doses ≤ 50 Gy
and > 50 Gy.
Five-year biochemical control was 77%, and at 7 years was
67%, with significantly more failures in the node-positive
cohort. Biochemical failures occurred in 44 patients (35%)
and 14 died from disease (11%). Overall survival was 92%
at 5 years and 87% at 7 years and significantly lower in
those with nodal metastases.
Conclusion
IG-IMRT with dose-escalation to both the pelvic lymph
nodes and prostate/seminal vesicles results in similar late
toxicity to standard dose pelvic irradiation using 2D/3D-
conformal techniques. There was no significant difference
in toxicity with pelvic doses > 50 Gy compared to ≤ 50 Gy.
Our biochemical control rates were comparable to that
reported in the dose-escalated randomized trials. Patients
with nodal metastases at diagnosis had worse outcomes
compared to those without nodal disease
.
PO-0737 elective pelvic radiotherapy in clinically node-
negative prostate cancer: a long-term analysis
F. Catucci1, C. Masciocchi1, A.R. Alitto 1, M. Vernaleone1,
G.C. Mattiucci1, V. Frascino1, V. Valentini1, G. Mantini1
1Università Cattolica del Sacro Cuore -Fondazione
Policlinico A. Gemelli, Radiation Oncology Division-
Gemelli-ART, Rome, Italy
Purpose or Objective
Whole pelvic radiotherapy(WPRT) remains highly
controversial in prostate cancer. Although randomized
trials failed to show a benefit for patients that received
prophylactic irradiation(46-50 Gy) of pelvic lymph-
nodes(PLN), elective WPRT could be considered in high-
risk patients, based on validated nomograms.
Aim of this long-term analysis is to update data about a
retrospective analysis, that supported WPRT only for
patients with a high risk of Limphonodal Involment(LNI),
using as threshold 30%, assessed by Roach equation.
Material and Methods
Patients classified in high- and very high-risk groups(Stage
T3 or T4 and/or GS 8-10 and/or PSA level>20 ng/mL)were
analyzed. LNI risk was assessed through Roach
was performed mainly with 3D technique
after 2000. Prone or supine immobilization were used
respectively in WPRT and Prostate Only RT(PORT). CTVs
were: CTV1 prostate(total dose 7020/1.8 cGy fx until 1999
and 73.8/1.8 cGy fx afterwards), CTV2 seminal vesicles
plus CTV1(total dose 55.8/1.8 cGy fx for cT1-T3a and
64.8/1.8 cGy fx for cT3b-T4), CTV3 PLN, in WPRT(total
dose 4500/180 cGy fx). PTVs derived from a common
margin of 1 cm to corresponding CTV.Long-term androgen
deprivation therapy(ADT) was prescribed.Toxicity was
graded according to the CTC v4.03.Statistical analysis was
performed using R statistical software 3.2.4.
Results
Among the 358 patients enrolled between 1994 and 2007,
we selected 319 high-risk ones:20 treated until 1999, by
2D RT, and 299, treated from 2000, by 3D RT; 147 (46.1%)
treated with WPRT and 172(53.9%) with PORT. Median age
at diagnosis was 70 years for WPRT(range 42 – 80) and 72
years for PORT(range 56 – 83) group. The two groups were
heterogeneous for age, with a statistically significant
difference between them(p=0,0017).With a median
follow-up of 128 months, there were no statistically
significant differences between WPRT and PORT groups,
in terms of surrogate outcomes. Only OS resulted in a
statistically significant difference between WPRT and
PORT group, probably due to the initial heterogeneity in
age; also among patients younger than 70 years, there
weren’t statistically significant differences between the
two groups. Then, a subgroup analysis was performed,
considering LNI risk, as assessed by the Roach formula,
using different cut-off levels(Fig.1, 15%,20%,25%, and
30%). The subgroup analysis confirmed no statistically