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12 months and yearly thereafter. The highest score of both
was used to identify toxicity.
Between
2010-2013,
validated
self-assessment
questionnaires, EORTC QLQ-C30 for health-related QoL
and EORTC PR-25 for PCa-specific QoL, were yearly sent
to all patients. All C30 functioning domains, global health
and fatigue and pain symptoms were evaluated. The
evaluated PR25 domains were sexual activity and
functioning, urinary and bowel symptoms, and
incontinence aid use. Raw scores of each domain were
linearly transformed into 0-100 scales. Higher functional
scores indicate higher functioning and better QoL, while
higher symptom scores indicate lower QoL.
Patients with toxicity were compared to patients without
late toxicity. A multi-level linear model was used to
statistically assess the QoL differences between the 2
groups over 6-10 years FU. Covariates were included in the
analysis to control for their influence: age, PSA, prostate
volume and FU time. Clinical relevance of the differences
was assessed by means of the minimally important
difference (MID): toxicity group mean scores ≥0.5 standard
deviation different from the non-toxicity group, were
considered clinically relevantly different.
Results
Late grade ≥2 toxicity was reported by 79 patients (46.2%),
of whom 57 (33.3%) had GU and 30 (17.5%) had GI
symptoms. Of both C30 and PR25, 364 questionnaires were
analysed (mean 2.1 per patient).
Generic QoL (C30)domains did not show any statistically
significant differences (Table 1). PR25 PCa-specific QoL
for both urinary and bowel symptoms showed clinically
relevant worse QoL scores for patients with grade ≥2
toxicity (p<0.001 and p=0.01, respectively). Of sexually
active patients, patients with toxicity reported better
sexual function (p=0.001); which was also clinically
relevant. The included covariates did not show any
associations
with
QoL
score
differences.
Conclusion
For patients treated with EBRT and HDR-BT boost, late
grade ≥2 toxicity was not associated with decreased QoL
for generic QoL domains, but associations between
toxicity and decreased PCa-specific QoL scores were
observed. The higher sexual functioning scores in the
toxicity group are hard to explain and worth more
investigation.
EP-1345 Dosimetric effect of seed-based prostate
localisation on Pelvic Lymph Nodes in High-Risk
Prostate Ca
R. Valentine
1
, E. Miguel Chumacero
2
1
NHS greater glasgow and clyde, Department of
Radiotherapy Physics, glasgow, United Kingdom
2
NHS greater glasgow and clyde- University of Glasgow,
Department of Radiotherapy Physics, Glasgow, United
Kingdom
Purpose or Objective
Prostate movement is unrelated to pelvic lymph nodes
(PLN) location. Therefore, for High-Risk Prostate Cancer
radiotherapy, set-up corrections based on image-guided
localisation of the prostate might not guarantee that the
other nodal PTV receives the intended dose. The aim was
to evaluate the impact that couch shifts applied for
prostate motion correction have on the dose delivered to
the PLN CTV and to determine their ideal PTV margins.
Material and Methods
Retrospective analysis of 21 VMAT treatments was realized
using the interfraction prostate-based couch shifts as new
isocentre coordinates in a verification plan. Then each
fraction dose was recalculated and the dose coverage of
the PLN CTV was assessed with DVHs. To reduce the
geometric miss new PLN PTV margins were proposed using
the Van Herk formula. Finally treatment plans using
current and proposed margins were compared based on
the dose to OARs and PTVs.
Results
The verification plans reported a mean PLN CTV D
99%
of
91.7% and this reduced between 4.8% and 9.0% (p<0.001)
compared to the mean of the original plans. 51.3% of the
verification plans did not meet the criteria, these showed
a prostate vector displacement larger than 0.62 cm. The
proposed margins: AP 0.91, SI 0.57, and RL 0.26 cm,
reported no significant difference in the dose to OARs and
PTVs compared to the current treatment plans margins.
Conclusion
When daily position correction is made considering only
the prostate there is potential dose degradation to the
PLN CTV. The proposed new recommended margins,
however, are expected to improve dose coverage of the
PLN CTV, without significantly affecting the associated
OAR doses.
EP-1346 Oligorecurrent nodal prostate cancer: long-
term results of an elective nodal irradiation approach
S. Tran
1
, S. Jorcano
2
, T. Falco
1
, G. Lamanna
1
, R.
Miralbell
1
, T. Zilli
1
1
Hôpitaux Universitaires Genève, Radiation Oncology,
Geneva, Switzerland
2
Instituto Oncológico Teknon, Radiation Oncology,
Barcelona, Spain
Purpose or Objective
The best strategy to irradiate oligorecurrent nodal
prostate cancer (PCa) remains debated with both elective
nodal radiotherapy (ENRT) and SBRT considered valid
alternatives. Aim of this study is to report long-term
results of ENRT in PCa patients (pts) with oligorecurrent
nodal disease after primary treatment.
Material and Methods
Data of 53 oligorecurrent PCa pts (N1 and/or M1a) with ≤
5 nodal metastases (n=108) treated with ENRT combined
with androgen deprivation (AD) between 2004 and 2016
were retrospectively reviewed. Median age and PSA at
diagnosis were 62 yrs (range, 47-77) and 8.6 ng/ml (range,
3.4-92.9 ng/ml), respectively. The primary treatment was
RT, radical prostatectomy (RP), RP + postoperative RT and
RT + salvage RP in 9 (17%), 23 (43%), 20 (38%) and 1 (2%)
pts, respectively. At recurrence (median time after
primary treatment of 34 mo, range 2-129 mo), all but one
patient were re-staged with 18F-choline PET-CT studies.
Median PSA and PSA doubling time (DT) were 3.4 ng/ml
(0.2-48.9 ng/ml) and 5 mo (range, 1-35 mo), respectively.
At restaging, 45.3% (n=24) of the pts presented a single
nodal metastasis, while 2, 3, 4 and 5 nodal metastases
were found in 30% (n=16), 7.5% (n=4), 9.5% (n=5) and 7.5%
(n=4) of the pts, respectively. Recurrences were mainly
located in the pelvis (n=38). A combined N1 and M1a
oligorecurrence or extrapelvic nodal progression (M1a)
was observed in 10 and 5 pts, respectively. All pts
underwent ENRT between 45 and 50.4 Gy with a boost on
positive nodes (median 64.4 Gy, 54-69 Gy) using mainly
VMAT (n=24) or IMRT (n=21) techniques. Concomitant AD
was administered to all pts for a median time of 6mo
(range, 3-30 mo).
Results