ESTRO 36 Abstract Book

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S516 ESTRO 36
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Conclusion
Our study shows an average systematic 16% smaller
prostate volume on TRUS compared to CT. This differs
from the 30 to 50% smaller volumes on TRUS reported in
the literature. This discrepancy is probably due to the
presence of catheters implanted under TRUS guidance in
CT based planning which means that catheters are
inserted under TRUS guidance in both planning modalities.
These catheters act as fiducial markers to delimit the
prostate capsule transversely on CT. The residual 16%
volume variation is largely due to the uncertainty in
identifying the prostate apex. A 2.8 mm isotropic
dosimetric margin should be used in order to treat
comparable volumes in TRUS compared to CT based
planning.
PO-0931 Clinical outcome and quality of life after MRI-
guided HDR boost for prostate cancer.
F. Lakosi1, A. Miovecz1, G. Antal 1, J. Pall2, D. Nagy3, M.
Csima 4, J. Hadjiev1, I. Rep a1, G. Toller1
1 Kaposvar University, Radiotherapy, Kaposva r, Hungary
2 Csolnoky Ferenc Hospital, Radiotherapy, Veszprem,
Hungary
3 Kaposi Mor Teaching Hospital, Urology, Kaposvar,
Hungary
4 Kaposvar University, Faculty of Pedagogy, Kaposvar,
Hungary
Purpose or Objective
To analyze 5-year clinical outcome and quality of life
(QoL) after MR-guided high-dose-rate brachytherapy
(HDR-BT) combined with 3D conformal external beam
radiotherapy (3D-EBRT).
Material and Methods
Fifty-two patients with intermediate (IR) (n=22) to high-
risk (HR) (n=30, 18 T3 diseases) localized prostate cancer
were treated with 46-60 Gy of 3D EBRT preceded and/or
followed by a single dose of 8-10 Gy MR-guided HDR-BT.
Template reconstruction, trajectory planning, image
guidance, contouring and treatment planning were
exclusively based on MR images. Ninety-six percent of the
patients received androgen deprivation. Biochemical
relapse–free survival (bRFS, Phoenix definition), local
relapse-free survival (LRFS), distant metastasis-free
survival (DMFS), cancer-specific survival (CCS) and overall
survival (OS) were analyzed actuarially. Morbidity were
scored using CTCAEv4.0, while patients self-reported
urinary and bowel QoL was measured with the Expanded
Prostate Cancer Index Composite (EPIC) instrument and
International Prostate Symptom Score (IPSS) at baseline
and at regular intervals up to 6 years.
Results
Median follow-up time was 73 (range:13-103) months. The
crude/5-year actuarial rates of bRFS, LRFS, DMFS, CSS and
OS were 94/97.4 %, 98/100 %, 96/97 %, 100/100 % and
92/91 %, respectively. Two distant failures occurred in HR
group, while one local recurrence in IR group. The main
urinary toxicity was dysuria, which were Gr. 2 in 24/52
cases, including 9 patients with alfa blocker use at
baseline. There were 3 urinary strictures including one Gr.
3 event. Late GI morbidity was mild, representing Gr. 1
diarrhea (10/51), Gr. 1 urgency (9/51), Gr. 2 proctitis
(1/52) and Gr. 2 fecal incontinence (1/52), respectively.
A significant decline in urinary domain was observed
within the first 3 months, which mostly recovered by 6
months, thereafter declined progressively (p>0.05) and
remained stable from 4th years follow up (p>0.05)
(Figure). A similar trend was seen for bowel QoL, where a
significant decline occured within the first 3 months that
subsequently returned to nearly baseline level within 6
months, however, in contrast to urinary functions
remained stable over time (p>0.05). The evolution of IPPS
scores showed the same pattern as EPIC urinary scores.
Conclusion
Five-year clinical outcome of MR-guided HDR-BT boost is
encouraging, providing excellent disease control and lack
of serious late side effects. A slight decline in long-term
urinary QoL was observed.
PO-0932 Prostate-specific Antigen bounce in patients
treated with 125I prostate brachytherapy: Keep calm
A. Pires1, D. Moreira1, C. Castro1, A. Oliveira1, J.
Oliveira 2, L. Trigo3
1Instituto Português de Oncologia do Porto Francisco
Gentil- EPE, Radioncology, Porto, Portugal
2Instituto Português de Oncologia do Porto Francisco
Gentil- EPE, Urology, Porto, Portugal
3Instituto Português de Oncologia do Porto Francisco
Gentil- EPE, Brachytherapy, Porto, Portugal
Purpose or Objective
Permanent low-dose-rate brachytherapy (BT) with 125I is
an established curative modality for the treatment of
localized prostate cancer. After treatment, prostate-
specific antigen (PSA) level may fluctuate and temporarily
increase without a clear reason. This phenomenon is
called “PSA bounce” (PSAb) and often causes anxiety in
patient and physician. Our aim was to analyse the kinetics
of PSA in our patients and the association between PSA
bounce and the long term disease outcome after prostate
BT with 125I.
Material and Methods
We analysed 134 patients treated with 125I implantation
monotherapy between 2004 and 2006 in a single
institution. All patients had tumour stage T1-T2cN0M0,
Gleason score ≤ 7 and follow-up time was ≥ 9 years.
Patients who received neo-adjuvant hormone
therapy were excluded. PSAb was defined as a rise
beyound 0.2 ng/ml the initial PSA nadir with a subsequent
decline to or below the initial nadir without treatment.
Biochemical failure (BF) was determined using the Phoenix
definition (nadir +2 ng/mL). Associations between PSAb
and the various pre and post-treatment factors were
assessed with logistic regression analysis, the association
between a PSAb and BF was examined with the log-rank
test and the Mann-Whitney U test was applied to test for
difference in the time to a PSA rise between PSAb and BF
patients.
Results
PSAb occurred in 53 (39,8%) patients with a median time
to bounce of 18,8 months. Only 7 (13,2%) patients with
PSAb developed BF, in contrast to 12 (15%) patients
without previous bounce (p = 0,084). Among the pre and
post-treatment factors, only younger age predicted a PSAb
on a multivariate analysis (p = 0.049). PSA levels during
the bounce reached levels as high as 8,85 ng/mL in this
cohort. BF occurred in 19 patients (14,4%). The 9-year
overall survival rate was 83,6%, the 9-year disease-specific
survival was 95,8% and the rate of survival at 9-year
freedom from BF was higher than 90%.
Conclusion
PSAb is a common finding in our population and is
associated with a lower rate of subsequent BF. Patients
should be advised for the eventual PSAb after
permanent 125I prostate BT. Those who experience a PSAb
are more likely to be younger. The physicians involved in
patients follow-up after prostate BT should also be aware