World Congress of Brachytherapy 10-12 May, 2012 - Estro-events.org

S64 World Congress of Brachytherapy 2012
clinical target volume and organs at risk was performed by the co
ordinating centre before image export. This was based on the existing
GECESTRO guidelines but with small adaptations given the postTURp
setting. Goals and constraints regarding the dosimetry were defined.
: 17 centres participated in this study. The mean number of
needles used was 18 ( min10 max 25). Mean number of seeds was 52
(min 27 max 63). 8 out of the 17 centres applied a classical seed
spacing with regular 1 cm seed centretocentre in the majority of
their needles, whereas 9 centres used specially loaded needles that
differed by having extra spacing between seeds. The mean seed
strength used was 0,486 U (range 0,458 – 1,0 U) or 0,383 mCi (range
0,361 – 0,787 mCi). The mean activity of the total implant was 27,8 U
(range 25,7 – 33,9 U) or 21,9 mCi (range20,2 – 26,7 mCi). All centres
fulfilled the requested dosimetry constraints for the prostate volume.
The mean Vp100 was 98 % (range 97,06 99,94%), the mean Dp90
was 187 Gy (range 159 219 Gy), the mean Vp150 was 73% (range 42
90%) and the mean Vp200 was 35 % (range 18 56%). All but 2 centres
fulfilled the CTV dosimetric constraints and these two centres
deviated from the requirements by only a small amount which could
have been corrected by movement of one or two seeds by a few
millimetres. The mean V100 for the CTV was 96,5 % (range 94
99,41%), mean V150 was 62 % (range 41 – 75,4%) and mean D90 was
171 Gy (range 157 – 186 Gy). In terms of urethral dosimetry, all but 2
institutions were able to fulfil the protocol requirements. These 2
centres exceeded the Du30 constraint achieving 133 Gy and 134 Gy
in contrast to the protocol constraint of ≤130Gy). The mean Du30 was
118 Gy (min 99 – max 134 Gy) and the mean Du10 was 124 Gy (min 104
– max 148 Gy). All centres achieved the required rectal dose
constraints. Sector analysis was performed for all plans. Given the
small prostatic volume, eight segments were defined. The typical
postTURp defect results in very small anterior segments. For each
segment, D90 and V100 were calculated. 3 centres showed perfect
coverage for D90 and V100 for all defined segments. Four centres had
a clear underdosage in the basal anterior segments and fourteen
centres had an underdosage in the apical anterior segments.
: Consistent preimplantation planning with adherence to
protocol guidelines is feasible in a postTURp setting. This study
validates the proposed standardized contouring in this specific
anatomical setting and the proposed dose goals and constraints. A
prospective study evaluating the outcome of prostate I125
brachytherapy performed after transurethral resection of the prostate
can therefore be undertaken with an expectation of consistent
dosimetry in the multicentre setting.
PO154
FOCAL BRACHYTHERAPY FOR PROSTATE CANCER: A PILOT STUDY
J.M. Cosset 1 , X. Cathelineau 2 , N. Pierrat 1 , D. Hajage 1 , G. Wakil 1 , F.
Rozet 2 , E. Barret 2 , G. Vallancien 2
1 Institut Curie, Radiotherapy, Paris, France
2 Institut Mutualiste Montsouris, Urology, Paris, France
: Permanent implant prostate brachytherapy (using
Iodine125 seeds) is now recognized as one of the standard therapies
for lowrisk localized prostate cancer. For strictly selected patients,
focal therapy is nowadays increasingly proposed to limit toxicity and
permit easier salvage in case of failure. Brachytherapy, which is able
to treat a welldefined partial prostate volume at a welldefined dose
level, appears to be particularly well adapted to focal prostate
therapy.
: Focal brachytherapy was initiated by our
group in February 2010, according to a protocol approved by our local
ethics committee, with all patients signing an informed consent.
Patient selection is based on (at least) two series of prostate biopsies
and on a highresolution MRI. Only patients with very limited and
localized tumors, according to strict criteria, were selected for the
procedure. The technique is directly derived from the 'realtime'
procedure with the implantation of 'free' Iodine125 seeds, with
dynamic dose calculation (continuous feedback as per the real
positioning of each seed). We chose to deliver to the focal volume the
dose usually recommended by GECESTRO for the whole prostate (145
Gy).
: To date, 12 focal implantations were performed. The treated
volume corresponded to a mean value of 34 % of the total prostatic
volume (range 2048 %). For the focal volume, mean D90 was 182 Gy (
range 176188 Gy), and the mean V100 was 99.6 % ( range 98.899.9
%). In our experience, the technique could be performed without any
problem in approximately an hour and a half, that is to say not
significantly different from a usual 'whole prostate' brachytherapy. On
our very preliminary results, early urinary toxicity seems to be inferior
to what is usually observed after brachytherapy of the whole prostate,
particularly for the focal 'apex only' cases. Incontinence score (ICS)
was nil in all cases, as well as rectal toxicity. As for sexual toxicity,
IIEF5 scores only showed very limited and transitory changes.
: Focal treatment by brachytherapy is easily feasible with
apparently little acute toxicity. Further investigation is needed to
assess the results in terms of tumor control and toxicity.
PO155
DOSIMETRIC CONSTRAINT OPTIMIZATION IN INTRAOPERATIVE
TREATMENT PLANNING OF PERMANENT SEED IMPLANTATION (PSI)
K.U. Kasch 1 , P. Wust 2 , F. Kahmann 3 , T. Henkel 3
1
Beuth University for Applied Sciences Berlin,
Mathematics/Physics/Chemistry, Berlin, Germany
2
Charité – University Medicine, CVK, Berlin, Germany
3
Outpatient Prostate Brachytherapy, Ullsteinhaus, Berlin, Germany
: Today, PSI is an established treatment modality
for (earlystage) prostate cancer. In comparison to alternatives the
method often results in lower toxicity at equal tumor control. Current
systems for the necessarily inverse treatment planning limit both type
and number of available dosimetric constraints. Considering these
limitations this study aims at a set of robust dosimetric constraints
that translate into optimal clinical outcome.
: The results presented here are based on the
experience of about 2000 implantations performed by the authors of
this study. For a subgroup of about 400 patients both CTbased post
implantation analyses were performed and standardized patient
questionnaires were evaluated. Subsequently, first the
correspondence of intraoperatively achieved dosimetric constraint
values and those showing in the postimplant analysis was analyzed.
Secondly, a possible correlation of dosimetric constraint values and
clinical outcomes concerning acute and subacute toxicities was
investigated. Finally, a set of robust dosimetric constraints was
derived.
This set was used by a supervised group of 20 medical physics master
students to retrospectively (re)plan more than 300 patients (different
from the above subgroup). The results were evaluated utilizing a
quadratic score function for the dosimetric constraints as well as
dosevolumehistograms (DVH) for prostate, urethra and rectum.
Planning time and score function value as a function of the
(increasing) number of patients planned by an individual student were
interpreted in a learning curve.
: The above derived set of dosimetric constraints results in a
significant correlation between score function (physics) and DVH
(clinical outcome). This, in conjunction with a steep learning curve in
the planning process itself clearly indicates the clinical usefulness and
robustness of the constraints found. The results can be used with
commercially available treatment planning systems and do not depend
on the seed activity.
: Evaluation of postimplant analyses in conjunction with
well designed patient questionnaires results in an optimized set of
dosimetric constraints. This, besides the growing experience with an
increasing number of implantations, significantly contributes to the
improvement of clinical outcome in PSI.
PO156
URINARY MORBIDITY RELATED TO PROSTATE BRACHYTHERAPY WITH
OR WITHOUT EXTERNAL BEAM RADIATION THERAPY
M. Ishida 1 , K. Kanao 1 , A. Sugawara 2 , R. Ohara 1 , S. Kashiyama 3 , M.
Katayama 3 , N. Tsukamoto 3 , Y. Nakajima 1
1 Saiseikai Yokohamashi Tobu Hosipital, Urology, Yokohama, Japan
2 Keio University School of Medicine, Radiology, Tokyo, Japan
3 Saiseikai Yokohamashi Tobu Hosipital, Radiology, Yokohama, Japan
: A combination of permanent seed implantation
brachytherapy (BT) and external beam radiation therapy (EBRT) is one
of the treatment options for localized prostate cancer with
intermediate or high risk. As for the difference of radiation field and
World Congress of Brachytherapy 2012 S 65
radiation dose between the cases treated with BT alone or BT
combined with EBRT (BT + EBRT), the divergence of posttreatment
urinary morbidity may be seen. This study is to clarify the difference
of urinary morbidity in the cases treated with BT alone or BT + EBRT.
: Seventyseven histologically confirmed
prostate adenocarcinoma patients underwent iodine125 seed BT in
our institute between October 2009 and June 2011. Among those
patients, 10 with incomplete data were excluded from this study. The
median age was 72, ranged from 45 to 81. Of those 67 patients
included in this study, 43 (64.2%) were treated with BT alone with
prescription dose of 160 Gy and the other 24, who were evaluated as
intermediate or high risk under D’Amico classification, were treated
with 110 Gy of BT followed by 45 Gy (1.8 Gy x 25) of EBRT.
International Prostate Symptom Score (IPSS) was obtained from those
67 patients before BT (baseline) and 3 months (3M) after BT or BT +
EBRT to evaluate voiding condition. To characterize urinary morbidity
related to BT, changes of the scores from the baseline and the
difference of the scores between two treatment groups were
statistically analyzed with MannWhitney Utest.
: Prostate volume was same in both treatment groups (BT
alone: 26.7 ± 6.5 cc, BT+EBRT: 25.2 ± 11.8 cc, p = 0.16). There was
no significant difference in total Biochemical Effective Dose (BED)
between two groups, but BED of brachytherapy was higher in BT alone
group (BT alone: 216.2 ± 25.1 Gy, BT+EBRT: 137.4 ± 17.7 Gy, p <
0.01). There were no significant differences in total IPSS and
obstructive urinary symptom score between the two treatment groups
at baseline, however, irritative urinary symptom score was higher in
BT+EBRT group (BT alone: 4.8 ± 2.8, BT+EBRT: 6.3 ± 3.2, p < 0.05).
The changes of total IPSS from baseline revealed difference between
the two treatment groups (BT alone: 8.7 ± 6.4, BT+EBRT: 0.6 ± 5.3, p
< 0.01) showing that BT+EBRT had better voiding condition. The
changes of obstructive urinary symptom score between the two
treatment groups showed significant difference (BT alone: 5.6 ± 3.9,
BT+EBRT 0.2 ± 3.3, p < 0.01). There was a significant difference
between the two treatment groups on the changes of irritative urinary
symptom score (BT alone: 3.0 ± 3.2, BT+EBRT 0.8 ± 2.8, p < 0.01).
Urinary retention was not observed in both treatment groups.
: According to the results of this study, urinary morbidity
during the first 3 months after BT was lower in cases treated with BT
combined with EBRT compared with cases treated with BT alone. It
suggests that urinary morbidity is rather related to the radiation dose
of implanted seeds than total BED.
PO157
RECTAL BALLOONS AND THE RISK OF SECONDARY RECTAL CANCER
AFTER COMBINED MODALITY PROSTATE RADIATION
R.J. Burri 1 , J. Ng 2 , D.P. Horowitz 2 , J.A. Cesaretti 3 , M. Terk 4 , J. Kao 5 ,
T. Stephens 5 , K.S.C. Chao 2 , D.J. Brenner 6 , I. Shuryak 6
1
Tampa Bay Cancer Center, Radiation Oncology, Sun City Center FL,
USA
2
Columbia University Medical Center, Radiation Oncology, New York
NY, USA
3
Tampa Bay Cancer Center, Radiation Oncology, Tampa FL, USA
4
Florida Radiation Oncology Group, Radiation Oncology, Jacksonville
FL, USA
5
Tampa Bay Cancer Center, Radiation Oncology, Brandon FL, USA
6
Columbia University Medical Center, Center for Radiological
Research, New York NY, USA
: An increased risk of secondary rectal malignancy
is an established problem following definitive external beam radiation
therapy (EBRT) for prostate cancer. Many highrisk, and some
intermediaterisk, patients are currently treated with combined
brachytherapy and EBRT, usually with an intensitymodulated
radiation therapy (IMRT) plan to 45 Gy. In this study, a biologically
based carcinogenesis model was used to quantitate and compare the
predicted risk of secondary rectal cancer in men treated with or
without a rectal balloon in place during the IMRT portion of combined
modality therapy.
: Treatment plans were developed for ten
clinically localized prostate cancer patients using CT scans obtained
both with and without a rectal balloon in place. Target volumes
(prostate and proximal 1.5 cm of seminal vesicles) and normal
structures were contoured, and dosevolume histograms (DVHs) for
these organs were determined with a planned IMRT dose of 45 Gy. A
biologicallybased mathematical model of spontaneous and radiation
induced carcinogenesis was used to determine the excess absolute risk
of secondary rectal malignancies both with and without the rectal
balloon in place. These risks were then compared to one another and
to the baseline population.
: Treatment with a rectal balloon in place resulted in a
significantly lower mean rectal wall dose in all patients compared
with treatment without a rectal balloon. The average mean rectal
wall dose with a rectal balloon in place was 17.2 Gy versus 20.7 Gy
without the rectal balloon (p=0.001). A significantly higher risk of
secondary rectal cancers was predicted for patients treated without
rectal balloons when compared with patients treated with balloons in
place (p=0.001, relative risk 1.22; 95% confidence interval 1.101.34).
: For prostate cancer patients treated with combined
brachytherapy and external beam radiation therapy, the use of a
rectal balloon during the IMRT portion of treatment is associated with
a significant reduction in the predicted risk of secondary rectal
malignancy.
PO158
PHASE II TRIAL OF HIGHDOSE RATE BRACHYTHERAPY AND EXTERNAL
RADIATION FOR INTERMEDIATERISK PROSTATE CANCER
I. Tsukiyama 1 , R. Kobayashi 1 , J. Hiratsuka 2 , S. Kariya 3 , S. Uehara 4 , T.
Dokiya 5 , H. Sekine 6 , T. Sato 7
1
Aidu Central Hospital, Radiology, Fukushima, Japan
2
Kawasaki Medical College, Radiation Oncology, Kurashiki, Japan
3
Kochi University, Diagnostic Radiology and Radiation Oncology,
Kochi, Japan
4
Kyushu Cancer Center, Radiology, Fukuoka, Japan
5
Saitama Medical University, Radiation Oncology, Hidaka, Japan
6
Jikei University School of Medicine, Radiation Oncology, Tokyo,
Japan
7
Kitasato University, Urology, Kanagawa, Japan
: To estimate the rate of early and late Grade 3 or
greater genitourinary and gastrointestinal adverse events after
treatment with external beam radiotherapy and prostate highdose
rate (HDR) brachytherapy.
: Patients with locally confined T2b,T2c or
10ng/ml < PSA ≤ 20ng/ml or Gleason score=7 prostate cancer were
eligible for the present study. All patients were treated 39 Gy in 13
fractions using external beam radiotherapy and one HDR implant
delivering 18 Gy in two fractions. All adverse event were graded
according to the Common Terminology Criteria for Adverse Event,
version 3.0. Early adverse events were those occurring less than 9
months and late adverse events were those occurring more than 12
months from the start of the protocol treatment. Primary endpoint of
this study is rate of late Grade 3 or later adverse event. Secondary
endpoints are rate of early Grade 3 adverse event and PSA failure
rate.
: A total of 92 patients from 5 institutions were enrolled in the
present study. Of the 92 patients, 84 were eligible. Each rate of early
adverse events of Grade 1 after three, six and nine months from the
irradiation was 63%, 70% and 37% respectively, and that of Grade 2
was 9%, 5%, and 3% respectively. Each rate of late adverse events of
Grade 1 after 12, 18 and 24 months from the irradiation was 28%, 73%
and 0% respectively, and that of Grade 2 was 4%, 0%, and 0%
respectively. No adverse events of Grade 3 or greater were observed.
Among 84 cases, only one patient caused PSA failure. The patient was
treated with endocrine therapy.
: As a result of highdose rate brachytherapy combined
with external irradiation for intermediaterisk prostatic cancer, early
and late adverse events of Grade 3 or greater did not occur, and only
one patient had biochemical failure among the 84 patient. The
technique and doses used in the present study resulted in acceptable
level of adverse events.
PO159
LONG TERM TOXICITY FOLLOWING CS131 PROSTATE BRACHYTHERAPY
R.P. Smith 1 , S. Beriwal 1 , R.M. Benoit 2
1
University of Pittsburgh, Radiation Oncology, Pittsburgh, USA
2
University of Pittsburgh, Urology, Pittsburgh, USA