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

S32 World Congress of Brachytherapy 2012
: The obtained results show that the proposed detector is
suitable for in vivo realtime dosimetry in high dose rate
brachytherapy. Further studies are currently in progress for the
application of this dosimeter in urethral dose measurements during
interstitial brachytherapy treatments of the prostate.
79
PERMANENT PERINEAL IMPLANT (PPI) SALVAGE OF PPI FAILURES: IS
LESS MORE IN HIGHLY SELECTED PATIENTS
M. Roach
Department of Radiation Oncology UCSF, San Francisco, CA, USA
Helen Diller Family Comprehensive Cancer Center, San Francisco, CA,
USA
It has been estimated that 15 to 75% of men treated with radiotherapy
(RT) will fail biochemically (Agarwal et al, Cancer 2008; 1230714).
Specifically given the outcomes of series reported by experienced
Practitioners upwards of 30% of men undergoing permanent perineal
implants (PPI) for prostate cancer fail within 10 years. Thus it is likely
that failure rates are higher in the community where less experienced
physicians. Based on a “back of the envelope” calculation I would
estimate that it is likely that well over 100,000 men who have
undergone are experiencing a rising PSA after PPI in the USA alone.
Among the men with rising PSAs post PPI some are failing distantly
and some locally. Given the typical selection criteria and the
likelihood of poor quality implants in the community performed by
low volume practitioners it seem probable that at least as many of
these recurrences are local as occurs after a radical prostatectomy
(RP). Since the vast majority of men undergoing salvage external
beam radiation (EBRT) after RP respond, it is also likely that a
relatively large number of men failing PPIs might benefit from
additional local treatment.
Currently nearly 95% of men failing any form of RT are managed with
androgen deprivation therapy (ADT) (Agarwal et al, Cancer 2008; 12
30714). Unfortunately this is not a curative intervention and it is
associated with a host of side effects. Previous series have
documented suboptimal control rates and significant morbidity when
PPI salvage has been attempted (Moman et al. Brachytherapy 9: 119
25, 2010, Nguyen et al. Cancer 110:1485 92, 2007 and Nguyen et al.
Brachytherapy 8:34552, 2009). However these series tended to treat
the entire gland to near full doses. Of note however, most clinically
significant local recurrences after RT appear to occur at the initial
site of the primary tumor (Pucar et al. IJROBP 69: 629, 2007). Thus
subsets of patients who are failing locally can be identified who might
be candidates for local therapy.
At UCSF we assessed feasibility of MRplanned focal partial prostate
salvage PPI (psPPI).
Our hypothesis going into this intervention was
based on several principles:
If the seeds were not distributed as planned but they were placed into
the prostate then we did not have to worry about cold spots
elsewhere and there was not need to retreat previously treated areas.
Patients who had limited disease to start out with who appeared to
have recurred in sites of previous disease where ideally suited for
psPPI.
An otherwise negative multiparametric MRI, supported by a care set
of biopsies combined with #2 above set the criteria for the ideal
patient for psPPI.
Most importantly, develop a strategy that maximized the chances that
our treatment would “at least do no harm”. To this end composite
plans combining the previous dose distribution and “salvage plan” had
to be “safe”.
The potential types of patients who might be considered for salvage
local therapies are shown diagrammatically in Figure 1. The typical
patients we at UCSF selected for psPPI belong to categories 3 and 4 as
shown in Figure 1 below.
From 20032009, fifteen patients without metastases underwent
MRI/MRS to identify coincident areas of recurrence following iPPI
(N=14 I 125, 144Gy, N=1 Pd103, 125Gy) underdosage in preparation
for possible psPPI (without hormone therapy). For the psPPI planning
the mean D90 CTV (focal recurrent disease) was set at 142Gy resulting
in a whole prostate gland doses of 37Gy and a mean V100 rectum of
0.5% (0.07cc) and urethra dose of 12% (0.3cc).
Although the followup definition following psPPI for PSA failure was
chosen as the Phoenix Definition (PSAF = nadir + 2.0) or the first
ASTRO definition (ASTROPSAF = three consecutive rises) we expected
substantially lower values to be reflective of success. Toxicity was
scored using CTCAE v4.0.
At psPPI the median age was 68, and the median PSA=3.5ng/mL
(range:0.9 5.6 ng/mL). Most patients (71%) had Gleason Score 6 or
less but 39% had Gleason Scores of ≥7. Only 40% had abnormal MRI/S
with one (80%) or two (20%) abnormal foci. The median interval
between iPPI and psPPI was 69mos (range 28132).
At median followup of 23.3mos (range 888), two patients (13%)
failed biochemically at 26 and 35mos however both underwent a
second psPPI with followup PSA at 11.7 and 26.4 mos of 0.6 and
0.7ng/mL, respectively. Counting these two patients as failure the
ASTROPFS at 1, 2 and 3 years was 86.7%, 78.4%, and 62.7% with 5
failures (N=3 with negative TRUSbiopsy). In contrast, the PhoenixPFS
at 1, 2, and 3years were 100%, 100%, and 71.4%. psPPI PSA
nadir 12 months is associated
with a low risk of systemic progression and 92% remain metastasis
free at 5 years.
Surgical technique
Nowadays with most patients undergoing EBRT, perineal low or high
dose brachytherapy the standard retropubic approach is preferred for
salvage RPE. Depending on the type of radiation technique there are
different anatomical areas in which the surgical procedure might be
complicated (table 1) and deserves specific experience.
Complications: Rectal injury has been described in 6% to 19% of
patients in former series whereas it is reported in only 25% of
patients in modern series.
Anastomotic strictures occur more frequently in 832%
The incidence if urinary stress incontinence is higher than in series of
primary RPE. Complete continence can be achieved in about 50%,
another 20% to 30% require only 1 pad per day. The radiation
technique used appears to be associated with the frequency of
incontinence: in the author’s experience a high continence rate of
90% could be achieved in patients having undergone LDR
brachytherapy.
Cancer control following SRP
The 5year progressionfree rates have improved and the results are
similar to those of standard RPE in cases of similar pathological
stages. The 10year cancer specific and overall survival rates are in
the range of 70% to 75% and 60% to 66% in contemporary series. In
most contemporary series, organconfined disease, negative surgical
margins and the absence of seminal vesicle and/or lymph node
metastases are favourable prognosticators associated with a better
diseasefree survival of approximately 7080%.
: With the advantage of PSA screening at regular followup
intervalls following RT, most local failures will be detected by an
asymptomatic PSA increase. Patients with PSA levels < 10 ng/ml, no
palpable disease, negative findings on CT and bone scans are most
suitable candidates for SRP. Contemporary series of SRP demonstrate
excellent local control, good longterm cancer specific survival rates,
minimal complication rates and a good health related quality of life.
SRP represents the therapeutic option if choice in well selected
patients with locally recurrent PCA preventing significant local
complications. Based on our most recent findings on 117 patients SRP
should only be performed at tertiary referral centres with an
extensive experience not only in radical prostatectomy but especially
in salvage surgery.
OC81
A MULTICENTRE COMPARISON OF INTER AND INTRAFRACTIONAL
ORGAN MOVEMENT IN CERVIX CANCER BT AND ITS DOSIMETRIC IMPACT
N. Nesvacil 1 , K. Tanderup 2 , T. PaulsenHellebust 3 , A. De Leeuw 4 ,
C. Anderson 5 , S. Mohamed 2 , R. Pötter 6 , C. Kirisits 6
1
Medical University of Vienna, Department of Radiotherapy and
Oncology Comprehensive Cancer Center, Vienna, Austria
2
Aarhus University Hospital, Department of Oncology, Aarhus,
Denmark
3
Oslo University Hospital, Department of Medical Physics Division of
Cancer and Surgery, Oslo, Norway
4
University Medical Center Utrecht, Department of Radiation
Oncology, Utrecht, The Netherlands
5
Mount Vernon Cancer Centre, Clinical Physics Department,
Northwood Middlesex, United Kingdom
6
Medical University of Vienna, Department of Radiotherapy and
Oncology Comprehensive Cancer Center & Christian Doppler
Laboratory for Medical Radiation Research for Radiation Oncology,
Vienna, Austria
: Inter and intrafractional organ motion plays an
important role in multifractional brachytherapy treatment when one
dose plan is used for multiple fractions, or when organ movement
happens in between imaging and dose delivery. The dosimetric impact
of such motions has been reported previously in singleinstitutional
studies.
The aim of this study is to compare the dosimetric impact of organ
position variations by a retrospective multicentre analysis with
different application techniques and fractionation schemes.
: Data from 5 centers in the GYNGEC ESTRO
Network using intracavitary (tandem/ovoid or tandem/ring)
applicators +/ interstitial needles were collected.
To assess dosimetric effects of the motion of critical organs (bladder,
rectum, sigmoid) between treatment fractions, multiple image scans
(MRI or CT) were analysed. OAR were contoured on images at the time
of BT planning as well as on a subsequent image series acquired prior
to treatment of a subsequent HDR or PDR fraction. Dose plans
generated by using the 1 st image series were superimposed onto the
subsequent image sets and DVH parameters were calculated.
DVH data for a total of 96 patients was available (323 image/contour
sets, 254 MRI, 69 CT). DVH data for 16 fractions were available for
each patient. The average time between consecutive image
acquisitions varied between centers, from several hours to several
days (mean 73 h, median 22 h, range 5 h – 22 d).
: For each patient, D2cc for bladder, rectum and sigmoid were
calculated based on images and contour sets acquired at different
times during the BT treatment (at time of planning (D2cc_1) + at time