405 / 1096
S390
ESTRO 36
_______________________________________________________________________________________________
IPI). Ipi was administered intravenously at a dose of 3
mg/kg over 90 min every 3 weeks for 4 doses. We treated
120 lesions whit median diameter size of 8 mm (2-42 mm).
67 SRS(dose range 10-24Gy) and 23 SRT(dose range 18-
24Gy). We evaluated the local response according to
RECIST criteria. We assessed LC as the sum of CR, PR and
SD, IC, and median OS from the date of the SRS/SRT
procedure.
Results
The median follow-up (FU) was 7 months (m) (range 0-26).
55 pts for a total of 109 lesions were evaluable for FU. The
median OS for all pts was 9.7 m and the median OS of 52
pts who received Ipi and RT was 10 m vs 9.7 m of 11 pts
IPI NO(P=0.82). The median OS for single group was: 9.7 m
for NO-IPI, 7.7 m for IPI PRE-RT, 9.7 m for IPI CONC RT and
11.5 m for IPI POST-RT (p=0.95). The 1-year OS was 41%
for IPI POST-RT, 32% for IPI PRE-RT, 36% for NO-IPI and 33%
for IPI CONC RT
.
The 1-year LC of all pts lesions was 43.2%,
and the 1-year LC of pts who received Ipi+RT was 48% vs
25% of pts NO IPI(p=0.06).The 1-year LC for single group
was 72% for IPI PRE-RT, 36% for IPI POST-RT, 25% for NO-
IPI and 33% for IPI CONC RT(p=0.08). The 1-year IC of all
pts was 40.1%, and the 1-year IC of pts who received Ipi
and RT was 41.5% vs 50% of pts NO IPI.
Conclusion
Our experience suggests that the combination of
Ipi+SRS/SRT in MBMs pts can obtain a better survival with
a low toxicity profile related to combined treatment. The
high precision of treatment with Cyberknife allows to
reduce radiation of organs at risk. The optimal timing of
combination Ipi+RT is not clear, but from our experience
it would seem to be a benefit of using the Ipi before
SRS/SRT on LC. The recruitment of a greater number of
pts and a longer follow-up are needed to demonstrate the
role of Ipi also in the treatment of melanoma pts with BMs
and the better sequence with RT.
Poster: Clinical track: Sarcoma
PO-0742 Target delineation conformity in extremity
STS within the UK phase II multi-centre IMRiS trial
H. Yang
1
, R. Simões
1
, F. Le Grange
2
, S. Forsyth
3
, D.
Eaton
1
, B. Seddon
2
1
Mount Vernon Cancer Centre, National Radiotherapy
Trials Quality Assurance Group, Northwood, United
Kingdom
2
University College Hospital, Sarcoma Unit, London,
United Kingdom
3
University College London, Cancer Research UK &
University College London Cancer Trials Centre, London,
United Kingdom
Purpose or Objective
Accurate target volume delineation is essential in the use
of intensity-modulated radiotherapy, where its role in the
treatment of bone and soft tissue sarcoma (STS) is being
investigated for the first time within the UK in IMRiS, a
prospective multi-centre phase II trial.
As part of radiotherapy trials quality assurance, we
determined the conformity of volume delineation of an
extremity STS benchmark training case in the post-
operative setting, and report target outlining variation in
relation to the trial protocol.
Material and Methods
The clinical history, operation/histology reports, pre-
operative magnetic resonance imaging and planning scans
of the training case were made available to participating
clinicians, who submitted outlines based on the protocol.
Both first and re-submissions were evaluated by two
clinicians, where GTV, CTV_6000 and CTV_5220 were
compared to the reference contours. The volumes were
quantitatively assessed using Dice Similarity Coefficient
(DSC) as:
, where A and B represent
regions of interest. Individual feedback based on trial
protocol variations was provided for all submissions.
Results
There was a total of 25 submissions from 23 centres.
Delineation of GTV, CTV_6000 and CTV_5220 were
deemed unacceptable according to the protocol in 5(20%),
10(40%) and 5(20%) submissions respectively.
The table details the unacceptable variations from the
protocol. All unacceptable GTV contours failed to
reconstruct the pre-operative disease in its entirety.
Incorrect margin expansion constituted the majority of the
unacceptable submissions for both CTVs.
The mean DSCs were systematically lower for the
unacceptable contours compared to accepted contours for
GTV [0.61 (range 0.55–0.66) vs 0.77 (range 0.60–0.81),
p<0.001], CTV_6000 [0.75 (range 0.53–0.82) vs 0.82 (range