ESTRO 36 Abstract Book

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S678 ESTRO 36 2017
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22 patients (9 prostate and 13 rectal cancer) received
pelvic re-irradiation with SBRT between 25.07.2011 and
20.04.2016. Median age was 66 years (range 30-85 years).
Median follow up was 18.5 months (range 3-58 months).
The median time between primary EBRT and SBRT re-
irradiation was 26 months (range 4-162 months). Median
SBRT dose was 30Gy/3# (range 24Gy-44Gy/3-5#). Prior
EBRT dose ranged from 20Gy/4#-70Gy/35# (median BED
63.72, range 30-84 assuming α/β = 10).
55% patients reported no measurable toxicity. No patients
experienced ≥Grade 3 toxicity.10/22 (45%) patients
experienced acute Grade 1/Grade 2 toxicities including
fatigue, sciatica, nausea, diarrhoea, rectal haemorrhage
and urinary symptoms. Only 1 patient experienced late
toxicity (asymptomatic pelvic insufficiency at 21 months
post SBRT, not requiring intervention).
The 1 and 2 year LC rate were 90%, 85% and DPFS rate 92%,
71% respectively. OS at 1 and 2 years were 91% and 71%
respectively.
Conclusion
Pelvic re-irradiation with SBRT is well tolerated and
effective at controlling local disease. No ≥Grade 3 toxicity
has been observed to date in our patient cohort although
longer term follow up is needed. Further research to
establish safe maximum cumulative doses to OARs for
pelvic re-irradiation is warranted.
EP-1274 Impact of concomitant radiotherapy boost in
locally advanced rectal cancer: dose escalation
M.A. Estornell1, D. Martinez2, V. Morillo3, M. López1, M.
Soler 1, J.L. Monroy1, A.V. Navarro1, A. Soler-Rodriguez 1
1 Hospital Universitario de la Ribera, Radiation Oncology
Department., Alzira, Spain
2 University Hospital.Valladolid, Department of Medical
Physics and Radiation Protection., Valladolid, Spain
3 Provincial Hospital. Castellon., Radiation Oncology
Department, Castellon., Spain
Purpose or Objective
The standard preoperative radiation dose for locally
advanced rectal cancer (LARC) is 45-50.4 Gy in 25-28
fractions. The aim of this study is to analyze the
correlation between escalation radiotherapy dose,
pathological complete clinical response (pCR) and
downstaging rate or even its relation with other
parameters of interest as toxicity, surgical margins,
locoregional recurrence-free survival (LRFSD), distant
metastasis free survival (DMFS) and overall survival (OS).
The efficacy of the dose escalation in terms of
pathological tumor response was evaluated as main end-
point.
Material and Methods
Between 2000 and 2013, 287 patients were treated with
preoperative chemoradiotherapy and surgical resection
for LARC in our hospital. 233 patients underwent the
standard chemoradiation schedule (median age 67 years;
stage III 73.3%, stage IV 1.7%; 41.1% low third rectum; 45-
50.4 Gy; 1.8-2 Gy/fraction) and 54 patients were treated
with simultaneous integrated boost-SIB (median age 66
years; stage III 74.5%, stage IV 1.8%; 21.8 % low third
rectum; 45 Gy to the pelvis volume with a 2.17 Gy SIB on
the tumor and macroscopical nodes).
Results
Dose escalation radiotherapy treatment reports a benefit
in pCR (9.5 % vs 20 % p= 0.029), tumoral downstaging rate
(42.7 % vs 60% p=0.020), nodal downstaging rate (62.9%
vs 7.7% p= 0.173) and ypT0 rate (10.3% vs 20 p= 0.049).
Complete microscopical resection increses on integrated
boost group (93.4% vs 98% statistically non-significant). In
the comparison between both groups by Contingency
Table , no statistically significant differences were found
on toxicity (G2 27.5% vs 37%; G3 3.1 % vs 9%) or surgical
complications (35.7% vs 40%). With a follow up of 181
months, the study reports a statistically significance on
disease free survival (56.1% vs 76.7 % p= 0.036 Kaplan-
Meier Test), and overall survival (21% vs 46.65 p=0.02) in
the SIB group. Locorregional recurrence-free survival also
improves but without statistical significance (88% vs 94.9
% Kaplan-Meir method). Tumoral downstaging was
considered as an independent factor on DFS (HR
1.914 p=0.004 Cox model.)
Conclusion
Escalation dose radiotherapy group achieved statistical
differences in pCR (ypT0 yN0), tumoral downstaging rate,
overall survival (OS) and distant disease free survival
(DFS). pCR could be considered as a prognostic factor on
OS. The variable tumoral downstaging demonstrate a
great value as an independent factor on DFS.
EP-1275 Patients with locally advanced rectal cancer
(larc): predictive factors of pathological response
S. Montrone1, A. Sainato1, R. Morganti2, C. Vivaldi3, B.
Manfredi1, C. Laliscia1, M. Cantarella1, G. Coraggio1, G.
Musettini 3, A. Gonnelli 1, G. Masi 3, P. Buccianti4, F.
Pasqualetti1, F. Paiar1
1OSPEDALE SANTA CHIARA, Radiotherapy, PISA, Italy
2OSPEDALE SANTA CHIARA, Oncology- Biostatistical
Consulting, PISA, Italy
3OSPEDALE SANTA CHIARA, Oncology, PISA, Italy
4OSPEDALE CISANELLO, Colon-rectal Surgery, PISA, Italy
Purpose or Objective
Preoperative RTCT followed by total mesorectal excision
(TME) is the standard of cure in patients (pts) with LARC.
After neoadjuvant RTCT the rate of complete pathologic
response (pCR) range between 15%-30% and many studies
are trying to find predictive factors of response in order
to select pts who could benefit from organ-preserving
options (local excision or “wait and see approach”). This
study aim to identify predictive factors of T and N
response of neoadjuvant RTCT.
Material and Methods
We analyzed retrospectively the data of 119 pts affected
by LARC (all of them cT3-T4 and 90,7% cN+) treated by
neoadjuvant RTCT (50.4 Gy in 28 FF + capecitabine 1650
mg/mq/day) followed by TME surgery, between January
2008 and April 2014, in Pisa Universitary Hospital. Based
on MR-images, we analyzed T characteristics (clinical
stage, site respect to anal verge, cranio-caudal extension,
number of involved quadrants, volume, distance from
mesorectal fascia) and N characteristics (clinical stage,
number of nodes with short axis ≥ 5mm and distance from
mesorectal fascia), at diagnosis and at restaging (before
surgery) and their variations, in order to find a correlation
with pathological T and N stage.
Results
All pts completed planned RTCT. The overall pCR rate was
25,2%. In the multivariate analysis (T parameters) only the
number of involved quadrants (p=0,002) and the cranio-
caudal extension at diagnosis (p=0,043) resulted to be
predictive of pCR. At the pathological findings, the rate
of pN+ was 21% compared to 90,7% of the clinical stage. In
the multivariate analysis (N parameters) only the number
of nodes (short axis ≥ 5mm) at diagnosis was shown to be
predictive of pN0, both as a continuous variable (p=0,004)
that as dichotomous variable (p<0,0001) with a threshold
value of 3 nodes. T and N variations, at pre-surgical
restaging, were not significantly correlated to
pathological outcomes.
Conclusion
To know predictive factors of pCR and pN0 after
neoadjuvant RTCT could influence the surgical approach.
T size and T distance from the anal verge seem to be two
well established predictive factors of response . Based on
our retrospective analysis, we can add that the number of
involved quadrants and the number of nodes (≥5mm) at
diagnosis could be additional predictive parameters.
EP-1276 Clinic and radiobiology of hypofractionated
radiotherapy for metastatic liver tumors. Pilot results.