ESTRO 36 Abstract Book

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S685 ESTRO 36
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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. Gonnelli1, G. Masi3, P. Buccianti4, F.
Pasqualetti1, F. Paiar1
1 OSPEDALE SANTA CHIARA, Radiotherapy, PISA, Italy
2 OSPEDALE SANTA CHIARA, Oncology- Biostatistical
Consulting, PISA, Italy
3 OSPEDALE SANTA CHIARA, Oncology, PISA, Italy
4 OSPEDALE 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.
T. Latusek1, L. Miszczyk1, J. Rembak-Szynkiewicz2
1Maria Sklodowska-Curie Memorial Cancer Center and
Institute of Oncology, Radiotherapy, Gliwice, Poland
2Maria Sklodowska-Curie Memorial Cancer Center and
Institute of Oncology, Radiology, Gliwice, Poland
Purpose or Objective
Liver metastases are the most common tumor in this organ
and majority of them are metastases of adenocarcinomas
of the gastrointestnal tract. Radiotherapy is often used as
alternative method to surgery. Due to promising results of
the extracranial stereotactic radiotherapy used to treat
primary metastatic tumors of the lung it is applied also for
primary or metastatic liver lessions. The aim was to
evaluate the efficacy of hypofractionated radiotherapy for
metastatic liver tumors.
Material and Methods
Clinical material consists of 28 liver malignant liver lesions
treated with stereotactic hypofractonated radiotherapy at
the Cancer Center, MSC Memorial Institute in Gliwice.
Tumor size and volume reflecting initial numer of cancer
cells were estimated Patient’s age was in the range of 33-
84 years (median 64). All liver metastases were irradiated
with a total dose of 45 Gy given in 3 fractions in 8 days.
Method of respiratory gating and CyberKnife were used.
Follow-up ranges from 1 to 12 months.
Results
Early 3-months results show 64% regression (14 cases), 4%
stagnation (1 case) and 32% progression (7- cases).
However, total dose of 45 Gy does not result in early
complete regression. Even in case of „twin tumores” with
the same initial volume (the same initial numer of cancer
cells) suprisingly showed different response: regression vs
progression what is difficult to interpret from the
radiobiological point of view.
Conclusion
Total dose of 45 Gy should result in complete regression,
but it doesn’t. From theoretical calculation it seem that
D10 dose may arise even to 21 Gy what seems not very
logical. It can not be excluded that reason for such
early answer could be „Hallo Phenomenon”- inflamation
around irradiated area suggesting false stagnation or even
regression.
EP-1277 Optimising RT dose for anal cancer – the
development of three clinical trials in one platform
D. Sebag-Montefiore1, R. Adams 2, S. Bell3, L. Berkman4,
D. Gilbert5, R. Glynne-Joones6, V. Goh7, W. Gregory 3, M.
Harrison6, L. Kachnic8, M. Lee9, L. McParland3, R.
Muirhead 10, B. O'Neil11, G. Hutchins1, S. Rao12, A.
Renehan13 , A. Smith3, G. Velikova1, M. Hawkins 14
1Leeds Institute of Cancer and Pathology University of
Leeds, Leeds Cancer Centre, Leeds, United Kingdom
2Cardiff University and School of Medicine, Velindre
Hospital, Cardiff, United Kingdom
3Leeds Institute of Clinical Trials Research, Clinical
Trials Research Unit, Leeds, United Kingdom
4NCRI, Consumer Forum, London, United Kingdom