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S165
ESTRO 36
_______________________________________________________________________________________________
Gambacorta
1
, R. Autorino
1
, M. Campitelli
1
, A. Testa
3
, G.
Chiloiro
1
, J. Lenkowicz
1
, C. Casà
1
, G. Scambia
3
, L.
Bonomo
2
, V. Valentini
1
1
Università Cattolica del Sacro Cuore -Policlinico A.
Gemelli, Radiation Oncology Department , Rome, Italy
2
Università Cattolica del Sacro Cuore -Policlinico A.
Gemelli, Radiology Department, Rome, Italy
3
Università Cattolica del Sacro Cuore -Policlinico A.
Gemelli, Gynecology Department, Rome, Italy
Purpose or Objective
Standard treatment in cervical cancer (CC) is largely based
on chemoradiation (CRT) for locally advanced stages. The
role of surgery after a first time of CRT is limited to
selected protocols. In such cases it is possible to assess the
pathological complete response (PCR). A fractal is an
object having geometric shape that can be divided into
subparts, each of which is a reduced copy of the whole.
This property, known as self-similarity, can be measured
by the Fractal Dimension (FD). Aim of this study is finding
an enhanced by FD radiomics signature detecting patients
with PCR.
Material and Methods
Pathologically proven CC patients underwent to CRT after
MR definition of the local stage. T2 High-Resolution images
were used for delineating GTV. A home-made software
was used for assessing radiomics features after pre-
processing images by Laplacian of Gaussian (LoG) filter
and tuning its σ parameter, and for extracting fractal
dimension (FD) on raw images. FD was extracted at
different threshold levels considering all deciles between
10% and 100% of signal intervals inside the GTV volume
analyzed slice by slice by using the box-counting
technique. Stepwise logistic regression (SLR) models were
used for predicting PCR using FIGO Stage, 1
st
order
features (skewness, kurtosis, entropy) and different
thresholds for FD. AUC of ROC and calibration, were
determined for internal validation.
Results
177 patients were retrospectively recruited (FIGO stage Ib
– IVb). FD was the only significant predictor for the whole
dataset in SLR (MaxDF@10%: P-Value<0.001, MinDF@0-
90%: P-Value<0.05, see fig. 1). AUC of ROC was 0.70 with
not significant deviance at calibration. After selecting
patients according to the MR pixel spacing (PS) the most
numerous group was found in patients having PS=0.58mm
(69 patients). A new SLR model showed significance of
entropy (σ=2.36mm, P-Value<0.05), kurtosis (σ=1.23mm,
P-Value<0.01) and MinDF@0-90% (P-Value<0.01), with AUC
of ROC=0.80 and not significant deviance in calibration.
Conclusion
Radiomics can be an interesting perspective for detecting
patients with CC who will show PCR and subsequently
could result in better prognosis. Even considering that CRT
followed by surgery is not a standard treatment this
workflow gave us the chance to analyze the relationship
between radiomics signature and pathological findings,
not feasible in CRT alone. An external validation of the
signature is planned to evaluate the stability of this model
by using different MR scanners at diagnosis time.
OC-0318 Hematological toxicity during bowel sparing
IMRT: Exploratory analysis from PARCER Phase III trial.
S. Lewis
1
, S. Chopra
1
, P. Naga
1
, N. Bharadwaj
1
, E.
Dandpani
1
, U. Mahantshetty
1
, R. Engineer
1
, J. Swamidas
1
,
J. Ghosh
2
, S. Gupta
2
, S. Shrivastava
1
1
Tata memorial centre, radiation oncology,
Mumbai,India
2
Tata memorial centre, medical oncology, Mumbai,India
Purpose or Objective
To report acute hematological toxicity (HT) and dose
volume correlates in patients receiving postoperative
bowel sparing intensity-modulated radiotherapy (IMRT)
and cisplatin within a Phase III trial for late bowel toxicity
reduction in patients with cervical cancer.
Material and Methods
Clinical database of Phase III trial (NCT01279135) that
randomizes patients to IMRT (Tomotherapy) and 3DCRT
was searched to select patient strata that received IMRT
(50 Gy/25#/5 wks) and concurrent cisplatin (40 mg/m
2
)
from Jan, 2011 to Jun, 2016. The IMRT planning aimed at
restricting V15 and V40 Small Bowel to ≤ 200 and 100 cc
respectively. No prospective bone marrow (BM)
constraints were applied. The data base was reviewed to
determine worst grade of HT toxicity. IMRT planning scans
were dearchived and pelvic BM was delineated in 2 sets;
whole bone (WB), and freehand (FH) inner cavity of bone
from top of L3 vertebra to ischial tuberosity. Various BM
sub-volumes namely whole pelvis + lumbar (WPL), lumbar
vertebra, sacrum, ilium, ischium, femoral head and neck,
whole pelvis (WP), lower pelvis(LP) were contoured and
dose volume histograms (DVH) parameters (V
5
, V10, V20,