ESTRO 36 Abstract Book

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S195 ESTRO 36 2017
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Figure: Descriptive statistics of D98 of pathologic nodes
according to regions.
Ext: external iliac, Int: internal iliac, Ing: inguinal, Com:
common iliac, Obt: obturator, Sac: presacral, Cent:
central (pararactal or parametrial). Red cross: mean
value, blue diamond: minimal and maximal values, lower
limit of the box: first quartile, upper limit of the box: third
quartile, central horizontal bar: median, whiskers: from
minimal value to 1.5 x box length.
Thus, to deliver a cumulative EQD2 ≥60 Gy to pathologic
nodes accounting a pelvic external beam radiation dose of
45 Gy in 25 fractions (44.3 in EQD2) and these estimations,
we propose nodal SIB of 2.2 Gy x 25 (55 Gy, 55.9 in EQD2)
in the obturator, external and internal iliac nodes, 2.3 Gy
x 25 (57.5 Gy, 58.9 in EQD2) in the common iliac nodes,
and 2.4 Gy x 25 (60 Gy, 62 Gy in EQD210) in the para-aortic
nodes (where the BT contribution can be considered as
negligible).Conclusion
The contribution of brachytherapy to the treatment of
pelvic nodes is significant: around 5 Gy in the obturator,
internal iliac, and external iliac areas and 2.5 Gy in the
common iliac, allowing the use of simultaneous integrated
boost. However, important individual variations have
been observed and evaluation of the genuine individual
brachytherapy contribution is recommended.
OC-0366 Cervical cancer with bladder invasion:
outcomes and vesicovaginal fistula prognostic factors
R. Sun1, R. Mazeron1, I. Koubaa2, I. Dumas3, C. Baratiny1,
F. Monnot1, P. Maroun1, E. Deutsch1, P. Morice4, C. Haie-
Meder 1, C. Chargari1
1 Gustave Roussy, Radiation oncology, Villejuif, France
2 Gustave Roussy, Radiology, Villejuif, France
3 Gustave Roussy, Medical physics, Villejuif, France
4 Gustave Roussy, Surgery, Villejuif, France
Purpose or Objective
Although brachytherapy (BT) is a mainstay of the
treatment of locally advanced cervical cancer, there are
only scarce data on its efficiency in cervical cancer with
bladder invasion. The aims were to report the treatment
outcomes in this particular situation, as well as
vesicovaginal fistula (VVF) incidence and its prognostic
factors.
Material and Methods
Consecutive patients with locally advanced cervical
cancer and bladder invasion treated in our institution from
1989 to 2015 were identified. Demographic and tumor
features, treatment characteristics, VVF rate,
progression-free survival (PFS), local control rate (LCR),
and overall survival (OS) were reviewed. Baseline
magnetic resonance imaging (MRI) scans reviews were
carried out blind to the clinical data with focus on
radiological parameters potentially correlated to the risk
of VVF (necrosis, tumor height of bladder involvement,
tumor volume). Times were calculated from the date of
diagnosis. Survival were estimated using the Kaplan-Meier
method and the Cox proportional hazards model.
Results
Seventy-one patients were identified. Bladder invasion
was diagnosed either on imaging in 59% or
endoscopically/histologically proven in 41%. All patients
received pelvic external beam radiotherapy (EBRT), 45 Gy
in 25 fractions ± nodal boost to macroscopically involved
lymph nodes. Nineteen of the 21 patients with para-aortic
nodal metastases received para-aortic EBRT. Concurrent
platinum-based chemotherapy (CT) was used in 76%,
neoadjuvant CT was used in 14%. After EBRT, 64 patients
(90%) received uterovaginal BT (low-dose rate in 48%,
pulsed-dose rate in 52%). Eight patients had VVF at
diagnosis. Among the 63 patients without VVF at diagnosis,
14 patients (22.2%) developed VVF later on: four before
(28.6%) and ten (71.4%) after BT (median time to onset:
3.5 months after the start of EBRT). Twelve of the 22
patients (54.5%) who presented VVF, either at diagnosis or
during follow-up, needed surgery (urinary or bowel
diversion ± pelvectomy). Estimated OS, PFS and LCR at 2
years were 57.3% (44.9-68.8), 45.0% (32.3-58.5) and 69.1%
(54.4-80.7) respectively. Presence of para-aortic nodal
metastases was significantly associated with poorer OS on
multivariate analysis (HR=4, p<0.001). Only the presence
of necrosis in the anterior part of the tumor on baseline
MRI was strongly associated with the risk of subsequent
VVF (57% vs O% at 1 year, HR=16.7, p=0.011 on a
multivariate analysis taking into account the tumor
volume). No correlation was found between bladder dose
and risk of VVF.
Conclusion
A curative intent strategy including BT as part of local
treatment is feasible in patients with bladder invasion,
with a rate of 22% of post-treatment VVF. MRI has a strong
predictive value of VVF occurrence. This result has to be
confirmed in an independent cohort. Prognosis remains
poor in regard to lower-staged lesions, with a high risk of
out-of-field failure. Intensification of systemic therapies
should be considered.
OC-0367 Dose-response curve for vaginal stenosis.
Final results of a prospective study.
M. Federico1, A. Tornero2, S. Torres2, B. Pinar1, M. Rey
Baltar1, M. Lloret1, P. Lara1
1Hospital Universitario de Gran Canaria Dr. Negrín,
Radiation Oncology, Las Palmas de Gran Canaria- Ca,
Spain