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ESTRO 36 2017
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Results
Three hundred forty-one patients were treated by IMRT
for gynecological or anal cancer between 2007 and 2014.
Fifteen patients had at least one pelvic fracture occurred
after external radiotherapy, an overall incidence of 4.4%.
The age and menopausal status were linked to an
increased fracture risk (p = 0.0274 and p <0.0001,
respectively). The site of the primary tumor
(gynecological or anal canal) was not related to an excess
risk of fracture. The median maximum dose received at
the fracture site was 50.3 Gy (range, 40.8-68.4).
Conclusion
The incidence of pelvic fracture after IMRT was low but
more important after age 50 and postmenopausal
patients. The pre-therapeutic assessment of bone density
by densitometry could be relevant for these patients.
PO-0717 Role of Radiation Therapy in Vulvar Cancer
Patients with One or More Positive Inguinal Lymph
Nodes
M.J. Kanis
1
, N. Rydzewski
2
, E.D. Donnelly
2
, J.R. Lurain
1
,
J. Strauss
2
1
Northwestern University, Gynecologic Oncology,
Chicago, USA
2
Northwestern University, Radiation Oncology, Chicago,
USA
Purpose or Objective
Using a large national cancer database, we aimed to
investigate outcomes for women with one or more than
one positive inguinal lymph nodes in squamous cell vulvar
cancer who were treated with external beam radiation
therapy (EBRT) compared to patients that received no
adjuvant radiation.
Material and Methods
The National Cancer Database (NCDB) was queried to
identify women with vulvar cancer that had one or more
positive lymph nodes diagnosed between 2004 and 2012.
All patients were surgically staged. Chi-square tests and
multivariate logistic regression were performed to analyze
factors associated with receipt of radiation. Survival
analysis was performed using overall survival confidence
intervals (CI), log-rank test, Kaplan-Meier estimates, and
Cox proportional hazards regression.
Results
Of 2,859 patients identified, 1,024 (36%) received no
adjuvant radiation compared to 1,835 (64%) who received
EBRT. Mean number of regional nodes examined was 12.7
for the no radiation group and 12.4 for the EBRT group.
Significant predictors of receiving EBRT over no radiation
included age younger than 70 and a closer distance to the
hospital. 5-year overall survival (OS) for the entire cohort
was 40% (95% CI, 38%-42%). 5-year OS for 1 node positive
was 47% (95% CI, 42%-52%) for no EBRT and 53% (95% CI,
49%-57%) in those receiving EBRT. 5-year OS for 2 or more
nodes positive was 19% (95% CI, 15%-23%) for no EBRT and
35% (95% CI, 32%-38%) for EBRT. Kaplan-Meier estimates
with log-rank test for equality of survivor functions
showed improved survival with EBRT in 1 node positive
(p=0.0129) and 2 or more nodes positive (p<0.0001). Cox
survival multivariate regression model controlling for
confounding variables observed a Hazard Ratio (HR) for
EBRT compared to no radiation of 0.88 (p=0.122) for 1
node positive, and 0.58 (p<0.001) for 2 or more nodes
positive. HR without covariates for 1 node positive was
0.82 (p=0.008).
Conclusion
In a large national cancer database, receipt of EBRT was
associated with improved survival in woman with vulvar
cancer and two or more positive inguinal nodes. In
patients with one positive node, a survival advantage was
seen using Kaplan-Meier estimates and Cox survival model,
but lost statistical significance in a multivariate regression
model. These data lend support to the role of EBRT in the
management of node positive vulvar cancer. Further
research with more detail of other known prognostic
factors are needed to validate these findings.
PO-0718 18-FDG PET/CT parameters to predict survival
and recurrence in cervical cancer
N. Scher
1
, F. Herrera
1
, A. Depeursinge
2
, T. Breuneval
1
, J.
Bourhis
1
, J. Prior
1
, M. Ozsahin
1
, J. Castelli
1
1
Centre Hospitalier Universitaire Vaudois, Radiation
Oncology department, Lausanne Vaud, Switzerland
2
Ecole Polytechnique Fédérale, imaging, Lausanne Vaud,
Switzerland
Purpose or Objective
In the context of locally advanced cervical cancer (LACC)
treated with chemo-radiotherapy, the aim of this study
was to identify the best predictive 18-FDG PET-based
parameters for local-control, disease free- and overall
survival, testing different threshold to compute MTV and
TLG.
Material and Methods
Thirty-seven patients treated with standard chemo-
radiotherapy followed by brachytherapy underwent a pre-
therapy 18-FDG PET/CT. Using different thresholds (from
2.5 to 8 mg/mL and from 30% to 70% of SUVMax), the
following PET parameters were computed: maximum
standardized uptake value (SUVmax), mean standardized
uptake value (SUVmean), metabolic tumor volume (MTV)
for primary tumor and lymph nodes, total lesion glycolysis
(TLG), and a new parameter combining the MTV and the
Euclidian distance between lymph nodes and the primary
tumor, namely metabolic nodes distance (MND).
Correlation between PET and clinical parameters with
clinical outcome (OS, DFS and LRC) was assessed using
univariate and multivariate Cox-model. An internal
validation of the final model was performed using a cross
validation with 5 folds.
Results
The median follow-up was 52 months (range: 7 - 128). The
3-year OS, DFS and LRC were 71.2 % (95% Confidence
Interval (95CI): 56%–86%), 64.1 % (95CI: 48–80) and 69.4 %
(95CI: 53 –84) respectively. In univariate analysis, PET/CT
parameters associated with OS and DFS were: MTV Tumor,
TLG Tumor, TLG Lymph Nodes, and MND. The most
predictive threshold segmentation for MTV and TLG was
48 % of SUV max for the primary tumor and 30% for the
lymph nodes. In multivariate Cox analysis, the TLG T 48%
and MND were the two independent risk factor for OS
(p<0.01), DFS (p<0.01) and LRC (p=0.046). The c-index of
the model for OS, DFS and LRC (adjusted after cross