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S289
ESTRO 36 2017
_______________________________________________________________________________________________
Purpose or Objective
The optimal adjuvant management of Stage IA
endometrial cancer with serous or clear cell histology is
controversial. The objective of this study is to explore the
role of adjuvant therapy in this population and identify
patient characteristics of those suitable for observation.
Material and Methods
Retrospective chart reviews for consecutive patients who
underwent hysterectomy for FIGO Stage IA endometrial
cancer with serous or clear cell histology between 2004-
2015 were conducted in 6 academic centres. After
excluding patients who were upstaged following surgery,
a pooled analysis was performed for relevant endpoints.
Results
A total of 414 patients with a median age of 67 years(range
41-90) met the inclusion criteria. The most common
histology were pure serous (64%,n=266) followed by mixed
(27%,n=112) and pure clear cell (9%,n=36). Myometrial
invasion was identified in 54%(n=222). Most patients
underwent some surgical staging including sampling of
pelvic lymph node (LN) (81%,n=335), para-aortic LN
(45%,n=146), omentum (58%,n=239) and peritoneal
washing (62%,n=219). Only 23% of patients (n=95) were
considered to have adequate staging (pre-defined as ≥10
pelvic LN, sampled para-aortic LN and omentum). Thirty-
four percent of patients (n=140) received adjuvant
chemotherapy and carboplatin/paclitaxel was most
commonly used (77%, n=108). Adjuvant RT was delivered
to 47%(n=178) of patients (external beam alone 16%,n=29;
brachytherapy alone 56%, n=99; both 28%,n=50). The
median follow-up was 2.7 years (range 0-12). Among
patients who did not received any adjuvant treatment, 5-
year actuarial estimates were as follows: local control(LC)
88%, regional control(RC) 93%, distant failure(DF) 15%,
disease free survival(DFS) 74%, cancer specific
survival(CSS) 91% and overall survival(OS) 82%. Adequate
staging was associated with better CSS in patients who did
not have adjuvant treatment (100% vs. 87%, logrank
p=0.0035). Adjuvant RT was associated with better LC(5-
year 96% vs. 84%, HR 0.32,logrank p=0.014). The 5-year
RC was 93%, which was not found to be significantly
improved by external beam RT. Adjuvant chemotherapy
was associated with better LC(5-year 94% vs. 84%,HR 0.29,
logrank p=0.0079), DFS(5-year 79% vs. 71%, HR 0.47,
logrank p=0.033), but not for RC, DF or CSS. The delivery
of at least 5 cycles of chemotherapy, was associated with
a trend towards better LC (4-year 98% vs. 88%, HR
0.18,logrank p=0.090). Myometrial invasion,
lymphovascular invasion, histological subtypes and the
proportion of type II component were not found to be
significant prognostic factors for LC, RR, DF or CSS.
Conclusion
Adjuvant radiotherapy and chemotherapy were associated
with better LC and DFS but not for RC, DF or CSS for stage
IA serous and clear cell uterine cancer. Observation may
be an acceptable strategy in patients who have had
adequate surgical staging.
PV-0549 National Cancer Data Base Analysis of SBRT,
IMRT, and Brachytherapy Boost for Cervical Cancer
M. Ludwig
1
, M. Bonnen
1
, J. Shiao
2
, B. O'Donnell
3
, T.
Pezzi
1
, N. Waheed
1
, S. Sharma
1
1
Baylor College of Medicine, Radiation Oncology,
Houston, USA
2
University of Texas San Antonio, Radiation Oncology,
San Antonio, USA
3
University of Texas Houston, Radiation Oncology,
Houston, USA
Purpose or Objective
Brachytherapy is a vital component of curative
radiotherapy for cervical cancer, but in certain patients,
brachytherapy is not feasible because of inaccessibility of
brachytherapy comorbidities, patient refusal, or
unfavorable anatomy. Our objective was to determine if
stereotactic body radiotherapy (SBRT) and intensity-
modulated radiation therapy (IMRT) boost techniques have
comparable overall survival (OS) with brachytherapy
boosts for patients with cervical cancer when adjusted for
known prognostic factors.
Material and Methods
We used the National Cancer Data Base to study women
who received radiation between 2004 and 2013 diagnosed
with squamous cell carcinoma, adenocarcinoma or
adenosquamous carcinoma of the cervix. Biological
effective doses (BED) were calculated for both SBRT and
IMRT treatments. A logistic regression model was built to
identify factors associated with the receipt of SBRT and
IMRT. Correlates of OS were determined using Kaplan-
Meier and propensity score matching.
Results
Of all 15,905 patients, 14,394 (90.5%) received
brachytherapy, 42 (0.8%) received SBRT, and 1468 (9.2%)
received IMRT. A multivariable binary logistic regression
model identified the following factors associated with
receipt of SBRT: advancing age, higher income status,
Asian ethnicity, and FIGO Stage III cervical cancer. The
following factors were associated with receipt of IMRT:
advancing age, treatment at an academic/research
program, treatment at an integrated network cancer
program, private insurance, lower income status, FIGO
Stage III, IVA, and IVB cervical cancer, positive nodal
status, metastatic disease, and not receiving
chemotherapy as part of the first course of treatment.
Median BED was 63.7 Gy for patients treated with IMRT
and 75.5 Gy for SBRT (p < 0.001). The median follow-up
was 4.8 years. Median survival was 99.1 months (95% CI:
94.4 – 103.8 months), 30.6 months (95% CI: 20.5 – 40.6.
months), and 29.8 months (95% CI: 26.0 – 34.7 months) for
patients who received brachytherapy, SBRT, and IMRT
boost, respectively. Using propensity score matching,
there was no significant difference in OS for patients who
received SBRT boost vs. brachytherapy boost (HR 1.477;
95% CI 0.746 – 2.926; p = 0.263). IMRT boost patients were
also matched and did significantly worse than those who
received brachytherapy boost (HR 1.455, 95% CI 1.300 -
1.628; p <0.001).