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ESTRO 36
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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).
Conclusion
BED was significantly higher in patients who received SBRT
compared with IMRT. Patients who receive non-
brachytherapy boosts tend to have factors correlated with
poor prognosis. In a propensity matched analysis, those
who received SBRT had equal OS in compared with
brachytherapy, but those who received IMRT had worse OS
than patients who received brachytherapy boost.
Prospective studies are needed to validate the use of SBRT
as boost technique in selected patients who are not
candidates for brachytherapy.
PV-0550 Combined high dose radiation and tyrosine
kinase inhibitors in renal cell carcinoma: a phase I trial
K. De Wolf
1
, S. Rottey
2
, K. Vermaelen
3
, K. Decaestecker
4
,
N. Sundahl
5
, G. De Meerleer
6
, N. Lumen
4
, V. Fonteyne
1
,
D. De Maeseneer
2
, P. Ost
5
1
University Hospital Ghent, radiotherapy and oncology,
Gent, Belgium
2
University Hospital Ghent, medical oncology, Ghent,
Belgium
3
University Hospital Ghent, laboratory of
immunoregulation and mucosal immunology, Gent,
Belgium
4
University Hospital Ghent, urology, Gent, Belgium
5
University Hospital Ghent, radiotherapy and oncology,
Ghent, Belgium
6
University Hospital Leuven, radiotherapy and oncology,
Leuven, Belgium
Purpose or Objective
Tyrosine kinase inhibitors (TKIs) targeti ng vascular
endothelial growth factor are currently standard of care
for patients with metastatic renal cell carcinoma (RCC) in
first and second line. Nevertheless, durable responses are
rare and most patients eventually develop progressive
disease. New therapeutic approaches are needed to
improve durable disease control. We studied a
combination of high-dose radiotherapy and TKIs because
of the immunomodulatory properties of both therapies.
The primary endpoint was to determine the maximum
tolerated radiotherapy doses. Secondary endpoints were
local control and tumour response in non-irradiated
lesions as per RECIST 1.1 or as per MD Anderson (MDA)
criteria for bone lesions next to progression-free survival.
Material and Methods
Treatment-naïve patients with clear cell metastatic RCC,
who had undergone cytoreductive treatment of their RCC
at least 6 weeks prior to inclusion, were treated with a
first line TKI, pazopanib, during a 1-week run-in period.
Stereotactic body radiotherapy (SBRT) was delivered to
the largest metastatic lesion concurrently with pazopanib
administration at day 8. SBRT doses were escalated in 3