ESTRO 36 Abstract Book

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S345 ESTRO 36 2017
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Radiation Therapy (SBRT) in 30 Gy single dose, for the
treatment of lung lesions.
Material and Methods
from December 2008 to Decembre 2015 a total of 201 lung
lesions in 160 patients affected by lung oligometastatic
disease or primary lung cancer were treated at our
Institution. All lesions were treated with a 30 Gy single
dose SBRT with a stereotactic body frame and a 3-D
conformal technique. One-hundred sixty-six (82.5%)
lesions were metastases, the remainder were primary lung
tumors; main primary tumor sites were lung and colon-
rectum (45.2% and 28.8%, respectively). Primary
endpoints were local progression-free survival (LPFS) and
toxicity, secondary endpoint were disease-free survival
(DFS), metastases-free survival (MFS), overall survival (OS)
and cancer specific survival (CSS).
Results
Median LPFS was not reached; 1- and 2-year LPFS were
88.2% and 77.5%, respectively. Overall response rate was
99.5%, complete response (CR) was achieved in 134
(66.6%) lesions, good or partial response in 43 cases
(21.3%), stable disease in 23 (11.4%) cases and progression
in one case. Local progression occurred in 34 (16.9%)
lesions after a median time of 17 months. Volume <20 cc
correlated with survival. Median survival time was 40
months (range 28-51 months) and 1- and 2-years OS were
84.7% and 63.9%, respectively. Median CSS was 48 months
(range 38-57 months) and 1- and 2-years CSS were 87.1%
and 67.6%, respectively. Median DFS and MFS were 16 and
22 months, respectively, while 1- and 2-years DFS and MFS
were 64.4% and 43.1% and 67% and 48.5%, respectively. On
the multivariate analysis CR was the most important factor
significantly associated with improvement and survival.
Acute toxicity occurred in 43 (21.3%) cases, with 10 (4.9%)
cases of Grade ≥3 toxicity. Late toxicity occurred in 80
(39.8%) lesions and the rate of Grade ≥3 toxicity was 5.9%
(12 lesions).
Conclusion
our study represents, at our knowledge, the largest series
in the literature on the use of SBRT 30 Gy single dose for
lung lesions. Our results confirm the safety and
effectiveness of this schedule, both in primary tumor and
metastases, achieving in selected patients, even long-
term survival. Single dose SBRT is characterized by high
patients’ compliance and it can be easily interfaced with
systemic therapies.
PO-0667 The differences between two groups of
patients with NSCLC depending on the imaging for
radiotherapy
A. Masarykova1, D. Scepanovic1, P. Bires1, D.
Lederleitner1, M. Pobijakova1, P. Povinec2
1 National Cancer Institute, Radiation Oncology,
Bratislava, Slovakia
2 BIONT PET Center, Nuclear Medicine, Bratislava,
Slovakia
Purpose or Objective
Background. – The target volumes of lung cancer are
underestimated on a standard three-dimensional positron
emission tomography/computed tomography (3D PET/CT)
scan when compared to target volumes defined on
respiratory gated or four-dimensional (4D) imaging. 4D
methods strive to achieve highly conformal radiotherapy
for lung tumours, in the presence of respiratory-induced
motion of tumours and normal tissues.
Purpose. - The differences between two groups of patients
with non small cell lung cancer depending on the imaging
for simulation of radiotherapy (3D vs 4D PET/CT), were
examined.
Material and Methods
A total of 58 patients with NSCLC (45 male and 13 female)
underwent an FDG-PET/CT for radiotherapy planning
purposes. There were 26 patients who performed 3D
PET/CT from 2011 to 2013 and 32 patients had 4D PET/CT
from 2014 to 2016 for the radiotherapy planning. Median
age was 63 (range, 49-89). All patients (58) had locally
advanced stage of NSCLC. Sixteen percent of patients had
atelectasis and 60% mediastinal lymph nodes. Squamous
cell lung cancer has been the most represented (72%
patients), a remnant was adenocarcinoma. All patients
were treated with radical radiotherapy. Dose prescription
ranged from 56 to 70.2Gy. Forty eight patients have
received chemotherapy sequentially.
Results
A comparison of the 3D and 4D volumes has shown that the
4D GTV was on average 58% smaller than the 3D GTV (p <
0.01). The 10 mm 4D planning target volume (PTV) was on
average 28% smaller than the 10 mm 3D PTV (p < 0.01).
There was not statistically significant difference between
two groups of patients regarding the rate of local
recurrence (p=0.3188). However, regarding the rate of
distant metastases there was statistically significant
difference in favour of the 3D imaging group (p=0.0455).
Seven patients in 3D imaging group and 9 from 4D imaging
group lived at the time of analysis. One year disease free
survival (DFS) was 42% for 3D imaging group and 37% for
4D imaging group (p=0.7903). Also, there was not
statistically significant difference regarding 1 year overall
survival (OS) between these two groups of patients
(3D=69% and 4D=50%, p=0.1834).
Conclusion
4D PET/CT is clinically a feasible method, to correct
respiratory motions in the thorax. Our analysis showed
that the definition of GTV and PTV are better in 4D
imaging group. However, there was not differences
between two groups of our patients regarding local
control, as well as DFS and OS.
PO-0668 Five-fraction SBRT for central NSCLC in-field
recurrences following high-dose conventional radiation
M.C. Repka1, N. Aghdam1, S. Kataria1, S. Suy1, E.
Anderson 2, S.P. Collins 1, B.T. Collins1, J.W. Lischalk1
1Georgetown University Hospital, Department of
Radiation Medicine, Washington, USA
2Georgetown University Hospital, Division of Pulmonary
and Critical Care Medicine, Washington, USA
Purpose or Objective
Local treatment options for patients with in-field non-
small cell lung cancer (NSCLC) recurrence following
conventionally fractionated external beam radiation
therapy (CF-EBRT) are limited. Stereotactic body
radiation therapy (SBRT) is a promising modality to
achieve local control, although toxicity remains a concern.
We report our experience using this novel technique.
Material and Methods
Patients previously treated with high-dose CF-EBRT (≥59.4
Gy, ≤3 Gy/fraction) for non-metastatic NSCLC who
underwent salvage SBRT for localized hilar or mediastinal
in-field recurrence were included in this analysis. Total
SBRT dose was stratified as low (<40 Gy) or high (≥40 Gy).
The Kaplan-Meier method was used to estimate local
control and overall survival. Durable local control was
defined as ≥12 months. Toxicity was scored per the CTC-
AE v4.0.
Results
Between November 2004 and August 2014, twenty patients
were treated with five-fraction robotic SBRT for central
in-field recurrence following CF-EBRT. Twelve recurrences
were identified within the mediastinum, and eight were
identified within the hilum. One-half of recurrences were
adenocarcinoma, while 35% of tumors were classified as
squamous cell carcinoma. The median interval between
the end of CF-EBRT and SBRT was 23.3 months (range: 2.6
- 93.6 months). The median CF-EBRT dose was 63 Gy
(range: 59.4 - 75 Gy), the median SBRT dose was 35 Gy
(range: 25 - 45 Gy), and the median total equivalent dose
in 2 Gy fractions (EQD2) was 116 Gy (range: 91.3 - 136.7
Gy). At a median follow-up of 12 months for all patients