ESTRO 36 Abstract Book

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S650 ESTRO 36 2017
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S.J. Ahn1, W. Jeon1, Y.C. Kim2, I.J. Oh2, J.U. Jeong1, M.S.
Yoon 1, J.Y. Song1 , T.K. Nam1, W.K. Chung1
1 Chonnam National University Medical School, Radiation
Oncology, Hwasun, Korea Republic of
2 Chonnam National University Medical School,
Pulmonology, Hwasun, Korea Republic of
Purpose or Objective
Stereotactic ablative radiotherapy (SABR) has been
replacing the role of surgery in the management of
operable stage I non-small cell lung cancer (NSCLC). We
aim to assess the outcomes of SABR performed in these
patients.
Material and Methods
Fifty-six patients with clinical stage I NSCLC who
underwent SABR between Nov. 2006 and Jan. 2015 were
analyzed retrospectively. Eligibility for SABR in our
practice was tumor size less than 5cm and peripherally
located tumors. Age ranged 54 to 87 (median 74) and male
to female was 43 to13. ECOG score was 0 in 16, 1 in 25,
and 2 in 15 patients, respectively. Adenocarcinoma was 24
and squamous cell carcinoma was 25. We defined the
patients as medically inoperable based on the lung
function (baseline FEV1 < 40% predicted, DLCO < 50%
predicted), age > 75 yrs & PS >2. Intensity-modulated
radiosurgery was planned and delivered consecutively
with median 60 Gy (range, 55 – 64 Gy) in 3 to 8 fractions.
Median follow-up time was 23.8 months (range, 1.9 - 93.5
months).
Results
The 3-year and 5-year overall (OS) rate of all 56 patients
was 82.9% and 82.9% and progression free survival (PFS)
was 54.8% and 45.6%, respectively. The possible
prognostic parameters such as tumor size, tumor location
(upper vs. lower lobe), gross tumor volume (GTV), SUVmax
of the primary tumor, BED, and operability were entered
into analysis regarding on OS or PFS. PFS was significantly
dependent on the tumor location (p=0.047), tumor size
(>3cm, p< 0.001), GTV (>19cm 3, p=0.02), and operability.
5-yr PFS of operable (n=42) and inoperable (n=14) was
52.9% vs. 31.3% (p=0.022). OS was significantly dependent
on the tumor size (p=0.046) and BED (>150 Gy, p=0.022).
5-yr OS of operable and inoperable patients was 90.1% vs.
67.7% (p=0.084), respectively.
Conclusion
SABR shows the survival outcomes similar to surgery in
operable stage I NSCLC. Tumor size (>3cm) was the most
significant prognostic factor affecting to OS. We need to
increase the BED of SABR over 150 Gy in cases with
tolerable lung compliances.
EP-1215 Risk factors of radiation pneumonitis after
SRT: the usefulness of the PTV to lung volume ratio.
T. Ueyama1, T. Arimura1, K. Takumi1, F. Nakamura1, R.
Higashi1 , S. Ito1, Y. Fukukura1, T. Umanodan1, M.
Nakajo 1, C. Koriyama 2, T. Yoshiura1
1 Kagoshima University, Radiology, Kagoshima, Japan
2 Kagoshima University, Epidemiology, Kagoshima, Japan
Purpose or Objective
To investigate the risk factors of severe radiation
pneumonitis (RP) after stereotactic radiation therapy
(SRT) for lung tumors.
Material and Methods
We retrospectively evaluated 68 lung tumors in 63 patients
treated with SRT between 2010 and 2015. RP was graded
according to the National Cancer Institute- Common
Terminology Criteria for Adverse Events (NCI-CTCAE)
version.4.0. SRT was delivered at 7.0-12.0Gy fractions
once daily to a total of 48-64Gy (median 50). Univariate
and multivariate analyses were performed to assess
patient- and treatment-related factors, including age,
gender, smoking index, pulmonary function, tumor
location, the value of serum Krebs von den Lungen-6 (KL-
6), and dose-volume metrics: V5, V10, V20, V30, V40, and
VS5, V2 of contralateral lung, homogeneity index of PTV
(HI), dose of PTV, mean lung dose (MLD), contralateral
MLD, PTV volume, lung volume, the PTV/Lung volume
ratio (PTV/Lung) . The value of PTV/Lung in predicting RP
was also analyzed with receiver operating characteristic
(ROC) curves.
Results
The median follow-up was 21 months. Ten patients (14.7%)
developed with RP of symptomatic grade2-5 after
completing SRT and three patients (4.4%) died from RP.
On univariate analysis, V10, V20, PTV volume, and
PTV/Lung were significantly associated with occurrence of
RP≧grade2 (P<0.05, respectively). On multivariate
analysis, only PTV/Lung was statistically significant
(P<0.05). ROC curves indicated that severe RP could be
predicted using PTV/Lung (area under curve: 0.88, CI:
0.78-0.95, cut off value: 1.09, sensitivity: 90.0%,
specificity: 72.4%)
Conclusion
PTV/Lung could well predict the risk for severe RP after
SRT.
EP-1216 Impact of the radiation dose on the pulmonary
perfusion assessed using lung scintigraphy
B. De Bari1, S. Godin2, M. Zeverino3, L. Deantonio4, T.
Breuneval2, J. Prior5, J. Bourhis2, R. Moeckli3, M. Ozsahin2
1Hôpital Univ. Jean Minjoz, Radiation Oncology,
Besançon, France
2Centre Hospitalier Universitaire Vaudois, Radiation
Oncology, Lausanne, Switzerland
3Centre Hospitalier Universitaire Vaudois, Medical
Physics, Lausanne, Switzerland
4University Hospital "Maggiore della Carità-", Radiation
Oncology, Novara, Italy
5Centre Hospitalier Universitaire Vaudois, Nuclear
Medicine, Lausanne, Switzerland
Purpose or Objective
We aimed at evaluating the impact of the dose of
radiotherapy on lung function (LF). LF variations were
evaluated by integrating SPECT/CT pulmonary perfusion
before and after radiotherapy (RT) in patients treated
with radiotherapy +/- chemotherapy for a lung tumor.
Material and Methods
Between 06.2014 and 09.2015, 15 pts presenting a primary
(n = 11) or secondary (n = 4) lung cancer were treated with
radiotherapy +/- chemotherapy (10x3 Gy, 1 pt; 13x3 Gy, 1
pt ; 6x8 Gy, 1 pt; 7x7.5 Gy, 1 pt; 3x18 Gy, 1 pt; 12x4.5 Gy,
1 pt; 5x11 Gy, 1 pt; 30x2Gy 4pts; 33x2Gy, 2 pts; 5x12Gy,
1pt; 12x5Gy, 1 pt). Three pts were treated in a context of
re-irradiation. All patients received a SPECT/CT to
evaluate the LF before and three months after
radiotherapy, which was co-registered with the planning
phase of the simulation CT-scan. For pts treated with
hypo-fractionated regimens, the biological equivalent
dose at 2 Gy/fraction (EQD2) was calculated (alpha / beta
= 10 Gy for acute toxicity). Isodoses (5, 10, 20, 30, 40, 50,
60, 70, 80, and 90 Gy) were drawn. Then, we calculated
the activity (MBq) in these volumes before and after
treatment.
Results
Linear regression analysis showed a significant reduction
in LF at three months, which was proportional to the
increase of the radiation dose (p = 0.00017, Figure 1). Our
analysis showed a reduction of 0.14% of the LF for each
delivered gray. Even with the limits of the small
population of this study, the linear equation showed a
predictive value in predicting the loss of LF/Gy of 98% (R2
= 0.9807).
Conclusion
SPECT/CT is a good imaging modality to assess changes in
LF after thoracic irradiation. This analysis shows a
functional decrease, which is proportional to the delivered
dose, reflecting the functional acute toxicity. These
function-based approaches could improve our knowledge