ESTRO 36 Abstract Book

299 / 1082

S286 ESTRO 36 2017
_______________________________________________________________________________________________
emerged after the first week of RT, patients who were not
followed for at least 7 days were excluded from the
analysis.
The incidence of DOG for patients with at least one
treated vertebra at Th8 or above was compared to the
incidence for patients treated below Th8 using Fisher’s
exact test. The relationships between the mean (D mean)
and maximum (Dmax ) esophageal doses and incidence of
DOG was examined using the Wilcoxon rank sum test,
comparing distributions of dose metrics in the two groups.
Results
30 patients (12 women / 18 men) participated in the
study, with prostate (8), breast (5) and lung (4) cancer as
the most common primary diagnoses. Median number of
vertebrae treated was 2 (range 1-9), with 9 patients
treated to more than one site. 4 patients were excluded
from this analysis due to withdrawal or inability to
complete questionnaires prior to the one week mark. Out
of the 26 patients, 11 reported DOG (Fig 1, Fig 2). For all
11 patients, the most cranially treated vertebra was Th8
or above; 4 of the 15 patients not reporting DOG were
treated to Th8 or above (p<0.001). The median Dmean was
7.8 Gy (range 0.0-15.9 Gy) for patients reporting DOG, and
2.2 Gy (0-10.8 Gy) for patients not reporting DOG,
p=0.0043. Corresponding values for Dmax were 24.7 Gy (0-
31.4 Gy) with DOG and 9.8 Gy (0-31.4 Gy) without DOG,
p=0.0043.
Conclusion
There is a high incidence of patient-reported DOG in
patients treated for SCC. This incidence correlates with
mean and maximum esophageal dose, but also appears to
depend strongly on irradiation of cranially located
vertebras. Our results indicate that it may be possible to
reduce the incidence of DOG in patients with SCC by
reducing the esophageal dose. This provides an argument
for the use of intensity-modulated radiotherapy optimized
to limit dose to the esophagus for the treatment of SCC.
OC-0543 Acute toxicity with helical IGIMRT for head
and neck cancer: Unilateral vs bilateral nodal
irradiation
A.M. Bates1, D.J. Noble2, O. Young1, E. Wong1, J.
Gemmill2 , R.J. Benson2, S.J. Jefferies2, G.C. Barnett2,
N.G. Burnet2
1Addenbrooke's Hospital - Oncology Centre University of
Cambridge, Cambridge Cancer Trials Center, Cambridge,
United Kingdom
2Addenbrooke's Hospital - Oncology Centre University of
Cambridge, Department of Oncology, Cambridge, United
Kingdom
Purpose or Objective
Most patients undergoing radical radiotherapy (RT) for
head and neck cancer (HNC) develop severe acute
toxicity, and treating physicians aim to spare uninvolved
neck nodal levels where possible. This study aimed to
determine rates of gr. 2+ and 3+ acute oral toxicities in
patients with HNC receiving helical IMRT with daily image
guidance. We compared acute oral toxicities in patients
who received unilateral nodal irradiation (UNI) and
bilateral nodal irradiation (BNI).
Material and Methods
This was a sub-study of the Cancer Research UK VoxTox
programme, that prospectively accrued high resolution
acute and late toxicity data in patients undergoing radical
RT. Selection criteria for this sub-study were: Prescription
dose 65Gy/30#, concurrent weekly cisplatin (min. 4
cycles), sub-sites including oropharynx, oral cavity, larynx
and hypopharynx. Patients were treated according to our
local 3 dose-level protocol: macroscopic disease CTV
65Gy, high risk CTV 60Gy, lower risk CTV 54Gy
(contralateral neck). Patients were reviewed at baseline,
weekly during treatment, and at weeks 4 and 8 post-
treatment. All data were collected using electronic
clinical report forms by a specialist HNC oncologist, or
experienced RTT. We collected data on 4 key oral toxicity
endpoints using CTCAE v4.03: oral mucositis, dry mouth,
salivary duct inflammation and dysphagia. Maximum
toxicity rates of these four were also considered.
Results
73 patients were selected; 11 had UNI, and 62 BNI. There
was no reported toxicity or differences between groups at
baseline. Plots of gr. 2+ and 3+ toxicity for all 4 endpoints
are shown in Figure 1A-D. Maximum weekly toxicities are
shown in Table 1.
Overall, there appears little difference in gr. 2+ toxicity
rates between groups. Furthermore, maximum or specific
toxicity rates are similar (max toxicity 83% BNI vs 80% UNI).
However, table 1 and figure 1 suggest that gr. 3+ toxicity
developed more quickly in BNI patients. Using 2x2 tables
and Fisher’s exact test, we compared rates at week 4.
Overall maximum toxicity at week 4 was 33% for UNI, 56%
for BNI, but this was not significant (p=0.33). This
procedure was repeated for all 4 endpoints. Rates of
mucositis were 8% (UNI) vs 33% (BNI); this trended towards
significance (p=0.08). Week 4 gr. 3+ toxicity rates were
also higher in the BNI group for dry mouth, ductal
inflammation and dysphagia (0% vs 16.4%, 16.7% vs 23%,
33% vs 41% respectively). None of these differences
showed statistical significance. Recovery rates post
treatment appeared similar between cohorts.
Conclusion
This study shows that gr. 2+ toxicity rates appear to be
similar between patients undergoing UNI or BNI
throughout treatment and recovery. Peak toxicity (ie
highest proportion of patients reporting gr. 3+ toxicity)
was also similar. However, our data indicate that BNI
patients may develop some acute toxicity earlier in
treatment and we will re-test this hypothesis once a larger
cohort has been recruited.
OC-0544 Stereotactic radiotherapy in elderly patients:
age, survival and performance status
J.L. Monroy Anton1, L. Tejedor Pedrosa2, M. Soler
Tortosa 1, M. López Muñoz1, A. Soler Rodríguez1, A.
Navarro Bergadá1, M. Estornell Gualde1
1Hospital universitario de la ribera, radiation oncology,
Madrid, Spain