ESTRO 36 Abstract Book

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S531 ESTRO 36 2017
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Tube feeding during treatment was given in 24%, for HAS,
ASO and ARCON 32%, 25% and 17% (p=ns). Severe late
laryngeal was equal for the schedules (table 1).
HyperfractionatedAcc.
Fractionation
(HAS) 1 n=28
Acceleratated
fractionation
only
(ASO) 1 ; n=283
ARCON
study2 n=86 p
n
(fractions);
d (Gy); T
(overall
treatment
time in
days)Total
Dose:
50;1.2/1.7; 33
Wk 1-3: 30 x 1.2 Gy,
BID
Wk 4-5: 20 x 1.7 Gy,
BID70 Gy
40;
2/1.8/1.5;33
Wk 1-2: 10 x 2
Gy
Wk 3-5: 15 x
1.8/1.5 Gy,
BID69.5 Gy
4; 2; 37
Wk 1-4: 20 x 2 Gy
Wk >5, 14 x 2Gy,
BID68 Gy
ERD
(α=0.3, α/
β =10,
Tpot=5)
67.7 66.5 64.5
ETD (α/
β=10)
103.7 116.9 113
5 yr local
control 56% 83% 75% 0.004
5 yr
disease
free
50% 76% 65% 0.02
Serious
late
toxicity
(larynx)
12% 10% 12% ns
Conclusion
In this large group of patients treated for intermediate
size laryngeal/ hypopharyngeal cancer superior local
control and disease free survival was seen when the
accelerated fractionation started in week three. The rate
of serious toxicity was equal for all three schedules. Also,
age ≥ 70 was not a negative prognostic factor for local
control, disease free survival and risk of complications..
For patients ≥ 70, with a WHO performance 0-1 excellent
outcome is shown.
1: Terhaard IJRBP. 2005 May 1;62(1):62
2. Janssens C Oncol. 2012 May 20;30(15):1777-83.
Poster: Radiobiology track: Radiobiology of prostate
cancer
PO-0970 Prostate brachytherapy; DNA damage
biomarker (gH2AX) induction rate correlates with late
toxicity
S. Osman 1, S. Horn 1, D. Brady1, S.J. McMahon1, A.B.
Mohamed Yoosuf2, D. Mitchell3, K. Crowther2, C.A.
Lyons1, A.R. Hounsell2, K.M. Prise1, C.K. McGarry 2, S.
Jain 1, J.M. O’Sullivan1
1 Queen's University Belfast, Centre for Cancer Research
& Cell Biology, Belfast, United Kingdom
2 Northern Ireland Cancer Centre- Belfast Health and
Social Care Trust, Radiotherapy Physics, Belfast, United
Kingdom
3 Northern Ireland Cancer Centre- Belfast Health and
Social Care Trust, Clinical Oncology, Belfast, United
Kingdom
Purpose or Objective
Low-dose-rate permanent prostate brachytherapy (PPB) is
an attractive treatment option and offers excellent
outcomes for patients with localised prostate cancer. As
standard CT-based post-implant dosimetry often
correlates poorly with late treatment toxicity, a study was
conducted to investigate correlations between radiations
induced DNA damage biomarker levels, bowel, urinary,
and sexual toxicity
Material and Methods
Twelve prostate cancer patients treated with 125I PPB
monotherapy (145Gy) were included in this prospective
study. Post-implant CT based dosimetry assessed the
minimum dose encompassing 90% (D90%) of the whole
prostate volume (global), sub-regions of the prostate (12
sectors) and the near maximum doses (D0.1cc, D2cc) for the
rectum and bladder. Six blood samples were collected
from each patient; pre-treatment, 1 hour (h) post implant,
4h, 24h, 4weeks (w) and at 3 months (m). DNA double
strand breaks were stained using the γH2AX and 53BP1
proteins. Patient self-scored quality of life from the
Expanded Prostate Cancer Index Composite (EPIC) were
obtained at baseline , 1 m, 3m, 6m, 9m, 1 year (y), 2y and
3y post treatment. Spearman’s correlation coefficients
were used to evaluate correlations between temporal
changes in γH2AX, dose and toxicity
Results
The minimum follow-up was 2 years. Population mean
prostate D90% was 144.6±12.1 Gy. Rectal near maximum
dose D0.1cc = 153.0±30.8 Gy and D2cc= 62.7±12.1 Gy and
bladder D0.1cc = 123.1±27.0 Gy and D2cc = 70.9±11.9 Gy.
Pre-treatment, mean (±SD) background foci (co-localising
γH2AX and 53BP1) was 0.42±0.20 foci per cell (Figure 1B).
A Shapiro-Wilk test confirmed the data was normally
distributed (w=0.943, p=0.540). Post seed implantation,
γH2AX/53BP1 foci numbers were significantly elevated as
early as 1 hour post implantation and remained so at 4 and
24 hours, 4 weeks and 3 months post implantation (Figure
1B). The γH2AX/53BP1 foci numbers continued to rise at 4
weeks (672 h) even after reduction in seeds activity due
to natural decay (Figure 2A) before dropping at 3 months.
EPIC summary scores for bowel, urinary, and sexual
domains are presented in Figure 2. Changes in EPIC scores
from baseline showed high positive correlation between
acute toxicity and late toxicity for both urinary and bowel
symptoms. Increased production of γH2AX at 24h relative
to baseline positively correlated with late bowel
symptoms, EPIC 1y (r= 0.67, p = 0.035), EPIC 2 y (r=0.86,
p = 0.001). Overall, no correlations were observed
between dose metrics (prostate global or sector doses)
and γH2AX foci counts.