992 / 1096
S976
ESTRO 36
_______________________________________________________________________________________________
Conclusion
The pilot study demonstrated the feasibility of
randomization between treatment with IGRT alone vs
IGRT + HDR boost. Treatment compliance was good
including adherence quality assurance.
EP-1775 Acute toxicity in early cancer prostate
patients: low dose rate vs high dose rate monotherapy.
S. Rodríguez Villalba
1
, A. Otal Palacín
1
, J. Richart
Sanchez
1
, J. Pérez-Calatayud
2,3
, M. Santos Ortega
1
1
Clinica Benidorm, Radiotherapy Department, Benidorm,
Spain
2
Clinica Benidorm and Hospital La Fe, Radiotherapy
Department, Benidorm, Spain
3
Hospital La Fe, Radiothetherapy Department, Valencia,
Spain
Purpose or Objective
Brachytherapy (BT) in their two modalities, Low dose rate
(LDR) and High Dose Rate (HDR) are used in prostate
cancer. At present, all available clinical data regarding
these two techniques suggests that they are equally
effective, providing high tumor control rates. We compare
our experience considering acute toxicity in patients with
low or intermediate stages treated with LDR BT or HDR BT
in monotherapy.
Material and Methods
Between January 2004 and June 2016 we have treated 113
patients with BT as an exclusively treatment, 85 patients
with permanent LDR with Iodine-125 seeds and 28 with
HDR Ir-192. Both modalities were performed using
ultrasound based intraoperative techniques.
Results
LDR BT PATIENTS:
Median age 68 years (48-81 y), median
Gleason 5 (2-7), median value of PSA at diagnosis 7,3
ng/ml (2,5-16,3). 70 patients (82%) low risk (DÁmico
classification) and 15 (18%) intermediate risk. In 25 cases
(29%) the prescription dose was 145 Gy and in 60 (71%) 160
Gy. Thirty-three (39%) received hormonal treatment.
HDR BT PATIENTS:
Median age 70,5 years (55-80 y),
median Gleason 6 (3-8), median value of PSA at diagnosis
9,08 ng/ml (3-19,75). 12 patients (42%) low risk (DÁmico
classification) and 16 (58%) intermediate risk. All patients
were treated with 2 applications of 13,5 Gy in
monotherapy. Twenty (71%) received hormonal
treatment.
We analyze the acute toxicity of both treatments
following criteria CTCEV.3 and the results are presented
on the table.
There are not Grade 3 o 4 acute toxicity.
GRADE
0
LDR/HDR
GRADE
1
LDR/HD
R
GRADE
2
LDR/HD
R
HAEMATURIA
100%/ 100% 0%/ 0% 0%/ 0%
CYSTITIS
35%/ 100%
3%/ 0% 21%/ 0%
INCONTINENCY
URYNARY
97%/ 87%
0%/ 8% 3%/ 4%
OBSTRUCCION
URYNARY
60%/ 100% 15%/ 0% 30%/0%
URINARY
FRECUENCY/URGEN
CY
41%/ 96%
9%/ 0% 47%/ 4%
URINARY RETENTION
94%/ 100%
3%/ 0% 3%/ 0%
DIARRHEA
94%/ 100% 3%/ 0% 3%/ 0%
RECTAL
INCONTINENCY
100%/ 100% 0%/ 0% 0%/ 0%
RECTITIS
94%/ 96% 6%/ 4% 0%/ 0%
Conclusion
In this analyses the acute genitourinary toxicity was higher
when the patient were treated with LDR BT including 2
patients (3%) who needed urinary catheter after the
implant. We did not find any differences in
gastrointestinal toxicity with and excellent tolerance in
both groups.
Electronic Poster: Brachytherapy: Gynaecolgy
EP-1776 Is a single CT plan for vaginal cylinder
brachytherapy adequate?
M. Zahra
1
, M. Doak
1
, W. Keough
2
1
Western General Hospital- Edinburgh Cancer Centre,
Clinical Oncology, Edinburgh, United Kingdom
2
Western General Hospital- Edinburgh Cancer Centre,
medical Physics, Edinburgh, United Kingdom
Purpose or Objective
To assess if the target coverage and dose to organs at risk
(OARs) from a vaginal vault brachytherapy CT plan are
representative of dose delivered during the actual
treatment.
Material and Methods
28 patients scheduled for post-operative vaginal vault
brachytherapy had an initial planning CT scan (CT1) done
a few days before the first fraction, with the vaginal
cylinder in-situ to generate a treatment plan. The PTV was
the cranial 4cm of the vagina to a depth of 0.5cm, and the
OARs outlined included the rectum, sigmoid, small
bowel and bladder. On the day of the first fraction the
patients has a second CT scan with the vaginal cylinder
(CT2) and the PTV and OARs were outlined. Then the plan
from CT1 was superimposed on CT2 to assess for variation
in V100 and d90 to the PTV and the d2cc to the OARs.
Prescribed dose was 21Gy in 3 fractions to the PTV, aiming
for a V100 of >95% and d90 of 7Gy per fraction.
Results
Total of 56 scans were analysed. Mean PTV V100 for CT1:
95.8% (range 99.6% - 83.2%); CT2: 96% (range 99.8% – 90%).
Mean d90 for CT1: 7.4Gy( range 7.8 – 6.7Gy); CT2: 7.3Gy
(range 7.9 – 6.3Gy). Mean difference in d90 per fraction
was 0.23 Gy per fraction (range: 0.56 – 0.01Gy).
Small
Bowel
Sigmoid Rectum Bladder
Mean d2cc (Gy)
CT1
3.16
(range
7.0
-
0.3)
4.1
(range
6.4 - 1.9)
5.5
(rnage
7.0 - 3.9)
6.0
(range
6.7 - 4.9)
Mean d2cc (Gy)
CT2
3.18
(range
6.8
-
0.3)
3.8
(range
5.9 - 1.4)
5.6
(range
7.1 - 3.6)
6.0
(range
7.2 - 4.9)
Man difference
in d2cc between
CT1 and CT2
0.8
0.7
0.9
0.5
Conclusion
The variation in d2cc doses when using the initial CT plan
on the second scan taken on the day of the first fraction
were minimal and not clinically significant. Differences in
PTV coverage are mostly due to slight differences in PTV
outlining mainly because of changes in the angle of the
cylinder compared to the treatment couch. There does not
appear to be the need to plan every single fraction for
post-operative vaginal vault brachytherapy as the
dosimetry using the initial plan was representative of the
dose delivered on the day of treatment.