HDR brachytherapy as monotherapy or a boost for high risk prostate cancer: 5 year single center data
PO-0243
Abstract
HDR brachytherapy as monotherapy or a boost for high risk prostate cancer: 5 year single center data
Authors: Sergey Novikov1, Sergey Kanaev1, Roman Novikov1, Nikolay Ilin1, Mary Gotovchikova2, Mikhail Girshovitch1
1N.N. Petrov Research National Medical Cancer Center, Radiotherapy, St Petersburg, Russian Federation; 2N.N. Petrov Research National Medical Cancer Center, Radiotehrapy, St Petersburg, Russian Federation
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Purpose or Objective
to compare efficacy and toxicity of interstitial
high-dose-rate (HDR) prostate brachytherapy when it was used as monotherapy or
as a boost to external beam radiotherapy for high risk prostate cancer.
Material and Methods
Material
and methods: 119 primary patients with clinically
localized high or very high risk prostate cancer that were treated from 1.07.2012
to 01.01.2017 were included in the study. HDR brachytherapy as a monotherapy
for high risk prostate cancer was performed in 21 patients (“monotherapy
group”). In all cases it was performed as 3 fractions (3 implantations) of
11.5Gy for prostate (with 5mm margins) and seminal vesicles. In 39 men with
high and 59 patients with very high risk prostate cancer we performed androgen
deprivation with external beam radiotherapy to the prostate and pelvic lymph
nodes (46Gy-50Gy in 23-25 fraction) and brachytherapy “boost” to the prostate
and seminal vesicles (1 fraction of 15Gy in 17 men; 2 fractions of 10Gy – in
another 85 cases) – “boost group”. The reported end points were biochemical
control rate according to Phoenix definition and overall/cancer-specific
survival. Toxicity was scored according to the RTOG scale.
Results
The median follow-up time was 59.2 months. In
“monotherapy group” the 5-year biochemical control was reached in 80.9%. Grade II late genitourinary toxicity detected in 4 (19%) observations.
Grade II rectal toxicity mentioned in 2 (9.5%) cases. Grade III was not
mentioned neither for rectal nor for
genitourinary toxicity. IIEF score before treatment was below 16 points in 28.5% and after brachytherapy – in 51% cases.
In the “boost group” the 5 year biochemical control was mentioned in 30
of 39 (76.9%) high risk and in 39 of 59 (66.1%) very high risk patients (p=0.04). Grade II late genitourinary toxicity detected
in 33 (33.6%), grade III – in 1 patient. Grade II rectal toxicity mentioned in 10
(10.2%), Grade III in no case. IIEF score before treatment was below 16 points in
29.6% and after treatment – in 69% cases.
In high risk patients there was no significant difference in biochemical
recurrence free survival between treatment groups (“monotherapy” vs “boost”).
Conclusion
in
patients with high risk prostate cancer high dose rate brachytherapy can be effectively
and safely used for monotherapy and as a boost after irradiation of the pelvis.