To investigate the technical feasibility of inserting a brachytherapy needle into the prostate to a defined tumour target point using a robotic device.
ID
Source
Brief title
Condition
- Reproductive neoplasms male malignant and unspecified
- Prostatic disorders (excl infections and inflammations)
- Male genital tract therapeutic procedures
Synonym
Research involving
Sponsors and support
Intervention
Outcome measures
Primary outcome
The primary endpoint is the technical feasibility of using the robotic
needle-implant device, which will be determined by the needle-to-tumour-target
distance.
Secondary outcome
- To determine the geometric accuracy of the brachytherapy needle position in
the prostate compared to the planned position (quantified by
needle-to-geometric-target (NTG) distance;
- To quantify the deformation of the prostate during and after needle insertion;
- To determine the duration of a robotic needle insertion procedure;
- To assess toxicity related to treatment.
Background summary
Focal treatment of localized recurrent prostate cancer after primary
radiotherapy has the potential to maintain cancer control, while decreasing
treatment-related toxicity that is associated with whole-gland salvage
treatments. A promising focal salvage technique is magnetic resonance imaging
(MRI)-guided high-dose-rate brachytherapy (HDR-BT). The department of
Radiotherapy at the University Medical Centre Utrecht (UMCU) is equipped with
an MRI HDR-BT facility: a shielded room with a 1.5T MRI scanner, where
brachytherapy needle implantation and dose delivery take place under MRI
guidance.
Within the current HDR-BT treatment, the prostate is directly visualised using
trans-rectal ultrasound (TRUS), whereas the target tumour volume is visualised
indirectly through delineations from a pre-radiation MRI scan which are fused
with the TRUS images. Using this visual guidance, brachytherapy needles are
manually inserted into the tumour for targeted radiation of the tumour volume,
by temporarily loading them with a radioactive source. A dose of 19 Gray (Gy)
is delivered from an iridium (Ir)-192 source.
A shortcoming in the current workflow is the indirect visualization of the
tumour volume: it requires registration of pre-operative MRI images to live
intra-operative TRUS images. This registration becomes less accurate during
needle implantation as the firm prostate tissue is displaced and deformed due
to oedema. Additionally, manual implantation can be time-consuming and lead to
more trauma as the (pre-irradiated) prostate can be difficult to manipulate and
needles often need to be repositioned repeatedly in order to ensure optimal
placement. However, since space is limited within the MRI bore itself, manual
brachytherapy needle insertion under real-time MRI guidance is physically not
possible.
To overcome these shortcomings, a robotic MRI-compatible implantation device
was developed at our institution to perform focal salvage HDR-BT under
MRI-guidance. The robot fits in a 1.5T MRI scanner and can be placed between
the patient*s legs. A first feasibility study showed that it was feasible to
use this robotic device for implantation of gold fiducial markers into the
prostate (protocol number NL21143.041.08). However, it was found that the
implantation momentum was not sufficient to avoid prostate deformation.
Hereafter the robot was optimized and redesigned to allow HDR-BT treatment of
the prostate with angulated needle trajectories. The accuracy of the needle
angulations was tested in air and in an agar phantom, with promising results
regarding needle alignment. We anticipate that the tested image-based workflow
is also feasible for in vivo validation of the robotic device.
To investigate the in vivo feasibility, part of the HDR-BT procedure will be
performed using the MRI-compatible robotic needle implantation device. Prior to
the standard manual implantation procedure, a single needle will be introduced
into the prostate by the robot and a radiation dose will be delivered.
In the future, an implantation procedure performed entirely by the robotic
device can allow for a reduction in the number of brachytherapy needles needed
due to optimization of radiation tumour coverage. This potentially leads to
lower toxicity rates: there will be less manipulation of the prostate and
healthy organs at risk (OAR) are spared due to optimal dose distribution.
Furthermore, we expect a reduction in the total procedure duration.
Additionally, we anticipate better tracking of the tumour volume during
complete MRI-guided implantation, thereby achieving increased tumour control.
Study objective
To investigate the technical feasibility of inserting a brachytherapy needle
into the prostate to a defined tumour target point using a robotic device.
Study design
Single-centre single-arm prospective development study.
Intervention
Single-needle insertion into the prostate by an MR-compatible robotic device,
prior to the conventional manual focal salvage HDR-BT procedure.
Study burden and risks
Within the conventional focal salvage HDR-BT procedure, the risk of toxicity is
minimized by applying strict dose constraints for the OAR (urethra, bladder and
rectum). State of the art planning procedures are used for dose calculations.
In the current study, the same planning procedure will be used.
Needle insertion by the robotic device will be MRI-guided. Deviation of the
needle position will be detected immediately and can be corrected for in the
dose calculation. Taking into account that only part of the dose will be
delivered through the robotically placed needle and the stringent
MRI-monitoring, we expect this treatment to be safe for the patient. No
additional anaesthesia will be required, since patients already receive spinal
anaesthesia for the conventional HDR-BT procedure. Approximately 2.5 hours will
be needed for preparation and execution of the robotic needle insertion
procedure, in addition to the 2-3 hours needed for the manual procedure.
Heidelberglaan 100
Utrecht 3584 CX
NL
Heidelberglaan 100
Utrecht 3584 CX
NL
Listed location countries
Age
Inclusion criteria
- All eligibility criteria for focal salvage high-dose-rate brachytherapy
(HDR-BT) as currently followed by the department of Radiotherapy at the UMCU:
o Age >=18 years;
o Local recurrence >2 years after primary treatment.
o Stage <=T3b tumour;
o Recurrent lesion visible on 68Ga-PSMA-PET-CT and at least 1 sequence of
the mp-MRI (T2 weighted (T2 weighted (T2W), DCE or DWI);
o Karnofsky score >=70.
- Prior prostate cancer treatment with standard external beam radiation therapy
(EBRT), for which fiducial gold markers were placed in the prostate;
- Tumour location technically feasible for robotic needle placement as
determined on diagnostic MRI scan and PET-CT scan;
- Written informed consent.
Exclusion criteria
- Any contra-indications for focal salvage HDR-BT as currently followed by the
department of Radiotherapy at the UMCU:
o Metastatic disease;
o Other prostate cancer treatments in the past (HIFU or cryosurgery),
except for radiotherapy;
o Trans-urethral resection of the prostate (TURP) within the past 6
months;
o Prior radiotherapy for a malignancy in the pelvic area, other than
prostate cancer;
o Continuously required anticoagulant administration, except for platelet
aggregation inhibitors (for example Ascal/Persantin).
- Hypofractionated EBRT as primary prostate cancer treatment;
- Less than 3 gold markers visible in the prostate on the pre-treatment
MRI-scan;
- Physical inability to spread the legs sufficiently for positioning in the leg
supports;
- Contra-indications for MRI.
Design
Recruitment
Medical products/devices used
Followed up by the following (possibly more current) registration
No registrations found.
Other (possibly less up-to-date) registrations in this register
No registrations found.
In other registers
| Register | ID |
|---|---|
| CCMO | NL67255.041.18 |