Primary objectiveThe objective of this pilot study is to test the hypothesis that the use of individual head supports will result in an actual given dose to both the target volumes as well as organs at risk that corresponds better to the planned…
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Source
Brief title
Condition
- Other condition
Synonym
Health condition
hoofd-hals tumoren
Research involving
Sponsors and support
Intervention
Outcome measures
Primary outcome
The primary endpoint of this study is the actual given dose. The actual given
dose is the dose administered to the patient during treatment, taking into
account patient positioning accuracy and patient deformations. This actual
given dose will in general deviate from the planned dose that was calculated
based on the planning CT only. The actual given dose for the two different
groups will be calculated and compared to the planned dose. The dose
distributions of the following structures will be taken into account:
- Gross Tumour Volumes (GTVprimary tumour and GTVlymph node metastases)
- Clinical Target Volumes (CTV70 and CTV54.5)
- Planning Target Volumes (PTV70 and PTV54.5)
- Spinal cord
- Parotid glands (ipsilateral and contralateral)
- Submandibular glands (ipsilateral and contralateral)
- Pharyngeal constrictor muscles (superior, medium and inferior)
- Thyroid gland
Secondary outcome
The first secondary endpoint is dose calculations on CBCT data.
A more sophisticated and efficient method to calculate the actual given dose
from the CBCT scans will be developed. The CBCT images are acquired on the
treatment table of the linac, just before start of treatment. Therefore, dose
calculations based on the CBCT images correspond better with the actual dose
distribution than calculations based on repeated CT scans. However, at the
moment the dose calculations based on CBCT scans are not as accurate as those
based on conventional CT scans. This is caused by the different imaging
technique that is used for CBCT*s resulting in less image quality than a
conventional CT. Using Deformable Image Registration (DIR) techniques will make
it possible to deform the planning CT to obtain new CT images with the
anatomical information of the CBCT scan and the image quality of a conventional
CT. The results obtained with this method will be validated with the results
obtained from the repeated CT-scans.
The second secondary endpoint is the positioning accuracy.
In head and neck patients, a curative treatment course generally consists of 35
treatment fractions in 6 to 7 weeks. The current procedure is to make CBCTs on
the first 4 treatment fractions and subsequently weekly. Based on the findings
of these images, inaccuracies are calculated in terms of standard deviations
and standard errors and translated into positions corrections according to a
standardised protocol. The following endpoints regarding repositioning
accuracies will be assessed:
- Translations (cranial-caudal, posterior-anterior and left-right)
- Rotations (Roll, yaw and pitch)
For the purpose of this study, position accuracies will be calculated for both
groups. This is part of the current standard procedure and does not require
extra patient burden.
Background summary
Radiotherapy plays a pivotal role in the treatment of head and neck cancer,
either as single modality or as part of a multimodality approach combined with
surgery and/or systemic treatment like chemotherapy or cetuximab.
Modern radiation delivery techniques enable increasing possibilities to
administer a high dose to the target volume (including the tumour) while organs
at risk (OARs) can be increasingly spared. These highly conformal techniques
require an accurate delineation of 3D target volumes and OARs on the planning
CT scan made prior to treatment. Based on this planning-CT, radiotherapy
treatment planning is carried out. Higher conformity of dose distributions to
the target volumes requires increasing quality assurance of patient positioning
during the course of treatment as tighter dose distributions around the target
increases the risk of geometric misses during treatment in case of relatively
small deviations. Therefore, all patients with high conformal techniques, such
as intensity modulated radiotherapy (IMRT) which is the current standard at our
department for head and neck cancer irradiation, are subjected to well defined
position verification and repositioning protocols during the entire course of
treatment. These protocols are aiming to ensure as much as possible that the
planned radiation dose as assessed on the planning-CT scan are actually given
to the patient during the entire course of treatment (actual given dose).
Deviations of the actual given dose with respect to the planned dose may result
from different sources, including:
- Translations (cranial caudal, anterior posterior and lateral directions):
these deviations can be compensated by repositioning during treatment by the
currently used position verification and repositioning protocol;
- Anatomical changes due to tumour shrinkage, radiation-induced swelling and/or
weight loss. These changes can only be accounted for by re-planning (adaptive
radiotherapy);
- Rotations, defined as deviation of the angle between the head and neck: these
deviation cannot be corrected by repositioning, as correction of the head-part
of the target volume will result in deviation of the neck-part and vice versa.
Rotations could possibly be prevented by using other fixation devices, which
will be the subject of this study.
For patients with tumours in the head and neck area fixation devices are used
during treatment to obtain a fixed and reproducible position of the head and
neck on the treatment table. The current fixation devices consist of an
individual thermoplastic mask in combination with a standard head support.
Results obtained by others indicate that using individual head supports instead
of standard head supports improve the positioning accuracy, in particular of
rotations between the neck and head, which cannot be corrected for by
repositioning of the patient. However, the effect of individual head supports
on the actual given dose has not been investigated yet.
The use of individual head supports is more expensive and more time-consuming
than the use of standard head supports. From this point of view, it is
worthwhile to investigate if and to what extend the individual head supports
will improve the actual given dose as this will be the most clinically relevant
outcome parameter.
Study objective
Primary objective
The objective of this pilot study is to test the hypothesis that the use of
individual head supports will result in an actual given dose to both the target
volumes as well as organs at risk that corresponds better to the planned dose
than with the currently used standard head supports.
Secondary objectives:
The secondary objectives are:
- Develop a method to calculate the actual given dose based on the CBCT scans
acquired on the treatment table of the linac, just before start of treatment.
- To compare reposition accuracies between the individual head support and the
standard head support.
Study design
This is a pilot study (feasibility study) to determine the difference between
the actual given dose with the two different head supports.
Patients that participate in this study will be treated will receive both head
supports and a planning-CT will be made with both supports. A treatment plan
will be made on both planning-CTs. The patients will, however, only be treated
with the individual head support. In weeks 1, 3, 5 and the last week of
treatment repeated-CTs will be made with both head supports.
During the treatment cone-beam CT (CBCT) scans will be used for position
verification. The CBCTs will also be made with both head supports. This means
that 10 extra CBCT images will be made for patients that participate in this
study.
Study burden and risks
If the patient decides to participate in this study he/she will have the
advantage to be treated with the individual head support, whereas the patients
that do not participate in this study will be treated on the standard head
support. The individual head support is more comfortable and is expected to
give better positioning of the patient. For this study, the patient will have
to spend some extra time on the department, due to the extra CT- and
CBCT-scans, but he/she will not have any additional visits to the department as
these investigations can be carried out in directly following there daily
visits to the department. The additional dose of these extra CT- and CBCT-scans
is 129.5 mSv. This extra radiation dose exposure is considered acceptable
(0.20%) in relation to the prescribed radiation dose (66.000-70.000 mSv).
Prior to the start of the study, the protocol has to be approved by the medical
ethics review committee. Approval will be indicated in writing with reference
to the final protocol number and date.
Postbus 30001
9700 RB Groningen
NL
Postbus 30001
9700 RB Groningen
NL
Listed location countries
Age
Inclusion criteria
- Intended curative primary or postoperative radiotherapy for cancer of the head and neck, either or not combined with systemic treatment (chemotherapy or cetuximab);
- Suitable for treatment on LINAC E (with cone beam CT);
- Age >18 years;
- WHO performance status 0-2;
- Women of childbearing potential must not be pregnant or lactating;
- Absence of any psychological, familial, sociological or geographical condition potentially hampering compliance with the study protocol and follow-up schedule; those conditions should be discussed with the patient before registration in the trial;
Exclusion criteria
Patients with postoperative wound healing problems
Design
Recruitment
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 | NL32387.042.10 |