Evaluation of tumor response during and after (chemo)radiotherapy for patients with oropharyngeal squamous cell carcinoma using functional imaging by diffusion-weighted MRI

About 50-60% of patients with oropharyngeal cancer still presented with
locally-advanced disease. Despite the major improvements achieved in the last
decades as a result of the implementation of different new treatment
strategies, the incidence of locoregional failure (LRF) remains disappointingly
high, especially in high-risk group. All types of treatment are associated with
troublesome toxicity, sometimes compromising vital functions with subsequent
deterioration of quality of life. Several studies have shown that recurrences
predominantly developed within the high dose area of the radiation treatment.
To achieve the full potential regarding tumor dose-escalation to improve
locoregional control (LRC) and normal tissue-sparing to reduce toxicity, highly
conformal radiotherapy techniques and accurate disease localization are
crucial. Highly-conformal radiation techniques such as brachytherapy and
Cyberknife stereotactic radiotherapy are nowadays available in our
institution. LRC may further be improved by tailoring treatment strategies to
an individually based response, but this requires early diagnostic biomarkers.
Few small studies suggest the robustness of diffusion-weighted MRI as a
potential biomarker for early prediction of treatment response. In all these
studies, it was not clear whether their results are reproducible across
different centers. Therefore, they advised that each center needs to establish
its own reference values. The accuracy of diffusion-weighted MRI to predict
tumor response needs first to be evaluated at our institution before an
individualized risk-adaptive treatment intensification by dose-escalated
radiotherapy can be offered to patients at high risk of poor initial response
and subsequently high risk of LRF.

To measure structural (volume) and functional (ADC value) changes in the
primary tumor on T1- and T2-weighted MRI and diffusion-weighted MRI during and
after (chemo)radiotherapy for oropharyngeal squamous cell carcinoma. By using
serial imaging before, during and after treatment we want to establish a
biological model of changes in order to early identify subgroup of patients who
will poorly respond to the initial treatment (persistently low ADC value).
These patients might be candidates for dose escalation of radiotherapy in the
nearby future.

This study will be a single center diagnostic study. The duration of the study
will be 12 months, with an inclusion rate of 1 patient per week.

Nature and extent of the burden:
If there is no contra-indication for MRI examination, the safety of MRI imaging
is guaranteed.
There are no short-term or long-term negative effects known for MRI
examinations.
After the MRI procedure the patients will be asked whether they have
experienced any strange sensation during scanning and whether they still have
complaints after the end of the scanning sessions.
The only burden related to the study is 3 times 30 minutes to undergo the MRI
scan and the noise caused by the MRI scan itslef.

Benefits and risks assessment, group relatedness
Subjects in this study will not be at risk due MRI examination. The additional
MRI scans will take up till 30 minutes. It has no benefit for the individual
patient in our study.
There are no risks for the individual subject.
There are no benefits to the individual subject.

Benefits to the Patient Population:
This study will show the volumetric and possible shape changes of the tumor
during radiotherapy. This study will result in a biological model to identify
the optimal cutoff ADV value predictive for poor response to the
(chemo)radiotherapy. Subsequently, poor responders will be offered a
dose-escalated highly-conformal radiotherapy in order to improve locoregional
control.