MRI for radiotherapy treatment planning of stage III NSCLC: an MRI optimization study in healthy volunteers and patients

Patients with stage III non-small cell lung cancer (NSCLC) have a poor survival
due to inadequate loco-regional control. Increasing the dose will lead to
better loco-regional control and survival. However, with the current treatment
planning strategies, increasing this dose would result in intolerable toxicity
of the organs at risk (OARs, healthy tissue surrounding the tumor).Therefore,
new treatment planning strategies have to be developed to improve local control
and therefore overall survival of patients with stage III NSCLC.
Currently, the radiation oncologist uses a combination of imaging modalities
for the delineation of the lung tumor and lymph nodes: 4D- computed tomography
(CT) scan, CT-scan with intravenous contrast and the positron emission
tomography(PET)-CT with fluorodeoxyglucose as a radioactive tracer. However
these imaging modalities have some disadvantages.In current clinical practice,
large treatment volumes are irradiated. This results in an increased dose to
OARs. Consequently, further increasing of the dose to the tumor would result in
intolerable toxicity.
We believe that MRI can be used to improve visualization of the tumor and lymph
nodes and characterize their motion, based on promising results in recent
literature. MRI can potentially be used to obtain more accurate (thus smaller)
treatment volumes. This will lead to a smaller dose to the OARs and enable safe
dose escalation.
Unfortunately there are no MRI protocols in the literature available aimed at
radiotherapy of lung cancer.

The objective of this study is twofold. We would first like to use MRI in
volunteers to select the appropriate techniques for motion compensation.
Furthermore, MRI settings will be sought which can be used to image lung and
mediastinal parenchyma. Second, we would like to assess the MRI sequences found
in volunteers for the visualization of tumors and lymph nodes in patients with
stage III NSCLC.

Furthermore, we would like to assess if MRI can be used for (automatic) motion
characterization of tumor, lymph nodes and organs at risk.
The sequences found in this study will be used in a future study on the added
value of MRI for radiotherapy treatment planning of stage III NSCLC, in which
MRI will also be compared to PET-CT.

Healthy volunteers
* To select the appropriate techniques to image lung and mediastinal
parenchyma. Furthermore, MRI settings will be sought which can be used for
motion compensation.

Patients
* To optimize and validate MRI for the visualization and motion
characterization of tumor, lymph nodes and mediastinal parenchyma in patients
with stage III NSCLC.

Observational study: 20 volunteers will receive an MRI-scan without contrast
and 20 patients with stage III NSCLC will receive a contrast-enhanced MRI-scan.

* Healthy volunteers will undergo an MRI scan with a maximal duration of 45
minutes. One visit to the hospital (lasting approximately 75 minutes) is
required and the healthy volunteers will receive a gift voucher with a value of
25 euros. MRI-safety screening is required before the MRI scan, and consists of
routine screening according to the clinical guidelines as determined by the
Department of Radiology of the UMCU.

* Patients will undergo an MRI scan with a maximal duration of 45 minutes. The
total visit to the department (including patient preparation, changing of
clothes etc.) will last approximately 75 minutes. For determination of renal
function, a recent value of the Glomerular Filtration Rate (GFR) (* 3 months)
has to be available.
After proper screening, the use of MRI is safe. The use of gadolinium contrast
(Gadovist) has a very low risk of contrast induced allergy.
For the patients included in the study there is no individual benefit.