Exploratory study on nasal high flow therapy for breath hold in radiotherapy (ENTheR-study)

Due to breathing and other motion, tumors, such as breast and lung cancer, as
well as their
surrounding organs (e.g. the heart), move, which poses a challenge for
radiotherapy treatment.
Reducing or even stopping breathing, e.g. by irradiating during inspiration, is
a way to decrease
tumor and organ motion resulting in a reliable target coverage with smaller
margins. These
smaller margins can result in a better sparing of normal tissues. Furthermore,
in some patients,
during inspiration the heart may move away from the target volume making it
possible to better
spare the heart. Finally, during inspiration, the lung volume is larger and the
lung density is
lower, which can lead to a lower dose to the surrounding normal lung tissue.
Reduction of
radiation dose to normal tissues leads to less radiation-induced toxicity. This
makes treating
breast and lung cancer patients in breath hold (BH) conditions an attractive
strategy. A BH has
to be stable and long enough for the duration of a planning CT-scan, cone beam
CT (CBCT)
scan and treatment delivery. Treatment of left-sided breast cancer with
radiotherapy in
moderate deep inspiration breath hold (mDIBH) is well established. Also, in
MAASTRO clinic,
left-sided breast cancer patients are treated in mDIBH, but this is done
without any support or
control of the breath hold. Standard BH durations in RT treatment are around 20
seconds,
which is not enough to perform a complete CBCT. The health status of lung
cancer patients is
generally worse compared with breast cancer patients, making it more difficult
to treat this
patient group during breath hold. mDIBH in lung cancer patients is therefore
not widely used,
and not yet performed in MAASTRO clinic. Ventilation techniques that can
support patients in
holding their breath might make it a feasible approach in patients with a less
favourable
performance status, and might increase the duration of a breath hold. Nasal
High Flow Therapy
(NHFT) is a non-invasive system that provides controlled oxygen concentrations
and low levels
of positive pressure via a nasal interface. NHFT improves oxygenation in
diverse patient
groups, and is increasingly used as an alternative to mechanical ventilatory
support. It has
been shown to be a safe device in several clinical situations and patient
populations, such as
in COPD patients, but also in apneic conditions under general anesthesia. It
has however
never been used in the context of breath hold support, neither has it been used
in radiotherapy
practice. We hypothesize that supporting BH with nasal high flow therapy (NHFT)
will allow
robust radiotherapy treatments of moving targets in a broad patient population
allowing for BHs
that are long enough, stable and reproducible during a whole treatment course.

The objective of this study is to investigate the feasibility of treating
breast and lung cancer
patients in mDIBH using nasal a high-flow therapy (NHFT) device.

Exploratory study

For the patient, the burden consists of an extra CT-scan and some extra time
for the instruction of the Nasal High Flow Therapy. The extra radiation is
minimal (12mSv) and the time spent by the patient for the use of the therapy is
predicted to benefit them during radiation.