PET-CT lymphoscintigraphy for sentinel node detection in head and neck cancer: a feasibility study

De sentinel node procedure appeared to be less reliable for tumors located in
the floor of mouth, compared to other sites in the oral cavity.
This is probably due to the short distance between the primary tumor and the
first draining lymph node(s), the sentinel node(s).
Current detection techniques (gamma camera or SPECT-CT) have a limited
resolution to detect these lymph nodes.
PET-CT has a better spatial resolution and can make dynamic images as well. The
latter allows for better differentiation between first and second echelon lymph
nodes, resulting in less sentinel nodes that should be harvested.
The improved resolution should be able to detect sentinel nodes in the close
proximity of the primary tumor.
Therefore, sentinel node detection using PET-CT may improve current procedure
in selected cases.

Evaluation of the feasibility of sentinel node detection by PET-CT
lymphoscintigraphy

Feasibility, monocenter study. PET-CT lymphoscintigraphic results will be
compared with conventional lymphoscintigraphic results (gamma camera or
SPECT-CT).

In the first part (part A), 5 patients will be asked to participate, and they
will receive an injection with the study drug 89Zr-Nanocoll, followed by PET-CT
imaging directly after injection and 24 hours later. One week later, they will
undergo the standard sentinel node procedure using 99mTc-Nanocoll and SPECT-CT.
Imaging results of both imaging modalities (PET-CT and SPECT-CT) will be
compared. If results are positive, an additional patient cohort of 5 patients
(part B) will be asked to undergo the whole sentinel node procedure using the
novel 89Zr-Nanocoll. These patients will be patients who have N1 disease of
the neck or for which a neck dissection will be performed for reconstructive
purposes, besides resection of the primary tumor. In these patients the use of
89Zr-Nanocoll will be validated, and the results of the procedure do not
influence the standard treatment of the patient. Intraoperative detection of
89Zr-nanocoll containing lymph nodes will be evaluated.

PET-CT provides a better spatial resolution and anatomical information can be
obtained at the same time which theoretically may show additional SN(s) that
may not be seen on planar lymphoscintigraphy. Furthermore, based on the
improved knowledge about the localization of the SN(s), exploration of the neck
in order to find the SN may be minimized. This should results in less scar
formation and tissue damage, factors that would hamper an eventual subsequent
neck dissection. The CT component of PET-CT and the addition of low dose of 5
MBq 89Zr, will result in an acceptable radiation burden to the patient, i.e
comparable to natural background level. No significant interference of the
addition of 89Zr during the standard sentinel node is anticipated.
In PART B of the study the patients will undergo one additional PET-CT scan
after administration of 5 MBq 89Zr-Nanocoll one day prior to surgery. The
results of the SN procedure will not influence standard treatment. From a
patient perspective the advantage of this study might be the visualisation of
unexpected drainage outside the surgical field, which can be discussed with the
patient, possibly leading to a better individualized treatment.