Within-patient comparison of Senti-Scint and ICG-99mTc-nanocolloid for sentinel node biopsy of melanoma of the head and neck, of the trunk or of an extremity

Sentinel node biopsy is routinely used for staging melanoma patients., The
sentinel node procedure is conventionally performed after injecting a
radiocolloid around the tumor site. In the head, neck and extremities,
drainage is fast and subsequent nodes are often depicted on the
lymphoscintigrams in addition to the sentinel node(s). This may complicate both
the interpretation of the images and the surgical procedure. The occurrence of
higher-echelon nodes is less frequent on the trunk but in this area aberrant
drainage is more often seen. Better visualization of lymphatic vessels running
to these sentinel nodes would be advantageous.
The number of visualized nodes depends on the size of radiocolloid particles
and the time between injection and imaging. The larger the radiocolloid
particles, the slower the drainage. The longer the time interval between
injection and imaging, the greater the number of visualized nodes.
99mTc-nanocolloid-ICG) is the traditional radiocolloid in Europe. Recently,
99mTc-Senti-Scint was introduced for sentinel node biopsy. The latter consists
of large particles (100-600nm) and as such it is claimed to have a lower rate
of visualisation of second-tier nodes. Aew studies reported on the use of
99mTc-Senti-Scint, but no comparative studies have been performed yet.

To compare ICG-99Tc-nanocolloid to 99mTc-Senti-Scint for sentinel node mapping
in patients with malignant melanoma of the trunk, an extremity or in the head
and neck area.

It is a prospective interventional study.

The study will be performed in a two-day protocol.
Day 1: The four sites for the radiocolloid injection deposits will be marked
with an indelible marker pen. Thereafter, 99mTc-Senti-Scint will be
administered intracutaneously around the lesion site and the 4 injections
locations will be marked on skin. Dynamic lymphoscintigraphy will be performed
immediately after injection followed by static lymphoscintigraphy at 15 minutes
and 2 hours. After 2 hours, SPECT/CT imaging will be performed.
Day 2: Prior to injection of ICG-99mTc-nanocolloid a static posterior or
anterior lymphoscintigram will be made (roughly 18 hours after the first
injection). ICG-99mTc-nanocolloid will be injected intracutaneously around the
lesion site at the locations marked on day 1. Similar to day 1, dynamic and
static lymphoscintigraphy will be performed followed by SPECT/CT imaging. The
operation will be performed on the afternoon of the second day. The operation
will be performed according to standard protocol. Sentinel nodes will be
examined by the pathologist in the standard fashion.

Instead of once, patients have to come to the hospital twice to receive an
additional tracer injection. This means that patients will also receive twice
the radioactivity dose. The additional radioactivity is comparable to other
standard nuclear medicine procedures. The use of 99mTc-Senti-Scint for
lymphatic mapping in colorectal cancer has been approved by the local ethics
committee of the NKI-AVL. The total dose of radioactivity lies within the
limits that are indicated by the Gezondheidsraad, in the *Normen voor de
toediening van radioactieve stoffen aan vrijwilligers*.
Rarely, nausea, urticarial and anaphylactic reactions (ICG: <1/10000) have been
reported after intravenous injection. Because of the proposed exclusion
criteria and the local, intracutaneous, injection, these numbers will be lower
within this study.