Pilot study on the use of fluorescence imaging of
lymph nodes during colorectal lymphadenectomy,
using indocyanine green.

Adjuvant systemic chemotherapy is indicated in colorectal carcinoma (CRC)
patients with metastatic lymph nodes (LN's), resulting in a 30% relative
increase in survival. To asses the actual LN status, optimal examination by
means of adequate LN dissection is mandatory. The Dutch CRC treatment
guidelines require a minimum of 10 LN's to be examined for adequate staging.
However, it has recently been demonstrated that often a median number of 6 LN's
are examined among CRC patients in the Netherlands. This may be due to the
difficulty of intraoperative detection of these LN's, demanding a technique
that enables the surgeon for more accurate identification of LN's during the
surgical procedure. In addition, the intraoperative detection of the sentinel
lymph node will allow the pathologist to examine in more detail the possibility
of metastasis.
Where other carcinomas such as breast cancer, have well established techniques
to guide SLN surgery, no such technique is yet available for CRC.
Recent studies suggest that a new procedure, using an FDA approved, fluorescent
(indocyanine green; ICG) could allow for highly sensitive detection of the
lymphatic outflow track and draining LN's. Therefore, ICG is expected to
improve lymphatic mapping, SLN detection and subsequent lymphadenectomy.
Consequently, staging of CRC and postoperative outcome will improve.

Prospective study: The potential use of intraoperative, ICG based, fluorescence
imaging of LN's during CRC lymphadenectomy.

No special patient preparation is required. During surgery 4 ml of ICG solution
(25 mg) diluted in human serum albumin (HSA), will be injected in/around the
tumor (similar to standard patent blue procedure in breast cancer). Dynamic
imaging by a dedicated camera during 15 minutes post injection will help detect
the lymphatic outflow track with visualization of the majority of draining
lymph nodes, including the first draining lymph node (sentinel node).
Subsequently, all the fluorescent LN's will be resected and marked for PA.

Other than intraoperative injection and tracking of ICG, this study will not be
any different of standard procedures. During the ICG-injection the patient will
be anesthetised and therefore experience no extra burden. Operating time may,
however, be prolonged by 15 minutes due to the imaging procedure. Conversely,
the value of an improved and more adequate lymphadenectomy could have a major
impact in the improvement of staging and postoperative outcome in CRC patients.
In rare cases (<1/10.000) nausea, urticaria and anaphylactic reactions have
been reported. Because of the proposed exclusion criteria, these numbers will
in fact be lower within this study.