Ronan A Cahill, MD, Mark Anderson, MD, James East, MD, Lai Mun Wang, MD, Richard Guy, MD, Oliver Jones, MD, Ian Lindsey, MD, Chris Cunningham, MD, Neil J Mortensen, MD. EISRI, Dublin, Ireland and Oxford Radcliffe Hospitals, Oxford, UK
Background: Appropriate lymphatic assessment is a corner-stone of definitive surgical resection for colorectal cancer. Here, we detail the use of near-infra red (NIR) laparoscopy after peri-lesional Indocyanine Green (ICG, Pulsion Medical Systems) injection in a series of consecutive patients undergoing laparoscopic resection with curative intent for colorectal neoplasia. This technology and technique aims to allow real-time, intra-operative road-mapping of the patient’s specific tumoral lymphatic drainage and, in particular, the detection of first order draining (or sentinel) lymph nodes.
Methods: Under Institutional Review Board (IRB) approval and after fully informed consent was obtained, fifteen patients (mean age 66.1 years, mean BMI 29.7 [range 24.9-39.9], 11 males) undergoing laparoscopic resection for radiologically localized colorectal neoplasia were studied. Three patients had highly dysplastic lesions which were inappropriate for endoscopic resection while the twelve others all had biopsy proven carcinoma (one with a Haggart 4 cancer found by prior polypectomy). Four patients were planned for a laparoscopic-assisted right hemicolectomy as their definitive treatment while the others each required a fully laparoscopic anterior resection.
All patients underwent NIR laparoscopy and lymphatic mapping in addition to standard oncologic laparoscopic resection. ICG was used as the mapping agent as this substance is capable of induced fluorescence when irradiated by NIR illumination in addition to possessing the dual physical characteristics of both submucosal persistence (as so has long been of proven utility as an endoscopic localization tattoo) along with immediate small particle diffusion into efferent lymphatics channels and nodes. 14 patients had their submucosal peri-tumoral injection of ICG intra-operatively (on-table colonoscopy immediately prior to commencement of laparoscopic mobilization) while the one remaining patient underwent endoscopy for tumor localization and tattoo 24 hours preoperatively. A prototype NIR laparoscopic system (Olympus Corporation) was used to provide both white light laparoscopy during the procedure as well as, by switch activation, NIR irradiation with and without discrete spectral filtration of the back-light energy.
Results: Mesenteric sentinel nodes (mean=3.8/patient) were rendered obvious by their clear fluorescent illumination within 15 minutes of dye injection in every case. In eleven cases, such nodes lay entirely within the planned resection specimen while four patients had additional sentinel nodes found lying outside the territory normally removed. Laparoscopic ultrasound was used for in vivo analysis of the sentinel nodes in five cases (all correctly demonstrated benign). Standard resection with additional berry-picking of aberrant nodes was then performed with the status of the sentinel node being compared to that of the non-sentinel nodes found by routine pathological scrutiny. In all cases, the sentinel node correctly reflected the residual regional mesenteric nodal yield.
Conclusions: NIR Laparoscopy in conjunction with ICG mapping allows ready and rapid identification of the lymphatic drainage and sentinel nodes within the supporting mesentery for patients with colorectal neoplasia. While further validation is necessary, this promises precise, tailored resectional surgery for those cancers whose lymph drainage may be variable (e.g. flexural cancers) and may prompt consideration of either localized excision or supra-radical extirpative surgery on an individualized basis for patients intraoperatively proven node negative or positive respectively.
Program Number: S027