Page 25 - Fluorescence-guided cancer surgery

INTRODUCTION
Gastric cancer is still one of the most frequent causes of cancer deaths worldwide with an incidence rate varying between countries1;2. The highest estimated mortality rates are in Eastern Asia (24 per 100,000 in men, 9.8 per 100,000 in women), the lowest in North America (2.8 and 1.5, respectively)3.
Surgical resection of the tumor is the only curative treatment option. Depending on the size, in ltration depth, and location of the tumor, surgery can be performed endoscopically, or by partial or total gastrectomy. In addition to resection of the a ected part of the stomach, a lymph node (LN) dissection is typically performed. This can either be done by extensive lymphadenectomy or by a sentinel lymph node (SLN) procedure, depending on T status and size of the tumor. Nodal involvement in gastric cancer occurs in only 2-18% when the depth of cancer invasion is limited to the mucosal or submucosal layer (T1), and in about 50% when tumors invade the subserosal layer (T2)4. In patients with tumor-negative lymph nodes, a SLN procedure could avoid the risk of morbidity and mortality of an unnecessary lymphadenectomy. Additionally, in patients who are undergoing a partial or total gastrectomy combined with lymphadenectomy, identi cation of potentially involved LNs outside the standard plane of resection is possible by detecting the SLN. In this way, also in tumors with higher T stages, one can nd the true rst tumor draining LN(s), and not leaving them in situ. As the lymphatic drainage route of gastric cancer is generally multidirectional and complicated5, intraoperative assistance in identi cation of potentially involved lymph nodes could improve gastric cancer treatment.
SLN detection in gastric cancer was rst described by Kitagawa et al.6 Since then, multiple studies were performed. A prospective multicenter trial in 433 patients with T1 or T2 stadium tumors showed an accuracy rate of 99% for identi cation of metastasis in SLNs with the use of a dual tracer consisting of radiolabeled tin colloid and blue dye7.
Near-infrared (NIR) uorescence imaging is an innovative technique to visualize tumors, vital structures, lymphatic channels, and LNs8. Soltesz et al.9 in a preclinical setting and Kusano et al.10 in a clinical setting were the rst to report the SLN procedure in gastric cancer using NIR uorescence imaging. Since then, multiple studies con rmed the feasibility of this technique for both open and laparoscopic surgery11-15. All clinical studies reported to date
SLN detection in gastric cancer 23