Ex vivo sentinel node mapping in colon cancer combining blue dye staining and fluorescence imaging.

Background: The sentinel lymph node procedure has been proposed to improve nodal staging in colon cancer patients. The aim of this study was to assess the added value of near-infrared (NIR) fluorescence imaging to conventional blue dye staining for ex vivo sentinel lymph node mapping.

Materials And Methods: We included 22 consecutive patients undergoing surgery for colon cancer. After tumor resection, we submucosally injected a premixed cocktail of the near-infrared lymphatic tracer HSA800 and blue dye around the tumor for detection of sentinel lymph nodes. We used the Mini-FLARE imaging system for fluorescence imaging.

Results: In 95% of patients, we identified at least one sentinel lymph node. Overall, a total of 77 sentinel lymph nodes were identified, 77 of which were fluorescent (100%) and 70 of which were blue (91%). Sentinel lymph nodes that were located deeper in the mesenteric fat could easily be located by NIR fluorescence. In four of five patients with lymph node metastases, tumor cells were present in at least one of the sentinel lymph nodes.

Conclusions: This study shows the successful use and added value of the NIR fluorescence tracer HSA800 to conventional blue dye for the ex vivo sentinel lymph node procedure in colon cancer.