Sentinel Lymph Node Biopsy Using Preoperative Computed Tomographic Lymphography and Intraoperative Indocyanine Green Fluorescence Imaging in Patients With Localized Tongue Cancer

Abstract

The indocyanine green method alone is unsuitable for sentinel lymph node biopsy in patients with oral cancer because of poor transcutaneous identification of the fluorescent signal through the platysma and sternocleidomastoid muscles. To assess the utility of a novel sentinel lymph node biopsy technique using preoperative computed tomographic (CT) lymphography followed by the intraoperative indocyanine green fluorescence method. In this prospective study performed at Akita University Hospital, Akita, Japan, participants comprised 18 patients with previously untreated cN0 tongue cancer (squamous cell carcinoma) were enrolled from November 2012 to November 2016. Median observer period was 38 (range, 14-62) months. Analysis was completed between January 10 and March 10, 2018. For preoperative sentinel lymph node mapping, CT lymphography was performed the day before sentinel lymph node biopsy. For sentinel lymph node biopsy, a minimum skin incision was made according to the predetermined location of sentinel lymph nodes. Sentinel lymph nodes were excised under indocyanine green fluorescence guidance. Identification rate of preoperative sentinel lymph node mapping by CT lymphography and the number of sentinel lymph node successfully identified by the intraoperative indocyanine green fluorescence method. Among 18 patients (8 men, 10 women; median age, 65.5 [range, 40-83] years), sentinel lymph nodes could be mapped by preoperative CT lymphography in 16 patients (89%). At least 1 sentinel lymph node was successfully identified and excised in each of these 16 patients using intraoperative indocyanine green fluorescence. Among the 16 patients in whom sentinel lymph nodes were excised, metastases to sentinel lymph nodes were found in 5 patients (31%). The novel sentinel lymph node biopsy technique of preoperative CT lymphography mapping with intraoperative indocyanine green fluorescence has a high potential for identifying sentinel lymph nodes in patients with cN0 tongue cancer. Because the intraoperative indocyanine green method alone cannot identify sentinel lymph nodes in the neck region, this combined method has clinical potential as a sentinel lymph node biopsy technique that does not require radioisotopes.