Real-time Fluorescent ICG and 99m-Tc Nanocolloid Tracer Navigation in Bilateral Sentinel Lymph Node Mapping of Vulvar Cancer

Abstract

The effectiveness of sentinel lymph node (SLN) biopsy has been validated by two prospective trials, GROINS VI and GOG 1731-2. According to ESGO guideline in patients with unifocal tumors with a diameter of <4 cm, in the absence of suspected inguinal lymph nodes, SLN biopsy is recommended. The use of a radioactive tracer is mandatory.2 Using Indocyanine green (ICG) increase the detection of the vulvar sentinel node from 89.7 to 100%3. Aim of this video is to share our experience about the feasibility, safety and usefulness of the surgical identification of SLN in vulvar cancer using real-time fluorescent indocyanine green with 99m-technetium nanocolloid. Stepwise demonstration of the technique with narrated video footage. Tertiary level hospital "IRCCS Istituto Nazionale dei Tumori", Milano, Italy. A 50-year-old woman was diagnosed with vulvar cancer on biopsy of 1.5 cm size vulvar lesion under the clitoris area and referred to our Operative Unit. F-18 fluorodeoxyglucose positron-emission tomography-computed tomography (PET) showed no extra-vulvar disease. The patient was scheduled for radical vulvectomy and bilateral inguinal sentinel lymph-node biopsy (SLN). In this video the surgical procedure involved double location of SLN, first with the 99m-technetium detector followed by ICG identification. We used an ICG dilution of 2.5 mg/mL in sterile water and injected 4 mL around the tumor 5-10 min before visualization. First a handheld gamma probe used to identify the location of the SLN(s) with 99m-technetium. The fluorescence imaging was performed by the quest imaging system (FLUOPTICS©, Middenmeer, The Netherlands) that combine autofluorescence and fluorescence perfusion imaging. Second, we carried out the SLN biopsy using a dark mood procedure to identify the IGC tracer. The fluorescence imaging enables the detection of these markers through some millimeters of tissue and ICG has the advantage that is visible through the skin4. This video shows a successful combined 99m-technetium and ICG fluorescence image-guided bilateral SLN biopsy in a vulvar cancer patient using a near-infrared (NIR) optical imaging system (FLUOPTICS©). ICG for SLN mapping appears to be safe in women with vulvar cancer with a satisfactory detection rate. This may help in retaining surgical radicality while minimizing operative complications.