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

Study objective: The effectiveness of sentinel lymph node (SLN) biopsy has been validated by 2 prospective trials, GROINS VI and GOG 173 [1,2]. According to the European Society of Gynaecological Oncology 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) increases the detection of the vulvar sentinel node from 89.7% to 100% [3]. This video aimed to share our experience about the feasibility, safety, and usefulness of the surgical identification of SLN in vulvar cancer using real-time fluorescent ICG with 99m-technetium (Tc) nanocolloid. Design: A stepwise demonstration of the technique with narrated video footage. Setting: Tertiary level hospital "IRCCS Istituto Nazionale dei Tumori," Milano, Italy. Interventions: A 50-year-old woman was diagnosed as having 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 showed no extravulvar disease. The patient was scheduled for radical vulvectomy and bilateral inguinal SLN biopsy. (Video still 1) In this video, the surgical procedure involved double location of SLN, first with the 99m-Tc 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 to 10 minutes before visualization. First a handheld gamma probe used to identify the location of the SLNs with 99m-Tc. The fluorescence imaging was performed by the quest imaging system (FLUOPTICS, Middenmeer, The Netherlands) that combines autofluorescence and fluorescence perfusion imaging (Video Still 2). Second, we performed the SLN biopsy using a dark mode procedure to identify the IGC tracer (Video Still 3). The fluorescence imaging enables the detection of these markers through some millimeters of tissue, and ICG has the advantage that is visible through the skin [4]. Conclusion: This video shows a successful combined 99m-Tc and ICG fluorescence image-guided bilateral SLN biopsy in a vulvar cancer patient using a near-infrared optical imaging system (FLUOPTICS). ICG for SLN mapping seems to be safe in women with vulvar cancer with a satisfactory detection rate. This may help in retaining surgical radicality while minimizing operative complications.