Safety of indocyanine green for lymph node mapping in early-stage vulvar cancer: multicenter evaluation and systematic review

PURPOSE: This study aimed to evaluate the rate and severity of allergic events associated with the use of indocyanine green (ICG) in sentinel lymph node biopsy (SLNB) for patients with early-stage vulvar cancer. The research question focused on whether ICG administration poses a significant risk of allergic reactions, especially in patients with a history of allergies to iodinated contrast. METHODS: We conducted a retrospective study after prospective multicenter recruitment endorsed by the Spanish Investigational Network Gynecologic Oncology Group. Data on patient demographics, history of allergic reactions, and ICG administration were collected. A systematic literature review was performed to assess existing studies on ICG-related allergic reactions in SLNB. RESULTS: Among the 75 patients, 66 (75%) have been exposed to iodinated contrasts and 2 (3%) had a documented iodinated contrast allergy with a mild reaction. There were no intraoperative complications. During the postoperative period, there were only minor complications (15 (20.0%) grade I and 13 (17.3%) grade II of Clavien-Dindo classification), and none associated with the injection of ICG or allergen-based that could be related. The systematic review of 11 studies involved 206 patients and 354 groins. The history of allergy to iodinated contrast was not recorded in any of them. We observed no patients with adverse reactions related to this tracer after peritumoral injection. CONCLUSION: Our findings suggest that peritumoral ICG injection for SLNB in early-stage vulvar cancer could be safe. This study reinforces the potential for ICG to be a reliable tracer in vulvar cancer staging.