Indocyanine green and methylene blue dye guided sentinel lymph node biopsy in patients with penile cancer (PeCa): results of 50 inguinal basins assessed at a single institution in India

Aim The primary aim of this study was to validate the reliability, sensitivity and safety profile of novel combination of ICG- methylene blue dye as an SN tracer for PeCa. Methods This is a validation and non-randomised prospective observational study involving 25 patients (50 inguinal basins) who underwent SLNB where in ICG and methylene blue were used for localisation. The patients with clinically node negative groins were recruited in the study. SNs were identified intraoperatively using near infrared fluorescence imaging (NIRF Imaging system, SPY-PHI, Stryker, Sweden) and blue dye. The numbers of SNs identified by each tracer and the rates of complications and nodal recurrence during the followup. Results Overall 137 SNs were identified intraoperatively. Among the 137 SNs excised fluorescence, blue dye and Combined (blue + green) identified 57(41.6%), 27 (19.7%), and 51 (37.2%), respectively. The average number of SLNs removed per patient was 5 (range, 1–11) with sentinel lymph nodes detection rate at 94% (47/50). Seven patients had malignancy on SLNB and underwent ipsilateral radical inguinal lymphadenectomy. One patient had false negative SN and positive node in modified inguinal lymphadenectomy specimen. No adverse events were observed in all cases. Conclusion The Novel combination of ICG fluorescence-Methylene blue dye technique is simple, reliable and safe. Moreover, it demonstrates a high SLN detection rate with a low false-negative rate, and it avoids radiation exposure.