RT Journal Article SR Electronic T1 30 Evolution and outcomes of sentinel lymph node mapping in vulvar cancer JF International Journal of Gynecologic Cancer JO Int J Gynecol Cancer FD BMJ Publishing Group Ltd SP A18 OP A18 DO 10.1136/ijgc-2019-IGCS.30 VO 29 IS Suppl 3 A1 V Broach A1 N Abu-Rustum A1 Y Sonoda A1 C Brown A1 E Jewell A1 G Gardner A1 D Chi A1 O Zivanovic A1 J Mueller A1 K Long Roche A1 M Leitao YR 2019 UL http://ijgc.bmj.com/content/29/Suppl_3/A18.1.abstract AB Objectives We sought to characterize our experience with SLN biopsy in patients with vulvar cancer, focusing on the modality of SLN detection.Methods We performed a retrospective analysis of patients who underwent inguinofemoral SLN biopsy for vulvar cancer at Memorial Sloan Kettering Cancer Center from 1/1/2000–4/1/2019. An “at-risk groin” was defined as the inguinofemoral lymph nodes from either the right or left groin for which SLN biopsy was performed. Pearson’s Chi-Squared test was used for comparison of categorical variables.Results 160 patients were included, representing 265 at-risk groins. Demographic and pathologic features are summarized in the table 1. Patients underwent mapping with a combination of Technicium-99 radiocolloid injection (TC-99), blue dye injection, or near-infrared imaging with indocyanine green (ICG) injection. SLN detection rate, irrespective of modality, was 96.2%. TC-99 + Blue dye detected SLNs in 91.8% of groins, and TC-99 + ICG detected SLNs in 100% of groins (p = 0.157). The use of ICG alone resulted in an SLN detection rate of 96.3% (26/27). Among the 110 groins that underwent mapping with TC-99 and blue dye, 4 patients mapped with TC-99 alone (3.6%). Among the 96 groins that underwent mapping with TC-99 and ICG, 14 mapped with ICG alone (14.6%).View this table:Abstract 30 Table 1 Conclusions The use of ICG for inguinofemoral SLN mapping has increased over the past decade and is associated with the highest rates of SLN mapping of any modality.