Indocyanine Green versus Radiotracer with or without Blue Dye for Sentinel Lymph Node Mapping in Stage >IB1 Cervical Cancer (>2 cm)

Abstract

Study objective: To compare sentinel lymph node (SLN) mapping in women with cervical cancer stage >IB1 (tumor size >2 cm) using indocyanine green (ICG) versus the standard technique using radioisotope technetium 99m radiocolloid (Tc99^m) radiotracer with or without blue dye.

Design: European multicenter, retrospective observational study (Canadian Task Force classification II-2).

Setting: Four academic medical centers.

Patients: Ninety-five women with stage IB1 cervical cancer (>2 cm) who underwent SLN mapping with Tc99^m with or without blue dye or ICG and radical hysterectomy.

Intervention: The detection rate and bilateral mapping rate were compared between ICG and standard Tc99^m radiotracer with or without blue dye. Lymphadenectomy was performed, and the false-negative rate was assessed.

Measurements and main results: Forty-seven patients underwent SLN mapping with Tc99^m with or without blue dye, and 48 did so with ICG. All patients underwent radical hysterectomy with or without bilateral salpingo-oophorectomy between 2008 and 2016. The overall detection rate of SLN mapping was 91.5% for Tc99^m with or without blue dye and 100% for ICG. A 91.7% rate of bilateral migration was achieved for ICG, significantly higher than the 66% obtained with Tc99^m with or without blue dye (p = .025). Nine of the 23 SLN-positive patients (39.1%) were diagnosed exclusively as a result of the ultrastaging used to identify micrometastases or isolated tumor cells only.

Conclusions: In advanced cervical cancer (stage IB1 >2 cm), the detection rate and bilateral migration rate on real-time fluorescent SLN mapping were higher with ICG than with Tc99^m radiotracer with or without blue dye. SLN mapping and ultrastaging can provide additional information for nodal staging in advanced cervical cancer. In this setting, ICG is a promising tool for mapping, appearing less affected by higher disease stage compared with traditional methods.

Keywords: Bilateral mapping; Early-stage cervical tumor; Lymphoscintigraphy.