Role of blue dye for sentinel lymph node detection in early endometrial cancer.

Background: Sentinel Lymphonode analysis has become a barely new and innovative way to treat early stages of endometrial cancer (Ballester et al., Lancet Oncol 469-476, 2011; Buda et al., Ann Surg Oncol 2975-81, 2016). Indocyanine green cervical injection is considered gold standard for mapping nodes' drainage. Blue dye is used as a valid alternative in many centers, due to the lower cost of execution. The objective of this video is to prove that methylene blue dye's cervical injection is a valid and "low-cost" method to obtain mapping of lymphatic drainage in patient with early endometrial cancer.

Methods: Fifty-four-year old women, with a recent diagnosis of endometrial cancer IA G2, we performed a radical Hysterectomy type A. We diluted in equal proportions the blue dye and saline and injected 1 cl in depth and 1 cl on the surface of the cervix, at 3 o'clock and 9 o'clock. After 20 min, it was shown with precision the lymphatic drainage until the first lymph node station from both sides.

Results: One external iliac lymph node and one obturator were resected on the left side and one external iliac on the right side. On histological analysis, none of the lymph nodes had any location of metastasis, neither micro-metastasis. Myometrial infiltration was 8/19 mm.

Conclusions: Blue dye cervical injection is a "low-cost", safe, and satisfactory procedure to point out Sentinel Lymph Node of uterus drainage. Other tracers, such as indocyanine green, are widely used in gynecological oncology, but with a higher cost of the product and the needing of a dedicated optical filter to be shown on human view.