Sentinel Lymph Node Technique in Apparent Early Ovarian Cancer: Laparoscopic Technique.

Study Objective: To demonstrate the feasibility of laparoscopic sentinel lymph node technique in presumed early-stage ovarian cancer.

Design: Video illustrating the laparoscopic performance of the sentinel lymph node technique in ovarian cancer.

Setting: The Oncologic Gynecology Department at the University Hospital La Fe.

Patients: Candidates for the technique presented an apparent early stage ovarian cancer. The technique was performed in the context of a clinical trial called SENTOV (NCT03452982).

Interventions: To date, lymphadenectomy is recommended after the diagnosis of apparent early-stage ovarian cancer as part of the surgical staging. Minimally invasive surgery can be considered for the purpose of restaging [1]. Up to 14% of the patients are upstaged because of positive lymph nodes after pelvic and para-aortic lymphadenectomy [2]. Regarding low-grade tumors, a lower rate of lymph node involvement has been reported [3]. Sentinel lymph node technique has been reported to be feasible in a recent pilot study [4]. Two clinical trials (Sentinel Lymph Node in Early Ovarian Cancer and Sentine Lymph Node in Early Ovarian Cancer) are currently ongoing to clarify the use of sentinel lymph node technique in early ovarian cancer. The injection points were at the infundibulopelvic and ovarian ligament stumps. Two hundred microliters of saline solution containing 37 MBq of technetium-99m nanocolloid followed by 0.5 mL of indocyanine green (ICG) was injected subperitoneally. We used a 27 G needle at each injection point. Immediately after injection and also at 15 and 30 minutes after injection, the operative field was checked guided by the acoustic signal of the gamma probe and the near-infrared camera. We performed a minimum dissection looking for the sentinel lymph node or nodes in the pelvic and para-aortic region. Any lymph node with a remarkable radioactivity count as high as 10 times the background and/or dyed with ICG was considered a sentinel lymph node and was harvested separately. A systematic surgical staging was performed after the sentinel lymph node procedure was completed. Because of its small size, the ICG molecule is not caught in the lymph node valve system and keeps migrating when performing lymphography. An exhaustive direct view of the dye path is required to avoid misleading detection of the real sentinel lymph node. This theoretical problem is resolved by the use of the 99mTC-nanocolloid. This tracer gets trapped into the lymph node valve system because of its molecular size and does not keep migrating as does ICG. As such, a combination of both methods is proposed.

Conclusion: Laparoscopic performance of sentinel lymph node technique in ovarian cancer seems to achievable. Between 2017 and 2019, this procedure was performed in 30 patients (13 laparoscopic), in the context of our pilot experience [4] and the Sentinel Lymph Node in Early Ovarian Cancer clinical trial (NCT03452982).