Indocyanine green guidance for combined robotic pelvic and para-aortic sentinel node mapping in cervical cancer.

Background: Indocyanine green (ICG) for pelvic sentinel lymph node (SLN) mapping is well established in endometrial cancer (Persson et al., 2019 Jul). However, the application for para-aortic SLNs is less reported; and the detection rate of para-aortic SLNs, mainly after cervical injection of ICG, varies between 14% and 71% (Rossi et al., 2013 Nov; Kim et al., 2020 Mar; Gallotta et al., 2019 Mar). One recent report differentiates between lower and upper para-aortic SLNs in endometrial cancer (Kim et al., 2020 Mar). Here we describe a technique using ICG for identifying pelvic SLNs, lower and upper para-aortic SLNs in cervical cancer.

Video: A 46-year old female presented with high grade cervical dysplasia/carcinoma in situ on cervical smear. Cervical cone biopsy revealed a grade two squamous cell carcinoma (depth of invasion 6.8mm, width 20.8mm). Clinically she was staged as an early FIGO-stage IB2 cervical cancer. NMR revealed bilaterally enlarged iliac lymph nodes. Additional PET-CT revealed FDG-uptake in the enlarged pelvic lymph nodes. In view of the imaging findings a staging Robotic pelvic and para-aortic SLN procedure was planned, prior to select the primary treatment (radical hysterectomy or chemo-radiation). ICG was injected into the cervical stroma, and a robotic pelvic and para-aortic SLN dissection (using Firefly System ®, Intuitive Surgical Inc.) was initiated 15 minutes and 35 minutes, respectively, after cervical injection.

Results: This video demonstrates the application of ICG for mapping bilateral primary pelvic SLNs, secondary and tertiary para-aortic SLNs in the lower and upper para-aortic region respectively, in cervical cancer. Pathology revealed one metastatic pelvic SLN on the left side, other four pelvic SLNs were negative; both the secondary/lower (n = 3) and tertiary/upper (n = 5) para-aortic SLNs were negative, as well as the non-SLNs (n = 8).

Conclusion: The application of ICG for para-aortic SLN mapping should further be investigated and validated in staging surgically locally advanced cervical cancer and those with suspicious lymph nodes on imaging.