Introduction/Background*SENTIX is a prospective cohort multicentric international study on sentinel lymph node (SLN) biopsy without pelvic lymph node dissection (PLND) in patients with early-stage cervical cancer. SLN frozen section (FS) and pathological ultrastaging were mandatory by the protocol. Samples from SLN were reviewed centrally for pathological assessment quality control. Only sites experienced in SLN biopsy technique could join the trial.

Methodology In total, 47 sites from 18 countries participated in the trial. Patients with FIGO 2009 stages T1A1/LVSI+ – T1B1 (<4 cm or ≤ 2 cm for fertility sparing), with common tumour types and no suspicious lymph nodes on imaging were registered in the trial. Patients remained in the trial after the surgery if SLN were detected on both sides of the pelvis and if SLN were negative on FS histological evaluation. Blue dye, radioactive tracer, indocyanine green or their combinations were all eligible tracers for SLN detection. Intraoperative SLN pathological processing consisted of SLN examination in one randomly selected slice. SLN ultrastaging protocol included a complete processing of all SLN tissue in slices of 2 mm thickness, 2 sections in 150 μm from each block until no tissue left, one stained with H&E and second examined immunohistochemically.

Result(s)*Altogether 733 patients were registered until Sentix enrolment closure in October 2020, 83 patients were excluded (table 1) and 650 patients was analysed. Patients` characteristics are shown in table 1. Bilateral SLN detection rate reached 95%. FS detected macrometastases (MAC) in 44 cases and micrometastasis (MIC) in 4 cases. SLN ultrastaging found additional 9 cases with MAC, 26 with micrometastases (MIC) and all 19 cases with isolated tumor cells (ITC). Sensitivity of FS was 83.0% for the detection of MAC, 57.8% for pN1 status (MAC or MIC) and 47.1% for any type of SLN involvement (MAC, MIC, ITC). Table 2.

Conclusion*High bilateral detection rate of 95% was achieved in Sentix sites experienced in the SLN biopsy technique. Intraoperative pathological assessment of SLN failed to detect majority of MIC (86.7%), all cases with ITC and 42.2% with pN1 (MIC or MAC).