Sentinel lymph node pathological ultrastaging: Final outcome of the Sentix prospective international study in patients with early-stage cervical cancer.

ABSTRACT

OBJECTIVE: To report the outcome of SLN staging in the SENTIX international prospective trial of SLN biopsy in patients with cervical cancer with an intensive ultrastaging protocol and central quality control and to evaluate how the intensity of pathological assessment correlates with metastatic detection rate in SLNs. METHODS: Eligible were patients with stages T1a1/LVSI+ to T1b2 (<4 cm, ≤2 cm for fertility sparing), common tumor types, no suspicious lymph nodes on imaging, and bilateral SLN detection. SLNs were examined intraoperatively and processed by an intensive protocol for ultrastaging (paraffin blocks sectioned completely in 150-µm intervals/levels). SLNs from each site were submitted for central quality control. RESULTS: In the SENTIX SLN study, 647 out of 733 enrolled patients underwent SLN ultrastaging, identifying 12.5% (81/647) with node positive, N1 cases. Intraoperative detection revealed metastases in 56.8% (46/81) of these cases, categorized into macrometastases (83.7%), micrometastases (26.3%), and isolated tumor cells (9.1%). Ultrastaging identified additional metastatic involvement in 43.2% (35/81) of patients, with detailed sectioning revealing metastases (MAC/MIC) at first level in 20 cases (24.7%), at levels 2-4 in 9 cases (11.1%), and at level ≥5 in 6 cases (7.4%). CONCLUSION: SLN ultrastaging detects additional 43% of N1 (MAC/MIC) in patients with negative LNs by imaging and intraoperative pathological assessment. The detection rate of positive SLN correlates with the intensity (number of levels) of ultrastaging. Examination of four levels from paraffin blocks, which detects >90% of patients with N1, is a reasonable compromise for an international standard for ultrastaging. STUDY REGISTRATION NCT02494063 (ClinicalTrials.gov).