526MO - Pathological assessment of sentinel lymph node in early-stage cervical cancer: Results from the prospective SENTIX trial (CEEGOG-CX01; ENGOT-CX2)

Background

Lymph node (LN) involvement is the key factor indicating adjuvant treatment in early-stage cervical cancer patients. Both macrometastases (MAC; >2mm) and micrometastases (MIC; 0.2-2 mm) are considered LN positive (pN1) since a negative impact of MIC similar to MAC has been confirmed by several studies. Although the majority of MIC are detected only by pathological ultrastaging of LN, no international protocol for pathological assessment has been agreed upon and still sparks controversy.

Methods

SENTIX is a prospective international observational study on sentinel lymph node (SLN) biopsy in cervical cancer patients conducted in 47 sites of 18 countries. Enrolled were patients with stage T1A1/L1 – T1B1 (<4 cm or ≤ 2 cm for fertility sparing; FIGO2018), common tumour types, no suspicious LN on imaging, and bilateral SLN detection. All detected SLN were intraoperatively examined by one section (standard assessment), and consequently processed by intensive protocol of pathological ultrastaging (2 mm slices embedded in paraffin; paraffin blocks sectioned completely in 150 μm intervals; two sections from each level, one stained with H&E and second examined immunohistochemically). Pathological SLN samples from randomly selected patients from each site were submitted for central quality assessment.

Results

Out of 647 prospectively enrolled patients, 82 were pN1 (12.7%), 43 with MAC and 39 with MIC (largest type of metastasis). Standard assessment detected only 56.1% of pN1 cases (83.7% MAC; 25.6% MIC) (Table). Additional 22 patients were diagnosed with isolated tumour cells (ITC; <0.2mm), 20 of them found by ultrastaging. Table: 526MO

SLN pathological assessment

ITC: isolated tumour cells; MAC: macrometastases; MIC: micrometastases

Conclusions

The number of patients diagnosed with pN1 is directly related to the intensity of SLN pathological assessment. Pathological ultrastaging of SLN should be mandatory in patients with cervical cancer as it detects almost half of the cases with pN1. The protocol should consist of at least 4 levels.

Clinical trial identification

NCT02494063.

Editorial acknowledgement

Legal entity responsible for the study

The authors.

Funding

Charles University in Prague (COOPERATIO) Ministry of Health of the Czech Republic (MH CZ – DRO-VFN64165) Czech Health Research Council (NV19-03-00023).

Disclosure

All authors have declared no conflicts of interest.