Risk of micrometastases in non-sentinel pelvic lymph nodes in cervical cancer

• Sensitivity of SLN ultrastaging is high for the presence of both macrometastases and micrometastases in non-SLN pelvic lymph nodes.
• Intraoperative pathologic SLN evaluation has high false negative rate in tumors at high risk of LN involvement.
• SLN status does not represent the status of the parametrial LNs.

ObjectiveA high sensitivity of sentinel lymph nodes (SLN) for pelvic lymph node (LN) staging has been repeatedly shown in patients with cervical cancer. However, since only SLN are evaluated by pathologic ultrastaging, the risk of small metastases, including small macrometastases (MAC) and micrometastases (MIC), in non-SLN is unknown. This can be a critical limitation for the oncological safety of abandoning a pelvic lymphadenectomy.MethodsThe patients selected for the study had cervical cancer and were at high risk for LN positivity (stage IB–IIA, biggest diameter ≥ 3 cm). The patients had no enlarged or suspicious LN on pre-operative imaging; SLNs were detected bilaterally and were negative on intra-operative pathologic evaluation. All SLNs and all other pelvic LNs were examined using an ultrastaging protocol and processed completely in intervals of 150 μm.ResultsIn all, 17 patients were enrolled into the study. The mean number of removed pelvic LNs was 30. A total of 573 pelvic LNs were examined through ultrastaging protocol (5762 slides). Metastatic involvement was detected in SLNs of 8 patients (1 × MAC; 4 × MIC; 3 × ITC) and in non-SLNs in 2 patients (2 × MIC). In both cases with positive pelvic non-SLNs, there were found MIC in ipsilateral SLNs. No metastasis in pelvic non-SLNs was found by pathologic ultrastaging in any of the patients with negative SLN Side-specific sensitivity was 100% for MAC and MIC. There was one case of ITC detected in non-SLN, negative ipsilateral SLN, but MIC in SLN on the other pelvic side.ConclusionsAfter processing all pelvic LNs by pathologic ultrastaging, there were found no false-negative cases of positive non-SLN (MAC or MIC) and negative SLN. SLN ultrastaging reached 100% sensitivity for the presence of both MAC and MIC in pelvic LNs.