Sectioning protocol determines accuracy of intraoperative pathological examination of sentinel lymph node in cervical cancer: A systematic review and meta-analysis

Objectives: To determine the diagnostic performance and optimal protocol of frozen section examination (FSE) in SLNB for cervical cancer.

Methods: PubMed, EMBASE, Web of Science, Cochrane Library, Wanfang Data and China National Knowledge Infrastructure were searched from inception to July 30, 2019, for studies concerning SLNB with FSE in cervical cancer. Sensitivity of FSE in detecting SLN metastasis was the primary diagnostic indicator for evaluation.

Results: The pooled sensitivity of FSE among 31 eligible studies (1887 patients) was 0.77 (95% CI 0.66-0.85) with high heterogeneity (I² = 69.73%). Two representative sectioning protocols for FSE were identified from 26 studies, described as equatorial (E-protocol, SLN was bisected) and latitudinal (L-protocol, SLN was cut at intervals). Meta-regression showed that FSE protocol was the only source of heterogeneity (p < 0.001). The pooled sensitivity was 0.86 (95% CI 0.79-0.91, I² = 0%) and 0.59 (0.46-0.72, I² = 58.47%) for FSE using L- (13 studies, 650 patients) and E- (13 studies, 1047 patients) protocol, respectively. Among the available data, marcometastases (>2 mm) were missed in 4 and 20 patients; small-volume metastases (≤2 mm) were detected in 13 and 2 patients, respectively, under L- and E-protocol. The pooled sensitivity of FSE using L-protocol would reach 0.97 (95% CI 0.89-0.99) if only marcometastases were considered. These findings were robust to sensitivity analyses.

Conclusion: The sectioning protocol determines the accuracy of FSE in SLNB. With L-protocol, FSE can provide precise intraoperative pathology for SLNB, which enables immediate decision-making for individualized managements.