Objective: To assess the diagnostic accuracy of intraoperative SLN frozen section analysis compared with ultrastaging in patients with early-stage cervical cancer.
Methods: A systematic literature review was conducted following the PRISMA checklist. MEDLINE (via Ovid), Embase, and the Cochrane Central Register of Controlled Trials were searched from inception until February 2023. The inclusion criteria were patients with early-stage cervical cancer (2018 FIGO stage I-II), consisting of the histological subtype squamous cell carcinoma, adenocarcinoma, or adenosquamous carcinoma (≥90% of the patients in each study), who underwent SLN detection (with any tracer) and intraoperative frozen section followed by SLN ultrastaging. Randomized controlled trials, prospective and retrospective observational studies were considered. The detection rates and measures of diagnostic accuracy were pooled using a random effects univariate model. A preplanned subgroup meta-analysis was conducted, with isolated tumor cells excluded as positive lymph nodes. The review was registered in PROSPERO (CRD42023397147).
Results: The search identified 190 articles, with 153 studies considered potentially eligible after removing duplicates. Fourteen studies met the selection criteria, including a total of 1720 patients. Seven studies were retrospective, and the other seven were prospective. Frozen section analysis detected 159 of 292 (54.5%) patients with lymph node metastases. In 281 patients the type of volume metastasis was reported: 1 of 41 (2.4%) patients had isolated tumor cells, 21 of 78 (26.9%) patients had micrometastases, and 133 of 162 (82.1%) patients had macrometastases. The pooled sensitivity of intraoperative SLN frozen section analysis was 65% (95% CI, 51-77%) for macrometastases, micrometastases, and isolated tumor cells. When we excluded patients with isolated tumor cells, the pooled sensitivity increased to 72% (95% CI, 60-82%).
Conclusion: SLN frozen section detects 65% of lymph node metastases compared with SLN ultrastaging and may prevent unnecessary radical surgery in some patients with early-stage cervical cancer.
Keywords: Frozen section; Sentinel lymph node; Uterine cervical cancer.
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