Key issues in diagnostic accuracy of sentinel lymph node biopsy in early-stage ovarian cancer: systematic review and meta-analysis

Objective Sentinel lymph node (SLN) mapping may reduce the morbidity of lymphadenectomy while maintaining diagnostic accuracy. Nevertheless, SLN mapping in epithelial ovarian cancer is still under investigation. This systematic review and meta-analysis aimed to assess the detection rate and diagnostic accuracy of SLN mapping for each field (pelvic and para-aortic), and to evaluate the tracers and doses used. Methods A systematic search was conducted in PubMed, Cochrane Library, Scopus, and Web of Science. Patients with clinical stages I–II ovarian cancer undergoing SLN biopsy (index test) and a systematic pelvic and para-aortic lymphadenectomy (reference standard) were included. Risk of bias was assessed using the Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2) tool. A meta-analysis was performed to assess SLN mapping detection rates and diagnostic accuracy for each field (pelvic and para-aortic) and by subgroups (type of tracer and dosage). Results 239 patients from four studies were included. The SLN detection rate was 59.5% (95% CI 50.2 to 68.1%) and 64.4% (95% CI 58.2 to 70.2%) for the pelvic and para-aortic fields, respectively. The use of technetium-99 (99mTc), alone or in combination, compared with the use of indocyanine green alone, was associated with a higher detection rate in both the pelvic (66.6%; 95% CI 53.3 to 78.3%; p=0.1211) and para-aortic (87.1%; 95% CI 76.9 to 93.9%, p=0.0000013) fields. The use of 0.2–0.5 mL of indocyanine green was associated with higher pelvic (68%; 95% CI 53.3 to 80.4%, p=0.1057) and para-aortic (88.3%, 95% CI 77.4 to 95.2%, p=0.0000018) detection rates compared with a 2 mL indocyanine green injection. Diagnostic accuracy, sensitivity, specificity, and negative predictive value of SLN for lymph node metastasis were: 100% each for the pelvic field and 98.1%, 85.7%, 100%, and 97.8%, respectively, for the para-aortic field. Conclusion The use of 99mTc in combination with a low volume injection (0.2–0.5 mL) of indocyanine green increased SLN detection rates. In apparent early stage epithelial ovarian cancer, SLN is a feasible technique with a high diagnostic accuracy.