Introduction
Over the past decades, sentinel lymph node biopsy (SLNB) has become an
attractive surgical procedure in many malignancies.1-5The benefits of SLNB mainly include a reduction in surgical morbidity
and time cost, achieved by replacing lymphadenectomies in selected
patients,6,7 and revelation of aberrant drainage
regions that are probably omitted during routine
lymphadenectomies.8 Furthermore, by pathological
ultrastaging of sentinel lymph nodes (SLN), the
micro-metastatic
burden in lymphatic system can be evaluated conveniently, enabling more
precise individualized treatments.9-11 With these
benefits and high accuracy.12 SLNB is currently
recommended as an alternative of pelvic lymph node dissection (PLND) in
early-stage cervical cancer.13,14
However, in clinical practice, only a few authors have attempted to
perform SLNB alone without a further PLND.6,7,15 A
recent international survey by the
Gynecologic Cancer Intergroup
showed great divergence regarding the SLNB strategy,16reflecting worldwide mistrust on intraoperative decisions made based on
SLNB. Indeed, previous studies had shown that the accuracy of SLNB
largely relied on postoperative ultrastaging,17,18which is time consuming and unavailable for intraoperative
decision-making. As a result, many gynecologists choose to directly
replace PLND with SLNB in radical surgery and wait for final pathology.
However, nodal metastasis has been included as IIIC stage in the latest
International Federation of Gynecology and Obstetrics (FIGO) staging
system,19 so it is becoming increasingly important to
acquire the lymphatic status before deciding treatment modality. The
European Society of Gynaecological Oncology/European Society for
Radiotherapy and Oncology/European Society of Pathology guidelines
(2018) therefore recommended submitting SLNs for intraoperative
assessment to immediately triage patients towards radical surgery or
definitive chemoradiotherapy.14 Consequently, accurate
intraoperative pathology of SLNs is urgently required.
Frozen section examination (FSE) is the most common method for
intraoperative SLN
assessment.20 Compared with other methods, FSE has a
natural superiority of almost 100% specificity.21-23However, the sensitivity of FSE
varies
considerably between the published studies.24-35 Some
authors had cautioned the high false-negative rate of FSE in
SLNB,24-27,29 whereas others provided
satisfying
results.30,32-35 The reason for such a discrepancy
remains unclear and
may
be associated with the heterogeneity among these studies, including the
differences in methodologies, patients’ characteristics, volume of
metastases, as well as pathologists’ experiences. However, few studies
had concerned the impacts of these factors on the sensitivity of
FSE.29,33 It spontaneously interests us whether there
exists an optimal protocol by which the FSE can yield the highest
sensitivity for intraoperative decision-making.
To our knowledge, there are several ongoing international multicenter
trials targeting the validation of SLNB in early-stage cervical
cancer.36,37 All these trials were designed with an
intraoperative randomization or assignment depended on the results of
FSE. Therefore, it is of great importance to validate the accuracy of
FSE first. In this systematic review and meta-analysis, we analyzed the
available data on this issue, in order to determine the diagnostic
performance and optimal protocol of FSE in SLNB for cervical cancer and
provide evidence for ongoing and future studies.