Data extraction and quality assessment
We extracted detailed information
from the full texts of included studies (supplementary p7). Outcomes of
interest was
the
diagnostic performance of FSE of SLN, including sensitivity, true
positives (TP) and false negatives (FN). The reference standard was DPE
based on the paraffin sections of SLN. Sensitivity was assumed as the
primary indicator of the diagnostic
performance and defined as the ratio of cases having both positive FSE
and DPE within all DPE-positive patients. TP were defined as cases
having both positive FSE and DPE, and FN as cases having negative FSE
and positive DPE. Isolated tumor cells (ITC) were defined as tumor
diameter <0.2 mm, micrometastasis (MIM) as between 0.2 and 2
mm, and macrometastasis (MAM) as >2 mm. We took these
parameters directly from the original papers or calculated them with
available
information.
We
excluded cases who had no SLN detected or did not underwent FSE.
Whenever a calculation was impossible, we contacted the authors for
necessary information.
In previous publications the term FN usually referred to cases
presenting positive non-SLN without a positive SLN. Of note, in this
study we redefined these cases as true negative given that their SLNs
were tumor-free. We assessed the qualities of the included studies using
Quality Assessment of Studies of Diagnostic Accuracy-2
(QUADAS2) tool.