Zekan 2012.

Study characteristics
Patient sampling	Prospective study; consecutive enrolment; withdrawals unclear
Patient characteristics and setting	25 women with vulval SCC (50 groins); clinical stage I and II; depth of invasion > 1 mm 14 women had midline lesions and 11 had lateralised lesions Excluded women with clinically suspicious groin nodes, previously treated vulval SCC Median age: 69 years (48 to 79) Setting: university hospital in Croatia; December 2007 to May 2011
Index tests	Tc‐99m only Histological methods: ultrastaging not described. Standard sections with H&E staining were performed on all SNs. If these were negative, IHC staining with cytokeratin was performed. H&E stains were used for all other RS nodes; if IHC staining of SNs was negative, IHC staining was done on other RS nodes
Target condition and reference standard(s)	TC: groin lymph node involvement RS: complete IFL
Flow and timing	3 hours pre‐operatively, Tc‐99m was injected peritumourally at 4 sites (15 to 20 MBq) and LSG was done. Detected intra‐operatively by gamma probe. Dissection was continued if more 'hot' nodes were identified (> 10% of the 'hottest' SN). SND and RS were performed during the same operation Withdrawals were not described
Comparative
Notes	In a preliminary report (Corusic 2011 conference abstract) 29 women underwent SN assessment. Zekan 2012 reports the results of only 25 women. The authors confirmed via e‐mail that these data are from the same series, however we were unable to ascertain the reasons for the 4 exclusions, therefore we considered the potential risk of bias to be high for patient flow. The same surgeon performed all procedures although the first 10 patients included represent the 'learning curve'. Investigators reported the results separately for the first 10 and subsequent procedures Tumours were classified as 'midline' if within 2 cm of the midline. All women had bilateral IFL regardless of proximity to midline
Methodological quality
Item	Authors' judgement	Risk of bias	Applicability concerns
DOMAIN 1: Patient Selection
Was a consecutive or random sample of patients enrolled?	Yes
Was a case‐control design avoided?	Yes
Did the study avoid inappropriate exclusions?	Unclear
		Unclear	Low
DOMAIN 2: Index Test Test group
Had the test operator performed 10 or more procedures?	Unclear
		Unclear	Low
DOMAIN 3: Reference Standard
Is the reference standards likely to correctly classify the target condition?	Yes
Were the reference standard results interpreted without knowledge of the results of the index tests?	Unclear
		Unclear	Low
DOMAIN 4: Flow and Timing
Was there an appropriate interval between index test and reference standard?	Yes
Did all patients receive the same reference standard?	Yes
Were all patients included in the analysis?	Unclear
Were other imaging tests performed prior to the index test to rule out groin lymph node metastases?	Unclear
		High

Abbreviations: FIGO = International Federation of Gynecology and Obstetrics; FNA = fine needle aspiration; H&E = haematoxylin and eosin; IFL = inguinofemoral lymphadenectomy; IHC = immunohistochemical; LN = lymph node; LND = lymph node dissection; LSG = lymphoscintigraphy; NPV = negative predictive value; NR = not reported; RS = reference standard; RT‐PCR = reverse transcriptase polymerase chain reaction; Tc‐99m = radiolabelled technetium