BackgroundThe evaluation of PD‐L1 expression in nonsmall cell lung carcinoma (NSCLC) is becoming increasingly important given the effectiveness of PD‐L1 inhibitors. Although cytologic specimens have been shown to be compatible with surgical specimens to evaluate PD‐L1 immunohistochemistry (IHC), evidence of the reproducibility of PD‐L1 in cytologic specimens is lacking. The aim of this study is to evaluate interobserver agreement in PD‐L1 IHC in cytologic specimens.MethodsPD‐L1 IHC was performed on 86 NSCLC cytology specimens using Dako PD‐L1 IHC 22C3 pharmDx. The digitally scanned whole slide images (WSI) were read by five pathologists. Each case was given a Tumor Proportion Score (TPS) and the results were compared between the observers. The interobserver concordance was assessed using 1% and 50% as cutoffs.ResultsTPSs were highly correlated among observers (Spearman correlation coefficient, 0.86‐0.94). Using greater than 1% as a cutoff, interobserver agreement measured by Fleiss Kappa was 0.74 for all pathologists and Cohen's Kappa coefficient ranged from 0.49 to 0.83, consistent with moderate to substantial agreement. With a cutoff of greater than 50%, Fleiss Kappa was 0.79 for all pathologists and the kappa values ranged from 0.63 to 0.90, consistent with substantial to almost perfect agreement. Several pitfalls were identified by reviewing discordant cases, including staining in macrophages, stromal cells, and intratumoral heterogeneity.ConclusionOur data suggest that TPS of PD‐L1 IHC on cytology specimens is reproducible, with a better agreement when using 50% as the cutoff value. However, special attention is required when the TPS is near the 1% cutoff.
BackgroundLiquid‐based cytology (LBC) tests SurePath (SP) and ThinPrep (TP) have largely replaced conventional Papanicolaou (Pap) tests for cervical cytology screening due to higher sensitivity. However, comparison between SP and TP test sensitivity and efficacy in detecting squamous abnormalities is lacking. Our study aims to compare high‐grade squamous intraepithelial lesion (HSIL) reporting rates, human papillomavirus (HPV) positivity rates, and histologic outcome between these two LBC methods.Materials and MethodsWe performed a retrospective search of the period between January 2014 and June 2017, when both TP and SP were utilized at our institution, to identify HSIL cases and collect the HPV testing and histologic follow‐up results for those cases.ResultsOne hundred twenty‐five HSILs were identified from the 15 382 TP specimens (0.81%) and 93 HSILs were identified from the 25 105 SP specimens (0.37%), a statistically significant difference (P < .0001). The corresponding HPV positivity rates were 95.6% and 89.7% in TP‐HSILs and SP‐HSILs, respectively, a statistically non‐significant difference. Histologic follow‐up showed HSILs or carcinomas were identified in 78% (49/63) of TP‐HSILs and 79% (45/57) of SP‐HSILs, with no statistically significant difference.ConclusionTP demonstrated a higher HSIL detection rate than SP with no significant difference in follow‐up HPV or histologic results.
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