Interobserver Reproducibility of PD-L1 Biomarker in Non-small Cell Lung Cancer: A Multi-Institutional Study by 27 Pathologists
- Author:
Sunhee CHANG
1
;
Hyung Kyu PARK
;
Yoon La CHOI
;
Se Jin JANG
;
Author Information
- Publication Type:Original Article
- Keywords: Programmed cell death-ligand 1; Reproducibility; Observer variation; Immunohistochemistry
- MeSH: Carcinoma, Non-Small-Cell Lung; Cell Death; Immunohistochemistry; Immunotherapy; Observer Variation; Pathology
- From:Journal of Pathology and Translational Medicine 2019;53(6):347-353
- CountryRepublic of Korea
- Language:English
- Abstract: BACKGROUND: Assessment of programmed cell death-ligand 1 (PD-L1) immunohistochemical staining is used for treatment decisions in non-small cell lung cancer (NSCLC) regarding use of PD-L1/programmed cell death protein 1 (PD-1) immunotherapy. The reliability of the PD-L1 22C3 pharmDx assay is critical in guiding clinical practice. The Cardiopulmonary Pathology Study Group of the Korean Society of Pathologists investigated the interobserver reproducibility of PD-L1 staining with 22C3 pharmDx in NSCLC samples.METHODS: Twenty-seven pathologists individually assessed the tumor proportion score (TPS) for 107 NSCLC samples. Each case was divided into three levels based on TPS: <1%, 1%–49%, and ≥50%.RESULTS: The intraclass correlation coefficient for TPS was 0.902±0.058. Weighted κ coefficient for 3-step assessment was 0.748±0.093. The κ coefficients for 1% and 50% cut-offs were 0.633 and 0.834, respectively. There was a significant association between interobserver reproducibility and experience (formal PD-L1 training, more experience for PD-L1 assessment, and longer practice duration on surgical pathology), histologic subtype, and specimen type.CONCLUSIONS: Our results indicate that PD-L1 immunohistochemical staining provides a reproducible basis for decisions on anti–PD-1 therapy in NSCLC.
