Can PD-L1 expression evaluated by biopsy sample accurately reflect its expression in the whole tumour in gastric cancer ?
Menée à partir de l'analyse immunohistochimique d'échantillons biopsiques et d'échantillons tumoraux prélevés sur 191 patients atteints d'un cancer gastrique traité par résection radicale, cette étude examine la concordance entre les résultats d'expression de PD-L1 obtenus à l'aide d'une seule biopsie et ceux obtenus à l'aide de plusieurs biopsies
Programmed death ligand 1 (PD-L1) expression as a predictive biomarker for programmed cell death 1 (PD-1) inhibitor efficacy in gastric cancer (GC) remains controversial. We hypothesised that the conflicting results may be due to the inaccurate assessment of PD-L1 expression using biopsy samples. A total of 191 patients with GC who received radical resection were enrolled. PD-L1 expressions in biopsy and paired resected samples by immunohistochemistry staining were compared according to the number of biopsies. The numbers of PD-L1-positive patients determined by biopsy and resected samples were 89 (46.6%) and 135 (70.1%), respectively. The accordance rate was 64.4% (κ = 0.31). Single biopsy showed a lower accordance rate compared with multiple biopsies. Our study revealed that single biopsy cannot fully reflect PD-L1 expression in the whole tumour in GC. Multiple biopsies are recommended for accurate diagnosis of PD-L1 expression in GC.
British Journal of Cancer , résumé, 2019