[Protein expression of PD-L1 and clinico-pathological data in a cohort of 53 patients with resectable non small cell lung cancer (NSCLC). Concordance between clones (22C3 and 28-8) and observers. Correlation and prognostic value of clinico-pathological data]

Abstract

Introduction: 85% of lung cancers are non-small cell carcinomas (NSCLC), the majority of which are diagnosed in an advanced stage. Immunotherapy has changed the treatment pattern for these tumors and created the need to find a marker for patient selection. Although not ideal, PD-L1 is the biomarker currently used in clinical practice.

Material and methods: Retrospective review by two pathologists of 53 cases of NSCLC from 2005 to 2007 in Hospital Universitario La Paz, using the WHO 2015 classification studying PD-L1 with clones 22C3 and 28-8. The consistency between observers and clones was assessed and all data studied were correlated with survival rates.

Results: We found a prevalence of PD-L1 expression in tumor cells (TC) similar to that previously reported in the literature and a very good consistency between clones in the evaluation of TC and immune cells (ICC 0.99-0.93, p<.001). Interobserver concordance was very good in the evaluation of TC (ICC 0.902, 95% CI: 0.836-0.942, p<.001 for clone 22C3 and ICC 0.927, 95% CI: 0.877-0.957, p<.001 for clone 28-8) and poor for immune cells (ICC of 0.413, 95% CI: 0.163-0.613, p=.001 with clone 22C3 and ICC of 0.313, 95% CI: 0.053-0.534, p=.010 with clone 28-8). Subtype and histological grade were the only variables related to prognosis.

Conclusions: The clones of PD-L1 22C3 and 28-8 are equivalent and there is good interobserver consistency in the evaluation of TC but not in immune cells.

Keywords: 22C3; 28-8; Carcinoma de pulmón de célula no pequeña; Concordancia interobservador; Interobserver concordance; Non-small cell lung carcinoma; PD-L1; Prognosis; Pronóstico.