Reproducibility and validation of tumour stroma ratio scoring on oesophageal adenocarcinoma biopsies

Abstract

BackgroundTumour stroma ratio (TSR) in histological sections of resected oesophageal adenocarcinomas proved to be a prognostic factor for patients’ survival. The objectives of this study were to assess inter- and intraobserver agreement for TSR scoring on biopsy material and to validate these biopsy results with the results derived from surgical specimens. MethodsBiopsies and surgical specimens of 91 patients with oesophageal adenocarcinoma were available. TSR was determined on the original haematoxylin–eosin (H&E) tissue sections from primary tumour biopsies. To assess interobserver variation, TSR was scored by three pathologists as 0–25%, 25–50%, 50–75% or 75–100%. A second scoring was done to examine intraobserver variation. The definitive TSR biopsy score was compared with the corresponding resection specimen score. Kappa statistics were applied to evaluate agreement. ResultsBiopsies of 10 (11%) patients were rejected because of poor quality. For 81 TSR biopsy scores, interobserver correlations ranged between 0.239 and 0.486 (P<0.001 for all). By classifying scores into two groups (<50% and ⩾50%), interobserver correlations ranged between 0.372 and 0.886 (P<0.001 for all). Intraobserver agreement was substantial to near-perfect (κ=0.780–0.848; P<0.001 for all). Definitive TSR biopsy score showed moderate correlation with TSR scores on surgical specimens (κ=0.506), but it was an independent prognostic factor for survival. ConclusionReproducibility of tumour stroma ratio scoring on oesophageal adenocarcinoma biopsies was good. The ease of TSR scoring on H&E sections together with its correlation with patients’ survival may have clinical relevance in this era of neoadjuvant therapy.