Reproducibility of Immunohistochemical Scoring for Epidermal Growth Factor Receptor Expression in Non–Small Cell Lung Cancer: Round Robin Test

Abstract

Context.-The addition of cetuximab to first-line chemotherapy substantially prolonged survival in patients with advanced non-small cell lung cancer whose tumors expressed high levels of epidermal growth factor receptor (EGFR; immunohistochemistry score of !200 on a scale of 0-300).Objective.-To evaluate the interobserver reproducibility of this EGFR immunohistochemistry scoring system, based on both the tumor cell membrane staining intensity (graded 0-3þ) and the percentage of cells staining at each intensity.Design.-In parts 1 (initial feasibility study) and 2 of this 2-part round robin test, sections of different non-small cell lung cancer tissue microarrays were stained in a central reference laboratory. Following reference evaluation, EGFR expression in 30 selected tumor cores was characterized in serial sections by lung cancer pathology specialists. The reproducibility of scoring by different raters was assessed. Analysis of between-rater agreement was based on the allocation of EGFR immunohistochemistry scores into low-(,200) and high-(!200) EGFR expression groups.Results.-After discussion with raters of the issues impacting reproducibility identified in part 1 and following adjustment of processes, part 2 of the round robin test showed a high interobserver agreement in EGFR immunohistochemistry scoring, with an overall concordance rate of 90.9% and a mean coefficient of 0.812. Specimens with a reference EGFR immunohistochemistry score of lower than 200 and of 200 or higher showed mean concordance rates of 94.7% and 85.6%, respectively.Conclusions.-After appropriate training, assessing EGFR expression by this immunohistochemistry-based method allowed a highly reproducible allocation of nonsmall cell lung cancers into clinically relevant high-or low-EGFR expression groups.

Reproducibility of the EGFR immunohistochemistry scores for tumor samples from patients with advanced non-small cell lung cancer

“…In the present study, a good interobserver agreement of 80-90% was observed with a mean coefficient of 0.983 among three pathologists, and the positivity in the samples was 70%, which is consistent with other studies (28,30). In the present study, a better concordance for the H-scores was observed when using a cut-off of 100 (73.4-83.4%); meanwhile, the concordance of the cut-off of 200 ranged from 67.5-77.3%.…”

“…Regarding the reproducibility of the H-score, Rüschoff et al (28) evaluated the interobserver reproducibility of this EGFR IHC scoring system. A high agreement was observed amongst the scores with an overall concordance rate of 90.9% and a mean coefficient of 0.812 (29).…”

“…In addition to gemcitabine and cisplatin chemotherapy, a second generation of recombinant, human immunoglobulin G1 EGFR monoclonal antibodies, including necitumumab, improves OS time (28). Tissues were evaluated by IHC to determine the level of EGFR protein expression (28). EGFR expression was high (≥200) in 38% of the tissues and low (<200) in 62% of the tissues.…”

“…EGFR expression level is a predictive value for the response of patients with advanced NSCLC to chemotherapy plus cetuximab treatment (14). In addition to gemcitabine and cisplatin chemotherapy, a second generation of recombinant, human immunoglobulin G1 EGFR monoclonal antibodies, including necitumumab, improves OS time (28). Tissues were evaluated by IHC to determine the level of EGFR protein expression (28).…”

The reliability of immunohistochemical analysis of the tumor microenvironment in follicular lymphoma: a validation study from the Lunenburg Lymphoma Biomarker Consortium

“…12 Similar issues with reproducibility were reported in solid malignancies for HER2 expression in breast cancer 13 and for EGFR in lung carcinoma. 14 The studies mentioned above for various markers in DLBCL, and on HER2 and EGFR in carcinomas, focused on analyzing protein markers expressed by tumor cells. In contrast, immunohistochemical studies in FL mostly report on densities and distribution patterns of non-malignant immune cell populations present in the microenvironment.…”