Concordance analysis between HER2 immunohistochemistry and in situ hybridization in non-small cell lung cancer.

PURPOSE: This study aimed to elucidate the concordance between human epidermal growth factor receptor 2 (HER2) immunohistochemistry (IHC) and in situ hybridization (ISH) and the diagnostic accuracy of HER2 IHC in non-small cell lung cancer (NSCLC) through a meta-analysis and diagnostic test accuracy review.

METHODS: Seven eligible studies and 1,217 patients with NSCLC were included in the review. The concordance between HER2 IHC and ISH was analyzed. To confirm the diagnostic accuracy of HER2 IHC, the sensitivity and specificity were analyzed and the area under the curve (AUC) in the summary receiver operating characteristic (SROC) curve was calculated.

RESULTS: The concordance rate between HER2 IHC and ISH was 0.795 (95% confidence interval [CI] 0.534-0.929). In the HER2 IHC-negative (score 0/1+) subgroup, the concordance rate was 0.975 (95% CI 0.854-0.996). The concordance rates of the HER2 IHC score 2+ and 3+ subgroups were 0.091 (95% CI 0.039-0.197) and 0.665 (95% CI 0.446-0.830), respectively. In diagnostic test accuracy review, the pooled sensitivity and specificity were 0.67 (95% CI 0.54-0.78) and 0.89 (95% CI 0.87-0.91), respectively. The AUC in the SROC curve was 0.891 and the diagnostic odds ratio was 16.99 (95% CI 5.08-56.76).

CONCLUSIONS: HER2 IHC was largely in agreement with ISH in cases of HER2 IHC score 0/1+. Because the concordance rates of HER2 IHC score 2/3+ cases were lower than that of HER2 IHC score 0/1+ cases, further studies for detailed analysis criteria for HER2 IHC score 2+ or 3+ are required.