The efficacy of trastuzumab for metastases coupled with the relatively poor prognosis of patients with node-positive, HER2-positive breast cancer has led to the evaluation of trastuzumab as an adjuvant therapy. A prospective, randomized, three-arm, phase III trial is being conducted by the Breast Intergroup (N9831) for women with primary, operable, histologically confirmed, node-positive breast carcinoma that strongly over-expresses (3+) HER2 protein and/or displays HER2/neu gene amplification, as determined by local laboratory testing. The protocol requires confirmatory central testing of HER2 status using the HercepTest™ immunohistochemistry and the Vysis PathVysion™ fluorescence in situ hybridization (FISH) assays. Tumor specimens from the first 119 patients enrolled in N9831 were centrally tested; 74% were found to be HercepTest™ 3+ and 66% were found to have HER2 gene amplification. Only six of nine (67%) of the specimens submitted by local laboratories as FISH positive could be confirmed by central assays. The concordance for central HercepTest™ and central FISH assays was 92%. The poor concordance (74%) between local and central testing for HER2 status has led to modifications in the eligibility criteria for N9831.
ASJC Scopus subject areas
- Cancer Research