HER-2 status in primary oesophageal cancer, lymph nodes and distant metastases.

BACKGROUND: Some 10-15 per cent of patients with oesophageal cancer overexpress human epidermal growth factor receptor (HER) 2 at the primary tumour site, leading to the hope that specific targeted systemic therapy might favourably influence clinical and subclinical disease at locoregional and distant sites. This approach is based on primary tumour characteristics, without knowledge of expression patterns at metastatic sites. In oesophageal cancer, concordance between HER-2 status at the primary tumour and other sites is unknown.
METHODS: The HER-2 status of primary tumours and corresponding metastatic sites (lymph node and distant) and local recurrence were evaluated in a series of patients with oesophageal cancer, using immunohistochemistry and dual colorimetric in situ hybridization.
RESULTS: There were 97 adenocarcinomas (ACs) and 79 squamous cell carcinomas (SCCs). Some 14 per cent of primary ACs and 1 per cent of primary SCCs were staged as HER-2-positive. The HER-2 status was identical in the primary tumour and lymph node metastases in 95 per cent of ACs and 99 per cent of SCCs respectively (P = 0·375, sign test). Nineteen of 22 distant metastases from AC and all from SCC had identical HER-2 status to the primary tumour. In two of 22 patients with AC the primary tumour was classed as negative but distant metastases were HER-2-positive.
CONCLUSION: With over 85 per cent concordance in HER-2 status between primary tumours and distant metastases in oesophageal cancer, routine HER-2 testing of metastases to confirm HER-2 positivity is not warranted. Assessment of HER-2 status at metastatic sites may be worthwhile in some patients with easily accessible metastases and negative HER-2 status at the primary tumour, or if adequate material cannot be obtained from the primary site.