Adjuvant trastuzumab for breast cancer: Assessing HER2/neu status incurs more costs for treatment

doi:10.1136/bmj.331.7526.1202

BMJ 2005;331:1202 (19 November), doi:10.1136/bmj.331.7526.1202

Letter

Adjuvant trastuzumab for breast cancer

Assessing HER2/neu status incurs more costs for treatment

The first 150 words of the full text of this article appear below.

EDITOR—The results of recent trials are likely to continueto fuel the demand for trastuzumab in the adjuvant setting ofearly breast cancer,¹ as well as a possible neoadjuvant treatmentin the near future. However, Dent and Clemons did not discussthe difficulty in obtaining accurate and reproducible assessmentof HER2/neu gene overexpression. Immunohistochemical testingmeasures HER2/neu protein expression whereas in situ hybridisationmeasures gene amplification.

Patients with equivocal immunohistochemical results requirein situ hybridisation to determine definitive status becauseinterobserver variability using immunohistochemical testingis appreciable.

At least 20% of patients with positive immunohistochemical resultswill be truly negative for HER2/neu gene amplification; thesepatients would not benefit from trastuzumab.²

These difficulties in assessing HER2/neu status have been encounteredin studies testing trastuzumab, and in situ hybridisation testinghas been used as the gold standard.³ As the clinical utilityof trastuzumab widens guidelines on HER2/neu testing must . . . [Full text of this article]

Malcolm R Kell, consultant surgeon

malcolm.kell@breastcheck.ie
Mater Misericordiae University Hospital, University College Dublin, Republic of Ireland

Colm P Power

Mater Misericordiae University Hospital, University College Dublin, Republic of Ireland