Information on use of breast cancer targeted testing is lacking
MedWire News: A review carried out by US scientists reveals that there is little information about the use of human epidermal growth factor receptor 2 (HER2) testing in routine clinical practice, which could provide insight into the evidence needed for testing emerging technologies.
“The limited evidence available suggests that there are important variations in testing practices and key gaps in knowledge about those practices,” say study author Kathryn Phillips (University of California, San Francisco) and colleagues.
Phillips and team explain that HER2 testing to target trastuzumab treatment for patients with breast cancer has been used in clinical practice for more than 10 years. For this reason, it provides an instructive case study to inform discussion of the use of emerging testing technologies in clinical practice, they say.
To examine the utilization and cost effectiveness of HER2 testing in clinical practice in the USA, the researchers carried out a literature review. They examined the percentage of eligible patients tested for HER2; test methods used, concordance of test results between community and central/reference laboratories, use of trastuzumab by HER2 test result, and cost effectiveness of testing strategies.
As reported in the journal Cancer, little evidence was available to determine whether all eligible patients are tested, how many are retested to confirm results, and how many patients with negative HER2 test results still receive trastuzumab.
The studies identified that up to 66% of eligible patients had no documentation of testing in their health insurance records, up to 20% of patients receiving trastuzumab were not tested or had no documentation of a positive test, and 20% of HER2 results may be incorrect.
Furthermore, few cost-effectiveness analyses of trastuzumab explicitly considered the economic implications of various testing strategies.
“Our findings should not be construed as reasons for attempting to slow the diffusion of new testing technologies into clinical practice and cancer care or as a critique on oncologists’ treatment decisions,” comment Phillips and co-authors.
“Rather, this case study highlights how and what evidence might be improved to help guide decisions regarding emerging tests and associated therapies in cancer care,” they conclude.
MedWire (www.medwire-news.md) is an independent clinical news service provided by Current Medicine Group, a part of Springer Science+Business Media. © Current Medicine Group Ltd; 2009
By Laura Dean