Accurately gauging whether a woman is human epidermal growth factor receptor (HER) positive is essential to prescribing the most effective treatment. Biologic agents like trastuzumab are most effective in patients who test positive for HER2. However, little trial information is available to detect whether adequate molecularmarker testing precedes the decision to prescribe trastuzumab.

Researchers from HealthCore, Wilmington, Delaware, evaluated administrative claims databases from three health plans. The records of patients with breast cancer who were diagnosed over 13 months, ending June 30, 2006, were chosen for review.

The review found that of 380 women with breast cancer, who saw 179 different physicians, 88% underwent HER2 testing. Seventy two (22%) had positive tests, and 52 women were given trastuzumab, 51 of whom tested positive for HER2 (98%).

Importantly, in 45 women who did not undergo HER2 testing, none received trastuzumab. The researchers did not evaluate whether the health plans in question employed prior authorization based on molecular testing, which may have altered practice. However, based on this investigation, they concluded that patients with breast cancer are appropriately receiving trastuzumab, based on systematic testing for HER2.

Barron J, Zhang B, Cziraky M: Human epidermal growth factor receptor-2 testing and treatment patterns among newly diagnosed breast cancer patients. Presented at the 2008 annual meeting of the Academy of Managed Care Pharmacy, San Francisco, April 16–19, 2008.