Abstract
Advances in identifying biomarker profiles in patients with early-stage breast cancer have improved 5-year curative rates. Identification of the HER2 receptor provides valuable information that has been shown to extend survival in adjuvant and metastatic settings. Current clinical guidelines discuss when confirmatory testing may be inappropriate. Using a quality improvement approach, the team at Duke Cancer Institute determined HER2 ordering practices in a large academic cancer center. HER2 ordering using immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) was abstracted from the charts of 314 patients with early-stage breast cancer. Qualitative responses to current clinical practices were obtained from clinicians. Of the patients included, duplicate IHC was performed for 36% and in triplicate for 6%; repeat testing resulted in clinically significant change in HER2 status for approximately 20%. Repeat biomarker testing on metastatic biopsy sites "all of the time" was favored by the surveyed physicians. FISH was ordered for each grade of IHC: 0+ (>20% of cases), 1+ (>20%), 2+ (99%), 3+ (54%). Most physicians "strongly" or "somewhat" favored solutions that integrate order sets and care pathways into the electronic medical record. This quality improvement project identified root causes and solutions to practice variance in breast cancer biomarker ordering and interpretation. Further investigations are planned to standardize best practices while appreciating the clinical challenges posed by discordant test results.