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Objectives: We evaluated adherence of human epidermal growth factor receptor-2 testing using immunohistochemistry and fluorescence in situ hybridization, as well as adjuvant trastuzumab treatment according to Canadian guidelines, and predictors of trastuzumab use in early-stage breast cancer in Ontario., Methods: Retrospective cohort of early-stage breast cancer patients identified in the Ontario Cancer Registry. Human epidermal growth factor receptor-2 test type, sequence, result(s), tumor grade, and hormone receptor status were abstracted from Ontario Cancer Registry pathology reports. Trastuzumab treatment was determined from provincial cancer agency records. Other variables were determined from administrative data sources. Logistic regression models were used to estimate adjusted odds ratios for factors associated with guideline adherence., Results: The first human epidermal growth factor receptor-2 test result was the strongest predictor of confirmatory testing ( p  < 0.05). Human epidermal growth factor receptor-2 testing by immunohistochemistry accounted for the majority of documented first tests (94%; n  = 8249). Overall, 27% ( n  = 2360) of tested patients received a second test by fluorescence in situ hybridization (46%) or immunohistochemistry (49%) assay. Most human epidermal growth factor receptor-2 equivocal patients (89%; n  = 784) received a confirmatory test. Among human epidermal growth factor receptor-2-positive patients, only 57% ( n  = 385) received trastuzumab treatment within the study period. Human epidermal growth factor receptor-2 status was the strongest predictor of trastuzumab use. Younger patients (<70 years at diagnosis) and negative hormone receptor status had higher odds of trastuzumab treatment ( p  < 0.05) compared to older and positive hormone receptor status patients., Conclusions: Immunohistochemistry use as a first test was largely consistent with Canadian guidelines; however, immunohistochemistry was frequently used as a confirmatory test, which is not guideline-concordant. Monitoring these testing and treating patterns is necessary to optimize health outcomes associated with trastuzumab.

Purpose: Decision makers must make decisions without complete information. That uncertainty can be decreased when economic evaluations use local data and can be quantified by considering the variability of all model inputs concurrently per international evaluation guidelines. It is unclear how these recommendations have been implemented in evaluations of targeted cancer therapy. By using economic evaluations of adjuvant trastuzumab, we have assessed the extent to which decision support recommendations were adopted. Study Design: Systematic review. Methods: Published economic evaluations of adjuvant trastuzumab treatment in early-stage breast cancer were examined as an established example of targeted therapy. Canadian, United Kingdom, and US economic evaluation guidelines were reviewed to establish extraction criteria. Extraction characterized the use of effectiveness evidence and local data sources for model parameters, sensitivity analysis methods (scenario, univariate, multivariate, and probabilistic) and uncertainty representation (ie, cost-effectiveness plane, scatterplot, confidence ellipses, tornado diagrams, cost-effectiveness acceptability curve). Results: Fifteen economic evaluations of adjuvant trastuzumab were identified in the literature. Local data were used to estimate costs (15 of 15) and utilities rarely (two of 15) but not trastuzumab efficacy. Univariate sensitivity analysis was most common (12 of 15), whereas probabilistic analysis was less frequent(10 of 15). Two thirds of all studies provided visual representation of results and decision uncertainty. Conclusion: Authors of adjuvant trastuzumab economic evaluations rarely use local data beyond costs. Quantification of uncertainty and its representation also fell short of guideline recommendations. This review demonstrates that economic evaluations of adjuvant trastuzumab, as an example of targeted cancer therapy, can be improved for decision-making support. [ABSTRACT FROM AUTHOR]

The article presents a study which examines the utilization and cost effectiveness of human epidermal growth receptor 2 (HER2) testing strategies in clinical practice in the U.S. It notes that HER2 testing aims to determine which breast cancer patients overexpress HER2 gene and to prove whether trastuzumab treatment to 20-30% patients is highly effective. It emphasizes on the importance of understanding the use of HER2 testing in cancer care because of its critical role in targeting therapy.

Trastuzumab is a targeted therapy for human EGF receptor-2 (HER2)-positive breast cancer. The effectiveness and cost--effectiveness of trastuzumab hinges not only on its clinical efficacy in responding patients, but on the ability to accurately identify appropriate therapeutic candidates. We sought to systematically review the cost--effectiveness of trastuzumab with a focus on the impact of the test(s) used for HER2 diagnosis. Our review included 17 economic evaluations or health technology assessments of trastuzumab therapy or HER2 testing. Trastuzumab was considered cost-effective in all early-stage disease studies, while one author concluded that trastuzumab was not cost-effective for metastatic disease. Only two papers considered the joint effects of test accuracy and sequencing with trastuzumab therapy. These demonstrated that trastuzumab cost--effectiveness is sensitive to HER2-test properties. [ABSTRACT FROM AUTHOR]