Abstract
Breast cancer is the type that affects more women worldwide. Approximately 30-50 % of patients diagnosed in the early stages will develop metastatic disease, which is considered incurable. At this stage of the disease, therapies aimed prolong survival and provide palliative symptom control. Trastuzumab, a monoclonal antibody targeted to the receptor of the human epidermal growth factor (HER2), has increased response rates, progression-free survival and/or overall survival in breast cancer and has recently been incorporated by the Sistema Unico de Saude (SUS) for treatment of early and locally advanced breast cancer. The aim of this study was to conduct a systematic review of the cost-effectiveness analyses of trastuzumab in patients with metastatic breast cancer overexpressing HER2. Searches were conducted between the period 1998-2013, on six electronic databases, two generic searches on the Internet, as well as manual search of references. We considered articles in English, Spanish and Portuguese, being excluded reviews, editorials, letters, case studies, review articles, systematic reviews and meta-analyses. The stages of study selection and data extraction were performed by two independent reviewers, and doubts were resolved by one third reviewer. Studies were assessed for quality according to approaches employed by Teerawattananon et al (2007). Data analysis was performed from the conversion of the costs and comments of the incremental cost-effectiveness ratios of trastuzumab were made. A quantity of 521 studies, all in English, was identified. Of these, we discarded 455 (294 did not meet the criteria for review and 161 duplicates). Sixty-six studies were included for reading the abstracts, resulting in 24 to read the full text. In total, 13 studies composed this review. The treatment regimens adopted on cost-effectiveness evaluations were varied. Eight studies compared the treatment of trastuzumab as 1st line for metastatic disease and five studies as 2nd line, which three of these used trastuzumab as comparator in the economic evaluation and not as an intervention. All studies using trastuzumab as 2nd line treatment did not consider it as a cost-effective intervention. Regarding the quality of the included studies, they showed a good quality, since most fulfilled the methodological guidelines for assessing costeffectiveness and used good evidence in the estimation of parameters. Finally, the evaluations used different thresholds to determine whether treatment with trastuzumab was cost-effective as well as differences in modeling costs, outcomes and treatment regimens. The use of trastuzumab, alone or associated, was cost-effective as treatment of 1st line, unlike when used as 2nd line. Differences were found in the quality of the included studies. Conducting new cost-effectiveness analyses of trastuzumab in metastatic breast cancer, allied to political, social and administrative factors, which helps decision makers about its incorporation, is required
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