Cost effectiveness of cytotoxic and targeted therapy for metastatic breast cancer : a critical and systematic review

Breast cancer is the leading cancer type diagnosed among women in Western countries. Despite great advances in cancer therapies, many of these patients develop non-curable metastases. The objective of cancer treatment in the metastatic setting is mainly to control symptoms and to prolong survival. The selection of the optimal chemotherapeutic regimen is affected by performance status, tumour biology, site and extent of the disease and the exposure to prior therapies. Recent developments in new kinds of cancer drugs have contributed not only to immense progress in clinical outcomes but also to dramatically increased treatment-related health costs. Cost-effectiveness analysis is a type of economic evaluation that compares costs and health outcomes of alternative intervention strategies in a systematic way. In this review, a systematic literature search was performed and the evidence on the cost effectiveness of conventional chemotherapy and targeted therapy for metastatic breast cancer was explored. Cost-effectiveness/-utility analysis of treatment regimens for metastatic breast cancer were identified using literature and reference searches (MEDLINE). Published reports on conventional and targeted cancer therapies were scrutinized and incremental cost-effectiveness ratios (ICERs) were abstracted. Furthermore, the quality of reporting, as well as methodological and modeling issues, were extensively discussed. From full-text article reviews, six cost-effectiveness analyses on conventional therapies and seven studies on targeted therapies were included. Eight analyses were conducted in European countries, three in the US and two in Canada. The economic models were primarily (69%) based on clinical trial data. Results from sensitivity analyses and study perspectives were reported by all studies. Discount rates were mentioned in five articles (39%). The methods of reporting costs and effects varied considerably, as did trial design across conventional chemotherapies which made it difficult to compare those analyses. The pharmacoeconomic studies came to different conclusions. The actual clinical evidence does not suggest one conventional chemotherapy regimen as superior. Studies on cytotoxic agents showed mainly favourable cost-effectiveness ratios. Targeted therapies indicated both favourable and non-favourable ratios. Currently, trastuzumab is the only antibody-based targeted therapy that is established in the clinic for the metastatic setting.