Cost-utility of adjuvant hormone therapies with aromatase inhibitors in postmenopausal women with breast cancer: upfront anastrozole, sequential tamoxifen-exemestane and tamoxifen-letrozole.
Skefgel C, Rayson D, Dewar R and Younis T
The Breast, 2007, Epub ahead of print
Adjuvant aromatase inhibitors for postmenopausal women are here to stay. Several strategies have now been shown to be more effective than 5 years of tamoxifen. Treatment with upfront aromatase inhibitor (anastrazole), sequential tamoxifen and aromatase inhibitor with a switch at between 2 and 3 years, and extended adjuvant therapy for 3 or more years beyond 5 years of initial tamoxifen treatment have all been shown in large clinical trials to improve outcomes. While one can take the individual trials and identify numerical differences between their respective outcomes, in truth it is impossible to know at present which of the three available strategies for use of aromatase inhibitors in the adjuvant setting leads to the greatest improvement in overall outcomes. Some clinicians are guided by the absolute risk of recurrence in the first few years, and where this is higher, opt for immediate aromatase inhibition, and, where it is lower, opt for earlier use of tamoxifen, with a switch either at 2-3 or 5 years.
Treatment with aromatase inhibitors is more expensive than treatment with tamoxifen. Each of the three possible strategies for use of aromatase inhibitors will have different costs. Where there is little in the way of clinical evidence to support one novel strategy over another, then clearly that which is most cost-effective is the one to which clinicians should default.
This paper reports the extension of an analysis of the cost-utility of upfront anastrazole and sequential tamoxifen/exemestane compared to tamoxifen alone, which was considered from the perspective of the Canadian health system. In the work reported here, the Canadian model was adapted and the costs and outcomes are considered from the perspective of the Belgian healthcare system. In addition, the authors considered the cost utility of an extended adjuvant strategy with 3 years of letrozole treatment. It is worth making a point here that this is likely to underestimate the true cost of an extended adjuvant letrozole-based strategy, as although the data have been reported only out to 3 years of treatment, the intention of the National Cancer Institute of Cancer Clinical Trial Group (NCIC CTG) MA. 17 trial was 5 years of treatment, and it is very likely that all those treated with extended adjuvant letrozole will continue on treatment for at least 5 years. A follow-on study is actually looking at continuation out to 10 years (i.e. 15 years following the initial cancer diagnosis).
It is pleasing to note that all three strategies come out as cost-effective alternatives, although the sequential strategy (i.e. 2-3 years of tamoxifen followed by 5 years of an aromatase inhibitor; exemestane in the analysis) would be the economically preferred one. The authors make the point that the fact that this conclusion is the same for two healthcare systems, a North American one (albeit Canada, which is somewhat different from the USA) and a European one, suggests that it is potentially widely generalisable.
It is useful to provide economic data about adjuvant hormonal treatment of breast cancer, but I think that many clinicians will be cautious about applying these findings uniformly. As indicated above, many will feel that those at higher risk of recurrence may benefit from the strategy of immediate introduction of an aromatase inhibitor.
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|Publication:||Advances in Breast Cancer|
|Date:||Jun 1, 2007|
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