6 Recommendations for further research
6.1 Ongoing clinical trials related to this guidance are:
a study with more than 6000 participants, comparing 5 years of exemestane with 5 years of anastrozole in preventing cancer recurrence in postmenopausal women who had undergone surgery for primary breast cancer
a study comparing 5 years of letrozole with 5 years of anastrozole in postmenopausal women with hormone-receptor-positive and lymph-node-positive breast cancer who had undergone recent primary surgery for breast cancer
a study comparing 5 years of exemestane with 5 years of tamoxifen in postmenopausal women who had undergone surgery to remove early-stage breast cancer; after publication of results from the study of exemestane in unplanned switching, this study was modified to compare 5 years of exemestane with 5 years of tamoxifen crossed over to exemestane
a study comparing 2 years of exemestane with placebo in women with hormone-receptor-positive breast tumours and very low risk of recurrence.
In addition, the results of the unplanned switching arms from a study discussed in the clinical effectiveness section of this document (comparison of letrozole and tamoxifen) have not been reported yet.
6.2 The Committee recommends research into the relative benefit of aromatase inhibitors in different subgroups of women with early breast cancer, stratified by risk of recurrence, and research into the relative cost effectiveness of the different treatment strategies (primary adjuvant, switching and extended adjuvant) that can be used with aromatase inhibitors.