Intergroup Exemestane Study mature analysis: overall survival data.

The findings of the Intergroup Exemestane Study (IES) challenge the standard adjuvant endocrine therapy consisting of 5 years of tamoxifen therapy in women with oestrogen receptor-positive breast cancer. The IES study confirmed that switching to an aromatase inhibitor (AI) such as exemestane after 2-3 years of tamoxifen therapy resulted in improved survival relative to women remaining on 5 years of tamoxifen therapy. Data from IES concur with the findings of other studies with AIs that support the rationale of switching from tamoxifen to an AI after 2-3 years of tamoxifen in postmenopausal women who remain disease-free.