Early-stage breast cancer: Switching to aromatase inhibitors after tamoxifen
In the "switch" treatment approach, the patient uses tamoxifen for two to three years, and then switches to an aromatase inhibitor. This anti-estrogen treatment lasts for five years in total. The decision regarding whether or not to switch to an aromatase inhibitor is made after the treatment with tamoxifen. The aromatase inhibitors anastrozole and exemestane have been approved for this treatment approach in Germany.
In 2016, the Institute for Quality and Efficiency in Health Care (IQWiG, Germany) looked into the advantages and disadvantages of using aromatase inhibitors in the "switch" treatment approach for early-stage breast cancer in women.
The Institute analyzed how switching to aromatase inhibitors after treatment with tamoxifen compared to continued treatment with tamoxifen. The Institute found seven relevant studies. Five studies involving a total of 4,845 women compared anastrozole with tamoxifen. The other two studies involving a total of 4,784 women compared exemestane with tamoxifen. All of the women had taken tamoxifen for two to three years before participating in the studies. The results are described below.