Endocrine therapy in premenopausal women with breast cancer: a critical appraisal of current evidence

ABSTRACT

Nearly 60% of all breast cancer premenopausal women are diagnosed with a hormone receptor positive tumor and, therefore, are candidates for adjuvant hormonal therapy. Treatment with tamoxifen for at least 5 years has been for a long time the standard of care, as it is associated with overall positive clinical outcomes. However, in the last decade, a number of studies on adjuvant endocrine therapy in premenopausal women with hormone receptor positive breast cancer have been published, adding a bulk of evidence to existing knowledge in this field. A critical appraisal of their results appears necessary in order to put the recently collected data into the current framework of treatment, and to discuss the several issues that remain open. Here, we review the most recent evidence on the following: the optimal duration of tamoxifen treatment, results of the studies comparing tamoxifen alone to tamoxifen plus ovarian function suppression (OFS), results of the studies comparing tamoxifen plus OFS to aromatase inhibitors plus OFS.

KEYWORDS:

• Breast cancer
• premenopausal
• tamoxifen
• ovarian function suppression

Acknowledgments

The authors would like to thank the other members of the Breast Academy Group: Daniela Aldigretti (Milan, Italy), Catia Angiolini (Florence, Italy), Michela Donadio (Turin, Italy), Francesco Giotta (Bari, Italy), Andrea Michelotti (Pisa, Italy), Gabriella Moretti (Reggio Emlia, Italy), Luca Moscetti (Viterbo, Italy), Nando Riccardi (Naples, Italy), and Giuseppina Sarobba (Nuoro, Italy).

Financial and competing interests disclosure

Lucia Del Mastro has received speaker’s honoraria from Ipsen, Takeda, Astrazeneca and Novartis. Filippo Montemurro has received speaker’s honoraria From Novartis and Astra Zeneca. Fabio Puglisi has received honoraria from Novartis. Michele De Laurentiis has received honoraria from Novartis, Ipsen, Takeda and Astrazeneca. Editorial assistance for the preparation of this manuscript was provided by Luca Giacomelli, PhD, on behalf of Content Ed Net and Ambra Corti; this assistance was funded by Novartis. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

Key issues

• Recent data on extending the duration of adjuvant treatment with tamoxifen until 10 years.

• Risks and benefits of prolonging treatment with tamoxifen in premenopausal women with breast cancer.

• Recent data on adding ovarian function suppression (OFS) to tamoxifen in premenopausal women with breast cancer.

• Risks and benefit of adding OFS.

• Recent data from studies comparing tamoxifen plus OFS to aromatase inhibitors (AIs) plus OFS in premenopausal women with breast cancer.

• Risks and benefit of AIs plus OFS treatment.

• Decision-making issues for the choice of the best adjuvant endocrine therapy in premenopausal women with breast cancer.