ANZ 0501 LATER trial

20 March 2016

Purpose

This trial is finding out whether taking the drug letrozole a year or more after finishing five years of treatment with hormonal therapy (e.g. tamoxifen); can prevent or delay breast cancer recurring in post-menopausal women.

Scientific Title

ANZ 0501: LATER. Randomised trial of letrozole plus usual care versus usual care without letrozole to prevent new breast cancer events in postmenopausal women who have completed a minimum of 4 years of adjuvant endocrine therapy for early, hormone-responsive breast cancer more than 1 year previous, and who are disease-free at trial entry.

Short title

Later Adjuvant aromatase inhibitor therapy for postmenopausal women with Endocrine Responsive breast cancer.

Background

The standard length of time that hormonal or endocrine treatment is taken (daily) is five years.  However, after reaching the end of their treatment there is still an ongoing risk for a woman of developing another breast cancer, or her original breast cancer returning in another part of her body. We know that 50% of recurrences occur after the first five years.   Long term management of early breast cancer after completion of five years of hormonal treatment, has until recently, been confined to annual checks and mammography.

Research has also shown that extending hormone or endocrine treatment with an aromatase inhibitor, after five years of tamoxifen, improves breast cancer outcomes. It is not certain if this is the case after five years of treatment including an aromatase inhibitor.

Results

The results of the LATER trial should be considered exploratory, but lend weight to data from other trials supporting longer duration endocrine therapy for hormone receptor-positive breast cancer, and offer insight into the reintroduction of AI therapy.

Main Publication

Observation versus late reintroduction of letrozole as adjuvant endocrine therapy for hormone receptor-positive breast cancer (ANZ0501 LATER): an open-label randomised, controlled trial. Zdenkowski N, Forbes JF, Boyle FM, Kannourakis G, Gill PG, Bayliss E, Saunders C, Della-Fiorentina S, Kling N, Campbell I, Mann GB, Coates AS, Gebski V, Davies L, Thornton R, Reaby L, Cuzick J, Green M, on behalf of the Australia and New Zealand Breast Cancer Trials Group. Annals of Oncology. 2016; epub 20 March 2016.