Long-term Anastrozole vs. Tamoxifen Treatment Effects

http://www.latte-studies.org.uk/

Summary

Breast cancer is increasingly becoming a “survivable” disease, and an increasing number of recurrences occur late, so that there is much interest about the long-term efficacy and safety of treatments. The Oxford Overview process has provided useful data on follow-up for 15-20 years after tamoxifen therapy. Such data are lacking for the newer aromatase inhibitors (AIs). This study provides a unique opportunity to address this issue.

The ATAC trial is the vanguard breast cancer trial for the use of AIs in the adjuvant setting, with a median follow-up of 100 months. With the LATTE Study, it is proposed to collect further follow-up information on the 6,000 patients randomised to mono-therapy (anastrozole or tamoxifen).

This research will aim to provide additional efficacy (including local and distant recurrence, and new contralateral tumours) data, and information on survival, new primary cancers at other sites, and other major ischaemic cardiac and cerebrovascular events.

Data will be collected during regular routine clinic visit, based on local practice and usually annually, and through the ONS “flagging” scheme and Hospital Episode Statistics in the UK, and similar systems in other countries where they are available. It is recommended that the participants medical notes are labelled as participating in the LATTE Study, for example by using study label stickers.

Where possible and only after explicit consent has been obtained, women participating in the LATTE study may be approached directly by the CPTU office for follow-up information.

As the largest single contributor of patients to the ATAC Trial, the UK is in an ideal position to manage a system of collection of follow-up data. Furthermore, the Cancer Prevention Trials Unit (CPTU) based in London would become the “hub” for the coordination of follow-up and the collation of data from international centres (381 centres in 21 countries).

Objectives

To compare patients randomised to receive anastrozole to those randomised to receive tamoxifen (and who have now all completed treatment) in terms of:-

Primary objectives (all subjects):

• Time to recurrence of breast cancer in the post 10 year period (defined as the earliest of local or distant recurrence, new primary breast cancer, or death)
• Death after recurrence

Secondary objectives (all subjects):

• Time to distant recurrence
• Cancer-specific survival
• New breast primaries
• Other cancers
• Ischaemic cardiac and cerebrovascular events

Study Design

Observational longitudinal cohort study.