EndoNET

EndoNET

Randomised controlled trial evaluating effectiveness of Neoadjuvant Endocrine Treatment (NET) in post-menopausal women with breast cancer

Overview

EndoNET is a Phase III, randomised, controlled trial evaluating whether a period of endocrine therapy prior to surgery (neoadjuvant endocrine therapy) reduces surgical burden for post-menopausal women with strongly ER+ invasive breast cancer who are not planned or have not started chemotherapy and/or anti-HER-2 therapy.

Objectives

Primary

• To evaluate whether 6 (+/-1) months of neo-adjuvant endocrine therapy reduces surgical burden resulting in a higher propotion of breast conservation surgery (BCS) in post-menopausal women with >15mm strongly ER+, invasive breast cancer who are not planned and/or have not started chemotherapy or anti-HER-2 therapy.

Secondary

• Disease free survival/recurrence
• Patient-reported outcome measures (PROMs) 
• Ki67 evaluation in NET setting
• Other surgical outcomes 

Key inclusion criteria

• Post-menopausal women
• Strongly ER+
• Tumour size ≥ 15 mm 
• Unifocal, newly diagnosed breast cancer visible on ultrasound (small satellite lesions included)
• Chemotherapy and/or anti-HER-2 therapy for current breast cancer not started or planned at randomisation

Planned sample size

1,060 participants (530 per arm) will be randomised (1:1) to either to the comparator arm (pre-surgical ET, surgery at 2-4 weeks) or the intervention arm (NET, surgery at 6 months).

Total number of sites planned

Approximately 50 sites planned.

EndoNET is open to new sites and would welcome expressions of interest by contacting the study team on endonet@nds.ox.ac.uk.

Timeline

Planned recruitment period is from August 2022 to June 2025 with a long-term follow up of up to 20 years (subject to additional funding and/or resource).