POSNOC - A Trial Looking at Axillary Treatment in Early Breast Cancer

POSNOC is a pragmatic, randomised, multicentre, non-inferiority trial. Aim For women with early stage breast cancer and one or two sentinel node macrometastases, to assess whether adjuvant therapy alone is no worse than adjuvant therapy plus axillary treatment, in terms of axillary recurrence within 5 years. Stratification: Institution, Age (\<50, ≥50), Breast-conserving surgery (BCS) or mastectomy, Estrogen receptor (ER) status (positive, negative), Number of positive nodes (1, 2), Intra-operative sentinel assessment using OSNA (yes, no). Interventions The study will compare adjuvant therapy alone with adjuvant therapy plus axillary treatment (axillary node clearance (ANC) or axillary radiotherapy (ART)). Sample Size: 1900 participants Follow-up: Participants will be followed up for 5 years. Adjuvant Therapy: All participants will receive adjuvant systemic therapy (chemotherapy and/or endocrine therapy). All participants may receive breast/chest wall radiotherapy. Axillary and supraclavicular fossa radiotherapy is not allowed when randomised to adjuvant therapy alone.

NCT Number	NCT02401685
Lead Sponsor	University Hospitals of Derby and Burton NHS Foundation Trust Collaborators: University of Nottingham, Sussex Health Outcomes Research & Education in Cancer (SHORE-C), NCRI Radiotherapy Trials QA Group (RTTQA), Breast Cancer Trials, Australia and New Zealand
Conditions	Breast Cancer
Enrollment	1,900 participants
Start Date	2014-08-01
Primary Completion	2026-07 (estimated)
Study Completion	2026-12-31 (estimated)
Updated on ClinicalTrials.gov	2025-07-10