Patients and procedures
PgR-positive invasive, breast cancer
DISEASE, SECONDARY
POETIC was a phase III, multicentre, randomised trial for postmenopausal women with ER- or PgR-positive invasive breast cancer. Women were randomised (2:1 allocation ratio) to perioperative therapy with a non-steroidal AI (POAI), anastrozole (1 mg/day) or letrozole (2.5 mg/day) (AI choice determined by centre policy) for two weeks before and two weeks after surgery or no perioperative therapy (control). Subsequent therapy was according to local standard of care. Ki67 was evaluated as a biomarker in relation to its effect on predicting disease outcomes and as a secondary endpoint to assess changes between baseline and surgery. Full details of the design and statistical analysis methods of the main study are available in the main clinical paper[Patients provided written consent for the use of core-cut biopsies taken at diagnosis or, if material was not available at diagnosis, for the taking of a core-cut for the purposes of the trial. Investigators were encouraged to take a further core-cut biopsy at the time of surgery but could alternatively provide a representative paraffin-embedded block. Provision of tissue sections was also acceptable at both baseline and surgery. All samples were fixed in formalin prior to paraffin embedding.