MKI67 and neoplasm: A small neoadjuvant trial (IMPACT) had already suggested this might be feasible: results showed that tumour Ki67 after 2 weeks (Ki672w) of endocrine treatment predicted outcome better than at baseline (Ki67B), remaining significant in multivariable analysis, whereas Ki67B did not.11, 12 Similar results have subsequently been reported from another small trial comparing letrozole with tamoxifen13 and from a further trial comparing anastrozole, letrozole, and exemestane with one another.14