How and on which specimens will you perform Ki-67 testing in newly diagnosed breast cancer?

In the trial, Ki67 testing was performed on the baseline tumour sample which would be a core biopsy of patients who are undergoing neo-adjuvant chemotherapy, which occurred in 37% of patients in the trial, or the surgical excision sample if they went straight to surgery. It is important that it is d...

Likely, this will depend on the institutional standard. Our group at Magee Women's Hospital has extensive experience with Ki67 on core biopsy and it is part of our standard biomarker workup. Other institutions may perform this differently. We may start performing Ki67 on the resected tumor if the in...

Many studies confirm that Ki67 is prognostic in early-stage breast cancer. However, these studies display substantial variability in both analytical validity and choice of cutoffs, and most have been studies of convenience in which selection of patients, the intrinsic subtypes of the cancers, and ap...

The requirement for the Ki-67 testing is problematic. In the trial, the benefit for abemaciclib was greater if Ki-67 was high, but still existed if Ki-67 was not high. In talking to our pathologists and lab, we learned that Ki-67 is a very difficult test to run and results can be very variable. So, ...