Haiku.

Top Line: Is there a benefit to peri-operative aromatase inhibitor (POAI) therapy for women with early stage, hormone receptor positive breast cancer?

The Study: There are two parts to this question. First, does POAI improve clinical outcomes? Given that these treatments are given for 5-10 years, you can guess the answer to that question. Another question is whether the response to a short course of POAI can be used to direct subsequent therapy. You’re probably thinking, “don’t we use genomic classifiers for that.” Yes, but as we learned recently, those tests can be heterogeneous in how they predict the benefit of adjuvant therapy, and some might argue they’re “expensive” and not universally available. POETIC was a large UK trial that randomized nearly 4500 post-menopausal women with early stage, ER+ breast cancer to standard therapy with or without POAI. Ki67 was used as a biomarker of proliferation and assessed before and after 2 weeks of POAI. In this report of long-term outcomes, there was no difference in any clinical outcome with or without POAI therapy. From a prognostic standpoint, though, the change in Ki67 with short-course POAI was associated with the risk of recurrence. At 5 years, recurrence risk was 4.3% for those with initially low Ki67, 8.4% for high→ low, and 21.5% for high→ high. Unfortunately, actual adjuvant systemic therapy was not dictated by response in this trial.

TBL: Change in Ki67 after a short course of POAI is prognostic of recurrence risk among post-menopausal women with hormone receptor positive breast cancer. | Smith, Lancet Oncol 2020