Clinical and pathological response to primary chemotherapy in patients with locally advanced breast cancer grouped according to hormonal receptors, Her2 status, grading and Ki-67 proliferation index.

OBJECTIVES: Biological markers that reliably predict clinical and pathological response to primary systemic therapy may have considerable clinical potential; this study evaluated response compared to expression of ER, PgR and Her2, grading and Ki-67 proliferation index before and after neoadjuvant chemotherapy in patients with locally advanced breast cancer (LABC). PATIENTS AND METHODS: Fifty-five patients received neoadjuvant chemotherapy for LABC. The incidence of clinical and pathological responses was assessed with respect to basal clinical stage, absent/low vs. high ER and PgR status, low vs. high proliferation index, grading and Her2 overexpression.
RESULTS: Overall, 30 patients (54%) underwent downstaging of their primary tumor; pathological complete remission was observed in only one patient with Her2 positive breast tumor. Patients with pre-treatment Ki-67 >20%, Her2 overexpression, T2b/T3 vs. T4 clinical stage achieved higher response rate.
CONCLUSION: The future of neoadjuvant therapy lies in tailoring treatment to individual patients by identifying response predictors; although the number of patients reported is small, this study confirms that clinical stage at diagnosis, Ki-67 reduction and Her2 overexpression are predictive of tumor response to neoadjuvant regimens.