Dynamics of pathological factors after «test» course of preoperative endocrine therapy in menopausal patients with earlyer positive breast cancer and its effect on survival
Authors: M.A. Frolova, M.B.Stenina, Y.I. Kochetkova, A.V. Petrovsky, O.V. Krohina, Y.V. Vishnevskaya, S.A. Tyulyandin
Background: the choice of adjuvant therapy in early ER positive Her2 negative breast cancer (BC) is difficult due to significant heterogeneity of these tumors. Additional instruments are needed to help in identifying the right tactics.
Goal: to research the Ki67 dynamics after the short «test» course of preoperative endocrine therapy and to evaluate its
impact on survival.
Materials and Methods: 100 postmenopausal patients (pts) with early stage (T1-2N0-1M0) ER positive Her2 negative BC were included in the study. They received the short (2–3 weeks) course of preoperative endocrine therapy with tamoxifen or aromatase inhibitors. Postoperative pathology report included repeated evaluation of Ki67, ER, PR, TILs.
Results: after the short course of endocrine therapy there was a significant decrease in Ki67 (p=0,001) and PR expression (p=0,001), ER expression did not change. Only the preoperative level of Ki67 impact its decrease to the goal evel of <10%. With the baseline level of 10–30% its decrease to the goal level was observed in 56% cases, while with baseline level >30% – in only 21%. The baseline level of Ki67 did not impact the survival in opposite to postoperative level. 5-year DFS was 100% with Ki67 <10%, 97,4% – with Ki67 10–30% and 76,4% – with Ki67 >30% (р=0,02).
Conclusion: the level of Ki67 <10% after the short course of preoperative endocrine therapy, was associated with excellent survival rates in postmenopausal pts and allows to consider omitting of chemotherapy and thus safely de-escalate adjuvant therapy.