Purpose: This study aims to investigate the change of Ki67 value pre- and post-neoadjuvant therapy (NAT) and evaluate its potential value in predicting survival outcomes in different molecular subtypes of breast cancer.
Methods: A total of 257 breast cancer patients who underwent NAT at Renmin Hospital of Wuhan University from July 2019 to Sep 2023 were included in this study. The Ki67 index of the patients was re-interpreted by two attending physicians, and the changes of Ki67 value pre- and post-NAT were compared. Chi-square test (χ2) and logistic regression were conducted to examine the correlation between various characteristics and the efficacy of NAT. Disease-free survival (DFS) was calculated using the Kaplan-Meier curve and compared using the log-rank test.
Results: Patients with higher histological grade, negative expression of estrogen receptor (ER) or progesterone receptor (PR), positive expression of human epidermal growth receptor 2 (HER2), higher pretreatment Ki67 index, absence of lymph node metastasis, and those with HER2 positive and triple-negative breast cancer were associated with improved efficacy of NAT. Our study identified that the optimal cut-off value for the changes in Ki67 index pre- and post-NAT related to the effectiveness of NAT was "-88.19 %" in whole chort, which was related to the aforementioned clinical characteristics. Besides, the optimal cut-off values for the luminal, HER2-enriched and triple-negative subtypes were "-91.83 %", "-46.12 %" and "-81.67 %", respectively. Survival analysis demonstrated that the changes in Ki67 value were significantly associated with DFS in the HER2-enriched and triple-negative subtype, but not in the luminal subtype.
Conclusions: Preoperative clinicopathological features and changes in Ki67 value pre-and post-NAT can contribute to providing patients with a more accurate prognosis.
Keywords: Breast cancer; Ki67; Neoadjuvant therapy; Residual cancer burden; Survival outcomes.
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