Prognostic predictive value of Ki-67 in stage I–II triple-negative breast cancer

Aim: Our research aimed to determine an optimal cutoff value and investigate the prognostic predictive function of Ki-67. Materials & methods: We retrospectively enrolled 1146 patients diagnosed with stage I–II triple-negative breast cancer. Disease-free and overall survival were analyzed using the Kaplan–Meier method and the Cox regression model. Results: We classified Ki-67 >45% as the high group (n = 716). A Ki-67 level of >45% was associated with poorer disease-free survival (p = 0.039) and overall survival (p = 0.029). Lymph node stage, neoadjuvant chemotherapy, and radiotherapy were independent predictive variables of prognosis. Conclusion: Triple-negative breast cancer may be further subcategorized according to the Ki-67 level. Neoadjuvant chemotherapy and postoperative radiotherapy can improve the prognosis of early triple-negative breast cancer. This study aimed to find the best value of Ki-67, which is a marker used in breast cancer. At last, according to the Ki-67 level over 45%, triple-negative breast cancer may be divided into two groups. Based on the level of Ki-67, treatment decisions may be better. However, we still need more studies to confirm this. Triple-negative breast cancer may be further subcategorized according to the Ki-67 level >45%, which is associated with a poorer prognosis. Treatment decisions based on the level of Ki-67 may be more favorable to the prognosis of patients. This research aimed to determine an optimal cutoff value and investigate the prognostic predictive function of Ki-67, which is a proliferation-related biomarker used in luminal breast cancer. We retrospectively enrolled 1146 patients diagnosed with stage I–II triple-negative breast cancer, between Jan 2013 and Dec 2020, at the Sun Yat-sen University Cancer Center. The best cutoff point for Ki-67 was 45%, which was found in the X-tile. For the 1146 patients, we classified Ki-67 >45% as the high group and Ki-67 ≤ 45% as the low group. Lymph node stage, neoadjuvant chemotherapy, and postoperative radiotherapy were independent predictive variables of prognosis. Triple-negative breast cancer may be further subcategorized according to the Ki-67 level >45%, which is associated with a poorer prognosis, particularly in the lymph node-negative group. Neoadjuvant chemotherapy and postoperative radiotherapy can improve the prognosis. Therefore, there is still a need for prospective studies with large sample sizes, specialized assay technicians, and standard operating procedures to explore the optimal detection procedure for Ki-67.