Factors Affecting Axillary Complete Response After Neoadjuvant Chemotherapy and the Importance of Ki-67 Level

We determined independent predictive factors influencing axillary response in patients with neoadjuvant chemotherapy (NAC) indication due to axillary metastases. The patients with T1-4, N1, and M0 tumors who underwent NAC were selected. The study included 105 patients, all women. The factors to be investigated for their effect on the axillary response to NAC were determined as the following: menopausal status (premenopause, postmenopause), pathological diagnosis (invasive ductal ca, other), radiological tumor size (T1 < 2 cm, T2 ≥ 2- < 5 cm, T3 ≥ 5 cm), estrogen receptor (positive, negative), progesterone receptor (positive, negative), HER2 (positive, negative), Ki-67 (cut-off 14%), Ki-67 (cut-off 25%), luminal A, luminal B, HER 2-positive groups, triple-negative group, the number of positive lymph nodes in the axilla before NAC (1, > 1), multifocal tumor, and inflammatory breast cancer. The axillary response to NAC was detected to be lower in ER + (p = 0.001), PR + (p = 0.002), luminal A (p < 0.001), the number of pathological lymph nodes before NAC > 1 (p = 0.018), multifocality (p = 0.04), and inflammatory breast cancer (p = 0.018). We observed that the axillary response to NAC was better in HER2 + (p = 0.09), Ki-67 (cut-off 14%) (p < 0.001), Ki-67 (cut-off 25) (p < 0.001), HER2 + subs type (p = 0.023), triple negative subtype (p = 0.046). According to the results of the multivariate logistic regression test performed Ki-67 (cut-off 25%) (p = 0.030) and inflammatory type breast cancer (p = 0.013) were found to be independent predictive factors affecting axillary response to NAC. We recommend that the Ki-67 value of 25% be used to predict axillary response in luminal B, HER2 + , and triple negative groups in patients scheduled for NAC due to the axillary lymph node involvement.