Retrospective evaluation of breast cancer patients with non-metastatic luminal subtype neoadjuvant chemotherapy received

Luminal breast cancer types are less responsive to chemotherapy, so pathological complete response rates are low comparing other subtypes. In this study, we aimed to investigate the factors affecting recurrence-free survival in patients with luminal breast cancer who received neoadjuvant chemotherapy, based on clinicopathological data. The electronic records of 396 patients who received chemotherapy for breast cancer between January 1, 2005 and December 31, 2019 in our center were reviewed retrospectively. The data about patients' age, date of diagnosis, pathological features of preoperative biopsy and surgery, neoadjuvant chemotherapy regimens, local recurrence, distant organ metastasis, total and recurrence-free survival were obtained. The findings were evaluated using the IBM SPSS 23.0 program. The median recurrence-free survival is 146.2 months. Recurrence was observed in 76 of 396 patients. Death was observed in 48 patients (12.1%). Five-year overall survival was 90.0%, 10-year overall survival was 74.8%. In the multivariate Cox regression analysis, it was shown that the lymph node positivity (p = 0.001) and the percentage of Ki67 in biopsy (median 21, p = 0.012) significantly affected recurrence-free survival. In Log-rank test, there was a significant difference between N0 and N1 patients (p <0.001) and Ki67 <21 and Ki67> 21 patients (p = 0.001) in terms of recurrence-free survival. Absence of axillary lymph node in pre-operative evaluation and posing lower Ki67 value than 21% in pre-operative biopsy are statistically significant good prognostic factors on recurrence-free survival. Keywords: luminal, breast cancer, neoadjuvant, lymph node, Ki67