Abstract
The neoadjuvant chemotherapy (NAC) is the gold standard initial treatment of the locally advanced breast cancer (LABC). However, the reliability of methods that used to assess response the NAC is still controversial. In this study, patients with LABC who underwent NAC were evaluated retrospectively. The assessment of response to NAC and the effect of axillary approach were investigated on LABC course.The study comprised 94 patients who received NAC with an LABC diagnosis between 2008 and 2020. In our center, magnetic resonance imaging, ultrasonography, and F-flouro deoxyglucose positron emission tomography/computed tomography, and, for some patients, fine-needle aspiration biopsy of suspicious axillary lymph nodes have been performed to assess the effects of NAC. Patients with positive hormone receptor status received adjuvant hormonotherapy, and those with human epidermal growth factor receptor 2 gene expression were treated with trastuzumab. Adjuvant radiotherapy was applied to all patients undergoing breast conserving surgery. Radiotherapy was applied to the peripheral lymphatic areas in the clinical N1 to N3 cases regardless of the response to NAC.The clinical response to the NAC was found that partial in 59% and complete in 19% of the patients. However, 21.2% of the patients were unresponsive. The mean of lymph nodes that excised with the procedure of sentinel lymph node biopsy (SLNB) was 2.4 (range 1-7). In 22 of the 56 patients who underwent SLNB, axillary dissection (AD) was added to the procedure upon detection of metastasis in frozen section examinations. There was no difference between the SLNB and AD groups regarding overall survival (OS; P = .472) or disease-free survival (DFS) rates (P = .439). However, there were differences in the OS (P < .05) and DFS (P = .05) rates on the basis of the LABC histopathological subtypes.The study found that a relationship between molecular subtypes and LABC survival. However, the post-NAC axillary approach had no effect on OS or DFS. Therefore, multiple imaging and interventional methods are needed for the evaluation of NAC response. In addition, morbidity can be avoided after AD by the use of SLNB in cN0 patients.