Yoshida A, et al. – The present study was undertaken to evaluate the change in HER2 status after neoadjuvant chemotherapy (NAC) in patients with primary breast cancer and the prognostic impact of such changes. According to the findings obtained, changes in HER2 status did not affect patients’ prognosis.

Methods

• The examination contained five hundred eighty-eight patients with a non-pathologic complete response who received anthracycline and/or taxane-based regimens in NAC setting.
• HER2 status was evaluated before NAC and in residual invasive tumor of the surgical specimens.
• The relationship between the change in HER2 status and clinicopathological factors were evaluated.

Results

• The results of this study showed that 489 (83%) of the 588 patients had HER2-negative tumors and 99 patients (17%) had HER2-positive tumors before NAC.
• Findings revealed that eleven (2.2%) of the HER2-negative tumors changed to HER2-positive, while 33 (33%) of the HER2-positive tumors changed to HER2-negative.
• It was noted that ER and PR-positivity before NAC were related to loss of HER2-positivity, whereas receiving trastuzumab was not.
• There was no difference between patients with and those without change in HER2 status after NAC in either the patients with HER2-negative tumors (P = 0.26) or with HER2-positive tumors before NAC (P = 0.23) in terms of disease-free survival.