The effect of neoadjuvant chemotherapy on pathological response and the hormone receptor profile in locally advanced breast carcinomas

Abstract

Background: The impact of neoadjuvant chemotherapy (NACT) on tumour biomarkers and the histopathological response to treatment in breast cancer specimens remains controversial. Chemotherapy and hormonal therapy decisions for breast cancer management are influenced by the expression of tumour biomarkers: estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth receptor 2 (HER2). On the other hand, pathological response is an indicator of chemotherapy effectiveness. The study of the effect of NACT in breast cancer is an important issue.
Objectives: To assess the changes to biological markers ER, PR, and HER2, and the pathological response in locally advanced breast cancer patients after neoadjuvant chemotherapy.
Methods: 100 patients with locally advanced breast cancer were assessed with core needle biopsy for biological markers (ER, PR, HER2) and pathological grading. Subsequently they were treated with six cycles of taxane based NACT followed by surgical resection. Biological markers and the pathological response (assessed by the Miller Payne grading system) were re-evaluated to assess changes.
Results: The patient mean age was 45.62 ± 7.12 years. Most patients (56%) were postmenopausal. Clinical disease stage ranged between any T N2, T3 N1-2, T4 N0-2. Post NACT, pathological complete response rate was 14%, ER positivity decreased from 80 (80%) to 78 (78%) (p = 0.67). PR positive dropped from 66 to 62% (p = 0.002), and HER2 receptor positivity was increased from 22% to 28% (p-value 0.000).
Conclusion: It was observed that biological markers (ER, PR, HER2) and the histopathological response of breast cancer may change after NACT. This change may affect treatment decisions.