Purpose: The aim of this study was to assess the changes in biologic markers of breast cancer ER, PR, HER 2 and Ki-67 in locally advanced breast cancer patients after neoadjuvant chemotherapy.
Methods: Data from 63 locally advanced breast cancer patients (stage II or III), whose histological diagnosis was made by core biopsies were retrospectively evaluated. The patients were given 4 cyles of 600 mg/m(2) cyclophosphamide, 60 mg/m(2) doxorubicin every 15 days followed by 4 cycles of paclitaxel 175 mg/m(2) every 15 days, and they underwent surgery within two weeks after the last chemotherapy cycle. Expressions in the preoperative and postoperative status of ER, PR, HER 2 and Ki-67 were compared.
Results: The patient mean age was 49.2 ±10.7 years and most (57.1%) were premenopausal. Clinical stages of patients ranged between T2N1 and T3N2. The pathological complete response (pCR) rate was 14.9 % (N=9). Two (5.7%) patients who were ER positive prior to treatment showed ER negativity after treatment. In 7 (21.17percnt;) patients PR became negative after neoadjuvant chemotherapy and in 3 (9.0%) patients PR became positive. Changes in ER and PR receptors were not statistically significant (ER p=0.500 and PR p=0.549, respectively), whereas in 2 (5. 8%) patients hormonal status changed significantly when compared to initial biopsies (p=0.003). In addition, median value for PR intensity decreased from 20 to 10% (p=0.003) and Ki-67 values decreased from 10 to 1% (p<0.001) following neoadjuvant therapy. Six (17%) patients exhibited some changes in HER 2 staining. HER 2 expression became 2+ in 3 patients who were HER 2 negative prior to treatment, and HER 2 expression became negative in two patients with HER 2 1+ and 2+ prior to treatment following neoadjuvant chemotherapy.
Conclusion: The biological markers ER, PR, HER 2 and Ki- 67 index demonstrated differences after neoadjuvant treatment in breast cancer patients. These changes may affect the treatment decision.