The alternation of estrogen receptor (ER) and progesterone receptor (PgR) expression in primary breast cancer patients treated with neoadjuvant chemotherapy (NAC)

Abstract

21165 Background: Currently, neoadjuvant chemotherapy (NAC) for the operable primary breast cancer has become standard treatment strategy. Primary treatment could affect the status of Estrogen receptor (ER) and Progesterone receptor (PgR) expressions in the tumor, and might have impact on the choice of adjuvant hormone therapy. Methods: We evaluated consecutive 165 primary breast cancer cases those treated with 4 cycles of FEC (500–100–500 mg/m2, q3wks) followed by 4 cycles docetaxel (75 mg/m2, q3wks) as their neoadjuvant treatment in our institution from January 2000 to February 2006. Except for the bilateral breast cancer cases and patients achieved pCR, 107 pairs of core needle biopsy before treatment and tumor block after surgery were evaluated by immunohistochemistry (IHC) for receptor status and analyzed by Allred scoring. Score 4 or more was designated as positive. Results: Median age of patients was 51 (23–71) years old. Hormone receptor (HR) phenotypes before treatment were following; ER+/PgR+:62(57.9%), +/ -:23(21.5%), -/ +:2(1.9%), -/ -:20(18.7%). As the HR status, 94.4 % of patients did not show any alternation for their HR evaluation. Only 4.7% of patients experienced changes from HR+ to HR-, and HR- to HR+ were extremely rare (0.9%). Although ER positivity was not changed in most of cases (95.1%), conversion from PgR + to - were observed in 35.5% of ER+/PgR+ cases. Particularly, the rate of negative conversion of PgR were found more frequently in patients with age under 50 (51.7% in <50y.o. vs. 22.6% in =50 y.o., p=0.03). Whereas, in older patients, negative conversion of PgR correlated to favorable pathological response. Conclusions: In most of patients, neoadjuvant chemotherapy did not affect the evaluation of HR status. Alternation of PgR expression seems to reflect the chemotherapy induced amenorrhea in younger patients. In the older patients, negative conversion of PgR may have some impact on pathological response. No significant financial relationships to disclose.