Efficacy of neoadjuvant toremifene (TOR) and intratumor expression of estrogen receptor (ER) A and B in elderly breast cancer (BC) patients

8164 Background: Endocrine therapy is effective in downstaging patients (pts) with primary BC and may be considered in elderly women. TOR is a triphenylethylene selective ER modulator differing from tamoxifen for the presence of a chlorine atom. Methods: A two-stage, phase II study was conducted to investigate efficacy of TOR (60 mg/day) as a short-term pre-operative therapy (3 months) in elderly pts with newly diagnosed, ERα+ operable or locally advanced (T2-T4b, N0–1) BC. The relationship of intratumor levels of mRNA ERα and β with objective responses was investigated, and serum markers of bone metabolism were also evaluated. Diagnosis was established by mammography and core-biopsy. A cut-off of 10% of stained cells was used to define ERα positivity. ER isoforms was assessed by RT-PCR. At baseline and monthly thereafter, tumor size was estimated clinically (by calipers). After 3 months of TOR, all pts were referred to the breast surgeon. Results: Forty-seven evaluable pts entered the study. Median age w...