Hormone receptors and her-2 expression in early breast ductal carcinoma; frequency, and impact on outcome of tamoxifen therapy

ABSTRACT

Recent clinical data have suggested that efficacy of tamoxifen in reducing the risk of local recurrence in breastductal carcinoma [DC] is limited to estrogen receptor [ER] positive lesions, however, a group of these patientshave conflicting results. The purpose of this study was to assess the frequency of Progesterone receptor [PR] and HER-2overexpression in [ER] positive breast ductal carcinoma, in relation to each other, to important prognostic factors,and to correlate the results to patients' response to tamoxifen.Methods: We have analyzed the clinical outcome of selected 100 cases of ER +ve breast ductal carcinoma atclinical stage O-II, represented to pathology and oncology departments, Medical Research Institute in the period January-March 2002, with a follow up period of four years [median 34.5 months]. The patients were treated with standard adjuvant therapy of Tamoxifen [alone or after chemotherapy]. For each case ER, PR and HER-2 wereimmunohistochemically determined. In 100 cases ofER+ breast duct carcinoma, 89% were PR+, and 22% were HER-2+ve. There was a strongpositive correlation between ER and PR [p<0.001], and strong negative correlation between both hormones andHER-2 [p<0.001]. It was found that ER+/PR - tumors were more frequent in older patients [P=<0.001] and withhigher tumor grade [P=0.018], while ER+/HER-2 +ve tumors were significantly associated with patient's age [P=0.005], tumor size [P<0.003] and tumor grade [P< 0.001].On median follow up period of 34.5 months; the overall recurrence rate was 6%, and was restricted toHER-2[3+] +cases. ER+/PR tumors express higher levels of HER-2 and display more aggressive features thanER+/PR+ tumors. Overexpression of HER-2 might limit or negate the beneficial effects of tamoxifen in ER+vebreast DC