HER2+ Tumors with Lack Steroid Receptors Showed a Shorter DFS but Similar OS Compared to HER2+ Tumors That Also Express ER and/or PR.

Abstract

Abstract Background: HER2 expression is widely measured on tumor tissue from breast cancer patients since it gives prognostic and predictive information. Data suggest that breast cancer growth is regulated by the coordinated action of the estrogen receptor (ER) and receptor tyrosine kinase signaling pathways. The aim of this retrospective analysis was to evaluate the additional prognostic value of the ER/PR status for the subset of patients with HER2-positive tumors.Methods: From 2000-2002, 203 breast tumors were tested for HER2 and steroid receptors levels. HER2-positivity was defined as ≥2 copies of the HER2 gene by FISH or 3+ by IHC. A cut-off point of 10 % was used as positivity for ER and/or progesterone receptor (PR) levels.Results: Among the 203 patients, 103 had HER2+/ER-/PR- tumors and 100 had HER2+/ER+ and/or PR+ tumors. Patients' characteristics were comparable between the two groups as far as age, menopausal status, pTNM (stage I-II-III) status and type of initial therapy. All patients had surgery followed by standard chemotherapy and radiotherapy and hormonal therapy if the tumor was ER+ or PR+. No patients received adjuvant treatment with trastuzumab. The median follow-up for the entire cohort was 73 months (range 12-110). Comparisons of disease-free survival (DFS), overall survival (OS) as well as site of first recurrence were made between the two groups. The 5-year DFS was statistically different between the two groups: 69.9% for HER2+/ER-/PR- patients and 81.0% for the HER2+/ER+ and/or PR+ (p=0.037). The 5-year OS was not different between the two groups with 82.5% for HER2+/ER-/PR- patients and 86.0% for the HER2/ER+ and/or PR+ (p=0.402).Conclusions: Patients with HER2+/ER-/PR- breast cancers treated with surgery and standard adjuvant chemotherapy exhibit a statistically worse DFS compared to patients with HER2+/ER+ and/or PR+ tumors. However, overall survival was similar in both groups; additional factors should be evaluated to explain this finding. Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 6052.