ABSTRACT
CONTEXT: Hormone receptors (estrogen receptor ER and progesterone receptor PR) are prognostic and predictive factors of outcome for invasive breast cancer. Some tumors only express one of these hormone receptors (ER or PR). ER negative/PR positive breast cancer is a rare subtype (1-4 %) and its existence still controversial. The aim of this study was to evaluate characteristics of this group of tumors. METHODS: We collected data of all consecutive patients managed in our institution for invasive breast cancer between the 1st January 2007 and 31 December 2013. The aim of the study was to compare data of patients with ER-/PR+tumors with the three other subgroups. RESULTS: Of the 2071 patients included during the study period, 1.2 % were ER-/PR+. These patients were younger than those with the two ER+groups (p<0.0001). The ER-/PR+tumors differed from the ER+groups for several histological prognostic factors: greater histological size (p=0.0004), higher histological grade, more HER2 overexpression/amplification, more association with ductal carcinoma in situ, more lymphovascular invasion, more nodal metastasis (p<0.0001). Chemotherapy was more often used as an adjuvant treatment in addition of endocrine therapy. Survival was equivalent for patients with ER-/PR+tumors and ER+tumors and significantly higher than patients with ER-/PR- tumors (p<0.0001). CONCLUSION: Women with ER-/PR+breast cancer have worse prognostic factors than women with ER+cancers but have better overall survival than women with ER-/PR- tumors. We may think that the more frequent association of chemotherapy and endocrine therapy is responsible for this better outcome.
