title: Survival outcomes in breast cancer patients with low estrogen/progesterone receptor expression.
abstract: BACKGROUND
  The prognostic value of low estrogen and progesterone receptors expression (ER/PgR 1%-10%) in early breast cancer patients is still unclear.
  
  
  METHODS
  We retrospectively analyzed 1424 consecutive patients with HER2/neu-negative and low endocrine receptors expression early breast cancer, submitted to surgery at the European Institute of Oncology between January 1995 and December 2009. Patients were classified according to the percentage of ER/PgR expression using immunohistochemistry. Group 1 with ER/PgR < 1%, and group 2 with ER/PgR 1% to 10%.
  
  
  RESULTS
  Group 1 (ER/PgR < 1%) included 1300 patients, and group 2 (ER/PgR 1%-10%) 124 patients. Median follow-up time was 74 months (range, 3-192 months). The 5-year disease-free survival (DFS) rate was 74% (95% confidence interval [CI], 72%-77%) for group 1, and 79% (95% CI, 70%-86%) for group 2 (P = .16). The 5-year overall survival (OS) rate was 86% (95% CI, 84%-88%) in group 1 and 90% (95% CI, 83%-95%) in group 2 (P = .13). In patients without lymph node involvement, the 5-year OS rate was 92% (95% CI, 89.5%-93.6%) for group 1 and 98% (95% CI, 90.2%-99.8%) for group 2 (P = .061). One hundred ten patients received endocrine therapy with no significant effect on DFS (P = .36) and OS (P = .30).
  
  
  CONCLUSIONS
  The ER/PgR 1%-10% group had a slight, but not statistically significant, better prognosis than the ER/PgR <1% group. Further studies are needed to identify the appropriate clinical approach in this subset of patients with low ER/PgR expression (ER/PgR 1%-10%), HER2-negative early breast cancer.
authors: Division of Medical Senology, European Institute of Oncology, Milan, Italy. Electronic address: alessandra.balduzzi@ieo.it.
authors: Alessandra
authors: A
authors: Balduzzi
authors: Division of Epidemiology and Biostatistics, European Institute of Oncology, Milan, Italy; Department of Statistics and Quantitative Methods, Unit of Biostatistics, Epidemiology and Public Health, University of Milan-Bicocca, Milan, Italy.
authors: Vincenzo
authors: V
authors: Bagnardi
authors: Division of Epidemiology and Biostatistics, European Institute of Oncology, Milan, Italy.
authors: Nicole
authors: N
authors: Rotmensz
authors: Division of Medical Senology, European Institute of Oncology, Milan, Italy.
authors: Silvia
authors: S
authors: Dellapasqua
authors: Division of Medical Senology, European Institute of Oncology, Milan, Italy.
authors: Emilia
authors: E
authors: Montagna
authors: Division of Medical Senology, European Institute of Oncology, Milan, Italy.
authors: Anna
authors: A
authors: Cardillo
authors: Division of Pathology and Laboratory Medicine, European Institute of Oncology, Milan, Italy; School of Medicine, University of Milan, Italy.
authors: Giuseppe
authors: G
authors: Viale
authors: School of Medicine, University of Milan, Italy; Molecular Senology Unit, European Institute of Oncology, Milan, Italy.
authors: Paolo
authors: P
authors: Veronesi
authors: Division of Senology, European Institute of Oncology, Milan, Italy.
authors: Mattia
authors: M
authors: Intra
authors: Division of Senology, European Institute of Oncology, Milan, Italy.
authors: Alberto
authors: A
authors: Luini
authors: Division of Pathology and Laboratory Medicine, European Institute of Oncology, Milan, Italy; School of Medicine, University of Milan, Italy.
authors: Giancarlo
authors: G
authors: Pruneri
authors: Division of Pathology and Laboratory Medicine, European Institute of Oncology, Milan, Italy.
authors: Giuseppe
authors: G
authors: Mastropasqua
authors: Vice-Scientific Director, European Institute of Oncology, Milan, Italy.
authors: Aron
authors: A
authors: Goldhirsch
authors: Division of Medical Senology, European Institute of Oncology, Milan, Italy.
authors: Marco
authors: M
authors: Colleoni
mesh_terms: D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000378:metabolism; D001943:Breast Neoplasms / Q000378:metabolism / Q000401:mortality* / Q000473:pathology / Q000628:therapy; D018270:Carcinoma, Ductal, Breast / Q000378:metabolism / Q000401:mortality* / Q000473:pathology / Q000628:therapy; D018275:Carcinoma, Lobular / Q000378:metabolism / Q000401:mortality* / Q000473:pathology / Q000628:therapy; D003131:Combined Modality Therapy; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007124:Immunoenzyme Techniques; D008875:Middle Aged; D060787:Neoplasm Grading; D009367:Neoplasm Staging; D011379:Prognosis; D011446:Prospective Studies; D011960:Receptors, Estrogen / Q000378:metabolism*; D011980:Receptors, Progesterone / Q000378:metabolism*; D012189:Retrospective Studies; D015996:Survival Rate
chemical_list: D014408:Biomarkers, Tumor; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone
keywords: Adjuvant treatment; Estrogen receptor; Histologic subtypes; Low endocrine responsiveness; Overall survival