Patients with only 1 positive hormone receptor have increased locoregional recurrence compared with patients with estrogen receptor-positive progesterone receptor-positive disease in very early stage breast cancer

Background: Estrogen receptor (ER) and progesterone receptor (PR) are important prognostic and predictive biomarkers in breast cancer. Patients with tumors positive for either receptor are generally considered hormone receptor-positive for treatment decisions. However, some data suggest that patients with ER⁺/PR^- or ER^-/PR⁺ tumors may have worse outcomes than those with ER⁺/PR⁺ tumors. Few data correlate these biomarkers with locoregional (LR) recurrence. Methods: The authors retrospectively reviewed records of 635 patients with T1a,bN0 disease who received definitive treatment at their institution between 1997 and 2002 and had archival tissue blocks for prospective assessment of ER/PR expression. They compared clinical outcomes of the 479 patients with ER ⁺/PR⁺ disease to the 156 patients with ER ⁺/PR^- or ER^-/PR⁺disease. Results: LR recurrence rates were higher in patients with 1 receptor positive compared with ER⁺/PR⁺ (7-year rate: 8.8% vs 2.5%, P =.024). There was no difference between the 2 groups in the rates of distant metastasis (DM) (P =.531) or overall survival (P =.491). One positive receptor predicted for LR recurrence in patients who did not receive hormonal therapy (P =.046), but not in patients who received hormonal therapy (P =.296). On multivariate analysis, 1 positive receptor predicted for LR recurrence in the overall group (hazard ratio, 2.81; 95% confidence interval, 1.06-7.48; P =.038). Conclusions: Patients with T1a,bN0 breast cancer with only 1 positive hormone receptor have increased rates of LR recurrence compared with patients with ER⁺/PR ⁺ disease, although this difference may be reduced or eliminated with systemic treatment. In contrast, the authors found no evidence of an increased rate of DM in these patients with favorable disease stage.