Estrogen/progesterone receptor negativity and HER2 positivity predict locoregional recurrence in patients with T1a,bN0 breast cancer

Purpose: Data have suggested that the molecular features of breast cancer are important determinants of outcome; however, few studies have correlated these features with locoregional recurrence (LRR). In the present study, we evaluated estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) as predictors of LRR in patients with lymph node-negative disease and tumors ≤1 cm, because these patients often do not receive adjuvant chemotherapy or trastuzumab. Methods and Materials: The data from 911 patients with stage T1a,bN0 breast cancer who had received definitive treatment at our institution between 1997 and 2002 were retrospectively reviewed. We prospectively analyzed ER/PR/HER2 expression from the archival tissue blocks of 756 patients. These 756 patients represented the cohort for the present study. Results: With a median follow-up of 6.0 years, the 5- and 8-year Kaplan-Meier LRR rate was 1.6% and 5.9%, respectively, with no difference noted in those who underwent breast conservation therapy vs. mastectomy (p = .347). The 8-year LRR rates were greater in the patients with ER-negative (10.6% vs. 4.2%, p = .016), PR-negative (9.0% vs. 4.2%, p = .009), or HER2-positive (17.5% vs. 3.9%, p = 0.009) tumors. On multivariate analysis, ER-negative and PR-negative disease (hazard ratio, 2.37; p = .046) and HER2-positive disease (hazard ratio, 3.13, p = .016) independently predicted for LRR. Conclusion: Patients with ER/PR-negative or HER2-positive T1a,bN0 breast cancer had a greater risk of LRR. Therapeutic strategies, such as the use of chemotherapy and/or anti-HER2 therapies, should be considered for future clinical trials for these patients.