Purpose: There is controversy regarding the survival benefit of endocrine therapy (ET) in elderly patients with early invasive hormone receptor-positive (HR+) breast cancer. In this study, we characterize a single institution's practice patterns using adjuvant ET for these patients and evaluated the effect of ET on outcomes.
Methods: A review of a prospectively maintained database identified 483 women ≥ 70 years old who underwent breast -conserving surgery (BCS) for stage I-III HR+ tumors from 2004-2013. We compared clinicopathologic characteristics, overall survival (OS), disease-free survival (DFS), locoregional recurrence (LRR), and breast cancer-specific survival (BCSS) in patients who did and did not receive ET.
Results: Compared to patients who did not get ET, patients who received ET were younger (median age 76 vs 78 years, p = 0.006), had larger tumors (median size 15 vs 14 mm, p = 0.016), underwent sentinel lymph node (LN) biopsy (83.7 vs 67.8%, p < 0.001), had positive LNs (25.5 vs 9.8%, p = 0.008), and received radiation (XRT, 76 vs 43%, p < 0.001). After adjusting for ASA score, age, LN status, tumor grade, and XRT, receipt of ET was associated with improved OS (HR 0.44; 95% CI 0.25-0.77; p = 0.004) and DFS (HR 0.42; 95% CI 0.28-0.64; p < 0.01). Receipt of ET was associated with improved LRR on univariate analysis (HR 0.25; 95% CI 0.09-0.70; p = 0.008); however, after adjusting for grade and XRT, this was not statistically significant on multivariable analysis (HR 0.38; 95% CI 0.13-1.08; p = 0.069) and was not associated with BCSS (HR 0.59; 95% CI 0.16-2.16; p = 0.43).
Conclusions: ET was associated with significant improvements in OS and DFS, regardless of clinicopathological features; however, receipt of ET did not impact LRR and BCSS.