1. Estimating survival benefit of adjuvant chemotherapy in postmenopausal women with pT1-2N0 early-stage breast cancer and Oncotype DX recurrence score > 26: A National Cancer Database (NCDB) analysis
- Author
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Lifen Cao, Christopher W. Towe, Nickolas Stabellini, Amanda L. Amin, and Alberto J. Montero
- Subjects
Cancer Research ,Oncology - Abstract
543 Background: Early validation studies using the Oncotype DX recurrence score (RS) in NSABP B20 demonstrated that women with node negative breast cancer and RS >31 had significant survival benefit from the addition of adjuvant chemotherapy to endocrine therapy (CET). Consequently, in the prospective TAILORx trial, node negative women with RS >26 received CET. These studies did not clearly delineate the magnitude of benefit of adjuvant chemotherapy for post-menopausal node negative women. A recently published well-designed adjuvant trial (RxPONDER) demonstrated that adjuvant chemotherapy was not beneficial in post-menopausal pts with ER+/HER2- breast cancer, 1-3 positive nodes, and RS 26 compared to endocrine therapy (ET) alone, given that CET is more beneficial in women 50 with ER+/HER2- pT1-2N0M0 breast cancer with RS >26, to assess real world utilization. We separated women into two groups based on adjuvant treatment: ET alone or CET. Chi-square and logistic regression analysis determined difference between different systemic treatment groups. OS was analyzed using a multivariable Cox model. Results: A total of 16,745 eligible women who underwent surgery and received ET were identified in the NCDB—4,740 (28.3%) received ET alone and 12,005 (71.7%) received CET. We observed that CET use increased over time. Women were more likely to receive CET if their tumors were moderately differentiated (OR = 1.853, p < 0.001), poorly/undifferentiated tumors (OR = 3.875, p < 0.001), or associated with lymph-vascular invasion (OR = 1.206, p = 0.001). After accounting for demographic and oncologic factors, 5-year OS rates in this cohort were significantly superior in women receiving CET compared to ET alone (95.4% vs 92.0%, Hazard Ratio = 0.680, p < 0.001). Conclusions: Utilizing the NCDB to represent real world outcomes, we observed that women > 50 years with pT1-2N0M0 ER+/HER2- breast cancer, and RS > 26 had a significantly superior 5-year OS when receiving adjuvant chemotherapy provides a measurable OS benefit for post-menopausal women in this setting and should be discussed with patients.
- Published
- 2022