V10: Neoadjuvant Therapy for Older Patients with Estrogen Receptor Positive Breast Cancer: Comparison of Chemotherapy and Endocrine Approaches

Tuesday, March 1, 2022

5:07 PM – 5:10 PM CST

Location: Zoom Meeting

Virtual Poster Presenter(s)

Krislyn N. Miller, DO, MS

Surgical Oncology Breast Fellow
Duke University
Cary, North Carolina, United States

Disclosure: Disclosure information not submitted.

Participants should be aware of the following financial/non-financial relationships:

Krislyn N. Miller, DO, MS: Disclosure information not submitted.

Introduction:

The benefits of a complete pathologic response (pCR) following neoadjuvant chemotherapy (NACT) or neoadjuvant endocrine therapy (NET) is well-established, yet responses specifically for older women are less well characterized. We sought to compare the pCR and survival rates of older vs younger women with estrogen receptor (ER) positive breast cancer receiving NACT vs NET.

Methods:

Women diagnosed with cT1-4, cN0-3, M0, ER+/HER2- breast cancer (2010-2018) who underwent surgery following NACT or NET were selected from the National Cancer Database and categorized by age (< 50, 50-69, ≥70). Pathologic response to neoadjuvant therapy was defined based on change from clinical T/N at presentation to pathologic T/N at final pathology. Differences between groups were tested, and unadjusted overall survival (OS) was estimated.

Results:

Of the 43,009 patients identified, 84.8% received NACT and 15.2% received NET. Of those age ≥70 (N=5623), 33.6% were cT3-4, 48.9% were cN+, 51.0% received NACT, and 49.0% received NET. Of those ≥70 receiving NACT (N=2870), 3% had a complete breast and nodal pCR, 5.5% had a breast-only pCR, and 6.4% had a node-only pCR. Compared to younger women receiving NACT, elderly patients were less likely to have either a breast or nodal pCR (no pCR by age: ≥70, 85.1% vs 50-69, 82.2% vs < 50, 77.7%, p< 0.001). However, rates of pCR were similarly low among younger and older women receiving NET (any pCR by age: ≥70, 4.4% vs 50-69, 5% vs < 50, 3.6%, p=0.28). The unadjusted OS rates were consistently lower for the oldest age group receiving NACT or NET, compared to younger patients (log rank p< 0.001). However, the OS rates for women ≥70 were similar for those receiving NACT or NET (1-year: 95.2 vs 96.1; 5-year: 70.5% vs 70.5%, respectively).

Conclusions: For women ≥70 with ER+/HER2- breast cancer, pCR rates after NACT are significantly lower compared to younger age groups, but are similarly low for those receiving NET regardless of age. However, survival outcomes in elderly women were comparable regardless of whether they received NACT or NET, which supports greater use of NET in this patient population.

Learning Objectives:

To describe the differences in pathologic complete response rates in older patients (age ≥70) with ER+/HER2- breast cancer receiving neoadjuvant chemotherapy or neoadjuvant endocrine therapy.
To describe the differences in survival outcomes in older patients (age ≥70) with ER+/HER2- breast cancer receiving neoadjuvant chemotherapy or neoadjuvant endocrine therapy.
To demonstrate understanding that due to the comparable survival outcomes in older patients receiving NACT or NET, a greater use of NET in this patient population can be supported.