2: Racial disparities in locoregional recurrence in patients with stage I-III, hormone receptor positive breast cancer enrolled in the NSABP B-42 trial

Friday, March 24, 2023

1:37 PM – 1:49 PM

Location: Veterans Memorial Auditorium

Abstract Presenter(s)

Charity C. Glass, MD MPP

Fellow
Dana-Farber Cancer Institute/ Brigham & Women's Hospital/ Massachusetts General Hospital
Medford, Massachusetts, United States

Disclosure(s): No financial relationships to disclose

First Author(s)

Charity C. Glass, MD MPP

Fellow
Dana-Farber Cancer Institute/ Brigham & Women's Hospital/ Massachusetts General Hospital
Medford, Massachusetts, United States

Disclosure(s): No financial relationships to disclose

Author(s)

Robert M. Pride, MD

Breast Surgical Oncology Fellow
Dana Farber Cancer Institute/Brigham & Women's Hospital/Massachusetts General Hospital
Brookline, Massachusetts, United States

Disclosure(s): No financial relationships to disclose

Author(s)

Rachel A. Freedman, MD, MPH

Medical Oncology
Dana-Farber Cancer Institute
Boston, MA, United States

Disclosure information not submitted.
EM

Erica L. Mayer, MD MPH

Medical Oncologist
Dana-Farber Cancer Institute, United States

Disclosure information not submitted.
EO

Esther R. Ogayo, BS

Research Assistant
Dana-Farber Cancer Institute, United States

Disclosure information not submitted.
MC

Mariana Chavez-MacGregor, MD

Associate Professor
MD Anderson Cancer Center, United States

Disclosure information not submitted.
Tari A. King, MD, FSSO, FASCO (she/her/hers)

Chief, Division of Breast Surgery
Brigham and Womens Hospital, Dana Farber/Brigham Cancer Center
Boston, Massachusetts, United States

Disclosure(s): Exact Sciences/Genomic Health: Advisor (Ongoing), Speaker (Ongoing)
Elizabeth A. Mittendorf, MD PhD

Rob and Karen Hale Distinguished Chair in Surgical Oncology
Brigham and Womens Hospital/Harvard Medical School
Boston, Massachusetts, United States

Disclosure information not submitted.
Olga Kantor, MD MS

Breast Surgeon
Brigham and Women's Hospital
Boston, Massachusetts, United States

Disclosure information not submitted.

Disclosure(s):

Charity C. Glass, MD MPP: No financial relationships to disclose

Robert M. Pride, MD: No financial relationships to disclose

Tari A. King, MD, FSSO, FASCO: Exact Sciences/Genomic Health: Advisor (Ongoing), Speaker (Ongoing)

Introduction: While racial disparities in breast cancer mortality are well documented, there are limited data examining differences in locoregional recurrence (LRR) among women with access to high quality care. We examined differences in late LRR events in patients with stage I-IIIa, hormone receptor-positive (HR+) breast cancer who participated in the NSABP B-42 trial.

Methods: From 2006-2010, 3966 postmenopausal women with stage I-IIIa HR+ breast cancer who were disease-free after 5 years of treatment with endocrine therapy were randomized to an additional 5 years of an aromatase inhibitor or placebo. Race was self-reported; patients with unknown race were excluded. LRR was defined as recurrence in the ipsilateral breast, chest wall, or regional nodes. Kaplan-Meier curves were used to estimate 6-year LRR from the time of trial registration. Cox proportional-hazards analysis adjusted for clinical and treatment factors was used to determine factors associated with LRR.

Results: 3926 NSABP B-42 patients were included; 3688 (93.9%) patients were White, 151 (3.8%) Black, and 90 (2.3%) Asian or Pacific Islander (API). Median follow-up time was 75.2 months. Estimated 6-year LRR from study registration (~11 years from initial diagnosis) was 1.7% in White, 4.9% Black and 0% in API women (Figure). When stratified by risk factors, rates of LRR were higher in Black (vs White) women with node-negative disease (6.2% vs 1.3%, p=0.01) and among those in the placebo arm (7.5% vs 1.6%, p< 0.01). On adjusted analysis, Black (vs White) women were more likely to have LRR (HR 2.4, 95% CI 1.01-5.49, p=0.047). Patients with positive nodes were also more likely to have LRR (HR 1.8, 95% CI 1.07-2.87, p=0.025); age, HER2 status, surgery type and study arm were not associated with LRR.

Conclusions: Among postmenopausal patients with stage I-IIIa breast cancer randomized in the NSABP B-42 trial, racial differences in rates of late LRR were present, with highest LRR in Black women. Further study should explore differences in risk factors for late recurrences as well as if differences in LRR contribute to disparities in breast cancer mortality.

Learning Objectives:

Appreciate that disparities exist in breast cancer mortality based on differences in race and ethnicity.
Describe racial disparities in locoregional recurrence in women who participated in the NSABP B-42 trial.
Describe that racial disparities in locoregional recurrence in women who participated in the NSABP B-42 trial exist despite equal access to high quality care.