5: Extremely Low Incidence of Local-Regional Recurrences Observed Among T1-2 N1 (1 or 2 Positive SLNs) Breast Cancer Patients Receiving Upfront Mastectomy Without Completion Axillary Node Dissection

Friday, March 24, 2023

4:41 PM – 4:51 PM

Location: Veterans Memorial Auditorium

Abstract Presenter(s)

Shruti Zaveri, MD MPH (she/her/hers)

Breast Surgical Oncology Fellow
MD Anderson Cancer Center
Houston, Texas, United States

Disclosure(s): No financial relationships to disclose

Author(s)

Shruti Zaveri, MD MPH (she/her/hers)

Breast Surgical Oncology Fellow
MD Anderson Cancer Center
Houston, Texas, United States

Disclosure(s): No financial relationships to disclose
Elizabeth FitzSullivan, MD

The University of Texas MD Anderson Cancer Center
Houston, TX

Disclosure information not submitted.
Rosa Hwang, MD

Professor and Associate Medical Director for Breast Surgery
The University of Texas MD Anderson Cancer Center
Houston, Texas, United States

Disclosure information not submitted.
Benjamin D. Smith, MD

Professor
The University of Texas MD Anderson Cancer Center
Houston, Texas, United States

Disclosure information not submitted.
HL

Heather Lin, PhD

Statistician
MD Anderson Cancer Center, United States

Disclosure information not submitted.
YS

Yu Shen, PhD

Statistician
MD Anderson Cancer Center, United States

Disclosure information not submitted.
Anthony Lucci, Jr., MD

Professor
The University of Texas MD Anderson Cancer Center
Houston, Texas, United States

Disclosure(s): No financial relationships to disclose
Mediget Teshome, MD, MPH, FACS (she/her/hers)

Associate Professor
The University of Texas MD Anderson Cancer Center
Houston, Texas, United States

Disclosure(s): Endomagnetics: Other (Terminated)
SS

Susie Sun, MD

Department of Breast Surgical Oncology
MD Anderson Cancer Center, United States

Disclosure information not submitted.
Kelly K. Hunt, MD (she/her/hers)

Chair, Department of Breast Surgical Oncology
The University of Texas MD Anderson Cancer Center
Houston, Texas, United States

Disclosure(s): Armada Health: Advisor (Ongoing); Astra Zeneca: Consultant (Ongoing); Cairn Surgical: Research Grant (Ongoing); Eli Lilly & Company: Research Grant (Ongoing); Lumicell: Research Grant (Ongoing)
Henry M. Kuerer, MD, PhD

Professor, Breast Surgical Oncology; Executive Director, Breast Programs MD Anderson Cancer Network
The University of Texas MD Anderson Cancer Center
Houston, Texas, United States

Disclosure information not submitted.

Disclosure(s):

Shruti Zaveri, MD MPH: No financial relationships to disclose

Anthony Lucci, MD, Jr.: No financial relationships to disclose

Mediget Teshome, MD, MPH, FACS: Endomagnetics: Other (Terminated)

Kelly K. Hunt, MD: Armada Health: Advisor (Ongoing); Astra Zeneca: Consultant (Ongoing); Cairn Surgical: Research Grant (Ongoing); Eli Lilly & Company: Research Grant (Ongoing); Lumicell: Research Grant (Ongoing)

Introduction: Since the widespread adoption of Z11, completion axillary node dissection (CLND) is routinely omitted in T1-2 breast cancer treated with upfront breast-conserving therapy and sentinel node biopsy (SLNB) showing 1-2 positive sentinel nodes (SLNs). Given many patients elect for mastectomy, it is of interest to determine the incidence and impact of axillary treatment among patients treated with mastectomy in a contemporary cohort.

Methods: A prospective institutional database was reviewed from 2006-2015 to identify patients with T1-2 breast cancer treated with upfront mastectomy and SLNB found to have 1-2 positive SLNs. Patients were stratified by axillary therapy received (including CLND and/or post-mastectomy radiation therapy (PMRT)), and clinicopathologic factors and outcomes were analyzed. Cumulative incidence rates of breast and nodal local-regional recurrence (LRR) were calculated in the presence of distant metastasis and/or death as competing risk factors and stratified by axillary treatment using the Grays’ test.

Results: A total of 552 patients eligible for analysis were identified, including 155 (28%) without CLND. Median follow-up was 84 months. Amongst 397 patients who underwent a CLND, 102 patients (25%) were found to have additional nodal metastases. Rates of PMRT were similar between those with and without CLND (35% vs. 30, p= 0.29). Table 1 summarizes the clinicopathologic features between the groups compared by receipt of CLND. Significant differences include older age, higher proportion with only 1 positive SLN and lower proportion receiving adjuvant chemotherapy and found to have LVI/ECE in those without CLND (p < 0.05). There were only 3 local-regional recurrences in the no CLND group, of which only 1 was an axillary recurrence. The cumulative incidence rate of LRR was not significantly different for those with and without CLND (2.2% vs. 1.1%, p=0.6). Receipt of PMRT was associated with a lower LRR rate in both groups (0% vs 2.2%, p=0.024).

Conclusions: We found extremely low rates of local-regional recurrence among those with T1-2 breast cancer undergoing upfront mastectomy with 1-2 positive SLNs. Further axillary surgery may not be indicated in selected patients treated with a multidisciplinary approach including PMRT.

Learning Objectives:

Identify the utility of axillary treatment in T1-2 N1 (1 or 2 positive SLNs) breast cancer patients undergoing mastectomy.
Identify the factors associated with increased risk of local-regional recurrence in T1-2 N1 (1 or 2 positive node) breast cancer patients undergoing mastectomy.
Describe national guidelines related to axillary management of known lymph node positive disease.