3: Changes in axillary surgical management over 10 years – report on > 1400 breast cancer patients treated with neoadjuvant chemotherapy on I-SPY2

Friday, March 24, 2023

2:01 PM – 2:13 PM

Location: Veterans Memorial Auditorium

Abstract Presenter(s)

Judy C. Boughey, MD, FACS, FSSO (she/her/hers)

Professor of Surgery, W.H. Odell Professor in Individualized Medicine, Chair-Division of Breast and Melanoma Surgical Oncology, Department of Surgery
Mayo Clinic
Rochester, Minnesota, United States

Disclosure(s): Cairns Surgical: Other (Ongoing); Eli Lilly: Research Grant (Ongoing); OncLive: Speaker (Terminated); Peer View: Speaker (Terminated); PER: Speaker (Terminated); SymBioSis: Research Grant (Ongoing); UptoDate: Royalties (Ongoing)

Author(s)

Judy C. Boughey, MD, FACS, FSSO (she/her/hers)

Professor of Surgery, W.H. Odell Professor in Individualized Medicine, Chair-Division of Breast and Melanoma Surgical Oncology, Department of Surgery
Mayo Clinic
Rochester, Minnesota, United States

Disclosure(s): Cairns Surgical: Other (Ongoing); Eli Lilly: Research Grant (Ongoing); OncLive: Speaker (Terminated); Peer View: Speaker (Terminated); PER: Speaker (Terminated); SymBioSis: Research Grant (Ongoing); UptoDate: Royalties (Ongoing)
LE

Laura Esserman, MD, MBA

Director of UCSF Breast Care Center, Co-leader of the Breast Oncology Program
UCSF, United States

Disclosure information not submitted.
QD

Qian Ding, M.S.

Principal Statistician
Quantum Leap Healthcare Collaborative
San Francisco, California, United States

Disclosure information not submitted.
HY

Hongmei Yu, Ph.D.

Data Scientist
Quantum Leap Healthcare Collaborative
San Francisco, California, United States

Disclosure information not submitted.
TW

The ISPY2 Surgical Working Group, n/a

Working Group of surgeons across all ISPY2 sites
multiple organizations, United States

Disclosure information not submitted.
Rita Mukhtar, MD

Assistant Professor of Clinical Surgery
University of California San Francisco
San Francisco, CA, United States

Disclosure information not submitted.

Disclosure(s):

Judy C. Boughey, MD, FACS, FSSO: Cairns Surgical: Other (Ongoing); Eli Lilly: Research Grant (Ongoing); OncLive: Speaker (Terminated); Peer View: Speaker (Terminated); PER: Speaker (Terminated); SymBioSis: Research Grant (Ongoing); UptoDate: Royalties (Ongoing)

Introduction: Axillary surgery after neoadjuvant chemotherapy (NAC) is evolving. We evaluated the changes in axillary surgery in breast cancer patients(pts) treated with NAC on the multi-institutional I-SPY2 prospective trial.

Methods: I-SPY2 is an adaptive platform trial of high-risk early breast cancer pts randomized to neoadjuvant novel systemic therapy agents with choice of surgery at the discretion of the surgeon. We examined the different surgical axillary management (sentinel lymph node (SLN) surgery only, axillary lymph node dissection (ALND) only, SLN & ALND) of pts enrolled across all arms of I-SPY2 from 1/1/2011 to 12/31/2020 by clinical N category at diagnosis, and by axillary pathologic nodal status. Cochran-Armitage trend tests and two sample t-tests were used.

Results: Of 1518 pts enrolled in I-SPY2 from 2011-2020, 1460 pts s completed NAC and had axillary surgery. Across 2011-2020 axillary surgery was SLN-only in 781 pts (53.5%), SLN & ALND in 207 pts (14.2%), ALND-only in 472 pts (32.3%). SLN-only was highest in pts that were cN0 at diagnosis (70.5%) and lower in cN1 and cN2/3 pts (40.0% and 33.1% respectively).

Over time, ALND-only decreased from 50.0% in 2011 to 27.5% in 2020 (p < 0.0001) with concomitant increase in use of SLN-only from 34.7% to 59.4%. By cN category at diagnosis; in the cN0 group, ALND-only did not change significantly over time with rates of 10-25% each year (p=0.7), while SLN-only surgery increased from 65.5% to 71.4% (p < 0.0001), and SLN & ALND decreased from 17% to 8% (p=0.0007). However, in pts with cN+ disease at diagnosis, ALND-only decreased strikingly from 72% to 31% (p < 0.0001) and SLN-only increased from 14% to 53% (p < 0.0001). This change was significant in all subtypes HR-/HER2-, HR+/HER2- and HER2+.

Among pts with confirmed pathologic positive nodes after NAC (n=477), ALND-only decreased from 67% to 33% (p < 0.0001) and SLN-only increased from 10% to 51% (p < 0.0001). All these changes were more striking in 2016-2020 than 2011-2015, p< 0.0001).

Conclusions: In this multicenter study of pts at high risk of distant disease treated with NAC, ALND has significantly decreased over the last decade. This is most pronounced in the clinically node positive group at diagnosis with an increase in the use of SLN surgery after NAC. Additionally, in pts with a pathologic positive node after NAC there has been a decrease in use of ALND, although we still await data from A11202 trial regarding oncologic outcomes of this approach.

Learning Objectives:

understand the evolution of surgical management of the axilla in patients diagnosed with clinically node negative breast cancer treated with neoadjuvant chemotherapy
understand the evolution of surgical management of the axilla in patients diagnosed with clinically node positive breast cancer treated with neoadjuvant chemotherapy
understand the evolution of surgical management of the axilla in patients with node positive disease after neoadjuvant chemotherapy