Dr. Ko Un “Clara” Park and Dr. Mylin Torres present the latest evidence-based changes to the SLNB in early-stage breast cancer guideline. They discuss the practice-changing trials that led to the updated recommendations and topics such as when SLNB can be omitted, when ALND is indicated, radiation and systemic treatment decisions after SLNB omission, and the role of SLNB in special circumstances. We discuss the importance of shared decision-making and other ongoing and future de-escalation trials that will expand knowledge in this space.

Read the full guideline update, “Sentinel Lymph Node Biopsy in Early-Stage Breast Cancer: ASCO Guideline Update” at www.asco.org/breast-cancer-guidelines.

TRANSCRIPT

This guideline, clinical tools, and resources are available at http://www.asco.org/breast-cancer-guidelines. Read the full text of the guideline and review authors’ disclosures of potential conflicts of interest in the Journal of Clinical Oncology, https://ascopubs.org/doi/10.1200/JCO-25-00099      

Brittany Harvey: Hello and welcome to the ASCO Guidelines podcast, one of ASCO's podcasts delivering timely information to keep you up to date on the latest changes, challenges and advances in oncology. You can find all the shows, including this one at asco.org/podcasts.

My name is Brittany Harvey and today I'm interviewing Dr. Ko Un "Clara" Park from Brigham and Women's Hospital, Dana-Farber Cancer Institute, and Dr. Mylin Torres from Glenn Family Breast Center at Winship Cancer Institute of Emory University, co-chairs on “Sentinel Lymph Node Biopsy in Early-Stage Breast Cancer: ASCO Guideline Update.”

Thank you for being here today, Dr. Park and Dr. Torres.

Dr. Mylin Torres: Thank you, it's a pleasure to be here.

Brittany Harvey: And before we discuss this guideline, I'd like to note that ASCO takes great care in the development of its guidelines and ensuring that the ASCO Conflict of Interest Policy is followed for each guideline. The disclosures of potential conflicts of interest for the guideline panel, including Dr. Torres and Dr. Park, who have joined us here today, are available online with the publication of the guideline in the Journal of Clinical Oncology, which is linked in the show notes.

To start us off, Dr. Torres, what is the scope and purpose of this guideline update on the use of sentinel lymph node biopsy in early-stage breast cancer?

Dr. Mylin Torres: The update includes recommendations incorporating findings from trials released since our last published guideline in 2017. It includes data from nine randomized trials comparing sentinel lymph node biopsy alone versus sentinel lymph node biopsy with a completion axillary lymph node dissection. And notably, and probably the primary reason for motivating this update, are two trials comparing sentinel lymph node biopsy with no axillary surgery, all of which were published from 2016 to 2024. We believe these latter two trials are practice changing and are important for our community to know about so that it can be implemented and essentially represent a change in treatment paradigms.

Brittany Harvey: It's great to hear about these practice changing trials and how that will impact these recommendation updates.

So Dr. Park, I’d like to start by reviewing the key recommendations across all of these six overarching clinical questions that the guideline addressed. So first, are there patients where sentinel lymph node biopsy can be omitted?

Dr. Ko Un "Clara" Park: Yes. The key change in the current management of early-stage breast cancer is the inclusion of omission of sentinel lymph node biopsy in patients with small, less than 2 cm breast cancer and a negative finding on preoperative axillary ultrasound. The patients who are eligible for omission of sentinel lymph node biopsy according to the SOUND and INSEMA trial are patients with invasive ductal carcinoma that is size smaller than 2 cm, Nottingham grades 1 and 2, hormone receptor-positive, HER2-negative in patients intending to receive adjuvant endocrine therapy, and no suspicious lymph nodes on axillary ultrasound or if they have only one suspicious lymph node, then the biopsy of that lymph node is benign and concordant according to the axillary ultrasound findings. The patients who are eligible for sentinel lymph node biopsy omission according to the SOUND and INSEMA trials were patients who are undergoing lumpectomy followed by whole breast radiation, especially in patients who are younger than 65 years of age. For patients who are 65 years or older, they also qualify for omission of sentinel lymph node biopsy in addition to consideration for radiation therapy omission according to the PRIME II and CALGB 9343 clinical trials. And so in those patients, a more shared decision-making approach with the radiation oncologist is encouraged.

Brittany Harvey: Understood. I appreciate you outlining that criteria for when sentinel lymph node biopsy can be omitted and when shared decision making is appropriate as well.

So then, Dr. Torres, in those patients where sentinel lymph node biopsy is omitted, how are radiation and systemic treatment decisions impacted?

Dr. Mylin Torres: Thank you for that question. I think there will be a lot of consternation brought up as far as sentinel lymph node biopsy and the value it could provide in terms of knowing whether that lymph node is involved or not. But as stated, sentinel lymph node biopsy actually can be safely omitted in patients with low risk disease and therefore the reason we state this is that in both SOUND and INSEMA trial, 85% of patients who had a preoperative axillary ultrasound that did not show any signs of a suspicious lymph node also had no lymph nodes involved at the time of sentinel node biopsy. So 85% of the time the preoperative ultrasound is correct. So given the number of patients where preoperative ultrasound predicts for no sentinel node involvement, we have stated within the guideline that radiation and systemic treatment decisions should not be altered in the select patients with low risk disease where sentinel lymph node biopsy can be omitted. Those are the patients who are postmenopausal and age 50 or older who have negative findings on preoperative ultrasound with grade 1 or 2 disease, small tumors less than or equal to 2 cm, hormone receptor-positive, HER2-negative breast cancer who undergo breast conserving therapy.

Now, it's important to note in both the INSEMA and SOUND trials, the vast