A Study of the Impact of Endocrine Therapy on Surgical Outcomes in People With Lobular Breast Cancer

June 2, 2026 updated by: Memorial Sloan Kettering Cancer Center

Impact of Neoadjuvant Endocrine Therapy on Surgical Outcomes in Patients With Stage 2 to 3 Invasive Lobular Carcinoma: A Prospective Study

The purpose of this study is to look at how effective neoadjuvant (before surgery) endocrine therapy (NET) is in participants with invasive lobular carcinoma (ILC) who have breast-conserving surgery (BCS). The main purpose of the study is to see if NET reduces the chance of having cancer cells at the edges of tissue removed during surgery (positive margins).

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

176

Phase

  • Phase 2

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact Backup

Study Locations

  • United States
    • New Jersey
      • Basking Ridge, New Jersey, United States, 07920
        • Recruiting
        • Memorial Sloan Kettering Basking Ridge (Limited Protocol Activities)
        • Contact:
          • Anita Mamtani, MD
          • Phone Number: 646-888-6864
      • Middletown, New Jersey, United States, 07748
        • Recruiting
        • Memorial Sloan Kettering Monmouth (Limited protocol activities)
        • Contact:
          • Anita Mamtani, MD
          • Phone Number: 646-888-6864
      • Montvale, New Jersey, United States, 07645
        • Recruiting
        • Memorial Sloan Kettering Bergen (Limited protocol activities)
        • Contact:
          • Anita Mamtani, MD
          • Phone Number: 646-888-6864
    • New York
      • Commack, New York, United States, 11725
        • Recruiting
        • Memorial Sloan Kettering Suffolk - Commack (Limited protocol activities)
        • Contact:
          • Anita Mamtani, MD
          • Phone Number: 646-888-6864
      • Harrison, New York, United States, 10604
        • Recruiting
        • Memorial Sloan Kettering Westchester (Limited protocol activities)
        • Contact:
          • Anita Mamtani, MD
          • Phone Number: 646-888-6864
      • New York, New York, United States, 10065
        • Recruiting
        • Memorial Sloan Kettering Cancer Center (All Protocol Activities)
        • Contact:
          • Anita Mamtani, MD
          • Phone Number: 646-888-6864
      • Uniondale, New York, United States, 11553
        • Recruiting
        • Memorial Sloan Kettering Nassau (Limited Protocol Activities)
        • Contact:
          • Anita Mamtani, MD
          • Phone Number: 646-888-6864

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Written informed consent by participant or legally authorized representative
  • Postmenopausal women aged ≥50 years with biopsy-proven cT2-T3 N0-1 ILC who opt to undergo and are medically fit to undergo BCS at enrollment.

  • Tumors of the ER+/HER2- subtype, defined as:

    1. ER+: Positive for ER staining as indicated by ≥10% immunoreactive tumor nuclei.
    2. HER2-: Immunohistochemistry assay demonstrating no or faint staining in ≤10% of tumor cells (IHC 0 or 1+) or negative by dual probe in situ hybridization assay.

Exclusion Criteria:

  • Patients with prior ipsilateral breast cancer.
  • Patients with advanced regional disease (cN2/cN3) or stage 4 disease.
  • Patients who would benefit from neoadjuvant chemotherapy, per the treating medical oncologist.
  • Patients who are not candidates for definitive breast surgery (inoperable or stage 4 disease).
  • Patients with gadolinium allergy, precluding the use of breast MRI.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Participants with ER+/HER2- Breast Cancer
Participants will be postmenopausal women aged ≥50 years with biopsy-proven cT2-T3 N0-1 ILC, ER+/HER2- subtype
Drug: Neoadjuvant endocrine therapy
The endocrine therapy used for the NET in this study will be anastrozole, letrozole, exemestane, or tamoxifen.
Other Names:
  • NET

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Rate of positive surgical margins after breast cancer surgery
Time Frame: up to 3 months
To prospectively evaluate rates of positive surgical margins after initial breast cancer surgery/BCS among postmenopausal women with cT2-3 N0-1 ER+/HER2- ILC who have undergone a course of NET.
up to 3 months

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Memorial Sloan Kettering Cancer Center

Investigators

  • Principal Investigator: Anita SKCCSC(P Mamtani, MD, Memorial Sloan Kettering Cancer Center

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

Helpful Links

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

March 13, 2026

Primary Completion (Estimated)

March 13, 2030

Study Completion (Estimated)

March 13, 2030

Study Registration Dates

First Submitted

March 16, 2026

First Submitted That Met QC Criteria

March 16, 2026

First Posted (Actual)

March 19, 2026

Study Record Updates

Last Update Posted (Actual)

June 4, 2026

Last Update Submitted That Met QC Criteria

June 2, 2026

Last Verified

June 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 26-095

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

Memorial Sloan Kettering Cancer Center supports the international committee of medical journal editors (ICMJE) and the ethical obligation of responsible sharing of data from clinical trials. The protocol summary, a statistical summary, and informed consent form will be made available on clinicaltrials.gov when required as a condition of Federal awards, other agreements supporting the research and/or as otherwise required. Requests for deidentified individual participant data can be made following one year after publication and for up to 36 months later. Deidentified individual participant data reported in the manuscript will be shared under the terms of a Data Use Agreement and may only be used for approved proposals. Requests may be made to: crdatashare@mskcc.org.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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