The OPBC-07/microNAC Study

Association of Axillary Lymph Node Dissection With Oncological Outcomes in Patients With Residual Micrometastases After Neoadjuvant Chemotherapy: The OPBC-07/microNAC Study

The aim of this multicenter retrospective cohort study is to determine the safety of omission of axillary lymph node dissection in patients with residual micrometastases after neoadjuvant chemotherapy.

Study Overview

• Status: Active, not recruiting
• Conditions: Breast Cancer

Detailed Description

Chemotherapy before surgery, known as neoadjuvant chemotherapy (NAC), is often used to treat patients with advanced breast cancer or aggressive early-stage breast cancer. Research shows that about one in four early-stage breast cancer patients receives this treatment.

For patients undergoing NAC, standard of care includes checking the lymph nodes under the arm (axillary lymph nodes) using a procedure called Sentinel lymph node biopsy to determine if the cancer has spread. In cases where the cancer has spread to the lymph nodes but then shrinks or disappears after chemotherapy, special techniques like dual tracer mapping, targeted axillary dissection, or the Marking Axillary Lymph Nodes with Iodine Seeds procedure are used to ensure accurate biopsy results.

For patients whose cancer shrinks completely in the lymph nodes, it is generally safe to skip further surgery to remove more lymph nodes, a procedure called axillary lymph node dissection (ALND). However, if cancer remains in the lymph nodes, more lymph nodes are typically removed because there is a high chance that cancer is still present.

An increasing number of surgeons are starting to omit ALND, especially when only tiny amounts of cancer (micrometastases) remain. To ensure this practice is safe, real-world data on patient outcomes over time is needed.

This multicenter retrospective cohort study aims to assess the safety of omitting ALND in patients with residual micrometastases after NAC for breast cancer. The study analyzes data of breast cancer patients treated between 2013 and 2024 at more than 50 centers that are part of the Oncoplastic Breast Consortium.

The results of this study will provide valuable information to help doctors determine the best treatment approach for their patients.

• Study Type: Observational
• Enrollment (Estimated): 2000

Contacts and Locations

Study Locations

• Argentina
  • Quilmes, Argentina, B1878
    • Sanatorio Modelo Quilmes
• Australia
  • Sydney, Australia, 2050
    • Chris O'Brien Lifehouse (COBL)
• Austria
  • Linz, Austria, 4020
    • Ordensklinikum Linz GMBH
  • Wien, Austria, 1090
    • Medical University of Vienna Chirurgie
• Brazil
  • Brasilia, Brazil, 70330-150
    • Hospital de Base do Distrito Federal
  • Brasilia, Brazil
    • Sirio Libanes Hospital Brasilia
  • Curitiba, Brazil, 80810-040
    • Hospital Nossa Senhora das Graças
  • Fortaleza, Brazil, 60150-160,
    • Hospital Geral de Fortaleza
  • Fortaleza, Brazil, 60430-230
    • Instituto Do Cancer Do Ceara
  • Goiânia, Brazil, 74110-060
    • Instituto de Mastologia e Oncologia
  • Goiânia, Brazil, 74605-070
    • Hospital de Câncer Araújo Jorge
  • Sao Paulo, Brazil, 01308-050
    • Sirio Libanes Hospital
  • Sao Paulo, Brazil, 01401-002
    • Instituto D'Or de Pesquisa e Ensino
• Canada
  • Montréal, Canada, H3T 1E2
    • Sir Mortimer B. Davis Jewish General Hospital
• Chile
  • Providencia, Chile, 7500921
    • Arturo Lopez Perez Foundation
  • Vitacura, Chile, 7630370
    • Institute of Radiation Medicine
• Croatia
  • Rijeka, Croatia, 51000
    • Clinical Hospital Center Rijeka
• Egypt
  • Mansoura, Egypt
    • Mansoura oncology center
• Germany
  • Augsburg, Germany, 86156
    • University Hospital Augsburg
  • Düsseldorf, Germany, 40225
    • University Hospital Düsseldorf
  • Essen, Germany, 45136
    • KEM | Clinics Essen-Mitte
  • Heidelberg, Germany, 69120
    • University Hospital Heidelberg
  • Lübeck, Germany, 23562
    • University Hospital Lübeck
• Greece
  • Heraklion, Greece, 71110
    • University General Hospital of Heraklion
  • Marousi, Greece, 151 25
    • Athens Medical Center
• Israel
  • Ramat Gan, Israel
    • Sheba Medical Center
• Italy
  • Milano, Italy, 20141
    • Insituto Europeo di Oncologia
  • Napoli, Italy, 80131
    • University Hospital Federico II
  • Padova, Italy, 35128
    • IOV Padua
  • Pavia, Italy, 27100
    • Clinici Scientifici Maugeri IRCCS
  • Roma, Italy, 00136
    • Fondazione Policlinico Universitario Agostino Gemelli IRCCS
• Korea, Republic of
  • Seoul, Korea, Republic of
    • Seoul National University Hospital
  • Seoul, Korea, Republic of
    • Asan Medical Center
  • Seoul, Korea, Republic of
    • Samsung Medical Center
  • Seoul, Korea, Republic of
    • Gangnam Severance Hospital
• Latvia
  • Riga, Latvia, LV-1002
    • Pauls Stradins Clinical University Hospital
• Lithuania
  • Vilnius, Lithuania, 08406
    • National Cancer Institute
• Netherlands
  • Amsterdam, Netherlands, 1066 CX
    • The Netherlands Cancer Institute - Antoni van Leeuwenhoek Hospital
• Norway
  • Oslo, Norway, N-0424
    • Oslo University Hospital
• Pakistan
  • Karachi, Pakistan, Sindh 74200
    • Dow University of Health Sciences
• Peru
  • La Victoria, Peru, 13
    • Hospital Nacional Guillermo Almenara Irigoyen
  • Surquillo, Peru, 15038
    • Instituto Nacional de Enfermedades Neoplasicas
• Poland
  • Zielona Gora, Poland, 65-046
    • University Hospital Zielona Gora
• Portugal
  • Lisboa, Portugal, 1400-038
    • Champalimaud Foundation
• Russian Federation
  • Saint Petersburg, Russian Federation, 197758
    • N.N. Petrov National Medical Research Center of Oncology
• Slovakia
  • Banská Bystrica, Slovakia, 974 01
    • AGEL Mammacentrum sv. Agáty
• Slovenia
  • Ljubljana, Slovenia, 1000
    • Institute of Oncology Ljubljana
• Spain
  • Barcelona, Spain, 08003
    • Hospital del Mar d'Investigacions Mèdiques
  • Madrid, Spain, 28027
    • Clinica Universidad de Navarra
  • Madrid, Spain, 28046
    • Hospital Universitario La Paz, ía Mamaria
• Sweden
  • Stockholm, Sweden, 112 19
    • Capio Saint Göran's Hospital
• Switzerland
  • Baden, Switzerland, 5404
    • Cantonal Hospital Baden
  • Basel, Switzerland, 4031
    • University Hospital Basel
  • Bern, Switzerland, 3001
    • Campus SLB Sonnenhof AG
  • Lugano, Switzerland, 6962
    • EOC Centro di Senologia della Svizzera Italiana
  • Luzern, Switzerland, 6000
    • Cantonal Hospital Luzern
  • St. Gallen, Switzerland, 9016
    • Tumor und Brustzentrum Ostschweiz
  • Winterthur, Switzerland, 8400
    • Cantonal Hospital Winterthur
  • Zürich, Switzerland, 8091
    • University Hospital Zurich
  • Zürich, Switzerland, 8008
    • Zürich Breast Center
• Turkey
  • Ankara, Turkey, 06010
    • Gulhane Training and Research Hospital
  • Fatih, Turkey, 34093
    • Istanbul University Faculty of Medicine
  • Istanbul, Turkey
    • Marmara University
  • Zonguldak, Turkey, 67100
    • Zonguldak Bülent Ecevit University
• United Kingdom
  • Cambridge, United Kingdom, CB2 0QQ
    • Cambridge University Hospitals
• United States
  • Arizona
    • Phoenix, Arizona, United States, 85008
      • Valleywise Health Medical Center
  • California
    • Los Angeles, California, United States, 90048
      • Cedars-Sinai Medical Center
    • San Francisco, California, United States, 94158
      • University of California
    • Santa Monica, California, United States, 90404
      • Providence Saint John's Cancer Institute
  • Florida
    • Coral Gables, Florida, United States, 33146
      • University of Miami
  • Massachusetts
    • Boston, Massachusetts, United States, 02215
      • Dana-Farber Cancer Institute
  • Michigan
    • Ann Arbor, Michigan, United States, 48109
      • University of Michigan
  • Minnesota
    • Rochester, Minnesota, United States, 55905
      • Mayo Clinic
  • New York
    • New York, New York, United States, 10065
      • Memorial Sloan Kettering Cancer Center
    • New York, New York, United States, 10016
      • NYU Langone Health
    • New York, New York, United States, 10467
      • Montefiore Medical Center
    • Rochester, New York, United States, 14642
      • University of Rochester
  • North Carolina
    • Durham, North Carolina, United States, 27708
      • Duke University
  • Pennsylvania
    • Philadelphia, Pennsylvania, United States, 19111
      • Fox Chase Cancer Center
    • Philadelphia, Pennsylvania, United States, 19104
      • University of Pennsylvania
    • Pittsburgh, Pennsylvania, United States, 15219
      • University of Pittsburgh Medical Center
  • Texas
    • Houston, Texas, United States, 77030
      • MD Anderson Cancer Center
  • Washington
    • Seattle, Washington, United States, 98195
      • University of Washington
    • Seattle, Washington, United States, 98104
      • Swedish Cancer Institute

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

The study assesses consecutive patients with residual micrometastases after neoadjuvant chemotherapy, treated with or without axillary dissection. The data originate from participating Oncoplastic Breast Consortium (OPBC) centers as well as from the US and Brazil, and have been collect within the clinical routine between 2013 and 2024.

Description

Inclusion Criteria:

• Consecutive women and men aged 18 years or older with a diagnosis of stage I-III breast cancer (any histological and receptor subtype)
• For Clinically Node negative (cN0) at presentation: any axillary staging technique including palpation is allowed. Dual tracer mapping is not required for Sentinel Lymph Node Biopsy (SLNB)
• For Clinically Node positive (cN+) at presentation: Biopsy proven confirmation is required. Staging techniques include: SLNB with dual mapping or targeted axillary dissection (Targeted Axillary Dissection, TAD: imaging-guided localization of sampled node in combination with Sentinel Lymph Node procedure with or without dual mapping) or the Marking Axillary Lymph Nodes with Iodine Seeds (MARI) procedure
• Completed neoadjuvant chemotherapy
• Residual micrometastases detected on SLNB or TAD or MARI (on frozen section or final pathology)
• Concomitant presence of Isolated Tumor Cells (ITCs) and micrometastases in other sentinel lymph nodes is allowed
• Received axillary treatment with completion axillary lymph node dissection (ALND), axillary Radiotherapy (ART), both or none
• At least 1-year follow-up (inclusion should end in May 2023)
• Had surgery at any time point until May 2023 at the latest
• Prior history of stage I-III (not stage IV) breast cancer is allowed

Exclusion Criteria:

• Did not undergo SLNB/TAD/MARI (e.g., went straight to ALND or ART)
• Presence of ITCs alone or macrometastases on the sentinel nodes (or TAD nodes or MARI node)
• Stage IV disease at presentation
• Inflammatory breast cancer at presentation
• Neoadjuvant endocrine therapy
• Micrometastases detected by One-step nucleic acid amplification (OSNA)

Study Plan

How is the study designed?

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
5-year rate of any axillary recurrence	Assessment of the incidence of any axillary recurrence, which is defined as isolated or combined with local or distant recurrence.	5 years
5-year rate of isolated axillary recurrence	Assessment of the incidence of isolated axillary recurrence.	5 years
Comparison of 5-year rate of axillary recurrence in patients treated with and without axillary dissection	The incidence of axillary recurrence is compared between patients that were treated with and without axillary dissection.	5 years

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Proportion of patients with additional micro- and macrometastases removed by axillary lymph node dissection	Assessment of the proportion of patients with additional micro- and macrometastases that were removed by axillary lymph node dissection.	5 years
5-year rates of locoregional and any invasive recurrence	Assessment of the incidence of locoregional and any invasive recurrence.	5 years
Comparison of 5-year rate of locoregional and any invasive recurrence in patients treated with and without axillary lymph node dissection	The incidence of locoregional and any invasive recurrence is compared between patients that were treated with and without axillary lymph node dissection.	5 years

Collaborators and Investigators

• Sponsor: University Hospital, Basel, Switzerland
• Collaborators: Memorial Sloan Kettering Cancer Center
• Investigators: Principal Investigator: Walter Paul Weber, Prof. Dr., University Hospital, Basel, Switzerland

Study record dates

Study Major Dates

• Study Start (Actual): May 15, 2024
• Primary Completion (Estimated): June 1, 2025
• Study Completion (Estimated): June 1, 2025

Study Registration Dates

• First Submitted: July 25, 2024
• First Submitted That Met QC Criteria: July 30, 2024
• First Posted (Actual): July 31, 2024

Study Record Updates

• Last Update Posted (Actual): March 25, 2025
• Last Update Submitted That Met QC Criteria: January 23, 2025
• Last Verified: January 1, 2025

More Information

Terms related to this study

• Keywords: Neoadjuvant chemotherapy; Axillary lymph node dissection; Residual micrometastases
• Other Study ID Numbers: 2024-00186; bb24Weber

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No