Breast CancerNCT06529302
The OPBC-07/microNAC Study
An observational study of Breast Cancer, run by University Hospital, Basel, Switzerland at 84 sites in 30 countries.
Trial summary
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. Read more about this study
- Who is it for?
- Ages 18 to 100 years
- Conditions the study is for
- Breast Cancer
- How many people
- 2,000 participants
- Where
- 84 sitesin 30 countries
- Study dates
- 15 May 2024to Jun 2025
- Phase
- Observational
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 100 years
- All sexes
- No healthy volunteers
- Adult, Older adult
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.
Who may be able to join
- 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
Show all 10Show fewer
- 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
Who cannot join
- 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)
Trial locations and contacts
84 sites in 30 countries.
84 sites in 30 countries
United States19 sites
University of Michigan
Ann Arbor, Michigan, 48109
Dana-Farber Cancer Institute
Boston, Massachusetts, 02215
University of Miami
Coral Gables, Florida, 33146
Duke University
Durham, North Carolina, 27708
MD Anderson Cancer Center
Houston, Texas, 77030
Cedars-Sinai Medical Center
Los Angeles, California, 90048
NYU Langone Health
New York, New York, 10016
Memorial Sloan Kettering Cancer Center
New York, New York, 10065
Montefiore Medical Center
New York, New York, 10467
University of Pennsylvania
Philadelphia, Pennsylvania, 19104
Fox Chase Cancer Center
Philadelphia, Pennsylvania, 19111
Valleywise Health Medical Center
Phoenix, Arizona, 85008
University of Pittsburgh Medical Center
Pittsburgh, Pennsylvania, 15219
Mayo Clinic
Rochester, Minnesota, 55905
University of Rochester
Rochester, New York, 14642
University of California
San Francisco, California, 94158
Providence Saint John's Cancer Institute
Santa Monica, California, 90404
Swedish Cancer Institute
Seattle, Washington, 98104
University of Washington
Seattle, Washington, 98195
Brazil9 sites
Hospital de Base do Distrito Federal
Brasília, 70330-150
Sirio Libanes Hospital Brasilia
Brasília
Hospital Nossa Senhora das Graças
Curitiba, 80810-040
Hospital Geral de Fortaleza
Fortaleza, 60150-160,
Instituto do Cancer do Ceará
Fortaleza, 60430-230
Instituto de Mastologia e Oncologia
Goiânia, 74110-060
Hospital de Câncer Araújo Jorge
Goiânia, 74605-070
Sirio Libanes Hospital
São Paulo, 01308-050
Instituto D'OR de Pesquisa e Ensino
São Paulo, 01401-002
Switzerland9 sites
Cantonal Hospital Baden
Baden, 5404
University Hospital Basel
Basel, 4031
Campus SLB Sonnenhof AG
Bern, 3001
Cantonal Hospital Luzern
Lucerne, 6000
EOC Centro di Senologia della Svizzera Italiana
Lugano, 6962
Tumor und Brustzentrum Ostschweiz
Sankt Gallen, 9016
Cantonal Hospital Winterthur
Winterthur, 8400
Zürich Breast Center
Zurich, 8008
University Hospital Zürich
Zurich, 8091
Germany5 sites
University Hospital Augsburg
Augsburg, 86156
University Hospital Düsseldorf
Düsseldorf, 40225
KEM | Clinics Essen-Mitte
Essen, 45136
University Hospital Heidelberg
Heidelberg, 69120
University Hospital Lübeck
Lübeck, 23562
Italy5 sites
Insituto Europeo di Oncologia
Milan, 20141
University Hospital Federico II
Naples, 80131
IOV Padua
Padova, 35128
Clinici Scientifici Maugeri IRCCS
Pavia, 27100
Fondazione Policlinico Universitario Agostino Gemelli IRCCS
Roma, 00136
South Korea4 sites
ASAN Medical Center
Seoul
Gangnam Severance Hospital
Seoul
Samsung Medical Center
Seoul
Seoul National University Hospital
Seoul
Turkey (Türkiye)4 sites
Gülhane Training and Research Hospital
Ankara, 06010
Istanbul University Faculty of Medicine
Fatih, 34093
Marmara University
Istanbul
Zonguldak Bülent Ecevit University
Zonguldak, 67100
Spain3 sites
Hospital del Mar d'Investigacions Mèdiques
Barcelona, 08003
Clinica Universidad de Navarra
Madrid, 28027
Hospital Universitario La Paz, ía Mamaria
Madrid, 28046
Austria2 sites
Ordensklinikum Linz GmbH
Linz, 4020
Medical University of Vienna Chirurgie
Vienna, 1090
Chile2 sites
Arturo Lopez Perez Foundation
Providencia, 7500921
Institute of Radiation Medicine
Vitacura, 7630370
Greece2 sites
University General Hospital of Heraklion
Heraklion, 71110
Athens Medical Center
Marousi, 151 25
Peru2 sites
Hospital Nacional Guillermo Almenara Irigoyen
La Victoria, 13
Instituto Nacional de Enfermedades Neoplasicas
Surquillo, 15038
Netherlands1 site
The Netherlands Cancer Institute - Antoni van Leeuwenhoek Hospital
Amsterdam, 1066 CX
Russia1 site
N.N. Petrov National Medical Research Center of Oncology
Saint Petersburg, 197758
About this study
Official title: 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.
Read the 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.
- Conditions
- Breast Cancer
- Keywords
- Neoadjuvant chemotherapy, Axillary lymph node dissection, Residual micrometastases
- Medical subject headings
- Breast Neoplasms
What is being measured
The primary outcome is the main question the study is designed to answer.
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.
Measured: 5 years
5-year rate of isolated axillary recurrence
Assessment of the incidence of isolated axillary recurrence.
Measured: 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.
Measured: 5 years
Secondary outcomes (3)
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.
Measured: 5 years
5-year rates of locoregional and any invasive recurrence
Assessment of the incidence of locoregional and any invasive recurrence.
Measured: 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.
Measured: 5 years
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted31 Jul 2024
- Study start15 May 2024
- Primary completionJun 2025 (estimated)
- Study completionJun 2025 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for Breast CancerStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Retrospective
- Enrolment
- 2,000 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University Hospital, Basel, Switzerland
- Sponsor type
- University, hospital or other
- Collaborators
- Memorial Sloan Kettering Cancer Center
- Responsible party
- Sponsor
- Investigators
- Walter Paul Weber, Prof. Dr., Principal investigator, University Hospital, Basel, Switzerland
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06529302
- Sponsor's protocol ID
- 2024-00186; bb24Weber
- Status last verified
- Jan 2025
- First submitted
- 25 Jul 2024
- Last updated
- 24 Jan 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
Publications
Montagna G, Alvarado M, Myers S, Mrdutt MM, Sun SX, Sevilimedu V, Barrio AV, van den Bruele AB, Boughey JC, Boyle MK, Crown A, Kesmodel SB, King TA, Kuerer HM, Leisha EC, Moo TA, Weiss A, Williams AD, Parmar P, Diskin B, Hlavin C, Diego EJ, Polidorio N, Abdelwahab K, Banys-Paluchowski M, Kurzeder C, Heidinger M, Goldschmidt M, Schulz A, Heil J, Karadeniz Cakmak G, Pislar N, Riis M, Prakash I, Ovalle V, Ugurlu MU, Franceschini G, Sergeevich EA, Morales J, Lee HB, Galimberti V, Ahn SG, Ryu JM, Muslumanoglu M, Cabioglu N, Yoo TR, Vrancken Peeters MJ, Ferrucci M, Morrow M, Weber WP; microNAC Study Group. Oncological outcomes with and without axillary lymph node dissection in patients with residual micrometastases after neoadjuvant chemotherapy (OPBC-07/microNAC): an international, retrospective cohort study. Lancet Oncol. 2026 Jan;27(1):57-67. doi: 10.1016/S1470-2045(25)00598-4.
PubMed 41449148
Study at a glance
From the registry record, last updated by the sponsor on 24 Jan 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Association of Axillary Lymph Node Dissection With Oncological Outcomes in Patients With Residual Micrometastases After Neoadjuvant Chemotherapy: The OPBC-07/microNAC Study
- ClinicalTrials.gov ID
- NCT06529302
- Acronym / sponsor ID
- 2024-00186; bb24Weber
- Conditions
- Breast Cancer
- Keywords
- Neoadjuvant chemotherapy, Axillary lymph node dissection, Residual micrometastases
- Study type
- Observational
- Recruitment status
- Active, not recruiting
- Enrolment
- 2,000 participants (estimated)
- Lead sponsor
- University Hospital, Basel, SwitzerlandUniversity, hospital or other
- Collaborators
- Memorial Sloan Kettering Cancer Center
- Study start
- 15 May 2024 (actual)
- Primary completion
- Jun 2025 (estimated)
- Study completion
- Jun 2025 (estimated)
- First posted
- 31 Jul 2024 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
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 design
- Observational model
- Cohort
- Time perspective
- Retrospective
Who may qualify
- Ages
- 18 to 100 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
- 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.
Key inclusion criteria (10 listed)
- 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)
Key exclusion criteria (6 listed)
- 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
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Primary outcome
5-year rate of any axillary recurrence
Time frame: 5 years
Assessment of the incidence of any axillary recurrence, which is defined as isolated or combined with local or distant recurrence.
5-year rate of isolated axillary recurrence
Time frame: 5 years
Assessment of the incidence of isolated axillary recurrence.
Comparison of 5-year rate of axillary recurrence in patients treated with and without axillary dissection
Time frame: 5 years
The incidence of axillary recurrence is compared between patients that were treated with and without axillary dissection.
3 secondary outcomes
Proportion of patients with additional micro- and macrometastases removed by axillary lymph node dissection
Time frame: 5 years
5-year rates of locoregional and any invasive recurrence
Time frame: 5 years
Comparison of 5-year rate of locoregional and any invasive recurrence in patients treated with and without axillary lymph node dissection
Time frame: 5 years
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 24 Jan 2025.
- Derived from this study: PubMed 41449148Montagna G, Alvarado M, Myers S, Mrdutt MM, Sun SX, Sevilimedu V, Barrio AV, van den Bruele AB, Boughey JC, Boyle MK, Crown A, Kesmodel SB, King TA, Kuerer HM, Leisha EC, Moo TA, Weiss A, Williams AD, Parmar P, Diskin B, Hlavin C, Diego EJ, Polidorio N, Abdelwahab K, Banys-Paluchowski M, Kurzeder C, Heidinger M, Goldschmidt M, Schulz A, Heil J, Karadeniz Cakmak G, Pislar N, Riis M, Prakash I, Ovalle V, Ugurlu MU, Franceschini G, Sergeevich EA, Morales J, Lee HB, Galimberti V, Ahn SG, Ryu JM, Muslumanoglu M, Cabioglu N, Yoo TR, Vrancken Peeters MJ, Ferrucci M, Morrow M, Weber WP; microNAC Study Group. Oncological outcomes with and without axillary lymph node dissection in patients with residual micrometastases after neoadjuvant chemotherapy (OPBC-07/microNAC): an international, retrospective cohort study. Lancet Oncol. 2026 Jan;27(1):57-67. doi: 10.1016/S1470-2045(25)00598-4.
Related trials for Breast Cancer
Active, not recruitingObservational study
Assessment of Cognitive Function in Breast Cancer and Lymphoma Patients Receiving Chemotherapy
Breast Cancer, Lymphoma
RecruitingObservational study
National Mammography Database
Breast Cancer Screening and Diagnosis
Active, not recruiting
Node Negative, Invasive Breast Cancer Single Fraction IOERT
Breast Cancer
RecruitingPhase 2
Prospective Evaluation Of High-Dose Systemic Methotrexate In Patients With Breast Cancer And Leptomeningeal Metastasis
Metastatic Breast Cancer, Leptomeningeal Disease
Active, not recruitingPhase 1/2
Accelerated Radiation Therapy (ART) to the Breast and Nodal Stations
Breast Cancer
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Walter Paul Weber, Prof. Dr. principal investigator
University Hospital, Basel, Switzerland
84 sites in 30 countries: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Breast Cancer, run by University Hospital, Basel, Switzerland at 84 sites in 30 countries.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 10 inclusion and 6 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: under way, not looking for participants, as of the sponsor's last update on 24 Jan 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 84 sites in United States, Brazil, Switzerland, Germany, Italy and 25 more countries. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
5-year rate of any axillary recurrence (time frame: 5 years). The study lists 3 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT06529302, which also lists 1 linked publication.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 24 Jan 2025; AzTrials last refreshed its copy on 28 Oct 2026.