Breast CancerMACRONACNCT07546695
Role of Axillary Lymph Node Dissection for Residual MACROMETASTASES After NEOADJUVANT Chemotherapy in Patients With HER2+ and Triple Negative Breast Cancer: The OPBC-11/MACRONAC Study
An observational study of Breast Cancer, run by University Hospital, Basel, Switzerland at 1 site in Switzerland.
Trial summary
In this multicenter retrospective cohort study the aim is to determine the safety of omission of axillary lymph node dissection in patients with TNBC and HER2+ tumors with residual macrometastases (in the SLN/TAD/TAS or MARI node) after NAC. Read more about this study
- Who is it for?
- Any age
- Conditions the study is for
- Breast Cancer
- What is being tested?
- Data Collection from medical records of from an already existing database "ONCOLOGICAL BREAST SURGERY DATABASE OF THE UNIVERSITY HOSPITAL OF BASEL" which was initiated in 2016.
- How many people
- 600 participants
- Where
- 1 siteSwitzerland
- Study dates
- 1 Feb 2026to Dec 2027
- 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 Any age
- All sexes
- No healthy volunteers
- Child, Adult, Older adult
Study population: Patients who presented with cT1-4 N0-3 TNBC (including ER-low tumors) or HER2+ BC who underwent NAC followed by axillary staging with either SLN surgery, TAD, TAS or the MARI procedure and were found to have residual macrometastases will be included. Data from "Universitätsspital Basel" will be extracted from medical records of from an already existing database.
Who may be able to join
- Women and men with a diagnosis of stage I-III TNBC or HER2+ breast cancer at diagnosis. HER2+ is defined as an Immunohistochemistry (IHC) score of 3+ or positive FISH. TNBC is defined as ER and Progesterone Receptor (PR) IHC expression of 0 and HER2 negativity defined as either IHC expression of 0-1+ or lack of gene amplification (FISH < 2.0). Patients with ER low (1-10%) and/or PR low (1-10%) tumors are allowed.
- Any histological subtype
- For Clinical Nodal Stage (cN) 0 at presentation: any axillary staging technique including palpation with or without imaging is allowed. Dual tracer mapping is not required for SLN surgery.
- For cN+ at presentation: Percutaneous biopsy proven confirmation is required at diagnosis. Staging techniques after NAC include: SLN surgery with dual mapping or Targeted Axillary Dissection (TAD: imaging-guided localization of sampled node in combination with SLN procedure with or without dual mapping) or Tailored Axillary Surgery (TAS: removal of the sentinel lymph nodes as well as selective removal of all palpable disease and documentation of the removal of the initially biopsy-proven and clipped lymph node metastasis by specimen radiography) or the MARI procedure (Marking Axillary Lymph Nodes with Iodine Seeds).
- Received neoadjuvant chemotherapy
- Residual macrometastases (metastasis greater than 2 mm in diameter) detected on SLN surgery or TAD ot TAS or MARI (on frozen section or final pathology)
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- Concomitant presence of Isolated Tumor Cells (ITCs) and micrometastases in other sentinel lymph nodes is allowed
- Following SLN surgery/TAD/TAS/MARI patients underwent completion ALND, nodal radiation therapy (RT), both or no further axillary treatment
- At least 1-year follow-up (had surgery at any time point until October 2024 at the latest) - Prior history of ductal carcinoma in situ (DCIS) is allowed
Who cannot join
- Did not undergo SLN surgery/TAD/TAS/MARI (e.g., went straight to ALND)
- Presence of ITCs or micrometastases alone in the sentinel nodes (or TAD nodes or MARI node or TAS nodes) without macrometastases
- HR+HER2- tumors (except ER low and or PR-low)
- Stage IV disease at presentation
- Inflammatory breast cancer at presentation
- Neoadjuvant endocrine therapy
- Macrometastases detected by Oncoplastic Breast Consortium (OSNA)
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Switzerland1 site, 1 recruiting
- Recruiting
Department Breast, Abdomen, Pelvis; Universitätsspital Basel
Basel, 4031
Walter P. Weber, Prof. Dr. med., +41 61 328 61 49, walter.weber@usb.ch
Andy Schneider, PhD, andy.schneider@usb.ch
About this study
In this multicenter retrospective cohort study the aim is to determine the safety of omission of axillary lymph node dissection in patients with TNBC and HER2+ tumors with residual macrometastases (in the SLN/TAD/TAS or MARI node) after NAC.
- Conditions
- Breast Cancer
- Being tested
- Data Collection from medical records of from an already existing database "ONCOLOGICAL BREAST SURGERY DATABASE OF THE UNIVERSITY HOSPITAL OF BASEL" which was initiated in 2016.
- Keywords
- Axillary lymph node dissection (ALND), Triple Negative Breast Cancer (TNBC), Breast Conserving Surgery (BCS), Human Epidermal Growth Factor Receptor 2 Positive/ Negative (HER2+/- ), Hormone Receptor Positive/ Negative (HR+/-), Neoadjuvant Chemotherapy (NAC), Targeted Axillary Dissection (TAD), Tailored Axillary Surgery (TAS), Marking Axillary Lymph Nodes with Iodine Seeds (MARI), Sentinel Lymph Node (SLN)
- Medical subject headings
- Breast Neoplasms, Triple Negative Breast Neoplasms
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Data Collection from medical records of from an already existing database "ONCOLOGICAL BREAST SURGERY DATABASE OF THE UNIVERSITY HOSPITAL OF BASEL" which was initiated in 2016.Other
All trial data are/ have been collected within the clinical routine between 2013 and October 2024. All data will be analyzed descriptively using adequate statistical measures and plots. Clinico-pathological characteristics will be compared between patients treated with and without ALND. Depending on the median follow-up of both cohorts (ALND, no ALND) the 3-year cumulative incidence rates will be compared between ALND and no ALND.
| Study group | Role | What they receive |
|---|---|---|
| Axillary lymph node dissection (ALND) cohort | Not described Receives: Other: Data Collection from medical records of from an already existing database "ONCOLOGICAL BREAST SURGERY DATABASE OF THE UNIVERSITY HOSPITAL OF BASEL" which was initiated in 2016. | |
| No Axillary lymph node dissection (ALND) cohort | Not described Receives: Other: Data Collection from medical records of from an already existing database "ONCOLOGICAL BREAST SURGERY DATABASE OF THE UNIVERSITY HOSPITAL OF BASEL" which was initiated in 2016. |
What is being measured
The primary outcome is the main question the study is designed to answer.
3-year rate of any axillary recurrence
3-year rate of any axillary recurrence (defined as isolated or combined with local or distant recurrence) in patients with residual macrometastases after NAC overall and by use of axillary dissection.
Measured: 3-year follow-up after diagnosis of stage I-III TNBC or HER2+ breast cancer and SLN surgery/TAD/TAS/MARI
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted23 Apr 2026
- Study start1 Feb 2026
- Primary completionDec 2027 (estimated)
- Study completionDec 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Breast CancerStudies of the same condition, open and under way.
- More trials run by University Hospital, Basel, SwitzerlandThe sponsor's other registered studies.
- 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
- 600 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University Hospital, Basel, Switzerland
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Walter P. Weber, Prof. Dr. med., Principal investigator, Department Breast, Abdomen, PelvisGiacomo Montagna, MD MPH, Study director, Breast Service, Department of Surgery; Memorial Sloan Kettering Cancer Center
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07546695
- Sponsor's protocol ID
- 2026-00317 bb26Weber2
- Acronym
- MACRONAC
- Status last verified
- May 2026
- First submitted
- 16 Apr 2026
- Last updated
- 19 May 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
Study at a glance
From the registry record, last updated by the sponsor on 19 May 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Role of Axillary Lymph Node Dissection for Residual MACROMETASTASES After NEOADJUVANT Chemotherapy in Patients With HER2+ and Triple Negative Breast Cancer: The OPBC-11/MACRONAC Study
- ClinicalTrials.gov ID
- NCT07546695
- Acronym / sponsor ID
- MACRONAC / 2026-00317 bb26Weber2
- Conditions
- Breast Cancer
- Keywords
- Axillary lymph node dissection (ALND), Triple Negative Breast Cancer (TNBC), Breast Conserving Surgery (BCS), Human Epidermal Growth Factor Receptor 2 Positive/ Negative (HER2+/- ), Hormone Receptor Positive/ Negative (HR+/-), Neoadjuvant Chemotherapy (NAC), Targeted Axillary Dissection (TAD), Tailored Axillary Surgery (TAS)
- Study type
- Observational
- Recruitment status
- Recruiting
- Enrolment
- 600 participants (estimated)
- Lead sponsor
- University Hospital, Basel, SwitzerlandUniversity, hospital or other
- Study start
- 1 Feb 2026 (actual)
- Primary completion
- Dec 2027 (estimated)
- Study completion
- Dec 2027 (estimated)
- First posted
- 23 Apr 2026 (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.
In this multicenter retrospective cohort study the aim is to determine the safety of omission of axillary lymph node dissection in patients with TNBC and HER2+ tumors with residual macrometastases (in the SLN/TAD/TAS or MARI node) after NAC.
Study design
- Observational model
- Cohort
- Time perspective
- Retrospective
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Axillary lymph node dissection (ALND) cohort | – | Other: Data Collection from medical records of from an already existing database "ONCOLOGICAL BREAST SURGERY DATABASE OF THE UNIVERSITY HOSPITAL OF BASEL" which was initiated in 2016. |
| No Axillary lymph node dissection (ALND) cohort | – | Other: Data Collection from medical records of from an already existing database "ONCOLOGICAL BREAST SURGERY DATABASE OF THE UNIVERSITY HOSPITAL OF BASEL" which was initiated in 2016. |
Who may qualify
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Child, Adult, Older adult
- Study population
- Patients who presented with cT1-4 N0-3 TNBC (including ER-low tumors) or HER2+ BC who underwent NAC followed by axillary staging with either SLN surgery, TAD, TAS or the MARI procedure and were found to have residual macrometastases will be included. Data from "Universitätsspital Basel" will be extracted from medical records of from an already existing database.
Key inclusion criteria (9 listed)
- Women and men with a diagnosis of stage I-III TNBC or HER2+ breast cancer at diagnosis. HER2+ is defined as an Immunohistochemistry (IHC) score of 3+ or positive FISH. TNBC is defined as ER and Progesterone Receptor (PR) IHC expression of 0 and HER2 negativity defined as either IHC expression of 0-1+ or lack of gene amplification (FISH < 2.0). Patients with ER low (1-10%) and/or PR low (1-10%) tumors are allowed.
- Any histological subtype
- For Clinical Nodal Stage (cN) 0 at presentation: any axillary staging technique including palpation with or without imaging is allowed. Dual tracer mapping is not required for SLN surgery.
- For cN+ at presentation: Percutaneous biopsy proven confirmation is required at diagnosis. Staging techniques after NAC include: SLN surgery with dual mapping or Targeted Axillary Dissection (TAD: imaging-guided localization of sampled node in combination with SLN procedure with or without dual mapping) or Tailored Axillary Surgery (TAS: removal of the sentinel lymph nodes as well as selective removal of all palpable disease and documentation of the removal of the initially biopsy-proven and clipped lymph node metastasis by specimen radiography) or the MARI procedure (Marking Axillary Lymph Nodes with Iodine Seeds).
- Received neoadjuvant chemotherapy
Key exclusion criteria (7 listed)
- Did not undergo SLN surgery/TAD/TAS/MARI (e.g., went straight to ALND)
- Presence of ITCs or micrometastases alone in the sentinel nodes (or TAD nodes or MARI node or TAS nodes) without macrometastases
- HR+HER2- tumors (except ER low and or PR-low)
- Stage IV disease at presentation
- Inflammatory breast cancer at presentation
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Data Collection from medical records of from an already existing database "ONCOLOGICAL BREAST SURGERY DATABASE OF THE UNIVERSITY HOSPITAL OF BASEL" which was initiated in 2016.All trial data are/ have been collected within the clinical routine between 2013 and October 2024. All data will be analyzed descriptively using adequate statistical measures and plots. Clinico-pathological characteristics will be compared between patients treated with and without ALND. Depending on the median follow-up of both cohorts (ALND, no ALND) the 3-year cumulative incidence rates will be compared between ALND and no ALND. | Other | Axillary lymph node dissection (ALND) cohort, No Axillary lymph node dissection (ALND) cohort |
Primary outcome
3-year rate of any axillary recurrence
Time frame: 3-year follow-up after diagnosis of stage I-III TNBC or HER2+ breast cancer and SLN surgery/TAD/TAS/MARI
3-year rate of any axillary recurrence (defined as isolated or combined with local or distant recurrence) in patients with residual macrometastases after NAC overall and by use of axillary dissection.
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 19 May 2026.
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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.
Walter P. Weber, Prof. Dr. med. principal investigator
Department Breast, Abdomen, Pelvis
Giacomo Montagna, MD MPH study director
Breast Service, Department of Surgery; Memorial Sloan Kettering Cancer Center
1 site in 1 country: 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 1 site in Switzerland.
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 9 inclusion and 7 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: looking for participants now, as of the sponsor's last update on 19 May 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Switzerland. 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?
Contact Walter P. Weber, Prof. Dr. med. (+41 61 328 61 49, walter.weber@usb.ch), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
3-year rate of any axillary recurrence (time frame: 3-year follow-up after diagnosis of stage I-III TNBC or HER2+ breast cancer and SLN surgery/TAD/TAS/MARI). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
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 19 May 2026.