An interventional study of Omission of axillary clearance in Breast Cancer, sponsored by Karolinska Institutet. Active, not recruiting at 33 sites in 3 countries. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-07-14.
Sponsored by Karolinska Institutet · Not applicable, Interventional, and Treatment
Since the introduction of sentinel node biopsy in breast cancer, it has become clear that its use is reliable and reproducible. Today, it is clinical routine to not remove further lymph nodes from the axilla (arm pit) in case the sentinel node (which is the first lymph node/s reached by lymphatic flow from the breast) is free of tumor deposits. It is also routine to leave remaining lymph nodes behind in case the sentinel node contains a minimal cluster of tumor cells, called isolated tumor cells (formerly submicrometastasis). Even in slightly larger tumor deposits, so called micrometastasis (up to 2 mm in size), it has been shown that a completion axillary clearance (removal of further lymph nodes from the arm pit) does not contribute to a better survival. Data from a randomized study indicate that it seems safe to omit axillary clearance even if the sentinel node biopsy shows up to 2 nodes with tumor deposits over 2 mm in size (macrometastasis). These studies have changed clinical practice in many countries, however, it is still debated whether it is safe to omit axillary clearance in the case of sentinel node macrometastasis due to under-recruitment in the aforementioned study. The rationale for omitting extensive axillary surgery is the avoidance of postoperative morbidity such as arm lymphedema, loss of sensation, pain and swelling.
The hypothesis is that refraining from axillary clearance in breast cancer patients with 1-2 sentinel nodes with macrometastasis will not worsen 5-year overall survival (primary endpoint) by more than a maximum of 2.5%.
This study is a prospective international randomized trial planning for enrolment of 3500 patients.
Breast cancer patients without signs of axillary nodal involvement will be eligible for sentinel node biopsy. Those who are found to have up to two sentinel node containing macrometastasis will be informed about this trial Those wishing to participate will be randomized to either undergo further axillary surgery (clearance) or not. Secondary endpoints are oncological outcomes at 1-5, 10 and 15 years (local, regional and distant recurrence, recurrence-free and breast cancer-specific survival and contralateral breast cancer), patient-reported arm morbidity at 1, 3, 5 and 10 years, patient-reported quality of life at 1, 3, 5, and 10 years, and health economic outcomes at 1, 3, 5 and 10 years.
Details can be found on www.senomac.se
12,543 studies on the registry are indexed under Breast Neoplasms; 2,892 are open to participants now.
This study's enrollment of 2,766 is above the median of 72 across 9,302 interventional studies indexed under Breast Neoplasms.
Browse Breast Neoplasms studies →Karolinska Institutet is the lead sponsor of 1,113 studies on the registry; 267 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Exclusion Criteria:
Patients in this arm will be treated by completion axillary clearance after a sentinel node biopsy showing 1-2 nodes with macrometastasis
Patients in this arm will not undergo further axillary surgery after a sentinel node biopsy showing 1-2 nodes with macrometastasis
Procedure: Omission of axillary clearance
The intervention is the omission of completion axillary clearance after the detection of sentinel node macrometastasis
overall survival
death of any cause in both arms measured at a median follow-up of 5
Time frame: up to 15 years
recurrence-free survival
Any invasive breast cancer recurrence and death of any cause are regarded as events
Time frame: 5, 10 and 15 years
breast cancer-specific survival
Death attributed to breast cancer is regarded as the event
Time frame: 5, 10 and 15 years
patient-reported outcomes
Patients report on any arm-related problems and functional outcomes at an early postoperative assessment and after 1, 3, 5 and 10 years. Questionnaires include EORTC QLQ-BR23 and C30 and Lymph-ICF.
Time frame: early postoperative, 1, 3, 5, and 10 years
health economy
The use of health care resources is assessed by QUALYs by means of the EQ5D questionnaire
Time frame: 1, 3, 5 and 10 years
additional oncological outcomes
local, regional and distant recurrences will be reported as events and reported within recurrence-free survival and as distinct events
Time frame: yearly 1-5 years, 10 and 15 years
Documents are hosted by the registry — open the source record to download them.
This study is active, not recruiting, as verified in Jul 2026. You cannot join it, but the record below documents what was studied.
Get an email when the registry record changes — status, dates, results — or when someone posts here.
Sign in to followQuestions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.
Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.
Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.
Karolinska Institutet