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The trial that closed the argument Z0011 opened. Even when a node holds a deposit bigger than two millimetres, and even after a mastectomy, leaving the rest of the armpit alone was as safe, provided the nodes were treated with radiotherapy.
SENOMAC was designed against the three criticisms of Z0011: too few patients, no mastectomy patients, and uncertainty about what the radiotherapy fields actually covered. Between January 2015 and December 2021 it enrolled 2,766 patients in five countries with clinically node-negative T1 to T3 breast cancer and one or two sentinel node macrometastases, and randomised them to completion axillary clearance or to sentinel node biopsy alone. The per-protocol population was 2,540. Radiotherapy including nodal target volumes was given to 89.9 percent of the sentinel node-only group and 88.4 percent of the dissection group, and that is recorded rather than assumed.
At a median 46.8 months, estimated five-year recurrence-free survival was 89.7 percent (95 percent confidence interval 87.5 to 91.9) with sentinel node biopsy alone and 88.7 percent (86.3 to 91.1) with clearance, a country-adjusted hazard ratio for recurrence or death of 0.89 (0.66 to 1.19), significantly below the non-inferiority margin of 1.44 (p<0.001).
What SENOMAC does not do is remove the nodal radiotherapy. Nine in ten patients had it, so the trial tests omitting the operation, not omitting treatment of the axilla. POSNOC, which forbids axillary and supraclavicular radiotherapy in its experimental arm, is the trial that tests the stronger claim.
Numbers are from the trial as recorded here; see the source links in the table below. This is orientation, not medical advice: ask your team how closely the trial population matches you.
2,766 enrolled.
95 percent confidence interval 87.5 to 91.9 · 95 percent confidence interval 86.3 to 91.1
Source| Endpoint | Arm | n | Value | HR (95% CI) | p | Source |
|---|---|---|---|---|---|---|
| Recurrence-free survival at 5 yearsprimary | Sentinel node biopsy only | 1,335 | 89.7% | 0.89 (0.66 to 1.19) | <0.001 for non-inferiority | link |
| Completion axillary lymph node dissection | 1,205 | 88.7% |
Shares Lymphoedema after breast cancer treatment, Doing less to the armpit, Sentinel node biopsy, Lymphadenectomy (lymph node dissection).
Shares ACOSOG Z0011 (Alliance), Lymphoedema after breast cancer treatment, Doing less to the armpit, Sentinel node biopsy.
Shares Lymphoedema after breast cancer treatment, Doing less to the armpit, Sentinel node biopsy, Sentinel lymph node biopsy.
Shares POSNOC, Lymphoedema after breast cancer treatment, Doing less to the armpit, Sentinel node biopsy.
Shares Lymphoedema after breast cancer treatment, Doing less to the armpit, Sentinel node biopsy, Sentinel lymph node biopsy.
Shares Doing less to the armpit, Sentinel node biopsy, Lymphadenectomy (lymph node dissection), Sentinel lymph node biopsy.
Shares ACOSOG Z0011 (Alliance), Doing less to the armpit, Lymphadenectomy (lymph node dissection), HER2-positive breast cancer.
Shares Sentinel node biopsy, Sentinel lymph node biopsy, HER2-positive breast cancer, Breast cancer (all types).