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Z0011 is the trial that stopped surgeons clearing the armpit when one or two sentinel nodes contain cancer. Ten years on, the women who kept their remaining nodes were no more likely to have died, and the cancer came back in the armpit in almost nobody.
Z0011 enrolled 891 women from 1999 to 2004 at 115 academic and community centres with clinical T1 or T2 breast cancer, no palpable axillary nodes, and one or two sentinel nodes containing metastases. All had lumpectomy, planned tangential whole-breast irradiation and adjuvant systemic therapy; a third radiotherapy field aimed at the nodes was prohibited. They were randomised to sentinel node dissection alone or to completion axillary clearance. Overall survival was the primary endpoint with a non-inferiority margin of 1.3.
The trial first reported in 2005 with a median follow-up of 6.3 years. Longer follow-up mattered because most of the tumours were oestrogen receptor-positive and recur late. At a median 9.3 years, ten-year overall survival was 86.3 percent with sentinel node dissection alone and 83.6 percent with clearance (hazard ratio 0.85, one-sided 95 percent confidence interval 0 to 1.16, non-inferiority p=0.02). Ten-year disease-free survival was 80.2 against 78.2 percent (hazard ratio 0.85, 0.62 to 1.17, p=0.32). Between year five and year ten there was a single regional recurrence in the sentinel node arm and none in the clearance arm.
Two criticisms have followed the trial and both are fair. It closed early and is underpowered for a small survival difference. And every patient had whole-breast tangential radiotherapy, whose upper field edge treats part of the low axilla incidentally, so "no axillary treatment" is not quite what the experimental arm received. SENOMAC was designed to answer both, and reached the same conclusion in a population including mastectomy patients.
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.
891 randomised.
| Endpoint | Arm | n | Value | HR (95% CI) | p | Source |
|---|---|---|---|---|---|---|
| Overall survival at 10 yearsprimary | Sentinel node dissection alone | 446 | 86.3% | 0.85 | 0.02 for non-inferiority | link |
| Axillary lymph node dissection | 445 | 83.6% | ||||
| Disease-free survival at 10 years | Sentinel node dissection alone | 446 | 80.2% | 0.85 (0.62 to 1.17) | 0.32 | link |
| Axillary lymph node dissection | 445 | 78.2% |
Shares NSABP B-32, Lymphoedema after breast cancer treatment, Doing less to the armpit, Sentinel node biopsy.
Shares NSABP B-32, Lymphoedema after breast cancer treatment, Doing less to the armpit, Sentinel node biopsy.
Shares NSABP B-32, Lymphoedema after breast cancer treatment, Doing less to the armpit, Sentinel node biopsy.
Shares POSNOC, Lymphoedema after breast cancer treatment, Doing less to the armpit, Sentinel node biopsy.
Shares Doing less to the armpit, Sentinel node biopsy, Lymphadenectomy (lymph node dissection), Sentinel lymph node biopsy.
Shares Sentinel node biopsy, Alliance for Clinical Trials in Oncology, Sentinel lymph node biopsy, HER2-positive breast cancer.
Shares Sentinel node biopsy, Sentinel lymph node biopsy, HER2-positive breast cancer, Breast cancer (all types).
Shares Sentinel node biopsy, Lymphadenectomy (lymph node dissection), Breast cancer (all types).