# ACOSOG Z1071 (Alliance)

Source: https://onco.cc/trials/acosog-z1071/  
OnCo record `acosog-z1071` (Trial). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

When chemotherapy is given first and clears the lymph nodes, can a surgeon trust the sentinel node to prove it? Z1071 found the sentinel node missed residual cancer about one time in eight, which is too often, and that finding forced the technique to be redesigned.

## Summary

Z1071 enrolled 756 women at 136 institutions between 2009 and 2011 with clinical T0 to T4, N1 to N2, M0 breast cancer and biopsy-proven nodal disease. After chemotherapy every patient had both sentinel node surgery and completion axillary clearance, so the sentinel node result could be checked against the truth.

Of 649 evaluable patients with cN1 disease, a sentinel node could not be found in 46 (7.1 percent) and only one was excised in 78 (12.0 percent). Among the 525 with two or more sentinel nodes removed, 215 had no cancer anywhere in the axilla, a pathological complete nodal response of 41.0 percent (95 percent confidence interval 36.7 to 45.3). In 39 patients the sentinel nodes were clear but the clearance specimen was not, a false-negative rate of 12.6 percent (90 percent Bayesian credible interval 9.85 to 16.05). The pre-specified acceptable threshold was 10 percent, and the trial did not meet it.

Z1071 is filed here as a negative trial because it failed its own bar, and it is one of the most useful negative trials in surgical oncology: the response to it was not to abandon sentinel node surgery after chemotherapy but to fix it, with dual tracer mapping, a minimum of three nodes, and marking the biopsied node before chemotherapy so it can be found again. That last idea became targeted axillary dissection.

## Fields

- Kind: Trial
- Status: negative
- Last checked: 2026-09-25
- Also known as: Z1071
- Registry id: NCT00881361
- Phase: 2
- Setting: Biopsy-proven node-positive breast cancer treated with chemotherapy before surgery: sentinel node surgery followed by axillary clearance in every patient, to measure the false-negative rate of the sentinel node after chemotherapy
- Sponsor: American College of Surgeons Oncology Group, now part of the Alliance for Clinical Trials in Oncology
- Enrolled: 756
- Result: False-negative rate of sentinel node surgery after chemotherapy 12.6 percent when two or more sentinel nodes were removed, above the 10 percent threshold; pathological complete nodal response 41.0 percent.
- Outcomes: False-negative rate of sentinel node surgery after chemotherapy (two or more sentinel nodes removed): Sentinel node surgery after chemotherapy 12.6%; Pathological complete nodal response: Node-positive at diagnosis, after chemotherapy 41%
- Replication: SENTINA in Europe and SN-FNAC in Canada found similar false-negative rates; the MD Anderson targeted axillary dissection study brought it down to 2.0 percent by marking the biopsied node.

## Sources

- ClinicalTrials.gov NCT00881361: https://clinicaltrials.gov/study/NCT00881361
- ACOSOG Z1071 (JAMA 2013): https://doi.org/10.1001/jama.2013.278932

## Connected records

- cancers: [Breast cancer (all types)](https://onco.cc/cancers/breast-cancer/), [HER2-positive breast cancer](https://onco.cc/cancers/breast-her2-positive/), [HR-positive / HER2-negative breast cancer](https://onco.cc/cancers/breast-hr-positive/), [Triple-negative breast cancer (TNBC)](https://onco.cc/cancers/tnbc/)
- technologies: [Sentinel lymph node biopsy](https://onco.cc/technologies/sentinel-node/)
- companies: [Alliance for Clinical Trials in Oncology](https://onco.cc/companies/alliance-oncology/)
- terms: [Drugs before or after the operation](https://onco.cc/terms/neoadjuvant-versus-adjuvant-breast/), [Pathologic complete response (pCR)](https://onco.cc/terms/pcr/), [Sentinel node biopsy](https://onco.cc/terms/sentinel-lymph-node-biopsy/), [Targeted axillary dissection](https://onco.cc/terms/targeted-axillary-dissection/)
- trials: [ATNEC](https://onco.cc/trials/atnec/), [NSABP B-51 / RTOG 1304](https://onco.cc/trials/nsabp-b51/), [Targeted axillary dissection (MD Anderson prospective study)](https://onco.cc/trials/targeted-axillary-dissection-md-anderson/)

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