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A large clinical trial exploring new treatments for breast cancer

Positive sentinel node: adjuvant therapy alone versus adjuvant therapy plus clearance or axillary radiotherapy


POSNOC is a pragmatic, randomised, multicentre, non-inferiority trial.


For women with early stage breast cancer and one or two sentinel node macrometastases, to assess whether adjuvant therapy alone is no worse than adjuvant therapy plus axillary treatment, in terms of axillary recurrence within 5 years.

Patient Population

Women with unifocal or multifocal invasive breast cancer, largest primary lesion ≤5cm, clinically and ultrasound node negative, who undergo sentinel node biopsy (SNB) and have 1 or 2 sentinel node macrometastases (>2mm), with no extranodal extension.


  • Institution
  • Age (<50, ≥50)
  • Breast-conserving surgery (BCS) or mastectom
  • Estrogen receptor (ER) status (positive, negative
  • Number of positive nodes (1, 2)


The study will compare adjuvant therapy alone with adjuvant therapy plus axillary treatment (axillary node clearance (ANC) or axillary radiotherapy (ART).

Primary Outcome

Axillary recurrence at 5 years

Secondary Outcomes

  • Arm morbidity
  • Quality of life
  • Anxiety
  • Local (breast or chest wall) recurrence
  • Regional (nodal) recurrence
  • Distant metastasis
  • Time to axillary recurrence
  • Axillary recurrence free survival
  • Disease free survival
  • Overall survival
  • Contralateral breast cancer
  • Non-breast malignancy
  • Economic evaluation

Sample Size

1900 participants

Duration of Recruitment and Follow-up

Recruitment will be for 45 months. Participants will be followed up for 5 years.

Adjuvant Therapy

All participants will receive adjuvant systemic therapy (chemotherapy and/or endocrine therapy). All participants may receive breast/chest wall radiotherapy. Axillary and supraclavicular fossa radiotherapy is not allowed when randomised to adjuvant therapy alone.

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