Surgery is the standard of care for axillary staging but has recognised problems such as infection, sensory disturbance and arm lymphoedema. Ultrasound technologies now offer the promise of a radiological alternative to surgical staging.

SENTINUS is a multicentre phase II trial to assess the technical feasibility and diagnostic accuracy of intradermal microbubbles and contrast-enhanced ultrasound (CEUS) to identify sentinel lymph node (SLN) metastases in breast cancer patients compared to axillary surgery.  The study incorporates a training and mentorship programme for participating imaging specialists.

If the research is successful, the next stage will be to design a RCT to test the non-inferiority of CEUS sentinel lymph node core biopsy compared to axillary surgery in terms of overall survival and locoregional recurrence. 


  1. Technical feasibility - To determine whether 10 experienced imaging specialists in 5 UK Breast Centres can be trained to consistently identify, core biopsy and clip mark axillary SLN in patients with breast cancer.
  2. Diagnostic accuracy - To determine the overall diagnostic accuracy of a CEUS SLN core biopsy as a test to identify SLN metastases as compared to the reference standard of axillary surgery.
  3. Patient/ imaging specialist satisfaction – To assess patient and imaging specialist satisfaction with the CEUS SLN procedure.


Inclusion/ Exclusion criteria

Patient Inclusion Criteria

  • Histologically confirmed invasive carcinoma of the breast without palpable axillary LN with planned primary surgical treatment.
  • Normal grey scale axillary ultrasound or benign biopsy of morphologically abnormal LN.
  • Participant is willing and able to give informed consent for participation in the trial.
  • Aged 18 years or above.


Patient Exclusion Criteria

  • Previous ipsilateral breast cancer treated with radiotherapy or chemotherapy or recurrent breast cancer.
  • Female participant who is pregnant, lactating or planning fertility preservation during the course of the trial.
  • Allergy to contrast.
  • Inflammatory or locally advanced breast cancer
  • Metastatic breast cancer
  • Inability to raise ipsilateral arm above head.
  • Multiple medical co-morbidities (ASA 4 or above)
  • Previous ipsilateral axillary surgery.


Planned sample size and timeline

The total number of patients recruited will be 250 from 5 sites.

Every site will put forward 2 imaging specialists for training who will then each perform 25 CEUS SLN core biopsy procedures.

The timeline is 2 years from October 2020 to October 2022.


Further information

Please see the ISRCTN website