Contents

Protocol for sentinel node biopsy for lymphatic staging of breast cancer at University College London Hospitals

Inclusion Criteria

Consider :

Exclusion Criteria

Patient Counselling

Pre-operative counselling to emphasise alternatives to SLNB, sensitivity of technique, potential for second surgical procedure if sentinel node positive, limitations of intra-operative diagnostic techniques
See attached written information sheet

Combined Technique for SLNB Localization

Radioisotope injection

No prior excision biopsy	20MBq in 0.2ml Nanocoll injected intradermally at periareolar margin in index quadrant
Prior excision biopsy	2 x 10MBq in 0.2ml Nanocoll injected intradermally on either side of excision Scar

Injected isotope may be reduced from 20 to 10MBq if surgery to be done on same day

For patients with a high degree of suspicion of internal mammary node drainage – 115MBq in 0.2ml Nanocoll injected intratumourally with imaging delayed to 2-4 hours later

Sentinel Lymph Node Imaging

Commenced 5 minutes after injection of isotope labelled colloid for superficial injections, or 2-4 hours after injection for deep injections:

- 4 standard views : Anterior-oblique emission. Static acquisition for 5 minutes

- Anterior-oblique transmission – using Cobalt⁵⁷ flood source for 2 minutes

- Lateral emission – Static acquisition for 5 minutes

- Lateral transmission – using Cobalt⁵⁷ flood source for 2 minutes

Combination image produced by combining emission and transmission images
2 copies of sentinel node imaging printed with standard 2 emission and 2 combination images – 1 copy in patient hospital notes, 2^nd copy in nuclear medicine folder

Patent Blue Dye Injection

Patent blue dye supplied by hospital pharmacy on named patient basis
DO NOT use methylene blue
Sterile draping of patient
Anaesthetist alerted to blue dye injection – risk of interference with oximetry, sensitivity reactions and rarely anaphylaxis. Recovery and ward staff to be made aware of blue dye injection mimicking cyanosis & discolouration of urine.
Injection techniques :
2ml Patent Blue dye injected at site of radionuclide injection

Operative Technique

Gamma probe used to determine counts over injection site and background count (generally suprasternal notch or contralateral upper arm)
10 second counts may be used if gamma probe has this facility
Hottest point of axilla determined and marked by surgeon prior to axillary skin incision
Skin incision and dissection through axillary fascia
Gamma probe used to determine direction of dissection within axillary fat
Any nodes with count greater than 5 times reference background defined as “hot”
Counts measured with node in situ and ex-vivo
All hot and blue nodes are removed as sentinel nodes
Following sentinel node biopsy – residual axillary count should be less than 3 times reference background count
Careful palpation of axilla, and removal of any pathologically palpable nodes
Surgeon to ensure all radiation safety procedures are followed (see below)

Intra-operative Diagnosis

Encouraged for all sentinel node cases
Either touch imprint cytology or frozen section – according to local practice and expertise
Frozen section – Node bivalved – frozen section on half, paraffin section on the other half. H&E staining of prepared frozen sections
Touch imprint cytology – Minimum of 4 imprints taken from each bivalved nodes. Staining of imprints using rapid Giemsa stain (or Pap stain). Note : Poor sensitivity for lobular carcinoma and micrometastases.

Histopathological Analysis

Sentinel nodes placed in formyl-saline and sent to histopathology department with main specimen.
After fixation in formalin – bivalved node sectioned through minimum of 3 levels
H&E staining of sections
If no metastases on H&E stain – Immunohistochemical staining for cytokeratin of bivalved node at minimum of 3 levels
Report issued as : Immunohistochemistry detected isolated tumour cells, submicrometastases/isolated tumour cells <0.2mm, micrometastases (0.2-2mm), macrometastases (>2mm), subtotal metastases, perinodal invasion

Management of Sentinel Node Positive Axilla

Until results of clinical trials in progress are known, in general proceed to full axillary lymph node dissection

Management of Radio-active Waste

As it is not permissible to dispose of radioactive clinical waste without specific authorization, all clinical waste arising from a sentinel node procedure both in theatre as well as recovery needs to be considered radioactive. Waste needs to be removed from the operating theatre without delay and stored in sealed bins in a safe location until it radioactively decays to a point where it can be safely and legally be considered non-radioactive, at which point it may be disposed of as per normal channels for this waste type.
At University College London Hospital, waste will be collected by the nuclear medicine department physicist on call, and stored for 7 days while ^99mTc undergoes decay, and then disposed of within routine waste. Waste from procedures done away from the University College London, should be labelled and stored within the theatre suite, and disposed of within routine waste after a minimum of 7 days, as per the protocols/local rules.
Technetium 99m has a half life of 6 hours
Separate protocols have been drawn up by the radiation protection officer, and should be referred to.

Record Keeping and Audit

Whilst we are operating on a routine ARSAC license, detailed records on a standard proforma should be kept.
A 4 monthly meeting reviewing the numbers of cases, identification techniques, identification rates, numbers of true positives, negatives & axillary recurrences. Recent significant publications to be reviewed, and protocol amended as appropriate.