MagSNOLL multicenter Study

The MagSNOLL Multicentre Trial is a phase II paired equivalence trial. The study will be coordinated from Kings's College Londen (Guy's Hospital) by the Chief Investigator Mr. Michael Douek. The trial aimed to recruit 160 patients.
Patients will receive a radioisotope injection and a intra tumoral Sienna+ injection. In cetres that also participate in the MRI sub protocol, patients will undergo a pre-operative MRI after the injection of Sienna+. At the Medisch Spectrum Twente pre-operative MRI scans will be performed depending on the availability of the MRI scanning slots.



Intra-operatively, patients will receive an intradermal injection of patent blue (Guerbet, Paris). The occult lesion and all sentinel nodes detected intra operatively using the the SentiMAG will be excised and sent separately to the pathology department. Then the standard technique, the gamma probe, is used to see whether there is activity remained behind. This tissue will be removed and sent to the pathology department separately. The removed breast tissue will be checked for the presence of the clip marker, at the radiology department.



All lymph nodes will be assessed histologically and the nodal status will be related back to the SLNB detection rate with each technique.
Patients will be followed post-operatively (7-14 days after surgery) to assess if staining occurs or for any other adverse event. If staining is present, photographs will be taken. Further follow-up is at 3 months and at 1 year. Patients will be followed up for a total of 5 years, in accordance with current local policies.

The current gold standard for the treatment of occult lesions is excision by wire- guided localization (WGL). (section 1 in protocol) However, despite being the current gold standard, the process has drawbacks. The flexible wire can be difficult for the surgeon to palpate, resulting in difficulty locating the tip. This could lead to incomplete lesion excision and re-excision rates of up to 43 percent as demonstrated in randomized controlled trials



The gold standard for sentinel node detection is the 'combined technique', using both blue dye and radioisotope injection. The combined technique has major drawbacks. The use of radioisotope exposes patients and healthcare workers to radiation, is heavily controlled by legislation (both on specific training for operators and subsequent disposal of surgical waste), and provides poor pre-operative imaging. As a result, some centers have stopped undertaking routine pre-operative lymphoscintigraphy.



Intra-operative blue dye injection can obscure the surgical field, frequently leaves skin residue (tattoo stain) which can take months to fade and has a 1:1000 risk of allergic reaction. There is thus a clinical need to develop new techniques for detecting sentinel nodes without these drawbacks.



The MagSNOLL multicentre study will evaluate a new technique for sentinel lymph node biopsy (SLNB) against the standard technique. The new technique uses 2 devises; a intra tumoral injection of a magnetic tracer (sienna+) and the use of a hand-held device (a magnetometer - The SentiMAG) to detect the sentinel node(s) intraoperatively (section 2 in the protocol). The magnetic tracer does not have the disadvantages related to the use of a radioactive tracer. Besides, the brown-black appearance of the iron nano particles act as a visual stain without obscuring the operating field.



The use of MRI imaging might obviate the poor pre-operative imaging results associated with lymphoscintigraphy (section 2.4 in the protocol). The MRI subprotocol will evaluate pre-operatively MRI (with magnetic tracer) for sentinel node imaging and characterization. The aim of the subprotocol is to evaluate MRI for both pre-operative and intra-operative detection of lymph node metastasis.



Magnetic tracers and hand-held magnetometer might just be what surgical researchers have been looking for as a tool that could be used to act on what is seen on MRI. MRI and SPIO directed SLNB would offer a technique to image the patient preoperatively with high spatial resolution and retrieve sentinel nodes without the use of radioisotopes.

Successful localization of the excised lesion, with Sienna+ and SentiMag. 2 measurements a week till 60 measurement are completed successfully.



Accuracy of MRI for the localization of SLNs. With MRI max 24 ours before surgery.

In addition to the Sienna+ injection, a clip marker will be placed in the MST for reference. In the ZGT the standard procedure with iodine seeds will be performed for reference. The patient will undergo a pre-operative MRI scan, after injection of Sienna+. The operation will be performed as already planned by the surgeon. In addition to the normal radioactive injection, an additional injection of Sienna+ is administered in the centre of the tumor. During surgery, the sentinel nodes and the tumor will be detected with the normal detector (gamma probe) and the magnetometer (SentiMAG).