New sentinel lymph node biopsy
A new standard of technology has been developed to assist in identifying sentinel lymph nodes; Sentimag and Sienna are currently widely available across Europe, Australasia, Singapore and Hong Kong and is soon to be launched in South Africa by Sysmex (80% of treatment is based on diagnostics-VDGH*).
Why is the sentinel lymph node so important?
First, let us start with what a sentinel lymph node is defined as: the first lymph node to which cancer cells are most likely to spread from a primary tumour. Sometimes, there can be more than one sentinel lymph node.
After initial diagnosis of a breast cancer, following a visit to the mammogram department, many patients will hear the term sentinel lymph node biopsy. This is an important diagnostic test that is scheduled when there does not appear to be any lymph node involvement both radiologically and clinically. This procedure then checks to see if any breast cancer cells have ‘travelled’ to the ‘first’ lymph node that these cells would ‘drain’ to, usually in the axilla (armpit region).
Doctors then use this result, either negative (no breast cancer cells were found in the lymph node) or positive (breast cancer cells were found in the lymph node) to determine staging of the cancer, and to make informed decisions with regard to the patient’s treatment going forward.
How does Sentimag and Sienna work?
The tracer, Sienna, is a dark brown water-based liquid which contains superparamagnetic iron oxide (SPIO) particles (60nm); these give off a tiny magnetic signature, when magnetised. In this way, the magnetic particles are detected by the Sentimag probe. Also, thanks to its brownish colour, Sienna is not only magnetically but also visually traceable.
How is Sentimag different from current methods of sentinel lymph node localisation?
Most importantly, this technique is surgeon controlled. The surgeon can inject the Sienna at a time that best suits them and the patient, from 20 minutes up to seven days in advance of surgery. No scheduling is required pre-operatively at another department. There is no need for radioisotopes or blue dye. It offers precise detection as there is no stray radiation. Particle size is optimal for retention by the sentinel lymph node.
What does this mean for the patient?
- Patient comfort levels are improved.
- Sienna injected at the time of surgery, under anaesthetic.
- There is no exposure to any radiation at any stage for patients.
- Patients admitted to hospitals that do not have a nuclear medicine department, don’t need to be transported to another hospital.
- • Patients can spend less time in hospital.
- • The admission to hospital can take place later in the day, as less pre-operative scheduling is required.