The application of magnetic nanotechnology to the surgical management of non-palpable breast cancer

Abstract

Background
Breast cancer is the most common cancer in the United Kingdom, with over one-third of all cases diagnosed annually being clinically occult (non-palpable). The current standard of care is surgical wide local excision using wire-guided localization and axillary staging by sentinel node biopsy. Wire-guided localization possesses limitations, which have resulted in alternative localization techniques being developed – although these have failed to gain mainstream acceptance. This thesis examined the current evidence supporting other localization techniques and aimed to develop an alternative, overcoming existing limitations.
Materials and methods
This thesis examined a handheld magnetometer and magnetic tracer for localization properties within pre-clinical phantom models, progressing to the development of an in vivo porcine model, which was also used to assess concurrent sentinel lymph node biopsy. This was followed by the establishment of the first, in-man feasibility study of a magnetic tracer for sentinel node and occult lesion localization using an intra-tumoral injection of magnetic tracer for patients with non-palpable breast cancer (MagSNOLL trial, UKCRN 14979).
Results
This thesis demonstrated the ability of a magnetic tracer to localise at a specific site within phantom models. This was replicated within an in vivo porcine model in addition to concurrent sentinel lymph node biopsy with a single injection of the magnetic tracer. These findings were translated into a clinical trial (MagSNOLL), which demonstrated that an intra-tumoral injection of magnetic tracer allowed successful lesion localization independently of a wire. Concurrent magnetic sentinel lymph node biopsy was demonstrated to be feasible but inferior to the standard ‘dual technique’ of radioisotope and blue dye.
Conclusion
Magnetic lesion localization is feasible without the need for a wire or radioisotopes. Further work to assess the retention of the magnetic tracer in vivo and optimisation of sentinel node identification rates are required.

Date of Award	2015
Original language	English
Awarding Institution	King's College London
Supervisor	Michael Douek (Supervisor)