Optimizing the magnetic tracer technique for sentinel lymph node detection and tumour localization in breast cancer surgery

• Breast cancer is the most common form of cancer in women, and the primary treatment modalities are still breast-conserving surgery (BCS) and sentinel lymph node dissection (SLND) in most cases. Superparamagnetic iron oxide nanoparticles (SPIO) are gaining momentum as a tracer for sentinel lymph node detection. The aim of this thesis is to further refine the magnetic method and investigate its postoperative effects.Paper I: This feasibility study, involving 79 patients, explored the use of SPIO-guided Magnetic resonance imaging (MRI)-lymphography and magnetic-guided axillary ultrasound (MagUS) with core biopsy for sentinel lymph node (SLN) localization and SLN status. MagUS, outperformed baseline axillary ultrasound and successfully traced SLNs in all cases, detecting macro-metastases accurately and missed only one micro-metastasis. The findings suggest that the MagUS technique enables minimally invasive approach in axillary mapping that can meet tailored patient needs and reduce the need for diagnostic surgery. Paper II: This study aimed to compare skin staining incidence and size between different doses of SPIO and blue dye (BD), evaluating their persistence over time. Among 270 women receiving SPIO, 204 also received BD. At six months, 21.5% had SPIO stains and 25% had BD stains Incidence and size decreased reciprocally, with no significant difference between the tracers regarding skin staining after 24 months. Paper III: This study compared the magnetic technique using Magseed® for non-palpable breast tumor localization with guidewire localization and SPIO for sentinel lymph node detection. In a prospective analysis of 426 women, reoperation rates, resection ratios, and SLN detection were assessed. No significant differences were found between the techniques in terms of re-excisions, resection ratios, or SLN detection. However, the magnetic technique showed more successful localizations, shorter operation time, and better overall experience among surgeons, radiologists, and theater coordinators, making it a good alternative for BCS.Paper IV: In this prospective observational study, the impact of postoperative MRI outcome was explored in patients undergoing BCS with a peritumoral SPIO injection for SLN detection. The study affirms SPIO as a safe tracer for SLN detection without compromising MRI interpretation after BCS, ensuring reliable breast cancer recurrence assessment.

Ämnesord

MEDICIN OCH HÄLSOVETENSKAP  -- Klinisk medicin -- Kirurgi (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Clinical Medicine -- Surgery (hsv//eng)

Nyckelord

Breast Cancer

Sentinel Node

Super paramagnetic ironoxide nanoparticles

SPIO

Skin Staining

Magnetic resonance imaging

magnetic seed

guidewire

Surgery

Kirurgi

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